4-Nitrophenol in freshwater and marine water

​​Toxicant default guideline values for protecting aquatic ecosystems

October 2000

Nitrophenols

Nitrophenols, as mono, di and tri-nitro derivatives of phenol, are used as dyes, pigments, pharmaceuticals, chemical intermediates, explosives and fungicides. Their major routes of entry to the aquatic environment are through the industrial effluents of production plants and chemical firms where these compounds are used as intermediates (CCREM 1987). Microbial degradation or photodegradation of compounds containing some form of nitrophenol may also release nitrophenols to the environment (USEPA 1980c).

Little information is available on the fate of nitrophenols in the aquatic environment. The few studies available on their biodegradation by natural communities of microorganisms indicate that nitrophenols appear to be more resistant to degradation than other phenols (CCREM 1987). Nitrophenols have low octanol-water partition coefficients and, therefore, bioaccumulation in most aquatic organisms is not expected to be significant (ANZECC 1992). The current analytical practical quantitation limit (PQL) for 2,4-dinitrophenol is 10 µg/L (NSW EPA 2000).

The five nitrophenols for which acute toxicity data in freshwater were available are 2,4-dinitro-6-methylphenol, 2,4-dinitrophenol, 4-nitrophenol, 2,4,6-trinitrophenol and 2-nitrophenol (listed in decreasing order of toxicity). Acute LC50s ranged upwards from 230 µg/L for bluegill exposed to 2,4-dinitro-6-methylphenol (USEPA 1980c, 1986).

The available acute toxicity data for saltwater species concerning 4-nitrophenol, 2,4-dinitrophenol and 2,4,6-trinitrophenol indicate that toxicity occurs at concentrations as low as 2100 µg/L (USEPA 1980c, 1986). No data were available regarding chronic toxicity to freshwater and saltwater aquatic organisms (USEPA 1986).

Description of chemical

4-nitrophenol (CAS 100-02-7)

Aquatic toxicology

Freshwater fish: nine species, 48 to 96-hour LC50, 1100 to 62,000 µg/L. Aplocheilus latipes and Oncorhynchus mykiss were most sensitive and Pimephales promelas least. Anomalous single figure for O. mykiss of 78,900 µg/L. Chronic NOEC for O. mykiss: growth (14 to 85 days) of 1160 to 6705 µg/L; mortality (7 to 85 days) of 2200 to 8750 µg/L.

Freshwater crustaceans: two species, 48 to 96-hour EC50 (immobilisation) or LC50, 2800 to 20,000 µg/L. An anomalous figure of 42,500 µg/L was reported for D. magna along with lower figures from the same study (AQUIRE 1994). A 21-day chronic NOEC (reproduction) for Daphnia magna was 1300 µg/L.
Freshwater algae: two species, 48 to 96-hour EC50, 26,000 to 32,000 µg/L.

Marine fish: three species, 96-hour LC50, 21,650 to 31,300 µg/L. Chronic NOEC figures for Cyprinodon variegatus (7 to 28 days) of 2700 to 10,600 for growth, and 2700 to 21,200 µg/L for mortality.

Marine crustaceans: two species, 48 to 96-hour LC50, 2400 to 18,300 µg/L.

Guideline

A freshwater low reliability trigger value of 58 µg/L was derived for 4-nitrophenol by applying an assessment factor (AF) of 20 to the lowest chronic figure (1160 µg/L). Lack of algal data prevented calculation of a marine guideline, so the freshwater figure of 58 µg/L was adopted as a marine low reliability trigger value. These figures should only be used as indicative interim working levels.

References

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.

ANZECC 1992. Water quality guidelines for fresh and marine waters. Australian and New Zealand Environment and Conservation Council, Australian Government Publishing Service, Canberra.

AQUIRE (Aquatic Toxicity Information Retrieval Database) 1994. AQUIRE standard operating procedures. USEPA, Washington, DC.

CCREM 1987. Canadian water quality guidelines. Canadian Council of Resource and Environment Ministers, Ontario.

NSW EPA 2000. Analytical Chemistry Section, Table of Trigger Values 20 March 2000, LD33/11, Lidcombe, NSW.

USEPA 1980c. Ambient water quality criteria for nitrophenols. Criteria and Standards Division, US Environmental Protection Agency, Washington DC. EPA-440/5-80-063.

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.