Hexachlorocyclopentadiene 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

Hexachlorocyclopentadiene (CAS 77-47-4) is a chemical intermediate used in the production of organochlorine pesticides (e.g. aldrin, chlordane, heptachlor, endrin, endosulfan) and in fire-retardant substances (CCREM 1987). It can enter the environment from industrial discharges and emissions from pesticides. Since hexachlorocyclopentadiene is highly photoreactive, photolysis is expected to be the primary removal mechanism in the aquatic environment; however, sorption and bioaccumulation may also play a significant role (CCREM 1987).

According to USEPA (1986), acute and chronic toxicity to freshwater aquatic life occurred at concentrations as low as 7.0 µg/L and 5.2 µg/L respectively. A 21-day no observed effect concentration (NOEC) figure of 9 µg/L for Daphnia magna could be assessed and 48-hour EC50 for algae Scenedesmus subspicatus was 80 and 240 µg/L (biomass and growth). A bioconcentration factor of less than 11 was reported for freshwater fish (Spehar et al. 1979). USEPA (1986) reported acute toxicity to saltwater aquatic life at 7.0 µg/L but no data could be assessed.


A low reliability trigger value for hexachlorocyclopentadiene of 0.05 µg/L was derived for use in both freshwater and marine water using an assessment factor (AF) of 200 on the lowest of a limited set of chronic data. This should 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.

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

Spehar RL, Veith GD, DeFoe DL & Bergstedt BV 1979. Toxicity and bioaccumulation of hexachlorocyclopentadiene, hexachloronorbornadiene and heptachloronorbonene in larval and early juvenile fathead minnow Pimephales promelas. Bulletin of Environmental Contamination and Toxicology 21, 576-583.

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.