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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Description of key information

The 48-hour EC50 for Daphnia magna was 1.64 mg/L Dowfax 2A1 (based on active ingredient).  

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
1.64 mg/L

Additional information

Three acute toxicity tests with invertebrates were assessed for this endpoint. Two acute toxicity tests with Dowfax 2A1 were conducted with Daphnia magna, and one acute toxicity test was conducted with Ceriodaphnia dubia. Only one of the studies conducted with Daphnia magna were considered reliable. The Dow Chemical Company study conducted with Daphnia magna in 1978 contained very little experimental detail, and therefore the reliability of the study could not be ascertained (Klimish score = 4). The other acute toxicity test with Daphnia magna conducted by the Dow Chemical Company in 1988 was rated as reliable (Klimish score = 2). In this study, the 48-hour LC50 value for D. magna was reported as 1.64 mg/L (based on active ingredient of Dowfax 2EP, a.k.a Dowfax 2A1). Additionally, an acute toxicity endpoint for Dowfax 2EP (a.k.a. Dowfax 2A1) was included in a 7-day chronic study with Ceriodaphnia dubia conducted by The Dow Chemical Company in 1990. This study was deemed reliable (Klimish score = 2), and the 48 hour LC50 for C. dubia was reported as 5.3 mg/L Dowfax 2EP (a.k.a. Dowfax 2A1). Since these toxicity tests were conducted with two different invertebrate species, the lower of the two values (1.64 mg/L based on active ingredient) was selected as the key parameter for this endpoint.

An additional, supporting study was included for this endpoint. In this study effluent spiked with Dowfax 2A1 elicited toxicity to Daphnia magna, whereas non-spiked effluent (negative control) and effluent containing biodegradation products from activated sludge treatment of Dowfax 2A1 did not elicit toxicity to daphnia.