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Short-term toxicity to fish

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Description of key information

With high probability acutely not harmful to fish

Key value for chemical safety assessment

LC50 for freshwater fish:
460 mg/L

Additional information

LC50 values of several acute fish toxicity tests covering five different species range from 460 to > 5000 mg/L.

The lowest effect value was determined in a guideline study (Environment Canada EPS 1/RM/9, 1990/1996) with Oncorhynchus mykiss as test species. The fish were exposed to a series of 5 test concentrations and a control in a static approach. The 96 -h LC50 was 460 mg/L (nominal, analytically verified; PTAC, 2006). This study was selected as key study. Based on this result and the supporting information, diethanolamine is with high probability acutely not harmful to fish.

The low toxic effect of diethanolamine on fish is supported by several studies.

In a static test according to ASTM-Standard E 729-80 (1980), the acute toxicity of DEA to Pimephales promelas was assessed. Fry (n = 20 per test vessel), juvenile and subadult fish (n = 10 per test vessel) were exposed for 96 hours to various nominal concentrations of DEA and to control water. The stability of the test concentrations was not verified analytically. The test concentrations were not pH-adjusted. Measured pH values ranged from 8 to 10.5. Therefore, it is likely that alkaline pH-effects might have contributed to the observed mortality. Based on nominal concentrations, the range of the 96 hour LC50 values was 1360 - 1630 mg/L for the fry, 1300 - 1990 mg/L for the juveniles and 1200 - 1580 mg/L for the subadult fish. The most sensitive result was obtained with the subadult fish (96-hour LC50 = 1370 mg/L). The geometric mean of the 96 hour LC50 values was 1460 mg/L (95% CL: 1200 - 1990 mg/L) (DOW Chemical, 1982a; Mayes et al., 1983).

In another study with P. promelas, the 96 -h LC50 was determined to be 1664 mg/L (95% CL: 1493 - 2175 mg/L) (TSCATS, 1987, Dow, 1978).

Data on other fish species were obtained according to protocols with shorter exposure periods than 96 hours. All studies were performed under static conditions without analytical verification of test item concentrations.

Juhnke & Lüdemann (1978) determined a 48 -h LC50 of 1430 - 1850 mg/L for Leuciscus idus according to German Inudstrial Standard DIN 38412, part 15.

Turnbull et al. (1954) observed a 48 -h LC50 of 1850 mg/L for Lepomis macrochirus.

Bridié et al. (1979) demonstrated in a 24 -hour test that a higher alkalinity increases the toxic effect on fish. In not pH-adjusted test media the LC50 was 800 mg/L, while the LC50 in neutralized media was greater than 5000 mg/L.