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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

Three acute fish toxicity tests were conducted with EDHO.  The most recent study was conducted according to the OECD 203 fish toxicity guideline.  The two older tests were conducted according to USEPA-660/ASTM, which were similar to the OECD 203 guideline.  All three tests were conducted under the auspices of GLP guidelines but only the most recent included analytical verification of exposure concentrations.  
The key study for the acute fish toxicity endpoint is the most recent rainbow trout test. This test was conducted using flow-through conditions to maintain concentrations of the parent EDHO. Analytical verification of test solutions was conducted and demonstrated that test concentrations averaged about 80% of target and remained stable for the duration of the exposure. The results are calculated based on mean measured concentrations. The 96-hour LC50 was 244 mg EDHO/L.
The two remaining tests were conducted under static conditions. These tests were conducted as static exposures in contrast to the more study which was conducted under flow-through conditions. The older (1982) rainbow trout study determined a 96-hour LC50 of 240 mg/L based on nominal concentrations. The bluegill sunfish study determined a 96-hour LC50 of 130 mg EDHO/L, based on nominal concentrations.

Key value for chemical safety assessment

LC50 for freshwater fish:
130 mg/L

Additional information

Three freshwater acute fish toxicity tests were conducted with EDHO. The most recent test (2007) was the key study. The most recent of the three tests (2007) was conducted under GLP with a flow-through exposure and analytical verification of exposure concentrations using rainbow trout (Oncorhynchus mykiss). The two older tests were static exposures conducted under GLP using bluegill (Lepomis macrochirus) and rainbow trout, but lacked analytical verification of exposure concentrations.  The 96 -hour LC50 values determined on these tests were 130, 240, and 244 mg EDHO/L, respectively, for the bluegill, rainbow trout (1982), and rainbow trout (2007) studies. The 2007 rainbow trout study was chosen as the key study as it was conducted with analytical verification and the exposure was flow-through. The similarity in acute toxicity determined between the two rainbow trout studies indicates that the toxicity seen in the bluegill acute study was accurate, even with the lack of analytical verification. As a result, the bluegill LC50 value was chosen as the key acute fish toxicity value for the chemical safety assessment. 

 

These results indicate that EDHO is not dangerous to freshwater fish species.