2,4-Dimethylphenol in freshwater and marine water

​​​​Toxicant default guideline values for protecting aquatic ecosystems

October 2000

Extracted from Section 8.3.7 ‘Detailed descriptions of chemicals’ ​of the ANZECC & ARMCANZ (2000) guidelines.

The default guideline values (previously known as ‘trigger values’) and associated information in this technical brief should be used in accordance with the detailed guidance provided in the Australian and New Zealand Guidelines for Fresh and Marine Water Quality.

Description of chemical

2,4-dimethylphenol (2,3-xylenol) (CAS 105-67-9) is a naturally occurring substituted phenol derived from fractions of petroleum and coal tar distillation (USEPA 1980p). The available data for freshwater aquatic life indicate that acute toxicity occurs at concentrations as low as 2120 µg/L (USEPA 1986). No data were available concerning the chronic toxicity of 2,4-dimethylphenol to sensitive freshwater animals.

Aquatic toxicology

Freshwater fish: two species, 96-hour LC50 7800 to 17,000 µg/L.

Freshwater crustacean: one species, 48-hour EC50, 2100 to 2370 µg/L.

Freshwater protozoans: one species, 60-hour IC50 (population growth), 130,510 µg/L.

No toxicity data were available for saltwater species (USEPA 1986).


A low reliability freshwater trigger value of 2 µg/L was derived for 2,4-dimethylphenol using an assessment factor (AF) of 1000. In the absence of marine data a marine low reliability trigger value of 2 µg/L was adopted from the freshwater figure. Both figures should be used as indicative interim working levels only.


ANZECC & ARMCANZ 2000. Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand, Canberra.

USEPA 1980p. Ambient water quality criteria for 2,4-dimethylphenol. Criteria and Standards Division, US Environmental Protection Agency, Washington DC.

USEPA 1986. Quality criteria for water. US Department of Commerce, National Technical Information Service, US Environmental Protection Agency, Springfield, Virginia. PB87-226759, EPA 440/5 86-001.