LIMONENE
CASRN: 138-86-3
For other data, click on the Table of Contents

Human Health Effects:

Evidence for Carcinogenicity:

Evaluation: No data were available on the carcinogenicity of d-limonene to humans. Overall evaluation: d-Limonene is not classifiable as to its carcinogenicity to humans (Group 3).
[IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man. Geneva: World Health Organization, International Agency for Research on Cancer,1972-PRESENT. (Multivolume work).,p. 56 158 (1993)]**QC REVIEWED**

Human Toxicity Excerpts:

NO TOXIC REACTIONS HAVE BEEN DESCRIBED OTHER THAN MILD LOCAL IRRITATION & SKIN SENSITIZATION, BUT ALBUMINURIA & HEMATURIA ARE PROBABLE IF INGESTED IN SUFFICIENT QUANTITY.
[Gosselin, R.E., R.P. Smith, H.C. Hodge. Clinical Toxicology of Commercial Products. 5th ed. Baltimore: Williams and Wilkins, 1984.,p. II-259]**PEER REVIEWED**

DIPENTENE TESTED /AS IRRITATION TEST/ AT 20% IN PETROLATUM PRODUCED NO IRRITATION AFTER A 48 HR CLOSED PATCH TEST IN 25 HUMAN SUBJECTS. A MAXIMIZATION TEST ... WAS CARRIED OUT ON 25 VOLUNTEERS. THE MATERIAL WAS TESTED @ CONCN OF 20%, IN PETROLATUM & PRODUCED NO SENSITIZATION REACTIONS.
[Opdyke, D.L.J. (ed.). Monographs on Fragrance Raw Materials. New York: Pergamon Press, 1979. 333]**PEER REVIEWED**

FOLLOWING DENTAL SURGERY, PATIENT PRESENTED WITH INTENSE SWELLING OF HIS TONGUE, LIPS, & GINGIVAL MUCOSA. TESTING REVEALED HYPERSENSITIVITY TO PEPPERMINT OIL (A DENTAL PREPN), DUE TO SENSITIZING PROPERTIES OF INGREDIENTS SUCH AS LIMONENE.
[DOOMS-GOOSSENS A ET AL; CONTACT DERMATITIS 3 (6): 304 (1977)]**PEER REVIEWED**

THREE CASES OF ALLERGIC CONTACT DERMATITIS FROM DIPENTENE IN SAME BRAND OF HONING OIL REPORTED. MANUFACTURER HAS SINCE REPLACED IT WITH AN ALTERNATIVE.
[RYCROFT R JG; CONTACT DERMATITIS 6 (5): 325 (1980)]**PEER REVIEWED**

The toxicokinetics of d-limonene were studied in human volunteers exposed by inhalation (2 hr, work load 50 W) in an exposure chamber on three different occasions. The exposure concn were approximately 10, 225, and 450 mg/cu m d-limonene. The relative pulmonary uptake was high, approximately 70% of the amount supplied. A decrease in vital capacity was observed after exposure to d-limonene at a high exposure level. The subjects did not experience any irritative symptoms or symptoms related to the CNS.
[Falk-Filipsson A et al; J Toxicol Environ Health 38 (1): 77-88 (1993)]**PEER REVIEWED**

Skin, Eye and Respiratory Irritations:

Skin irritant.
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 865]**PEER REVIEWED**

Liquid irritates eyes; ingestion causes irritation of GI tract.
[U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.]**PEER REVIEWED**

Probable Routes of Human Exposure:

Occupational exposure to limonene may occur by inhalation or dermal contact during its production, formulation, transport or use. Exposure to the general population may occur by inhalation due to its presence in the atmosphere as a result of its release from natural sources(1,2), its presence in household products, or by ingestion of food in which it occurs either naturally or has been added as a flavor or fragrance(SRC).
[(1) Isidorov VA et al; Atmos Environ 19: 1-8 (1985) (2) Altshuller AP; Atmos Environ 17: 2131-65 (1983) (3) Tichenor BA, Mason MA; JAPCA 38: 264-8 (1988) (3) Tichenor BA; Organic Emission Measurements via Small Chamber Testing. USEPA, Research Triangle Park, NC. PB87-199154 (1987)]**PEER REVIEWED**

NIOSH (NOES Survey 1981-83) has statistically estimated that 94,910 workers are exposed to limonene in the USA(1). Limonene was detected in the air of the vulcanization area of a shoe-sole factory at a concn of 25-130 ug/cu m, and at 5-1700 ug/cu m in the vulcanization area of a tire retreading factory(2). Limonene was detected indoors in an office building, 1987, at a concn ranging from 43-63 ug/cu m(3). Limonene was qualitatively detected in air samples taken at 2 Stockholm preschools, 1981-2(4).
[(1) NIOSH; National Occupational Exposure Survey (NOES) (1989) (2) Cocheo V et al; Am Ind Hyg Assoc J 44: 521-7 (1983) (3) Weschler CJ et al; Am Ind Hyg Assoc J 51: 261-8 (1990) (4) Noma E et al; Atmos Environ 22: 451-60 (1988)]**PEER REVIEWED**

Body Burden:

Limonene has been identified in the expired air of urban volunteers(1). Limonene was qualitatively detected in 8 of 8 samples of mother's milk obtained from residents of urban centers in PA, NJ, and LA(2).
[(1) Krotoszynski B et al; J Chromat Sci 15: 239-44 (1977) (2) Pellizzari ED et al; Bull Environ Contam Toxicol 28: 322-8 (1982)]**PEER REVIEWED**

Emergency Medical Treatment:

Emergency Medical Treatment:

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The following Overview, *** LIMONENE ***, is relevant for this HSDB record chemical.

Life Support:
  o   This overview assumes that basic life support measures
      have been instituted.                           
Clinical Effects:
  SUMMARY OF EXPOSURE
   0.2.1.1 ACUTE EXPOSURE
     o   HUMAN - Limonene is most likely of low toxicity.  Mild
         dermal irritation and skin sensitization may occur.
         Hematuria and albuminuria might occur if large amounts
         are ingested.
     o   MICE - Somnolence and hypothermia have been noted in
         mice.  Gastric epithelial irritation was caused by oral
         administration in mice.
     o   CATS completely wetted with a limonene-containing
         insecticidal dip developed skin excoriation,
         hypersalivation, transient blepharospasm in directly
         exposed eyes, hypothermia, muscle tremors, and ataxia.
  RESPIRATORY
   0.2.6.1 ACUTE EXPOSURE
     o   Aspiration might produce lipoid pneumonitis.
  GENITOURINARY
   0.2.10.1 ACUTE EXPOSURE
     o   Hematuria and albuminuria might occur.
  DERMATOLOGIC
   0.2.14.1 ACUTE EXPOSURE
     o   Dermal irritation and sensitization may occur.
         Percutaneous absorption may occur.
Laboratory:
  o   Monitor urinalysis, urine output, and renal function tests
      in patients with significant exposure.      
Treatment Overview:
  SUMMARY EXPOSURE
    o   Inducing emesis should be avoided if gastric irritation
        occurs.  If somnolence and ataxia occur, adequate
        respirations and oxygenation should be assured.  Monitor
        temperature and instituted warming measures for
        hypothermia.  Urinalysis, urine output, and renal
        function tests should be monitored in significant
        exposures.
    o   Dermal irritation and skin sensitization may require
        treatment with standard topical therapies.
  ORAL EXPOSURE
    o   DILUTION:  Following ingestion and/or prior to gastric
        evacuation, immediately dilute with 4 to 8 ounces (120
        to 240 mL) of milk or water (not to exceed 15 mL/kg in a
        child).
    o   GASTRIC LAVAGE:  Consider after ingestion of a
        potentially life-threatening amount of poison if it can
        be performed soon after ingestion (generally within 1
        hour).  Protect airway by placement in Trendelenburg and
        left lateral decubitus position or by endotracheal
        intubation.  Control any seizures first.
     1.  CONTRAINDICATIONS:  Loss of airway protective reflexes
         or decreased level of consciousness in unintubated
         patients; following ingestion of corrosives;
         hydrocarbons (high aspiration potential); patients at
         risk of hemorrhage or gastrointestinal perforation; and
         trivial or non-toxic ingestion.
    o   ACTIVATED CHARCOAL:  Administer charcoal as slurry (240
        mL water/30 g charcoal).  Usual dose:  25 to 100 g in
        adults/adolescents, 25 to 50 g in children (1 to 12
        years), and 1 g/kg in infants less than 1 year old.
    o   Observe patients with ingestion carefully for the
        possible development of esophageal or gastrointestinal
        tract irritation or burns.  If signs or symptoms of
        esophageal irritation or burns are present, consider
        endoscopy to determine the extent of injury.
    o   Carefully observe patients for the development of any
        systemic signs or symptoms and administer symptomatic
        treatment as necessary.
  INHALATION EXPOSURE
    o   INHALATION:  Move patient to fresh air.  Monitor for
        respiratory distress.  If cough or difficulty breathing
        develops, evaluate for respiratory tract irritation,
        bronchitis, or pneumonitis.  Administer oxygen and
        assist ventilation as required.  Treat bronchospasm with
        beta2  agonist and corticosteroid aerosols.
    o   If aspiration occurs, monitor temperature, WBC, arterial
        blood gases, and chest x-ray.  Administer oxygen as
        required.
  EYE EXPOSURE
    o   DECONTAMINATION:  Irrigate exposed eyes with copious
        amounts of tepid water for at least 15 minutes.  If
        irritation, pain, swelling, lacrimation, or photophobia
        persist, the patient should be seen in a health care
        facility.
  DERMAL EXPOSURE
    o   DECONTAMINATION:  Remove contaminated clothing and wash
        exposed  area thoroughly with soap and water.  A
        physician may need to  examine the area if irritation or
        pain persists.
    o   Treat dermal irritation or burns with standard topical
        therapy.  Patients developing dermal hypersensitivity
        reactions may require treatment with systemic or topical
        corticosteroids or antihistamines.
    o   Some chemicals can produce systemic poisoning by
        absorption through intact skin.  Carefully observe
        patients with dermal exposure for the development of any
        systemic signs or symptoms and administer symptomatic
        treatment as necessary.                             
Range of Toxicity:
  o   Minimum lethal human exposure is unknown.    


[Rumack BH: POISINDEX(R) Information System. Micromedex, Inc., Englewood, CO, 2001; CCIS Volume 110, edition exp November, 2001. Hall AH & Rumack BH (Eds):TOMES(R) Information System. Micromedex, Inc., Englewood, CO, 2001; CCIS Volume 110, edition exp November, 2001.] **PEER REVIEWED**

Animal Toxicity Studies:

Evidence for Carcinogenicity:

Evaluation: No data were available on the carcinogenicity of d-limonene to humans. Overall evaluation: d-Limonene is not classifiable as to its carcinogenicity to humans (Group 3).
[IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man. Geneva: World Health Organization, International Agency for Research on Cancer,1972-PRESENT. (Multivolume work).,p. 56 158 (1993)]**QC REVIEWED**

Non-Human Toxicity Excerpts:

D-LIMONENE SOLUTION INJECTED AS BOLUS INTO BILIARY TRACT OF CATS PRODUCED HEPATOBILIARY TISSUE DAMAGE, DEPENDING ON CONTACT TIME, VOLUME AND FLOW DIRECTION OF THE SOLUTION. /D-LIMONENE/
[SCHENK J ET AL; Z GASTROENTEROL 18 (7): 389 (1980)]**PEER REVIEWED**

STUDY OF CHROMATOGRAPHIC DATA OF GLC PROFILES FROM TOTAL PARTICULATE MATTER OF 8 EXPTL CIGARETTES. D-LIMONENE WAS 1 PEAK IDENTIFIED THAT CORRELATED WITH CARCINOGENIC ACTIVITY WHEN PAINTED ON MICE SKIN. D-LIMONENE IS BEST INDICATOR THUS FAR OF TOBACCO SMOKE BIOLOGICAL ACTIVITY. /D-LIMONENE/
[HO CH ET AL; ANAL CHEM 48 (14): 2223 (1976)]**PEER REVIEWED**

2363 MG/KG GIVEN ORALLY TO MICE FOR 6 DAYS FROM DAY 7 TO DAY 12 OF GESTATION DECR BODY WT GAIN & INCR INCIDENCE OF ABNORMAL BONE FORMATION IN FETUSES. ALSO DECR BODY WT GAIN IN MALE OFFSPRING. TOXICITY WAS NOT SEVERE.
[KODAMA R ET AL; OYO YAKURI 13 (6): 863 (1977)]**PEER REVIEWED**

ADMIN TO DOGS @ 1.2-3.6 ML/KG/DAY FOR 6 MONTHS CAUSED FREQUENT VOMITING & NAUSEA & DECR IN BODY WT, BLOOD SUGAR & CHOLESTEROL. NO SIGNIFICANT CHANGE OBSERVED IN ORGANS EXCEPT IN THE KIDNEY.
[TSUJI M ET AL; OYO YAKURI 9 (5): 775 (1975)]**PEER REVIEWED**

AMINOPYRINE DEMETHYLASE & ANILINE HYDROXYLASE INCR 26 & 22% BY REPEATED ORAL ADMIN OF 400 MG/KG FOR 30 DAYS TO RATS. DECR PLASMA & LIVER CHOLESTEROL & ALTERED FATTY ACIDS OF LIVER PHOSPHOLIPIDS. ENZYMES NOT AFFECTED AFTER SINGLE DOSE OF 200-1200 MG/KG.
[ARIYOSHI T ET AL; XENOBIOTICA 5 (1): 33 (1975)]**PEER REVIEWED**

ORALLY 227-1385 MG/KG/DAY CAUSED SLIGHT DECR IN BODY WEIGHT, LITTLE OR NO CHANGE IN WATER & FOOD CONSUMPTION IN RATS. NO HISTOPATHOLOGICAL CHANGES, EXCEPT GRANULAR CASTS IN KIDNEY OF SOME MALE RATS.
[TSUJI M ET AL; OYO YAKURI 9 (3): 403 (1975)]**PEER REVIEWED**

LIMONENE WAS INHIBITORY /HEPATIC HMGCoA (HYDROXY-3-METHYLGLUTARYL-CoA) REDUCTASE/ WHEN ADMIN INTRAGASTRICALLY @ 3 MMOL/KG TO RATS.
[CLEGG RJ ET AL; BIOCHEM PHARMACOL 29 (15): 2125 (1980)]**PEER REVIEWED**

Naturally occurring compounds belonging to two chemical groups were studied for their capacities to inhibit N-nitrosodiethylamine-induced carcinogenesis in female A/ mice. One group consisted of D-limonene and D-carvone. ... Test compounds were given orally either 15 min or 1 hr prior to NDEA. Under these conditions, D-limonene and D-carvone reduced forestomach tumor formation by about 60% and pulmonary adenoma formation by about 35%. /D-limonene/
[Wattenberg LW et al; Cancer Res 49 (10): 2689-92 (1989)]**PEER REVIEWED**

Adult male and female Sprague Dawley rats were given single oral doses of 0, 0.1, 0.3, 1, or 3 mmol d-limonene/kg (0, 14, 41, 136, or 409 mg/kg) in corn oil. A dose response relationship for acute exacerbation of hyaline droplets by d-limonene treatment was observed. Hyaline droplets were graded according to size, eosinophilic intensity, and the number of tubules loaded with droplets. Control rats received a mean score of 3. At 3 mmol/kg, admin of d-limonene resulted in a score of 10. At 0.1 mmol/kg, no effect on hyaline droplet accumulation was seen in male rats. 24 hr after admin of 3 mmol d-limonene/kg, the renal concentration of d-limonene equivalents was approximately 2.5 times higher in male rats than in female rats. Equilibrium dialysis in the presence or absence of sodium dodecyl sulfate indicated that approximately 40% of the d-limonene equivalents in male rat kidney associated with proteins in a reversible manner, whereas no significant association was observed between d-limonene equivalents and female rat kidney proteins. Gel filtration HPLC indicated that d-limonene in male rat kidney is associated with a protein fraction having a mol wt of approximately 20,000. Using reverse phase HPLC, d-limonene was shown to be associated with alpha-2u-globulin which was identified by amino acid sequencing. The major metabolite associated with alpha-2u-globulin was d-limonene-1,2-oxide. Parent d-limonene was also identified as a minor component in the alpha-2u-globulin fraction. /D-limonene/
[Lehman McKeeman LD et al; Toxicol Appl Pharmacol 99 (2): 250-9 (1989)]**PEER REVIEWED**

d-Limonene was not mutagenic in four strains of Salmonella typhimurium (TA98, TA100, TA1535, or TA1537), did not significantly increase the number of trifluorothymidine resistant cells in the mouse L5178Y/TK + or - assay, and did not induce chromosomal aberrations or sister chromatid exchanges in cultured chinese hamster ovary cells. All assays were conducted in the presence and absence of exogenous metabolic activation (S9).
[DHHS/NTP; Toxicology and Carcinogenesis Studies of d-Limonene (gavage Studies) p. 3 (1990) Technical Rpt Series No. 347 NIH Pub No. 90-2802]**PEER REVIEWED**

Inhibition of cholesterol biosynthesis occurred in the small intestine of rats after administration of d-limonene for 7 days, but no significant effect on the secretion of radiolabeled cholesterol into bile and feces was observed. d-Limonene increased the perfusion pressure of the sphincter of Oddi in dogs when injected iv or directly into the common bile duct. d-Limonene has also been used successfully for the postoperative dissolution of retained cholesterol gallstones. /D-limonene/
[DHHS/NTP; Toxicology and Carcinogenesis Studies of d-Limonene (Gavage Studies) p. 13 (1990) Technical Rpt Series No. 347 NIH Pub No. 90-2802]**PEER REVIEWED**

There is a diverse group of hydrocarbons that induce a specific spectrum of nephropathic alterations. Examples include d-limonene, an aromatic hydrocarbon. Only male rats develop kidney alterations upon exposure. Other mammals such as female rats, mice, guinea pigs, dogs and monkeys evidently are refractory to kidney injury upon exposure. The male rat hydrocarbon nephropathy should not be predictive of a normal human renal response.
[Alden CL; Toxicol Pathol 14 (1): 109-11 (1986)]**PEER REVIEWED**

The role of alpha2-microglobulin in xenobiotic induced nephropathy was examined in rats. Male NCI Black Reiter rats were administered various cmpd including 1650 mg/kg d-limonene by gavage daily for 4 days. Twenty four hours after the last dose, the animals were killed and the kidneys were removed and sectioned. Nephrotoxicity was assessed by examining the sections for the presence of hyaline droplets and other histological changes. The sections were assayed for alpha2-microglobulin using a histochemical technique. Lindane induced hyaline droplet formation in male, but not female, F344 rats. d-Limonene did not induce hyaline droplet formation or alpha2-microglobulin production in male NCI Black Reiter rats. It was concluded that the presence of alpha2-microglobulin is necessary for the development of kidney disease in male rats exposed to d-limonene.
[Dietrich DR, Swenberg JA; Fund Appl Toxicol 16 (4): 749-62 (1991]**PEER REVIEWED**

The monocyclic monoterpenoid compounds limonene and sobrerol have anticarcinogenic activity when fed during the initiation stage of dimethylbenz(a)anthracene induced rat mammary carcinogenesis. The potential roles of hepatic glutathione-S-transferase and uridine diphosphoglucuronosyl transferase were studied in monoterpene-mediated chemoprevention. Diets containing the isoeffective anticarcinogenic terpenes, 5% limonene or 1% sobrerol, elevated hepatic glutathione-S-transferase activity > 2 fold when measured using the general substrate 1-chloro-2,4-dinitrobenzene and 3,4-dichloronitrobenzene for the glutathione-S-transferase dimer 3-3. However, there were no significant changes in hepatic glutathione-S-transferase activity when 1,2-epoxy-3-(p-nitrophenoxy)propane was used. Liver glutathione-S-transferase subunit 3 had the greatest increase followed by 1 and 4 with no change in subunit 2. Both terpene diets significantly increased the activity of the methylcholanthrene inducible and the phenobarbital inducible uridine diphosphoglucuronosyl transferase isozymes. It was proposed that much of the anticarcinogenic activity of these monocyclic monoterpenes during the initiation phase of dimethylbenz[a]anthracene carcinogenesis is mediated through the induction of the hepatic detoxification enzymes glutathione-S-transferase and uridine diphosphoglucuronosyl transferase.
[Elegbede JA et al; Carcinogenesis 14 (6): 1221-3 (1993)]**PEER REVIEWED**

The nephrotoxicity of d-limonene was studied in rats and mice. Kidney sections taken from male rats, strain not specified, that had been part of a 91 day oral dosing study of limonene in rats and mice, were examined by light microscopy. The study showed that renal alterations were induced only in male rats. Dose related decreases in absolute weight gain and relative weight gain (expressed as a percentage of the control weight gain) also occurred. The 2400 mg/kg dose killed nine of ten female rats. Kidney sections of male rats showed that limonene caused cytoplasmic basophilia of proximal convoluted tubule cells, tubular hyperplasia or atrophy, fibrosis of Bowman's capsule, and an interstitial fibrolymphocytic response. The severity of the lesions was dose related except in rats given 2400 mg/kg limonene. The severity of the lesions in the 2400 mg/kg group was similar to those seen in rats given 150 mg/kg. Occasional foci of proximal convoluted tubule epithelial cell necrosis of degeneration were seen in all treated rats. Granular casts were seen in the outer medulla of animals that survived to the end of the study except for one rat in the 2400 mg/kg group. No hyaline droplet accumulation within the cytoplasm of proximal convoluted tubule epithelial cells was seen. Except for the absence of hyaline droplet formation, the changes induced by limonene are similar to those seen in male rats exposed to decalin.
[Kanerva RL, Alden CL; Food Chem Toxicol 25 (5): 355-8 (1987)]**PEER REVIEWED**

The allergenic potential of d-limonene oxidation products was examined. Samples of d-limonene were exposed to air or unexposed in a preliminary experiment. The concn of d-limonene decreased after 8 wk air exposure. Carvone, cis and trans limonene oxide, and cis and trans carveal were the major oxidation products detected. Only slight decomposition was seen in nonexposed d-limonene. Dunkin-Hartley guinea pigs were induced by topical application of (+)-limonene oxide, (R)-(-)-carvone, (-)-carveal, or air exposed d-limonene. (+)-Limonene oxide and (-)-carveal consisted of mixtures of cis and trans isomers of the two compounds. The sensitizing potential of the compounds was assessed by the Freund complete adjuvant test after challenge with (+)-limonene oxide. Other guinea pigs were induced with air exposed d-limonene. The sensitizing potential of air exposed or nonexposed d-limonene, (+)-limonene oxide, or (R)-(-)-carvone was evaluated by the guinea pig maximization test. Air exposed d-limonene was a strong sensitizer in both the Freund complete adjuvant test and guinea pig maximization test. d-Limonene that was not air exposed exhibited no sensitizing potential. (+)-Limonene oxide and R-(-)-carvone, but not (-)-carveal, were potent sensitizers. Air oxidation of d-limonene is necessary for its sensitizing potential. Air oxidation produces potent allergens such as limonene oxide and carvone.
[Karlberg AT et al; Contact Dermatitis 26 (5): 332-40 (1992)]**PEER REVIEWED**

d-Limonene, a monocyclic monoterpenoid with known insecticidal properties, was assayed (by a standard method of cutaneous exposure) for general lethality effects as well as neurotoxic effects on escape reflex pathways in earthworms, Eisenia fetida (Savigny). Neurotoxicity was assessed by noninvasive electrophysiological techniques involving (a) quantification of the impacts of chronic and acute sublethal exposures on impulse conduction in the worms' medial and lateral giant nerve fiber pathways, (b) determination of whether such effects were generalized or localized within various body regions, and (c) determination of the reversibility of neurotoxic effects. The LD50 value for d-limonene alone was 6.0 ppm, and the LT50 value for exposure to 12.6 ppm was 4.9 hr. Effects on lethality were not synergized significantly by either piperonyl butoxide or sesame oil. Generally, chronic and acute intoxication involved a rapid and predictable cascade of behavioral and morphological symptoms, including increased mucus secretion, writhing, clitellar swelling, and elongation of the body. In addition, chronic d-limonene exposures induced significant weight loss, but there was no effect on median giant nerve fiber and lateral giant nerve fiber conduction velocities, even though abnormal rebounding of median giant nerve fiber impulses and spontaneous lateral giant nerve fiber spiking were often evident. Acute exposures, however, induced significant decreases in conduction velocity in both the median giant nerve fiber and lateral giant nerve fiber, but the effects were regionally specific; for example, lateral giant nerve fiber velocities were significantly reduced in the posterior half of the body but not in the anterior half. The magnitude of conduction velocity decreases was directly related to both concn and duration of exposure. Decreases in conduction velocities after acute exposures were reversed once d-limonene exposure ceased.
[Karr LL et al; Pestic Biochem Physiol 36 (2): 175-86 (1990)]**PEER REVIEWED**

The anticarcinogenic effects of monocyclic monoterpenes such as limonene were demonstrated when given during the initiation phase of 7,12-dimethylbenz[a]anthracene induced mammary cancer in Wistar-Furth rats. The possible mechanisms for this chemoprevention activity including limonene's effects on 7,12-dimethylbenz(a)anthracene-DNA adduct formation and hepatic metabolism of 7,12-dimethylbenz[a]anthracene were investigated. Twenty four hours after carcinogen administration, there were approx 50% decreases in 7,12-dimethylbenz(a)anthracene-DNA adducts found in control animals formed in the liver, spleen, kidney and lung of limonene fed animals. While circulating levels of 7,12-dimethylbenz(a)anthracene and/or its metabolites were not different in control and limonene fed rats, there was a 2.3 fold increase in 7,12-dimethylbenz(a)anthracene and/or 7,12-dimethylbenz(a)anthracene derived metabolites in the urine of the limonene fed animals. Limonene and sobrerol, a hydroxylated monocyclic monoterpenoid with increased chemoprevention activity, modulated cytochrome p450 and epoxide hydrolyase activity. The 5% limonene diet increased total cytochrome p450 to the same extent as phenobarbital treatment, while 1% sobrerol (isoeffective in chemoprevention to 5% limonene) did not. However, both 5% limonene and 1% sobrerol diets greatly increased the levels of microsomal epoxide hydrolyase protein and associated hydrating activities towards benzo[a]pyrene 4,5-oxide when compared to control and phenobarbital treatment. These changes also modified the rate and regioselectivity of in vitro microsomal 7,12-dimethylbenz(a)anthracene metabolism when compared to phenobarbital treatment or control. Identification of the specific isoforms of cytochrome p450 induced by these terpenoids was performed with antibodies to cytochrome p450 isozymes in Western blot analysis and inhibition studies of microsomal 7,12-dimethylbenz(a)anthracene metabolism. Five percent limonene was more effective than 1% sobrerol at increasing the levels of members of the cytochrome p450 2B and 2C families but was equally effective at increasing epoxide hydrolyase. Furthermore, both terpenoid diets caused increased formation of the proximate carcinogen, 7,12-dimethylbenz(a)anthracene 3,4-dihydrodiol.
[Maltzman TH et al; Carcinogenesis 12 (11): 2081-7 (1991)]**PEER REVIEWED**

National Toxicology Program Studies:

Two year studies of d-limonene /more than 99% pure/ were conducted by administering 0, 75, or 150 mg/kg d-limonene in corn oil by gavage to groups of 50 F344/N male rats, 5 days per week for 103 weeks; groups of 50 female F344/N rats were administered 0, 300, or 600 mg/kg. Mean body weights of rats dosed with d-limonene were similar to those of vehicle controls throughout the studies. Survival of the high dose female rats after week 39 and of the vehicle control male rats after week 81 was significantly reduced (survival at week 104--male: vehicle control, 29/50; low dose, 33/50; high dose, 40/50; female: 42/50; 40/50; 26/50). The kidney was confirmed as the primary target organ for chemically related lesions. No lesions were observed in female rats. For males, the nonneoplastic lesions included exacerbation of the age-related nephropathy, linear deposits of mineral in the renal medulla and papilla, and focal hyperplasia of the transitional epithelium overlying the renal papilla. Uncommon tubular cell adenomas and adenocarcinomas of the kidney also occurred in dosed male rats, and this effect was supported by a dose-related increased incidence of tubular cell hyperplasia. ... There was clear evidence of carcinogenic activity of d-limonene for male F344/N rats, as shown by increased incidences of tubular cell hyperplasia, adenomas, and adenocarcinomas of the kidney. There was no evidence of carcinogenic activity of d-limonene for female F344/N rats that received 300 or 600 mg/kg. /D-Limonene/
[DHHS/NTP; Toxicology and Carcinogenesis Studies of d-Limonene (Gavage Studies) p. 3 (1990) Technical Rpt Series No. 347 NIH Pub No. 90-2802]**PEER REVIEWED**

Groups of 50 male B6C3F1 mice were administered 0, 250, 500 mg/kg, ... /5 days per week for 103 weeks/; groups of 50 female B6C3FI mice were administered 0, 500, or 1000 mg/kg. Mean body weights of dosed and vehicle control male mice were similar throughout the studies. Mean body weights of high dose female mice were notably lower than those of the vehicle controls after week 28. Survival of the low dose group-of male mice was significantly lower than that of vehicle controls at the end of the study (33/50; 24/50; 39/50). No difference in survival was observed between vehicle control and dosed female mice (43/50; 44/50; 43/50). ... No chemically related increases in neoplasms were observed. The incidence of neoplasms of the anterior pituitary gland in high dose female mice was lower than that in vehicle controls (adenomas or carcinomas, combined: vehicle control, 12/49; high dose, 2/48). Cells with an abnormal number of nuclei (8/49; 32/50) and cytomegaly (23/49; 38/50) were observed in the liver of high dose male mice. There was no evidence of carcinogenic activity of d-limonene for male B6C3Fl mice that received 250 or 500 mg/kg. There was no evidence of carcinogenic activity of d-limonene for female B6C3Fl mice that received 500 or 1000 mg/kg.
[DHHS/NTP; Toxicology and Carcinogenesis Studies of d-Limonene (gavage Studies) p. 3 (1990) Technical Rpt Series No. 347 NIH Pub No. 90-2802]**PEER REVIEWED**

Non-Human Toxicity Values:

LD50 Mouse oral 5.6-6.6 g/kg
[DHHS/NTP; Toxicology and Carcinogenesis Studies of d-Limonene (Gavage Studies) p.13 (1990) Technical Rpt Series No. 347, NIH Pub No. 90-2802]**PEER REVIEWED**

LD50 Mouse ip 1.3 g/kg
[DHHS/NTP; Toxicology and Carcinogenesis Studies of d-Limonene (Gavage Studies) p.13 (1990) Technical Rpt Series No. 347, NIH Pub No. 90-2802]**PEER REVIEWED**

Metabolism/Pharmacokinetics:

Metabolism/Metabolites:

AFTER ORAL ADMIN, MAJOR METABOLITE IN URINE WAS PERILLIC ACID 8,9-DIOL IN RATS & RABBITS, PERILLYL-BETA-D-GLUCOPYRANOSIDURONIC ACID IN HAMSTERS, P-MENTH-1-ENE-8,9-DIOL IN DOGS, & 8-HYDROXY-P-MENTH-1-EN-9-YL-BETA-D-GLUCOPYRANOSIDURONIC ACID IN GUINEA PIGS AND MAN.
[KODAMA R ET AL; XENOBIOTICA 6 (6): 377 (1976)]**PEER REVIEWED**

Adult male and female Sprague Dawley rats were given single oral doses of 0, 0.1, 0.3, 1, or 3 mmol d-limonene/kg (0, 14, 41, 136, or 409 mg/kg) in corn oil. Gel filtration HPLC indicated that d-limonene in male rat kidney is associated with a protein fraction having a mol wt of approximately 20000. Using reverse phase HPLC, d-limonene was shown to be associated with alpha-2u-globulin which was identified by amino acid sequencing. The major metabolite associated with alpha-2u-globulin was d-limonene-1,2-oxide. Parent d-limonene was also identified as a minor component in the alpha-2u-globulin fraction. /d-Limonene/
[Lehman-McKeeman LD et al; Toxicol Appl Pharmacol 99 (2): 250-9 (1989)]**PEER REVIEWED**

The major urinary metabolites of d-limonene were identified as perillic acid-8,9-diol in rats and rabbits, perillyl-beta-D-glucopyranosiduronic acid in hamsters, p-menth-l-ene-8,9-diol in dogs, and 8-hydroxy-p-menth-1-ene-9-yl-beta-D-glucopyranosiduronic acid in guinea pigs andhumans. ... Five new metabolites /were isolated/ from dog and rat urine after oral administration of radiolabeled d-limonene: 2-hydroxy-p-menth-8-en-7-oic acid, perillylglycine , perillyl-beta-D-glucopyranosiduronic acid, p-mentha-1,8-diene-6-ol, and probably p-menth-1-ene-6,8,9-triol. /d-Limonene/
[DHHS/NTP; Toxicology and Carcinogenesis Studies of d-Limonene (Gavage Studies) p. 13 (1990) Technical Rpt Series No. 347 NIH Pub No. 90-2802]**PEER REVIEWED**

Absorption, Distribution & Excretion:

THE DATA SUGGEST THAT MONOTERPENES ARE POORLY RESORBED IN THE GI TRACT. THE RESORBED PORTION OF HYDROCARBONS ACCUMULATES IN THE LIPOPHILIC BODY COMPARTMENTS & IS METABOLIZED & THEN EXCRETED BY THE KIDNEYS.
[KOPPEL C ET AL; ARCH TOXICOL 49 (1): 73 (1981)]**PEER REVIEWED**

AFTER ORAL ADMIN OF (14)C-LABELED D-LIMONENE TO ANIMALS & MAN, 75-95 & LESS THAN 10% OF THE RADIOACTIVITY WAS EXCRETED IN THE URINE & FECES RESPECTIVELY WITHIN 2-3 DAYS. /D-LIMONENE/
[KODAMA R ET AL; XENOBIOTICA 6 (6): 377 (1976)]**PEER REVIEWED**

PERCUTANEOUS ABSORPTION OF RADIOACTIVE LIMONENE FROM FOAM BATH WAS MEASURED IN ANIMALS. MAXIMUM BLOOD LEVEL REACHED AFTER 10 MIN OF EXPOSURE & THE CONCN WAS PROPORTIONAL TO THE SKIN EXPOSED.
[SCHAFER R ET AL; ARZNEIMITTELFORSCH 32 (1): 56 (1982)]**PEER REVIEWED**

The toxicokinetics of d-limonene were studied in human volunteers exposed by inhalation (2 hr, work load 50 W) in an exposure chamber on three different occasions. The exposure concn were approximately 10, 225, and 450 mg/cu m d-limonene. The relative pulmonary uptake was high, approximately 70% of the amount supplied. The blood clearance of d-limonene observed in this study, 1.1 l/kg/hr, indicates that d-limonene is metabolized readily. About 1% of the total uptake was eliminated unchanged in the expired air after the end of exposure, while approximately 0.003% was eliminated in the urine. A long half-time in blood was observed in the slow elimination phase, which indicates accumulation in adipose tissues.
[Falk-Filipsson A et al; J Toxicol Environ Health 38 (1): 77-88 (1993)]**PEER REVIEWED**

Interactions:

RAUSCHER MURINE LEUKEMIAVIRUS INFECTED F344 RAT EMBRYO CELLS WERE NOT TRANSFORMED TREATED WITH SUBEFFECTIVE DOSES OF 3-METHYLCHOLANTHRENE. THESE CELLS TREATED WITH LIMONENE SHOWED CARCINOGENIC TRANSFORMATION.
[TRAUL KA ET AL; J NATL CANCER INST 66 (1): 171 (1981)]**PEER REVIEWED**

The monoterpene d-limonene has been shown to an effective, non-toxic chemopreventive agent in mammary and other rodent tumor models. The studies reported here investigated structure activity relationships among limonene and three hydroxylated derivatives in the prevention of dimethylbenz[a]anthracene induced mammary cancer. Rats were fed control or 1% limonene, carveol, uroterpenol or sobrerol diets from 2 wk before to one week after carcinogen administration. Carveol, uroterpenol and sobrerol significantly prolonged tumor latency and decreased tumor yield. Sobrerol was the most potent of the monoterpenes tested, decreasing tumor yield to half that of the control, a level previously achieved with 5% limonene diets. Excretion of radioactivity from (3)H dimethylbenz(a)anthracene was doubled in rats fed 5% limonene and nearly tripled in rats fed 1% sobrerol. Sobrerol is thus 5 fold more potent than limonene in both enhancing carcinogen excretion and in preventing tumor formation. These data demonstrate that hydroxylation of monoterpenes affects chemopreventive potential, with 2 hydroxyl groups greater than 1 greater than 0. Sobrerol, carveol and uroterpenol are novel cancer chemopreventive agents with little or no toxicity.
[Crowell PL et al; Carcinogenesis 13 (7): 1261-4 (1992)]**PEER REVIEWED**

To identify possible hazards of combined exposure to chemicals with the same target organ, a 24 hr single dose experiment was carried out in which the renal toxicity of mercuric chloride, potassium dichromate, d-limonene and hexachloro-1:3-butadiene administered simultaneously was compared with the nephrotoxicity of the individual compounds in 12 wk old male Wistar rats. The dose levels used were based on the results of a range finding study with the individual compounds in the same strain of rats kept under similar experimental conditions, and comprised the 'Minimum Nephrotoxic Effect Level' and the 'No Nephrotoxic Effect Level' of each of the four compunds alone and in combination. A group of vehicle treated rats served as controls. At the 'Minimum Nephrotoxic Effect Level' of the combinations, antagonism of effects was encountered, seen for example as less severely increased activity of gamma-glutamyl transferase in the urine. Synergism of effects was also observed, for example increased severity of renal tubular necrosis, and more markedly increased activity of urinary lysozyme, lactate dehydrogenase, alkaline phosphatase and N-acetyl-beta-glucosaminidase. More importantly, however, at the 'No Nephrotoxic Effect Level' of the combination no signs of impaired renal function or renal damage were observed, suggesting absence of both dose additivity and potentiating interaction at the tested subeffective levels of the individual nephrotoxicants.
[Jonker D et al; Food Chem Toxicol 31 (1): 45-52 (1993)]**PEER REVIEWED**

Mouse mammary glands respond to carcinogen stimulus to form mammary lesions in organ culture. In this study it was determined whether the effective chemopreventive agents are active against initiation or the promotion phase of lesion development. Mammary glands were subjected to 24 hr exposure to 2 mg/ml dimethylbenz(a)anthracene followed by a 5 day exposure to 7,12-tetradecanoyl phorbol-13-acetate. This treatment protocol allows the study of initiation and promotion aspects of lesion development. Chemopreventive agents effective when present prior to the carcinogen were considered as anti-initiators, whereas agents effective when present after the dimethylbenz[a]anthracene treatment along with 7,12-tetradecanoyl pherbol-13-acetate were considered as anti-promoters. Within the chemopreventive agents evaluated limonene was an anti-initiator.
[Mehta RG, Moon RC; Anticancer Res 11 (2): 593-6 (1991)]**PEER REVIEWED**

The effects of D-limonene and citrus fruit oils, ie orange oil and lemon oil, on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone induced neoplasia of the lungs and forestomach of female A/J mice were investigated. D-Limonene and the citrus fruit oils given orally 1 hr prior to 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, also administered orally, inhibited pulmonary adenoma formation and the occurrence of forestomach tumors. In an additional experiment, D-limonene given orally 1 hr prior to 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone administered ip again showed pronounced inhibition of pulmonary adenoma formation.
[Wattenberg LW, Coccia JB; Carcinogenesis 12 (1): 115-7 (1991)]**PEER REVIEWED**

Pharmacology:

Interactions:

RAUSCHER MURINE LEUKEMIAVIRUS INFECTED F344 RAT EMBRYO CELLS WERE NOT TRANSFORMED TREATED WITH SUBEFFECTIVE DOSES OF 3-METHYLCHOLANTHRENE. THESE CELLS TREATED WITH LIMONENE SHOWED CARCINOGENIC TRANSFORMATION.
[TRAUL KA ET AL; J NATL CANCER INST 66 (1): 171 (1981)]**PEER REVIEWED**

The monoterpene d-limonene has been shown to an effective, non-toxic chemopreventive agent in mammary and other rodent tumor models. The studies reported here investigated structure activity relationships among limonene and three hydroxylated derivatives in the prevention of dimethylbenz[a]anthracene induced mammary cancer. Rats were fed control or 1% limonene, carveol, uroterpenol or sobrerol diets from 2 wk before to one week after carcinogen administration. Carveol, uroterpenol and sobrerol significantly prolonged tumor latency and decreased tumor yield. Sobrerol was the most potent of the monoterpenes tested, decreasing tumor yield to half that of the control, a level previously achieved with 5% limonene diets. Excretion of radioactivity from (3)H dimethylbenz(a)anthracene was doubled in rats fed 5% limonene and nearly tripled in rats fed 1% sobrerol. Sobrerol is thus 5 fold more potent than limonene in both enhancing carcinogen excretion and in preventing tumor formation. These data demonstrate that hydroxylation of monoterpenes affects chemopreventive potential, with 2 hydroxyl groups greater than 1 greater than 0. Sobrerol, carveol and uroterpenol are novel cancer chemopreventive agents with little or no toxicity.
[Crowell PL et al; Carcinogenesis 13 (7): 1261-4 (1992)]**PEER REVIEWED**

To identify possible hazards of combined exposure to chemicals with the same target organ, a 24 hr single dose experiment was carried out in which the renal toxicity of mercuric chloride, potassium dichromate, d-limonene and hexachloro-1:3-butadiene administered simultaneously was compared with the nephrotoxicity of the individual compounds in 12 wk old male Wistar rats. The dose levels used were based on the results of a range finding study with the individual compounds in the same strain of rats kept under similar experimental conditions, and comprised the 'Minimum Nephrotoxic Effect Level' and the 'No Nephrotoxic Effect Level' of each of the four compunds alone and in combination. A group of vehicle treated rats served as controls. At the 'Minimum Nephrotoxic Effect Level' of the combinations, antagonism of effects was encountered, seen for example as less severely increased activity of gamma-glutamyl transferase in the urine. Synergism of effects was also observed, for example increased severity of renal tubular necrosis, and more markedly increased activity of urinary lysozyme, lactate dehydrogenase, alkaline phosphatase and N-acetyl-beta-glucosaminidase. More importantly, however, at the 'No Nephrotoxic Effect Level' of the combination no signs of impaired renal function or renal damage were observed, suggesting absence of both dose additivity and potentiating interaction at the tested subeffective levels of the individual nephrotoxicants.
[Jonker D et al; Food Chem Toxicol 31 (1): 45-52 (1993)]**PEER REVIEWED**

Mouse mammary glands respond to carcinogen stimulus to form mammary lesions in organ culture. In this study it was determined whether the effective chemopreventive agents are active against initiation or the promotion phase of lesion development. Mammary glands were subjected to 24 hr exposure to 2 mg/ml dimethylbenz(a)anthracene followed by a 5 day exposure to 7,12-tetradecanoyl phorbol-13-acetate. This treatment protocol allows the study of initiation and promotion aspects of lesion development. Chemopreventive agents effective when present prior to the carcinogen were considered as anti-initiators, whereas agents effective when present after the dimethylbenz[a]anthracene treatment along with 7,12-tetradecanoyl pherbol-13-acetate were considered as anti-promoters. Within the chemopreventive agents evaluated limonene was an anti-initiator.
[Mehta RG, Moon RC; Anticancer Res 11 (2): 593-6 (1991)]**PEER REVIEWED**

The effects of D-limonene and citrus fruit oils, ie orange oil and lemon oil, on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone induced neoplasia of the lungs and forestomach of female A/J mice were investigated. D-Limonene and the citrus fruit oils given orally 1 hr prior to 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, also administered orally, inhibited pulmonary adenoma formation and the occurrence of forestomach tumors. In an additional experiment, D-limonene given orally 1 hr prior to 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone administered ip again showed pronounced inhibition of pulmonary adenoma formation.
[Wattenberg LW, Coccia JB; Carcinogenesis 12 (1): 115-7 (1991)]**PEER REVIEWED**

Environmental Fate & Exposure:

Environmental Fate/Exposure Summary:

Limonene is both a naturally occurring and a synthetic terpene which is used in flavors and fragrances, as a solvent and for numerous other commercial uses. If released to soil, limited data indicate that limonene is expected to be resistant to biodegradation under aerobic conditions. Limonene is expected to exhibit low to slight mobility in soil. It is expected to rapidly volatilize from both dry and moist soil to the atmosphere although adsorption to soil may attenuate the rate of this process. If released to water, limited data indicate that limonene is expected to be resistant to biodegradation under aerobic conditions. Limonene may bioconcentrate in fish and aquatic organisms and it may significantly adsorb to sediment and suspended organic matter. It is expected to rapidly volatilize from water to the atmosphere. The estimated half-life for volatilization of limonene from a model river is 3.4 hr, although adsorption to sediment and suspended organic matter may attenuate the rate of this process. If released to the atmosphere, limonene is expected to rapidly undergo gas-phase oxidation reactions with photochemically produced hydroxyl radicals, ozone, and at night with nitrate radicals. Calculated lifetime for these processess in a clean and moderately polluted atmosphere are 2.0 hr and 30 min, 36 min and 11 min, and 9 min and 0.9 min, respectively. Occupational exposure to limonene may occur by inhalation or dermal contact during its production, formulation, transport or use. Exposure to the general population my occur by inhalation due to its presence in the atmosphere as a result of release from natural sources, its presence in household products, or by ingestion of food in which it is contained. (SRC)
**PEER REVIEWED**

Probable Routes of Human Exposure:

Occupational exposure to limonene may occur by inhalation or dermal contact during its production, formulation, transport or use. Exposure to the general population may occur by inhalation due to its presence in the atmosphere as a result of its release from natural sources(1,2), its presence in household products, or by ingestion of food in which it occurs either naturally or has been added as a flavor or fragrance(SRC).
[(1) Isidorov VA et al; Atmos Environ 19: 1-8 (1985) (2) Altshuller AP; Atmos Environ 17: 2131-65 (1983) (3) Tichenor BA, Mason MA; JAPCA 38: 264-8 (1988) (3) Tichenor BA; Organic Emission Measurements via Small Chamber Testing. USEPA, Research Triangle Park, NC. PB87-199154 (1987)]**PEER REVIEWED**

NIOSH (NOES Survey 1981-83) has statistically estimated that 94,910 workers are exposed to limonene in the USA(1). Limonene was detected in the air of the vulcanization area of a shoe-sole factory at a concn of 25-130 ug/cu m, and at 5-1700 ug/cu m in the vulcanization area of a tire retreading factory(2). Limonene was detected indoors in an office building, 1987, at a concn ranging from 43-63 ug/cu m(3). Limonene was qualitatively detected in air samples taken at 2 Stockholm preschools, 1981-2(4).
[(1) NIOSH; National Occupational Exposure Survey (NOES) (1989) (2) Cocheo V et al; Am Ind Hyg Assoc J 44: 521-7 (1983) (3) Weschler CJ et al; Am Ind Hyg Assoc J 51: 261-8 (1990) (4) Noma E et al; Atmos Environ 22: 451-60 (1988)]**PEER REVIEWED**

Body Burden:

Limonene has been identified in the expired air of urban volunteers(1). Limonene was qualitatively detected in 8 of 8 samples of mother's milk obtained from residents of urban centers in PA, NJ, and LA(2).
[(1) Krotoszynski B et al; J Chromat Sci 15: 239-44 (1977) (2) Pellizzari ED et al; Bull Environ Contam Toxicol 28: 322-8 (1982)]**PEER REVIEWED**

Natural Pollution Sources:

Limonene is a naturally occurring compound and it is found in many natural oils including orange, lemon, grapefruit, berry, leaf, caraway, dill, bergamot, peppermint and spearmint oils(1,2,3,4). Limonene emissions to the environment are associated with wax myrtle, sweet acacia, oranges, tomatoes, grasses, and California western sagebrush(5). Emissions of limonene are also associated with balsam poplar, European larche, European fir, scots pine, Siberian pine, silver fir, common juniper, zeravshan juniper, pencil cedar, evergreen cypress, northern white cedar, chinese arbor vitae, marsh tea and deciduous moss(6).
[(1) Rogers JAJR; Kirk Othmer Encycl Chem Tech, NY: Wiley 3rd ed. 16: 307-32 (1981) (2) Bauer K et al; pp. 141-250 in Ullmann's Encycl Indust Tech, 5th ed. Gerhartz W et al Eds. VCH Publ A11 (1988) (3) Windholz M et al; The Merck Index Rahway, NJ: Merck & Co Inc 10th ed (1983) (4) Sax NI, Lewis RJSR; Hawley's Condensed Chemical Dictionary 11th ed NY: Van Nostrand Reinhold Co pp. 425, 701 (1987) (5) Altshuller AP; Atmos Environ 17: 2131-65 (1983) (6) Isidorov VA et al; Atmos Environ 19: 1-8 (1985)]**PEER REVIEWED**

Artificial Pollution Sources:

0.2-0.3 OF THE SMOKE CONDENSATE FROM BOTH BRIGHT (FLUE-CURED) BURLEY TOBACCO & A COMMERCIAL BLEND OF BRIGHT, BURLEY, TURKISH & MARYLAND TOBACCO.
[MOLD JD ET AL; SCIENCE 144 (1): 1572 (1964)]**PEER REVIEWED**

Limonene is used as a flavor and fragrance(1,2). It is also used as a solvent, wetting agent, in resins, and as a monomer and copolymer(2,3). Limonene may be released to the environment as a fugitive emission during its production, use or transport, from volatilization during its use as a solvent, from landfills, and in industrial effluent(4,5,SRC). Limonene emissions have been associated with effluent from the following industries: extraction of pine gum, paper and pulp mills, plastics materials-synthetic resins and non vulcanizable elastomers, perfumes, cosmetics and other toilet preparations, organic solvents and lubricating oils and greases(6). Limonene may be emitted to household environments from furniture polishes and room fresheners(7).
[(1) Rogers, JAJR: Kirk Othmer Encycl Chem Tech, NY: Wiley 3rd ed. 16: 307-32 (1981)) (2) Sax NI, Lewis RJSR; Hawley's Condensed Chemical Dictionary 11th ed. NY: Van Nostrand Reinhold Co pp. 701, 425 (1987) (3) Holohan SF et al; Kirk-Othmer Encycl Chem Tech, NY: Wiley 3rd ed. 12: 852-69 (1980) (4) Young P, Parker A; Vapors, pp. 24-41 in Hazardous and Industrial Waste Management and Testing, 3rd Symp. Amer Soc Test Mater (1984) (5) Bursey JT, Pellizzari ED; Analysis of Industrial Wastewater for Organic Pollutants in Consent Degree Survey. Research Triangle Park, NC: (1982) (6) Abrams EF et al; Identification of Organic Compounds in Effluents from Industrial Sources. Washington, DC: USEPA-560/3-75-002 (1975) (7) Tichenor BA, Mason MA; JAPCA 38: 264-8 (1988)]**PEER REVIEWED**

Environmental Fate:

TERRESTRIAL FATE: If released to soil, limited data indicate that limonene is expected to be resistant to biodegradation under aerobic conditions(1,2). Based on limonene's water solubility, 13.8 mg/l at 25 deg C(3) and an estimated log octanol/water partition coefficient of 4.232(4,SRC), soil adsorption coefficients ranging from 1030-4780 can be calculated using an appropriate regression equation(5,SRC) indicating that it will display low to slight mobility in soil(6). Its vapor pressure, 20 mm Hg at 68.2 deg C(7) and a calculated Henry's Law constant of 0.380 atm cu m/mole at 25 deg C(8,SRC) indicate that limonene will rapidly volatilize from both dry and moist soil to the atmosphere although strong adsorption to soil may significantly attenuate the rate of this process(SRC).
[(1) Perry JJ; The role of Co-Oxidation and Commensalism in the Biodegradation of Recalcitrant Molecules. US Army Res Off DAAG-29-76-G0159 (1980) (2) Abrams EF et al; Identification of Organic Compounds in Effluents from Industrial Sources Washington, DC: USEPA-560/3-75-002 (1975) (3) Massaldi HA, King CJ; J Chem Eng Data 18: 393-7 (1973) (4) GEMS; Graphic Exposure Modeling System CLOGP USEPA (1987) (5) Lyman WJ et al; Handbook of Chemical Property Estimation Methods NY: McGraw-Hill pp. 4-1 to 4-33 (1982) (6) Swann RL et al; Res Rev 85: 17-28 (1983) (7) Riddick JA et al; Organic Solvents 4th ed. NY: Wiley Interscience (1986) (8) Hine J, Mookerjee PK; J Org Chem 40: 292-8 (1975)]**PEER REVIEWED**

AQUATIC FATE: If released to water, limited data indicate that limonene is expected to be resistant to biodegradation under aerobic conditions(1,2). Based on limonene's water solubility, 13.8 mg/l at 25 deg C(3) and an estimated log octanol/water partition coefficient of 4.232(4,SRC) bioconcentration factors ranging from 246-262 can be calculated using an appropriate regression equation(5,SRC) indicating that it may bioconcentrate in fish and aquatic organisms(SRC). Estimated soil adsorption coefficients ranging from 1030 to 4780(3,4,5,SRC) indicate that limonene may significantly adsorb to sediment and suspended organic matter. A calculated Henry's Law constant of 0.380 atm cu m/mole at 25 deg C(7,SRC) suggests that limonene will rapidly volatilize from water to the atmosphere. The estimated half-life for volatilization of limonene from a model river 1 m deep flowing at 1 m/sec with a wind speed of 3 m/sec is 3.4 hr(4,SRC), although adsorption to sediment and suspended matter may attenuate the rate of this process(SRC).
[(1) Perry JJ; The role of Co-Oxidation and Commensalism in the Biodegradation of Recalcitrant Molecules. US Army Res Off DAAG-29-76-G0159 (1980) (2) Abrams EF et al; Identification of Organic Compounds in Effluents from Industrial Sources. Washington, DC: USEPA-560/3-75-002 (1975) (3) Massaldi HA, King CJ; J Chem Eng Data 18: 393-7 (1973) (4) GEMS; Graphic Exposure Modeling System CLOGP USEPA (1987) (5) Lyman WJ et al; Handbook of Chemical Property Estimation Methods NY: McGraw-Hill pp. 4-1 to 4-33, 5-1 to 5-30 (1982) (6) Riddick JA et al; Organic Solvents 4th ed. Wiley NY: Interscience (1986) (7) Hine J, Mookerjee PK; J Org Chem 40: 292-8 (1975)]**PEER REVIEWED**

ATMOSPHERIC FATE: If released to the atmosphere, limonene is expected to rapidly undergo gas-phase oxidation reactions with photochemically produced hydroxyl radicals, ozone, and at night with nitrate radicals. Based on experimental rate constants, calculated lifetimes for the gas-phase reaction between limonene and photochemically produced hydroxyl radicals are 2.0 hrs in a clean atmosphere and 30 mins in a moderately polluted atmosphere(1). Corresponding values for the gas-phase reaction with ozone are 36 min and 11 min, respectively(1). Calculated lifetimes, based on experimentally determined rate constants, for the night time reaction of alpha-pinene with nitrate radicals of 9 min in a clean atmosphere and 0.9 min in a moderately polluted atmosphere have been reported(1). The atmospheric lifetime of limonene was estimated at 0.2-0.8 hr depending on both the local hydroxyl radical and ozone concn(2).
[(1) Winer AM et al; Science 224: 156-9 (1984) (2) Altshuller AP; Atmos Environ 17: 2131-65 (1983)]**PEER REVIEWED**

Environmental Biodegradation:

Organisms isolated from soil and water were, in general, unable to oxidize limonene in laboratory experiments(1). Limonene was listed as a compound difficult to biodegrade and was classified in level 3 (difficult to biodegrade) in a 5 tiered rating system on ease of biodegradability(2). The concn of limonene between the influent and effluent of aerated treatment lagoons was found to decrease significantly which the author ascribed to a biological removal process although complete documentation was not provided(3).
[(1) Perry JJ; The role of Co-Oxidation and Commensalism in the Biodegradation of Recalcitrant Molecules. US Army Res Off DAAG-29-76-G0159 (1980) (2) Abrams EF et al; Identification of Organic Compounds in Effluents from Industrial Sources. Washington, DC: USEPA-560/3-75-002 (1975) (3) Wilson D, Hrutfiord B; Pulp and Paper Canada 76: 91-3 (1975)]**PEER REVIEWED**

Environmental Abiotic Degradation:

An experimental rate constant for the gas-phase reaction of limonene with photochemically produced hydroxyl radicals of 1.49X10-10 atm/cu m molec at 32 deg C(1) translates to a half-life of 2.6 hr using an average atmospheric hydroxyl radical concn of 5X10+5 molec/cu m(2,SRC). A calculated lifetime for the reaction of limonene with photochemically produced hydroxyl radicals in a clean atmosphere is 2.0 hr or 30 min in a moderately polluted atmosphere(3). Limonene was classified as group V in a 5 tiered rating system of relative reactivities towards photochemically produced hydroxyl radicals (methane =1, limonene=18,800), indicating a atmospheric half-life of <0.24 hr(4). An experimental rate constant for the gas-phase reaction of limonene with ozone of 6.5X10-16 atm/cu m molec(1) translates to a half-life of 25 min using an average atmospheric ozone concn of 7X10+11 molec/cu cm(3,SRC). A calculated lifetime for the reaction of limonene with ozone in a clean atmosphere is 36 min or 11 min in a moderately polluted atmosphere(3).
[(1) Winer AM et al; J Phys Chem: 80: 1635-9 (1976) (2) Atkinson R; Chem Rev 85:69-201 (1985) (3) Winer AM et al; Science 224: 156-9 (1984) (4) Darnall KR et al; Environ Sci Tech 10: 692-6 (1976) (5) Gaffney JS et al; J Am Chem Soc 97: 5049-51 (1975)]**PEER REVIEWED**

A calculated lifetime for the reaction of limonene with nitrate radicals in a clean atmosphere is 9 min or 0.9 mins in a moderately polluted atmosphere(1). Limonene was listed as a compound amenable to direct photochemical degradation in the presence of nitrogen oxides(2). Photolysis of limonene in the presence of nitrogen oxides produces formaldehyde, formic acid, carbon monoxide, carbon dioxide, acetaldehyde, peroxyacetyl nitrate and acetone(5). The daytime atmospheric lifetime of limonene was estimated at 0.2-0.8 hr depending on both the local hydroxyl radical and ozone concn(4).
[(1) Winer AM et al; Science 224: 156-9 (1984) (2) Westberg HH, Rasmussen RA; Chemosphere 4: 163-8 (1972) (3) Darnall KR et al; Environ Sci Tech 10: 692-6 (1976) (4) Altshuller AP; Atmos Environ 17: 2131-65 (1983)]**PEER REVIEWED**

Environmental Bioconcentration:

Based on limonene's water solubility of 13.8 mg/l at 25 deg C(1), and an estimated log octanol/water partition coefficient of 4.232(2,SRC), bioconcentration factors of 246 and 262, respectively, can be calculated using an appropriate regression equation(3,SRC). These values indicate that limonene may bioconcentrate in fish and aquatic organisms(SRC).
[(1) Massaldi HA, King CJ; J Chem Eng Data 18: 393-7 (1973) (2) GEMS; Graphic Exposure Modeling System CLOGP USEPA (1987) (3) Lyman WJ et al; Handbook of Chemical Property Estimation Methods NY: McGraw-Hill pp. 5-1 to 5-30 (1982)]**PEER REVIEWED**

Soil Adsorption/Mobility:

Based on its water solubility of 13.8 mg/l at 25 deg C(1) and an estimated log octanol/water partition coefficient of 4.232(2,SRC), soil adsorption coefficients of 1030 and 4780, respectively, can be calculated for limonene using an appropriate regression equation(3,SRC). These values indicate that limonene is expected to display slight to low mobility in soil(4).
[(1) Massaldi HA, King CJ; J Chem Eng Data 18: 393-7 (1973) (2) GEMS; Graphic Exposure Modeling System CLOGP USEPA (1987) (3) Lyman WJ et al; Handbook of Chemical Property Estimation Methods NY: McGraw-Hill pp. 4-1 to 4-33 (1982) (4) Swann RL et al; Res Rev 85: 17-28 (1983)]**PEER REVIEWED**

Volatilization from Water/Soil:

Based on its vapor pressure, 20 mm Hg at 68.2 deg C(1), limonene may volatilize rapidly from dry soil to the atmosphere(SRC). A calculated Henry's Law constant of 0.380 atm cu m/mole(2,SRC) indicates that limonene will rapidly volatilize from both water and moist soil to the atmosphere(3,SRC). The estimated half-life for volatilization of limonene from a model river 1 m deep flowing at 1 m/sec with a wind speed of 3 m/sec is 3.4 hr(3,SRC).
[(1) Riddick JA et al; Organic Solvents 4th ed. NY: Wiley Interscience (1986) (2) Hine J, Mookerjee PK; J Org Chem 40: 292-8 (1975) (3) Lyman WJ et al; Handbook of Chemical Property Estimation Methods NY: McGraw-Hill pp. 15-15 to 15-29 (1982)]**PEER REVIEWED**

Environmental Water Concentrations:

SURFACE WATER: The concn of limonene in seawater samples from Resurrection Bay, AK, was 84 ng/l in June 1985 and 0.47 ng/l in June, 1986(1). Limonene has been qualitatively detected in the Black Warrior River, near Tuscaloosa, AL, 1975(2). Limonene was identified in the River Glatt, Switzerland, 1975(3). It was detected, but not quantified, in water samples taken from the River Lee, in the UK, date not given(4).
[(1) Button DK, Juttner F; Marine Chem 26: 57-66 (1989) (2) Bertsch W et al; J Chromatog 112: 701-18 (1975) (3) Zurcher F, Giger W; Vom Wasser 47: 37-55 (1976) (4) Waggott A et al; Chem Water Reuse 2: 55-9 (1981)]**PEER REVIEWED**

GROUNDWATER: Limonene was detected in contaminated groundwater in The Netherlands at a maximum concn of 10 ug/l(1). Limonene was detected in 11 of 11 ground water samples at the site of a former pine tar manufacturer in Gainsville, FL, at concn ranging from 1 ug/l to 130 ug/l(2).
[(1) Zoeteman BCJ et al; Sci Total Environ 21: 187-202 (1981) (2) McCreary JJ etal; Chemosphere 12: 1619-32 (1983)]**PEER REVIEWED**

DRINKING WATER: Limonene was listed as a compound identified in U.S. drinking water supplies(1,2). It was qualitatively detected in treated drinking water supplies in the U.K., 1976(3).
[(1) Kopfler FC et al; Adv Environ Sci Technol 8: 419-33 (1977) (2) Kool HJ et al; CRC Crit Rev Env Control 12: 307-57 (1982) (3) Fielding M et al; Organic Micropollutants in Drinking Water TR-159 Medmenham, Eng Water Res Cent 49 pp. (1981)]**PEER REVIEWED**

Effluent Concentrations:

Limonene was detected as a component of landfill gases from sites in the UK at measured concns of 21-84 mg/cu m in probes buried underground and 7.4 mg/cu m at above ground vents(1). It was qualitatively detected in 2 of 46 U.S. industrial effluent samples(2). Limonene was detected in 6 of 7 samples of kraft pulp mill wastewater at concns ranging from 10-220 ppb in 2 Canadian mills monitored in 1973(3). It was qualitatively detected in landfill leachate(4). Limonene was qualitatively identified in the effluent gas from refuse waste obtained from a food center in an experiment designed to determine the gases emitted from decaying waste matter at refuse sites, landfills, and trash transfer sites(5). Limonene has been associated with effluent from the following industries: extraction of pine gum, paper and pulp mills, plastics materials-synthetic resins and non vulcanizable elastomers, perfumes, cosmetics and other toilet preparations, organic solvents and lubricating oils and greases(6).
[(1) Young P, Parker A; pp. 24-41 Hazardous and Industrial Waste Management and Testing 3rd Symp Amer Soc Test Mater (1984) (2) Bursey JT, Pellizzari ED; Analysis of Industrial Wastewater for Organic Pollutants in Consent Degree Survey. Res Triangle Park, NC: USEPA (1982) (3) Wilson D, Hrutfiord B; Pulp and Paper Canada 76: 91-3 (1975) (4) Venkataramani ES, Ahlert RC; J Water Purif Contr Fed 56: 1178-84 (1984) (5) Koe LC, Ng WJ; Water, Air Soil Pollut 33: 199-204 (1987) (6) Abrams EF et al; Identification of Organic Compounds in Effluents from Industrial Sources Washington, DC: USEPA-560/3-75-002 (1975)]**PEER REVIEWED**

Sediment/Soil Concentrations:

Limonene was detected in soil samples at the site of a former pine-tar manufacturer in Gainsville, FL, at concn ranging from not detected to 920 ug/g(1).
{(1) McCreary JJ et al; Chemosphere 12: 1619-32 (1983)]**PEER REVIEWED**

Atmospheric Concentrations:

URBAN/SUBURBAN: Limonene was detected in 97% of 17 indoor air samples taken at residences in Ruston, WA, 1985-6, at a concn ranging 1.6-78 ug/cu m (mean and median 18 ug/cu m and 11 ug/cu m, respectively), outdoor concns were typically 12 times lower(1). It was detected in 37 indoor and 12 outdoor samples from 36 houses (50 total measurements) in the Chicago area, concn not provided, indoor/outdoor ratio 3.1(2). The concn of limonene in the air above Moscow Mountain, ID, 1976-1977, ranged from <10 ppt to 50 ppt(3). The mean and maximum concn of limonene in 40 homes in Oak Ridge/Knoxville, TN, 1982-3, was 16 ug/cu m and 77.5 ug/cu m, respectively(4). The concn of limonene in Houston, TX, ranged from not detected to 5.7 ppb(5). Limonene was detected indoors in an office building, 1987, at a concn ranging 43-63 ug/cu m(6). It was listed as a compound typically identified in both indoor and outdoor air(7).
[(1) Montgomery DD; Kalman DA; Appl Ind Hyg 4: 17-20 (1989) (2) Jarke FH et al; Ashrae Trans 87: 153-6 (1981) (3) Holdren MW et al; J Geophys Res 84: 5083-8 (1979) (4) Hawthorne AR et al; pp. 574-26 in Spec Meas Monit Non-Criter Contam. Frederick, ER ed. Pittsburgh, PA: APCA (1983) (5) Bertsch W et al; J Chromatog Sci 12: 175-82 (1974) (6) Weschler CJ et al; Am Ind Hyg Assoc J 51: 261-8 (1990) (7) Harrison RM et al; Environ Tech Lett 9: 521-30 (1988)]**PEER REVIEWED**

URBAN/SUBURBAN: Limonene was qualitatively detected in the air of Leningrad, 1976, and 5 other Russian cities(1,2). It was detected in suburban air samples in Germany, 1985, at concns ranging from not detected-2.0 ng/cu m(3,4). Limonene was qualitatively detected in air samples taken at 2 Stockholm preschools, 1981-2(5). Limonene was detected in indoor and outdoor air in Northern Italy, 1983-8, at mean concns of 140 ug/cu m and 2 ug/cu m, respectively(6).
[(1) Ioffe BV et al; J Chromatog 142: 787-95 (1977) (2) Ioffe BV et al; Environ Sci Technol 13: 864-9 (1979) (3) Juttner F; Chemosphere 17: 309-17 (1988) (4) Juttner F; Chemosphere 15: 985-92 (1986) (5) Noma E et al; Atmos Environ 22: 451-60 (1988) (6) DeBortoli M et al; Environ Int 12: 343-50 (1986)]**PEER REVIEWED**

RURAL/REMOTE: The concn of limonene in the air over a forest in Soviet Georgia, July, 1979, ranged from 0.004 ug/cu m to 0.010 ug/cu m in 8 samples(1). The concn of limonene 1.7 m above a maple forest in Quebec ranged from approximately 100-1750 parts per trillion over a two day period in June, 1989(2). Limonene was detected in forest air samples in southern black forest region, Germany, 1985, at concns ranging from 1.0-89 ng/cu m(3,4). Traces of limonene were found in the air over the Landes Forest, France, 1984, which consists mainly of maritime pines(5).
[(1) Shaw RWJR et al; Environ Sci Tech 17: 389-95 (1983) (2) Clement B et al; Atmos Environ 24A: 2513-6 (1990) (3) Juttner F; Chemosphere 17: 309-17 (1988) (4) Juttner F; Chemosphere 15: 985-92 (1986) (5) Riba ML et al; Atmos Environ 21: 191-3 (1987)]**PEER REVIEWED**

Food Survey Values:

Limonene has been identified as a volatile component of fried chicken(1), chickpea seed(2), orange juice essence(3), mangos(4), roasted filberts(5), Beaufort (Gruyere) cheese(6) and baked potatoes(7). It has been detected in a headspace analysis of intact, tree ripened nectarines, but not in an analysis of the blended fruit(8).
[(1) Tang J et al; J Agric Food Chem 31: 1287-92 (1983) (2) Rembold H et al; J Agric Food Chem 37: 659-62 (1989) (3) Moshonas MG, Shaw PE; J Agric Food Chem 38: 2181-4 (1990) (4) MacLeod AJ, Snyder CH; J Agric Food Chem 36: 137-9 (1988) (5) Kinlin TE et al; J Agr Food Chem 20: 1021-8 (1972) (6) Dumont JP, Adda J; J Agr Food Chem 26: 364-7 (1978) (7) Coleman EC et al; J Agric Food Chem 29: 42-8 (1981) (8) Takeoka GR et al; J Agric Food Chem 36: 553-60 (1988)]**PEER REVIEWED**

Plant Concentrations:

Limonene was identified as a volatile constituent of Kiwi fruit flowers(1).
[(1) Tatsuka K et al; J Agric Food Chem 38: 2176-80 (1990)]**PEER REVIEWED**

Milk Concentrations:

Limonene was qualitatively detected in 8 of 8 samples of mother's milk obtained from residents of urban centers in PA, NJ, and LA(1).
[(1) Pellizzari ED et al; Bull Environ Contam Toxicol 28: 322-8 (1982)]**PEER REVIEWED**

Environmental Standards & Regulations:

FDA Requirements:

Synthetic flavoring substances and adjuvants that are generally recognized as safe (GRAS) for their intended use include limonene.
[21 CFR 182.60 (4/1/91)]**PEER REVIEWED**

Chemical/Physical Properties:

Molecular Formula:

C10-H16
**PEER REVIEWED**

Molecular Weight:

136.23
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 865]**PEER REVIEWED**

Color/Form:

COLORLESS MOBILE LIQUID
[Opdyke, D.L.J. (ed.). Monographs on Fragrance Raw Materials. New York: Pergamon Press, 1979. 333]**PEER REVIEWED**

Odor:

PLEASANT, LEMON-LIKE ODOR FREE FROM CAMPHORACEOUS & TURPENTINE-LIKE NOTES
[Fenaroli's Handbook of Flavor Ingredients. Volume 2. Edited, translated, and revised by T.E. Furia and N. Bellanca. 2nd ed. Cleveland: The Chemical Rubber Co., 1975. 319]**PEER REVIEWED**

CITRUS ODOR
[Furia, T.E. (ed.). CRC Handbook of Food Additives. 2nd ed. Volume 2. Boca Raton, Florida: CRC Press, Inc., 1980. 283]**PEER REVIEWED**

Taste:

SWEET, CITRUS TASTE
[Furia, T.E. (ed.). CRC Handbook of Food Additives. 2nd ed. Volume 2. Boca Raton, Florida: CRC Press, Inc., 1980. 283]**PEER REVIEWED**

Boiling Point:

175.5-176.5 DEG C @ 763 MM HG
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 865]**PEER REVIEWED**

Melting Point:

-95.5 DEG C
[Lide, D.R. (ed.). CRC Handbook of Chemistry and Physics. 73rd ed. Boca Raton, FL: CRC Press Inc., 1992-1993.,p. 3-308]**PEER REVIEWED**

Density/Specific Gravity:

0.8402 @ 20.85 DEG C/4 DEG C
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 865]**PEER REVIEWED**

Heat of Combustion:

-19,520 Btu/lb = -10,840 cal/g = -454x10+5 J/kg
[U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.]**PEER REVIEWED**

Heat of Vaporization:

140 Btu/lb = 77 cal/g = 3.2x10+5 J/kg
[U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.]**PEER REVIEWED**

Octanol/Water Partition Coefficient:

log Kow= 4.232 (est)
[SRC; GEMS; Graphic Exposure Modeling System CLOGP USEPA (1987)]**PEER REVIEWED**

Solubilities:

MISCIBLE WITH ALCOHOL
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 865]**PEER REVIEWED**

Miscible in ... ether.
[Sax, N.I. Dangerous Properties of Industrial Materials. 6th ed. New York, NY: Van Nostrand Reinhold, 1984. 1738]**PEER REVIEWED**

Water solubility: 13.8 mg/l at 25 deg C
[Massaldi HA, King CJ; J Chem Eng Data 18: 393-7 (1973)]**PEER REVIEWED**

Spectral Properties:

INDEX OF REFRACTION: 1.4727 @ 20 DEG C/D; MAX ABSORPTION (ISOOCTANE): 220 NM (LOG E= 2.41); 250 NM (LOG E= 1.36)
[Lide, D.R. (ed.). CRC Handbook of Chemistry and Physics. 73rd ed. Boca Raton, FL: CRC Press Inc., 1992-1993.,p. 3-308]**PEER REVIEWED**

MASS: 318 (National Bureau of Standards EPA-NIH Mass Spectra Data Base, NSRDS-NBS-63)
[Weast, R.C. and M.J. Astle. CRC Handbook of Data on Organic Compounds. Volumes I and II. Boca Raton, FL: CRC Press Inc. 1985.,p. V1 567]**PEER REVIEWED**

Surface Tension:

26 dynes/cm = 0.026 N/m at 20 deg C
[U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.]**PEER REVIEWED**

Vapor Density:

4.7 (AIR= 1)
[National Fire Protection Guide. Fire Protection Guide on Hazardous Materials. 10 th ed. Quincy, MA: National Fire Protection Association, 1991.,p. 325M-45]**PEER REVIEWED**

Vapor Pressure:

20 mm Hg at 68.2 deg C
[(1) Riddick JA et al; Organic Solvents NY: Wiley Interscience (1986)]**PEER REVIEWED**

Other Chemical/Physical Properties:

IS THE OPTICALLY INACTIVE FORM OF LIMONENE
[Fenaroli's Handbook of Flavor Ingredients. Volume 2. Edited, translated, and revised by T.E. Furia and N. Bellanca. 2nd ed. Cleveland: The Chemical Rubber Co., 1975. 319]**PEER REVIEWED**

WT/GAL: 7.15 LB @ 15.5 DEG C
[Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 12th ed. New York, NY: Van Nostrand Rheinhold Co., 1993 427]**PEER REVIEWED**

WITH DRY HYDROGEN CHLORIDE OR HYDROGEN BROMIDE IT FORMS MONOHALIDES, & WITH AQ HYDROGEN CHLORIDE OR HYDROGEN BROMIDE, THE DIHALIDE.
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 865]**PEER REVIEWED**

Henry's Law constant= 0.380 atm cu m/mole at 25 deg C (calc)
[SRC; Hine J, Mookerjee PK; J Org Chem 40: 292-8 (1975)]**PEER REVIEWED**

PEROXIDE VALUE: NOT MORE THAN 2.0
[Fenaroli's Handbook of Flavor Ingredients. Volume 2. Edited, translated, and revised by T.E. Furia and N. Bellanca. 2nd ed. Cleveland: The Chemical Rubber Co., 1975. 319]**PEER REVIEWED**

LIQUID; BP: 175.5-176.5 DEG C @ 763 MM HG; DENSITY: 0.8407 @ 20.5 DEG C/4 DEG C;INDEX OF REFRACTION: 1.474 @ 21 DEG C/D; SPECIFIC OPTICAL ROTATION: -101.3 DEG C @ 19.5 DEG C/D /L-LIMONENE/
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 865]**PEER REVIEWED**

BP: 177-8 DEG C @ 755 MM HG, 64.4 DEG C @ 15 MM HG; DENSITY: 0.8422 @ 20 DEG C/4DEG C; INDEX OF REFRACTION: 1.4746 @ 20 DEG C/D; MAX ABSORPTION (ISOOCTANE): 220 NM (LOG E= 2.4), 250 NM (LOG E= 1.1); SPECIFIC OPTICAL ROTATION: -122.1 DEG @ 20 DEG C/D (UNDILUTED) /L-LIMONENE/
[Lide, D.R. (ed.). CRC Handbook of Chemistry and Physics. 73rd ed. Boca Raton, FL: CRC Press Inc., 1992-1993.,p. 3-308]**PEER REVIEWED**

MP: 95.5 DEG C; BP: 178 DEG C @ 760 MM HG, 64.4 DEG C @ 15 MM HG; DENSITY: 0.8402 @ 21 DEG C/4 DEG C; MAX ABSORPTION (ISOOCTANE): 220 NM (LOG E= 2.41), 250 NM (LOG E= 1.36); INDEX OF REFRACTION: 1.4727 @ 20 DEG C/D /DL-LIMONENE/
[Lide, D.R. (ed.). CRC Handbook of Chemistry and Physics. 73rd ed. Boca Raton, FL: CRC Press Inc., 1992-1993.,p. 3-308]**PEER REVIEWED**

LIQUID; PLEASANT LEMON-LIKE ODOR; PRACTICALLY INSOL IN WATER; MISCIBLE WITH ALCOHOL; BP: 175.5-176.5 DEG C @ 763 MM HG; DENSITY: 0.8402 @ 20.85 DEG C/4 DEG C; INDEX OF REFRACTION: 1.4744; WITH DRY HYDROGEN CHLORIDE OR HYDROGEN BROMIDE IT FORMS MONOHALIDES, & WITH AQ HYDROGEN CHLORIDE OR HYDROGEN BROMIDE, DIHALIDES /DL-LIMONENE/
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 865]**PEER REVIEWED**

IR: 4996 (Coblentz Society Spectral Collection) /DL-Limonene/
[Weast, R.C. and M.J. Astle. CRC Handbook of Data on Organic Compounds. Volumes I and II. Boca Raton, FL: CRC Press Inc. 1985.,p. V1 815]**PEER REVIEWED**

NMR: 400 (Johnson and Jankowski, Carbon-13 NMR Spectra, John Wiley & Sons, New York) /DL-Limonene/
[Weast, R.C. and M.J. Astle. CRC Handbook of Data on Organic Compounds. Volumes I and II. Boca Raton, FL: CRC Press Inc. 1985.,p. V1 815]**PEER REVIEWED**

MASS: 704 (Atlas of Mass Spectral Data, John Wiley & Sons, New York) /DL-Limonene/
[Weast, R.C. and M.J. Astle. CRC Handbook of Data on Organic Compounds. Volumes I and II. Boca Raton, FL: CRC Press Inc. 1985.,p. V1 815]**PEER REVIEWED**

IR: 4996 (Coblentz Society Spectral Collection) /L-Limonene/
[Weast, R.C. and M.J. Astle. CRC Handbook of Data on Organic Compounds. Volumes I and II. Boca Raton, FL: CRC Press Inc. 1985.,p. V1 815]**PEER REVIEWED**

NMR: 400 (Johnson and Jankowski, Carbon-13 NMR Spectra, John Wiley & Sons, New York) /L-Limonene/
[Weast, R.C. and M.J. Astle. CRC Handbook of Data on Organic Compounds. Volumes I and II. Boca Raton, FL: CRC Press Inc. 1985.,p. V1 815]**PEER REVIEWED**

MASS: 704 (Atlas of Mass Spectral Data, John Wiley & Sons, New York) /L-Limonene/
[Weast, R.C. and M.J. Astle. CRC Handbook of Data on Organic Compounds. Volumes I and II. Boca Raton, FL: CRC Press Inc. 1985.,p. V1 815]**PEER REVIEWED**

Chemical Safety & Handling:

DOT Emergency Guidelines:

Fire or explosion: HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Some may polymerize (P) explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water. Substance may be transported hot.
[U.S. Department of Transportation. 1996 North American Emergency Response Guidebook. A Guidebook for First Responders During the Initial Phase of aHazardous Materials/Dangerous Goods Incident. U.S. Department of Transportation (U.S. DOT) Research and Special Programs Administration, Office of HazardousMaterials Initiatives and Training (DHM-50), Washington, D.C. (1996).,p. G-128]**QC REVIEWED**

Health: Inhalation or contact with material may irritate or burn skin and eyes. Fire may produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution.
[U.S. Department of Transportation. 1996 North American Emergency Response Guidebook. A Guidebook for First Responders During the Initial Phase of aHazardous Materials/Dangerous Goods Incident. U.S. Department of Transportation (U.S. DOT) Research and Special Programs Administration, Office of HazardousMaterials Initiatives and Training (DHM-50), Washington, D.C. (1996).,p. G-128]**QC REVIEWED**

Public safety: CALL Emergency Response Telephone Number on Shipping Paper first. If Shipping Paper not available or no answer, refer to appropriate telephone number listed on the inside back cover. Isolate spill or leak area immediately for at least 25 to 50 meters (80 to 160 feet) in all directions. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate closed spaces before entering.
[U.S. Department of Transportation. 1996 North American Emergency Response Guidebook. A Guidebook for First Responders During the Initial Phase of aHazardous Materials/Dangerous Goods Incident. U.S. Department of Transportation (U.S. DOT) Research and Special Programs Administration, Office of HazardousMaterials Initiatives and Training (DHM-50), Washington, D.C. (1996).,p. G-128]**QC REVIEWED**

Protective clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Structural firefighters' protective clothing will only provide limited protection.
[U.S. Department of Transportation. 1996 North American Emergency Response Guidebook. A Guidebook for First Responders During the Initial Phase of aHazardous Materials/Dangerous Goods Incident. U.S. Department of Transportation (U.S. DOT) Research and Special Programs Administration, Office of HazardousMaterials Initiatives and Training (DHM-50), Washington, D.C. (1996).,p. G-128]**QC REVIEWED**

Evacuation: Large spill: Consider initial downwind evacuation for at least 300 meters (1000 feet). Fire: If tank, rail car or tank truck is involved in a fire, isolate for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions.
[U.S. Department of Transportation. 1996 North American Emergency Response Guidebook. A Guidebook for First Responders During the Initial Phase of aHazardous Materials/Dangerous Goods Incident. U.S. Department of Transportation (U.S. DOT) Research and Special Programs Administration, Office of HazardousMaterials Initiatives and Training (DHM-50), Washington, D.C. (1996).,p. G-128]**QC REVIEWED**

Fire: Caution: All these products have a very low flash point: Use of water spray when fighting fire may be inefficient. Small fires: Dry chemical, CO2, water spray or regular foam. Large fires: Water spray, fog or regular foam. Do not use straight streams. Move containers from fire area if you can do it without risk. Fire involving tanks or car/trailer loads: Fight fire from maximum distance or use unmanned hose holders or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. Always stay away from the ends of tanks. For massive fire, use unmanned hose holders or monitor nozzles; if this is impossible, withdraw from area and let fire burn.
[U.S. Department of Transportation. 1996 North American Emergency Response Guidebook. A Guidebook for First Responders During the Initial Phase of aHazardous Materials/Dangerous Goods Incident. U.S. Department of Transportation (U.S. DOT) Research and Special Programs Administration, Office of HazardousMaterials Initiatives and Training (DHM-50), Washington, D.C. (1996).,p. G-128]**QC REVIEWED**

Spill or leak: Eliminate all ignition sources (no smoking, flares, sparks or flames in immediate area). All equipment used when handling the product must be grounded. Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. A vapor suppressing foam may be used to reduce vapors. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. Use clean non-sparking tools to collect absorbed material. Large spills: Dike far ahead of liquid spill for later disposal. Water spray may reduce vapor; but may not prevent ignition in closed spaces.
[U.S. Department of Transportation. 1996 North American Emergency Response Guidebook. A Guidebook for First Responders During the Initial Phase of aHazardous Materials/Dangerous Goods Incident. U.S. Department of Transportation (U.S. DOT) Research and Special Programs Administration, Office of HazardousMaterials Initiatives and Training (DHM-50), Washington, D.C. (1996).,p. G-128]**QC REVIEWED**

First aid: Move victim to fresh air. Call emergency medical care. Apply artificial respiration if victim is not breathing. Administer oxygen if breathing is difficult. Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush skin or eyes with running water for at least 20 minutes. Wash skin with soap and water. Keep victim warm and quiet. Ensure that medical personnel are aware of the material(s) involved, and take precautions to protect themselves.
[U.S. Department of Transportation. 1996 North American Emergency Response Guidebook. A Guidebook for First Responders During the Initial Phase of aHazardous Materials/Dangerous Goods Incident. U.S. Department of Transportation (U.S. DOT) Research and Special Programs Administration, Office of HazardousMaterials Initiatives and Training (DHM-50), Washington, D.C. (1996).,p. G-128]**QC REVIEWED**

Skin, Eye and Respiratory Irritations:

Skin irritant.
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 865]**PEER REVIEWED**

Liquid irritates eyes; ingestion causes irritation of GI tract.
[U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.]**PEER REVIEWED**

NFPA Hazard Classification:

Health: 0. 0= Materials that, on exposure under fire conditions, offer no hazard beyond that of ordinary combustible material.
[National Fire Protection Guide. Fire Protection Guide on Hazardous Materials. 10 th ed. Quincy, MA: National Fire Protection Association, 1991.,p. 325M-45]**PEER REVIEWED**

Flammability: 2. 2= Includes materials that must be moderately heated before ignition will occur and includes Class II and IIIA combustible liquids and solids and semi-solids that readily give off ignitible vapors. Water spray may be used to extinguish fires in these materials because the materials can be cooled below their flash points.
[National Fire Protection Guide. Fire Protection Guide on Hazardous Materials. 10 th ed. Quincy, MA: National Fire Protection Association, 1991.,p. 325M-45]**PEER REVIEWED**

Reactivity: 0. 0= Includes materials that are normally stable, even under fire exposure conditions, and that do not react with water. Normal fire fighting procedures may be used.
[National Fire Protection Guide. Fire Protection Guide on Hazardous Materials. 10 th ed. Quincy, MA: National Fire Protection Association, 1991.,p. 325M-45]**PEER REVIEWED**

Flammable Limits:

UPPER LIMIT: 6.1%; LOWER LIMIT: 0.7% (IN AIR: % BY VOLUME, @ 302 DEG C)
[National Fire Protection Guide. Fire Protection Guide on Hazardous Materials. 10 th ed. Quincy, MA: National Fire Protection Association, 1991.,p. 325M-45]**PEER REVIEWED**

Flash Point:

113 DEG F (45 DEG C) CLOSED CUP
[National Fire Protection Guide. Fire Protection Guide on Hazardous Materials. 10 th ed. Quincy, MA: National Fire Protection Association, 1991.,p. 325M-45]**PEER REVIEWED**

Autoignition Temperature:

458 DEG F
[National Fire Protection Guide. Fire Protection Guide on Hazardous Materials. 10 th ed. Quincy, MA: National Fire Protection Association, 1991.,p. 325M-45]**PEER REVIEWED**

Hazardous Reactivities & Incompatibilities:

The inhibitor monomer will explode if ignited. Liquid tetrafluoroethylene, being collected in an liquid nitrogen-cooled trap open to air, formed a peroxidic polymer which exploded.
[Bretherick, L. Handbook of Reactive Chemical Hazards. 3rd ed. Boston, MA: Butterworths, 1985. 213]**PEER REVIEWED**

... Tetrafluoroethylene gas supply system with iodine pentafluoride caused a violent explosion in the cylinders. Exothermic reaction of the limonene inhibitor with the contaminant present in the gas cylinders may have depleted the inhibitor and initiated explosive polymerization.
[Bretherick, L. Handbook of Reactive Chemical Hazards. 3rd ed. Boston, MA: Butterworths, 1985. 213]**PEER REVIEWED**

Hazardous Decomposition:

When heated to decomp it emits acrid smoke and fumes.
[Sax, N.I. Dangerous Properties of Industrial Materials. 6th ed. New York, NY: Van Nostrand Reinhold, 1984. 1738]**PEER REVIEWED**

Preventive Measures:

SRP: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.
**PEER REVIEWED**

Shipment Methods and Regulations:

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./
[49 CFR 171.2 (7/1/96)]**QC REVIEWED**

The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials.
[IATA. Dangerous Goods Regulations. 38th ed. Montreal, Canada and Geneva, Switzerland: International Air Transport Association, Dangerous Goods Board, January, 1997. 142]**QC REVIEWED**

The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article.
[IMDG; International Maritime Dangerous Goods Code; International Maritime Organization p.3133 (1988)]**QC REVIEWED**

Occupational Exposure Standards:

Other Occupational Permissible Levels:

Workplace Environmental Exposure Level (WEEL): 8-hr Time-weighted Average (TWA) 30 ppm.
[American Industrial Hygiene Association. The AIHA 1999 Emergency Response Planning Guidelines and Workplace Environmental Exposure Level Guides Handbook.American Industrial Hygiene Association. Fairfax, VA 1999. 40]**QC REVIEWED**

Manufacturing/Use Information:

Major Uses:

PAINT BRUSH CLEANSER & PRESERVATIVE.
[Arena, J.M. Poisoning: Toxicology-Symptoms Treatments. Third Edition. Springfield, Illinois: Charles C. Thomas, 1974. 81]**PEER REVIEWED**

MONOMER IN TERPENE RESINS; SOLVENT FOR OLEORESINOUS PRODUCTS; GENERAL WETTING AND DISPERSING AGENT; CHEMICAL INTERMEDIATE FOR VARIOUS ORGANIC COMPOUNDS; FLAVOR INGREDIENT (ORANGE-LIKE).
[SRI]**PEER REVIEWED**

d-Limonene is used to synthesize l-carvone. /D-Limonene/
[Royals EE, Horne SE; J Am Chem Soc 73: 5856-7 (1951)]**PEER REVIEWED**

Limonene ... has been utilized to produce carvacrol.
[Sattar A et al; Pakistan J Sci Ind Res 23(5):177-9 (1980)]**PEER REVIEWED**

Gallstone solubilizer
[Shepard, T.H. Catalog of Teratogenic Agents. 5th ed. Baltimore, MD: The Johns Hopkins University Press, 1986. 342]**PEER REVIEWED**

Manufacturers:

International Paper Co, Hq, Subsidiary: Arizona Chemical Co, 1001 E Business Highway 98, Panama City, FL 32401, (904) 785-6700; Production sites: Panama City, FL 32402; Pensacola, FL 32596
[SRI. 1992 Directory of Chemical Producers-United States of America. Menlo Park, CA: SRI International, 1992. 657]**PEER REVIEWED**

Tecnal Ltd Partnership, Hq, 708 North Texas Rd, Anacortes, WA 98221, (206) 293-3200; Production site: Anacortes, Wa 98221
[SRI. 1992 Directory of Chemical Producers-United States of America. Menlo Park, CA: SRI International, 1992. 657]**PEER REVIEWED**

Union Camp Corp, Hq, 1600 Valley Rd, Wayne, NJ 07470, (201) 628-2000; Terpene Division; Production site: Jacksonville, FL 32236
[SRI. 1992 Directory of Chemical Producers-United States of America. Menlo Park, CA: SRI International, 1992. 657]**PEER REVIEWED**

SMC Corp, Glidco Organics, PO Box 389, Jacksonville, FL 32201, (904) 768-5800
[United States International Trade Commission. Synthetic Organic Chemicals-United States Production and Sales, 1991. USITC Publication 2607, February 1993.Washington, DC: United States Trade Commission, 1993.,p. 7-4]**PEER REVIEWED**

Methods of Manufacturing:

EXTRACTION FROM SOUTHEASTERN PINE STUMPS, AND CITRUS FRUITS (ESPECIALLY FROM THE PEELS OF ORANGES AND LEMONS); FROM PYROLYSIS OF ALPHA-PINENE
[SRI]**PEER REVIEWED**

ISOLATION OF D-LIMONENE FROM MANDARIN PEEL OIL (CITRUS RETICULATA BLANCO, RUTACEAE).
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 865]**PEER REVIEWED**

AS A BY-PRODUCT IN THE MANUFACTURE OF TERPINEOL AND IN VARIOUS SYNTHETIC PRODUCTS MADE FROM ALPHA-PINENE OR TURPENTINE OIL.
[Opdyke, D.L.J. (ed.). Monographs on Fragrance Raw Materials. New York: Pergamon Press, 1979. 333]**PEER REVIEWED**

General Manufacturing Information:

CONCN IN FINAL PRODUCT (%): AS USUAL TO MAXIMUM RANGE IS 0.05-0.75 IN SOAP; 0.05-0.075 IN DETERGENT; 0.5-2.0 IN PERFUME AND 0.25 MAXIMUM IN CREAMS & LOTIONS. /FROM TABLE/
[Opdyke, D.L.J. (ed.). Monographs on Fragrance Raw Materials. New York: Pergamon Press, 1979. 333]**PEER REVIEWED**

FEMA NUMBER 2633 (DL-FORM); NON-ALCOHOLIC BEVERAGES 31 PPM; ICE CREAM, ICES, ETC 68 PPM; CANDY 49 PPM; BAKED GOODS 120 PPM; GELATINS & PUDDINGS 48-400 PPM; CHEWING GUM 2,300 PPM.
[Fenaroli's Handbook of Flavor Ingredients. Volume 2. Edited, translated, and revised by T.E. Furia and N. Bellanca. 2nd ed. Cleveland: The Chemical Rubber Co., 1975. 319]**PEER REVIEWED**

USE IN FRAGRANCES IN THE USA AMOUNTS TO LESS THAN 1000 LB/YR.
[Opdyke, D.L.J. (ed.). Monographs on Fragrance Raw Materials. New York: Pergamon Press, 1979. 333]**PEER REVIEWED**

DIPENTENE (DL-LIMONENE) WAS GRANTED GRAS STATUS BY FLAVOR AND EMOLLIENT MANUFACTURING ASSOCIATION (1965) ... . THE COUNCIL OF EUROPE (1970) INCLUDED DIPENTENE (DL-LIMONENE) IN THE LIST OF ADMISSIBLE ARTIFICIAL FLAVORING SUBSTANCES, WITH A TECHNOLOGICAL LIMIT EXCEPT FOR CHEWING GUM. /DL-LIMONENE/
[Opdyke, D.L.J. (ed.). Monographs on Fragrance Raw Materials. New York: Pergamon Press, 1979. 333]**PEER REVIEWED**

WIDELY DISTRIBUTED OPTICALLY ACTIVE TERPENE, CLOSELY RELATED TO ISOPRENE. IT OCCURS NATURALLY IN BOTH D- & L-FORMS. RACEMIC MIXTURE OF 2 ISOMERS IS KNOWN AS DIPENTENE.
[Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 12th ed. New York, NY: Van Nostrand Rheinhold Co., 1993 700]**PEER REVIEWED**

FLAVORS USEFUL IN: CITRUS FLAVOR, ARTIFICIAL ESSENTIAL OILS /FROM TABLE/
[Furia, T.E. (ed.). CRC Handbook of Food Additives. 2nd ed. Volume 2. Boca Raton, Florida: CRC Press, Inc., 1980. 283]**PEER REVIEWED**

ONE OF THE TERPENE HYDROCARBONS FOUND IN TURPENTINE.
[Gosselin, R.E., R.P. Smith, H.C. Hodge. Clinical Toxicology of Commercial Products. 5th ed. Baltimore: Williams and Wilkins, 1984.,p. II-259]**PEER REVIEWED**

Formulations/Preparations:

GRADES: STEAM-DISTILLED; DESTRUCTIVELY DISTILLED.
[Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 12th ed. New York, NY: Van Nostrand Rheinhold Co., 1993 427]**PEER REVIEWED**

Laboratory Methods:

Analytic Laboratory Methods:

The analyte can be GC as determined by Athens-ERL or S-Cubed.
[USEPA/SCC; Environmental Monitoring Methods Index p.59 (1992)]**PEER REVIEWED**

Some citrus essential oils were analyzed by HPLC with both microbore and std columns in reversed and normal phase. Volatile and non-volatile fraction were investigated. In the non-volatile fraction some coumarins were identified. Fractions are detected spectrophotometrically at 220 and 320 nm before and after evap of samples.
[Benincasa M et al; Chromatographia 30 (5-6): 271-6 (1990)]**PEER REVIEWED**

Graphpac was investigated to see if carbon was a better GC support than silica for columns of 3% of the liq crystal bismethoxybenzylidenebitoluidine or (MBT)2. Six volatile oil component solutes exhibited the same elution sequence as from silica, but with lower relative retention times with respect to linalool - about 50% for some aroms., reflecting the much lower polarity of the carbon-supported packing indicated by cuminal/caryophyllene ratio. Caryophyllene had greatly increased relative retention, and this was further raised if a low-loading of 0.3% (MBT)2 was used on Graphpac, indicating even lower polarity. This column was not reliable below 200 deg C, but an initial period at 203 deg C, followed by rapid heating to 230 deg C, gave reasonable results for some significant constituents of teatree oil. Nevertheless, 3% (MBT)2 on Graphpac was preferable for assaying this and sweet fennel oil by providing a more reliable melted liq crystal stationary phase, with low temp versatility.
[Betts TJ; J Chromatogr 641 (1): 189-93 (1993)]**PEER REVIEWED**

Volatile org determination of indoor air tobacco smoke by multisorbent thermal desorption/GC/mass selective detection in relation to tracers ethenylpyridine, as indicator of environmental tobacco smoke.
[Heavner DL et al; Environ Sci Technol 26 (9): 1737-46 (1992)]**PEER REVIEWED**

Sampling Procedures:

Air analysis Volatile org cmpd detn in indoor air from tobacco smoke by using multisorbent thermal desorption/GC/mass selective detection.
[Heavner DL et al; Environ Sci Technol 26 (9): 1737-46 (1992)]**PEER REVIEWED**

Special References:

Synonyms and Identifiers:

Synonyms:

ACINTENE DP DIPENTENE
**PEER REVIEWED**

CAJEPUTEN
**PEER REVIEWED**

CAJEPUTENE
**PEER REVIEWED**

CINEN
**PEER REVIEWED**

CINENE
**PEER REVIEWED**

CYCLOHEXENE, 1-METHYL-4-(1-METHYLETHENYL)-
**PEER REVIEWED**

DIPENTEN
**PEER REVIEWED**

DIPENTENE
**PEER REVIEWED**

DIPENTENE 200
**PEER REVIEWED**

EULIMEN
**PEER REVIEWED**

INACTIVE LIMONENE
**PEER REVIEWED**

4-ISOPROPENYL-1-METHYL-1-CYCLOHEXENE
**PEER REVIEWED**

KAUTSCHIN
**PEER REVIEWED**

LIMONEN
**PEER REVIEWED**

ALPHA-LIMONENE
**PEER REVIEWED**

P-MENTHA-1,8-DIENE, DL-
**PEER REVIEWED**

P-MENTHA-1,8-DIENE
**PEER REVIEWED**

1,8(9)-P-MENTHADIENE
**PEER REVIEWED**

1-METHYL-4-ISOPROPENYL-1-CYCLOHEXENE
**PEER REVIEWED**

1-METHYL-4-(1-METHYLETHENYL)CYCLOHEXENE
**PEER REVIEWED**

NESOL
**PEER REVIEWED**

DELTA-1,8-TERPODIENE
**PEER REVIEWED**

Associated Chemicals:

(DL)-Limonene;7705-14-8
(L)-Limonene;5989-54-8

Formulations/Preparations:

GRADES: STEAM-DISTILLED; DESTRUCTIVELY DISTILLED.
[Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 12th ed. New York, NY: Van Nostrand Rheinhold Co., 1993 427]**PEER REVIEWED**

Shipping Name/ Number DOT/UN/NA/IMO:

UN 2052; Dipentene
IMO 3.3; Dipentene

RTECS Number:

NIOSH/OS8100000

Administrative Information:

Hazardous Substances Databank Number: 1809
Last Revision Date: 20010809
Last Review Date: Reviewed by SRP on 3/2/1994
Update History:

Complete Update on 08/09/2001, 1 field added/edited/deleted.
Complete Update on 02/02/2000, 1 field added/edited/deleted.
Complete Update on 09/21/1999, 1 field added/edited/deleted.
Complete Update on 08/26/1999, 1 field added/edited/deleted.
Complete Update on 05/11/1999, 1 field added/edited/deleted.
Complete Update on 06/02/1998, 1 field added/edited/deleted.
Complete Update on 04/08/1998, 2 fields added/edited/deleted.
Complete Update on 02/27/1998, 1 field added/edited/deleted.
Complete Update on 10/23/1997, 1 field added/edited/deleted.
Complete Update on 05/08/1997, 1 field added/edited/deleted.
Complete Update on 04/23/1997, 2 fields added/edited/deleted.
Complete Update on 01/21/1996, 1 field added/edited/deleted.
Complete Update on 12/28/1994, 1 field added/edited/deleted.
Complete Update on 05/18/1994, 69 fields added/edited/deleted.
Field Update on 03/21/1994, 1 field added/edited/deleted.
Field update on 12/22/1992, 1 field added/edited/deleted.
Complete Update on 10/05/1990, 4 fields added/edited/deleted.
Field Update on 11/27/1989, 1 field added/edited/deleted.
Field Update on 11/27/1989, 1 field added/edited/deleted.
Complete Update on 04/13/1989, 1 field added/edited/deleted.
Complete Update on 10/14/1986

Record Length: 100584