Tris[2-[2-(2-methoxyethoxy)ethoxy]ethyl] orthoborate

Short-term toxicity to fish

Description of key information

LC50 > 222.2 mg/L Oncorhynchus mykiss acute (OECD 203)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

222.2 mg/L

Additional information

For the assessment of the acute toxicity on freshwater fish one key study (Shell 1999a) and one supporting study (Shell1987 a) are available, both with B-TEGME containing mixtures.

In the GLP compliant key study of Shell (1999a), the acute toxicity of methyl borate esters (containing 22% B-TEGME) was investigated on O. mykiss. The EU C.1 and OECD 203 guideline compliant limit test was performed as 96 hour semi-static study with 24 hour renewal intervals. No relevant restrictions appeared and the only disadvantage of this study is the fact that the study was performed with a B-TEGME containing mixture and not with B-TEGME as pure substance itself. The effective test concentration was 222.2 mg B-TEGME/L (applied as 1010 mg methyl borate esters/L, mean measured concentration). During the 96 hours of exposure, no adverse effects were observed in the control and the treated test group. Hence, the 24, 48, 72, and 96-hour LC50 were > 222.2 mg B-TEGME/L.

In the GLP compliant supporting study of Shell (1987a), the acute toxicity of a brake fluid (containing 17% B-TEGME) was investigated on O. mykiss. The study was performed as 96 hour semi-static test with 24 hour renewal intervals. The study was not performed according to a specific guideline, but the test design was similar to OECD 203. Following restrictions apply: (1) dose verification analysis was not performed, and (2) the temperature variation of 3.5°C (13.5 to 17.0°C) exceeded the maximum variation of 2°C allowed by modern EU, OECD and OPPTS test guidelines. Nominal test concentrations were: 213, 533 and 1065 mg brake fluid/L, equivalent to 36.2, 90.6 and 181.1 mg B-TEGME/L. After 96 hours of exposure, 0, 0, 2 and 10 out of 10 fish had died in the control, 36.2, 90.6 and 181.1 mg B-TEGME/L treatment groups, respectively. The 96-hour LC50 was 100.3 mg B-TEGME/L.

The results of the key study show that the LC50 fish was > 222.2 mg B-TEGME/L. The results of the supporting study show that the LC50 of B-TEMGE was 100.3 mg B-TEGME/L.

For following reasons, the LC50 of > 222.2 mg B-TEGME/L is considered reliable and sufficiently conservative to assess the toxicity of B-TEGME on fish: (1) the above mentioned restrictions of the supporting study (no analytical dose-verification, temperature deviation) may lead to less reliable results and (2) other additives of the brake fluid may have caused the mortality in the supporting study.

The above LC50 value is higher than the limit for classification and labeling, i. e., higher than 100 mg B-TEGME/L.