2,4-Dinitrophenol 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.


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

2,4-Dinitrophenol (2,4-DNP) (CAS 51-28-5)

Aquatic toxicology

Freshwater fish: nine species, 48 to 96-hour LC50, 60 to 27 100 µg/L. Chronic NOEC, two species: (growth) 500 to 1300 µg/L and (mortality) 3050 µg/L. The lowest figure for Notopterus notopterus appeared anomalous and the geometric mean was 1170 µg/L. The lowest mean for this species was 550 µg/L.

Freshwater crustaceans: two species, 48 to 96-hour LC50 or EC50 immobilisation geometric means of 3800 to 4600 µg/L. A 21-day NOEC (reproduction) of 2000 µg/L for Daphnia magna.

Freshwater mollusc: one species, 96-hour LC50, 6490 µg/L.

Freshwater algae: one species, 48-hour EC50 (biomass), 26,000 µg/L.

Marine fish: three species, 48 to 96-hour LC50, 1500-41,700 µg/L.

Marine crustaceans: Artemia salina, 48-hour LC50, 200 µg/L; Palaeomonetes sp. 96-hour LC50, 23,000 to 50,000 µg/L.


A freshwater moderate reliability trigger value of 45 µg/L was derived for 2,4-DNP by the statistical distribution method (95% protection) and the default acute-to-chronic ratio (ACR). The limited marine data appeared to be within a similar range of sensitivity and the freshwater figure of 45 µg/L was adopted as a marine low reliability trigger value to be used only as an indicative interim working level.


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.

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.