2,2'-oxydiethanol

Long-term toxicity to fish

Description of key information

From the available test data in combination with the QSAR calculation it can be concluded, that the test substance shows a very low long-term toxicity to fish.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

NOEC

Effect concentration:

> 40 mg/L

Additional information

Within the category of 'ethylene glycol and higher glycols'data on long-term effects to fish are available only for triethylene glycol (CAS 112-27-6, Montgomery et al., 1985).  Therefore, the read-across approach was performed in order to assess the long-term toxicity of diethalene glycol to fish.

The early life stage test was conducted with triethylene glycol according to the standard of ASTM (E-47.01, Draft No. 3, 1980 - Standard for Toxicity Tests With the Early Life Stages of Fisheries). In this study survival, hatching and growth (weight) of embryos from the saltwater species Menidia peninsulae were monitored. The test organisms were exposed under flow-through conditions for 28 days. Statistically significant differences were found in weight and survival at the highest test concentrations (230 and 1500 mg/L, measured). Nevertheless, since the survival of the embryos was significantly different from the control at 230 mg/L but not at 1500 mg/L, the effect observed was not concentration dependent. Hence, it have to be expected that the effect in the 230 mg/L treatment may not be caused by toxicity of the test item. However, the key NOEC of > 40 mg/L (measured, based on weight and mortality) was used as the key value as the worst-case consideration.

Additionaly, for the test substance itself and for the each structurally similar substance long-term toxicity to fish was determined using a valid QSAR model (ECOSAR v2.0; BASF SE, 2022). The model predicts the chronic value ChV, which is defined as the geometric mean of the no-observed-effect concentration (NOEC) and the lowest-observed-effect concentration (LOEC). The ChV for the test substance was predicted to be 20734 mg/L. The substance is within the applicability domain of the model. The estimated chronic values are presented in the table 1.

Table 1. Overview of the estimated ChVs for the substance and its structurally similar substance.

CAS Nr.	ChV (mg/L)	Applicability Domain
107 -21 -1	913.9	in AD
111 -46 -6	20734	in AD
112 -27 -6	18640	in AD
112 -60 -7	41268	in AD
4792 -15 -8	86666	in AD

Overall, experimental and estimated chronic values are clearly greater than 1 mg/L with regard to classification limits and also greater than 10 mg/L, which the limit concentration in long-term toxicity testing; therefore, long-term effects on fish are not to be expected.