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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

A short term toxicity test with rainbow trout (O. mykiss) exposed to ‘benzene, ethylenated, by-products from’ and conducted under GLPs, flow-through conditions and following standard test guidelines (USEPA OTS 797.1400) resulted in 96-hour LC50 value of >0.97 mg/L.

Key value for chemical safety assessment

LC50 for freshwater fish:
0.97 mg/L

Additional information

Four acute freshwater fish studies were available for ‘benzene, ethylenated, by-products from’ with two considered reliable for assessment for this endpoint. One of the reliable studies was conducted with rainbow trout (Oncorhynchus mykiss), while the other study was conducted with fathead minnow (Pimephales promelas). The rainbow trout study was conducted under flow-through conditions, followed standard test guidelines and GLPs, had measured test concentrations and resulted in a 96-hour LC50 value of >0.97 mg/L. Though an oily film was present in all treatment solutions during the study, no fish mortality was observed and therefore the study still considered reliable. The fathead minnow study was conducted under static-renewal conditions, used the water-accommodated fraction method to prepare the test solutions, followed standard test guidelines and GLPs, had measured test concentrations and resulted in a 96-hour LC50 value of 1.65 mg/L. Since the toxicity results from these reliable studies were from different fish species, the lower of the two values (>0.97 or 0.97 mg/L) was selected as the key parameter for this endpoint.

The remaining 2 supporting studies (one rainbow trout and one fathead minnow) were not considered reliable for assessment due to an unsuitable test design. The test substance has limited solubility and, whilst chemically stable in water, it is does not form consistent aqueous solutions. Both studies were conducted under static conditions and with no measured verification of test concentrations. The reported 96-hour LC50 value for the rainbow trout and fathead minnow test were 2.2 mg/L and >16 mg/L, respectively.