2,4,5Trichlorophenol [factsheet]

2,4,5-TRICHLOROPHENOL

Please Note: The main sources of information for this fact sheet are EPA's Integrated Risk Information System (IRIS), which contains information on oral chronic toxicity of 2,4,5-trichlorophenol and the RfD, and EPA's Health and Environmental Effects Document for Chlorinated Phenols. Other secondary sources include the Hazardous Substances Data Bank (HSDB), a database of summaries of peer-reviewed literature, and the Registry of Toxic Effects of Chemical Substances (RTECS), a database of toxic effects that are not peer reviewed.

Environmental/Occupational Exposure

* The most probable routes of human exposure to 2,4,5-trichlorophenol are inhalation and dermal contact of workers involved in the manufacture, formulation, or application of pesticides containing this compound. (1)

* 2,4,5-Trichlorophenol may be released through its production and use as a pesticide and pesticide intermediate. (2)

* 2,4,5-Trichlorophenol may also be released in emissions from incinerators to the ambient air. It has also been detected in drinking water. The general population may be exposed to low levels of 2,4,5-trichlorophenol through air, food, or drinking water. (1,2)

Assessing Personal Exposure

* No information was located regarding the measurement of personal exposure to 2,4,5-trichlorophenol.

Health Hazard Information

Acute Effects:

* Acute (short-term) dermal exposure to 2,4,5-trichlorophenol may burn the skin and produce redness and edema in humans. It also irritates the eyes, nose, pharynx, and lungs in humans. (1)

* Tests involving acute exposure of animals, such as the LD₅₀ test in rats, mice, and guinea pigs, have demonstrated 2,4,5-trichlorophenol to have moderate acute toxicity by oral exposure. (3)

Chronic Effects (Noncancer):

* No information is available on the chronic (long-term) effects of 2,4,5-trichlorophenol in humans.

* In one study, slight degenerative changes were observed in the liver and kidneys of rats chronically exposed to 2,4,5-trichlorophenol in their diet. (2,4,5)

* EPA has not established an RfC for 2,4,5-trichlorophenol. (5)

* The RfD for 2,4,5-trichlorophenol is 0.1 mg/kg/d based on liver and kidney pathology in rats. (5)

* EPA has medium confidence in the study on which the RfD was based because, while five dose groups were tested and several parameters were monitored, only a few animals were tested per dose; low confidence in the database because little supporting data exist; and, consequently, low confidence in the RfD. (5)

Reproductive/Developmental Effects:

* No information is available on the reproductive or developmental effects of 2,4,5-trichlorophenol in humans.

* In several studies of mice exposed to 2,4,5-trichlorophenol via gavage (experimentally placing the chemical in the stomach), no birth defects were observed. In one study, a reduction in litter size was reported. (1,4)

* No changes in maternal or fetal parameters were noted in rats exposed to 2,4,5-trichlorophenol by injection. (4)

Cancer Risk:

* No information is available on the carcinogenic effects of 2,4,5-trichlorophenol in humans.

* EPA has classified 2,4,5-trichlorophenol as a Group D, not classifiable as to human carcinogenicity due to inadequate human and animal data. (4)

Physical Properties

* The chemical formula for 2,4,5-trichlorophenol is C₆H₃Cl₃O, and it has a molecular weight of 197.45 g/mol. (4)

* 2,4,5-Trichlorophenol occurs as gray flakes or needles that are sparingly soluble in water. (1,2,4)

* 2,4,5-Trichlorophenol has a strong unpleasant phenolic odor; the odor threshold has not been established. (4,6)

* The log octanol/water partition coefficient (log K_ow) of 2,4,5-trichlorophenol is 3.72. (4)

Uses

* 2,4,5-Trichlorophenol is used as a fungicide in paper and pulp mills, as an herbicide, and as an intermediate in the manufacture of other pesticides. (1,2,6)

Health Data from Oral Exposure

Concentration (mg/kg/d)	Health numbers^a	Regulatory, advisory numbers^b	Reference
10,000.0
_ _ _ _ 1,000.0	* LD₅₀ (guinea pigs) (1,000 mg/kg)		3
_ _ _ _ 100.0	* LD₅₀ (rats) (820 mg/kg) * LD₅₀ (mice) (600 mg/kg) * LOAEL^c (rats) (300 mg/kg/d) * NOAEL^c (rats) (100 mg/kg/d)		3 3 5 5
_ _ _ _ 10.0
_ _ _ _ 1.0
_ _ _ _ 0.1	* RfD (0.1 mg/kg/d)		5

LD₅₀ (Lethal Dose₅₀)CA calculated dose of a chemical in water to which exposure for a specific length of time is expected to cause death in 50% of a defined experimental animal population.

LOAELCLowest-observed-adverse-effect level.

NOAELCNo-observed-adverse-effect level.

RfDCReference dose.

^a Health numbers are toxicological numbers from animal testing or risk assessment values developed by EPA.

^b Regulatory numbers are values that have been incorporated in Government regulations, while advisory numbers are nonregulatory values provided by the Government or other groups as advice.

^c The LOAEL and NOAEL are from the critical study used as the basis for the EPA RfD.

References

1. U.S. Department of Health and Human Services. Hazardous Substances Data Bank (HSDB, online database). National Toxicology Information Program, National Library of Medicine, Bethesda, MD. 1993.

2. International Agency for Research on Cancer (IARC). IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans: Some Halogenated Hydrocarbons. Volume 20. World Health Organization, Lyon. 1979.

3. U.S. Department of Health and Human Services. Registry of Toxic Effects of Chemical Substances (RTECS, online database). National Toxicology Information Program, National Library of Medicine, Bethesda, MD. 1993.

4. U.S. Environmental Protection Agency. Health and Environmental Effects Document for Chlorinated Phenols (Final Draft). ECAO-CIN-G013. Environmental Criteria and Assessment Office, Office of Health and Environmental Assessment, Office of Research and Development, Cincinnati, OH. 1987.

5. U.S. Environmental Protection Agency. Integrated Risk Information System (IRIS) on 2,4,5-Trichlorophenol. Environmental Criteria and Assessment Office, Office of Health and Environmental Assessment, Office of Research and Development, Cincinnati, OH. 1993.

6. The Merck Index. An Encyclopedia of Chemicals, Drugs, and Biologicals. 11th ed. Ed. S. Budavari. Merck and Co. Inc., Rahway, NJ. 1989.