2,2'-oxydiethanol

Long-term toxicity to aquatic invertebrates

Description of key information

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

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

NOEC

Remarks:

Daphnia magna

Effect concentration:

> 15 000 mg/L

Fresh water invertebrates

Dose descriptor:

NOEC

Remarks:

Ceriodaphnia dubia

Effect concentration:

8 590 mg/L

Marine water invertebrates

Marine water invertebrates

Dose descriptor:

NOEC

Remarks:

Americamysis bahia

Effect concentration:

>= 1 000 mg/L

Additional information

Experimental data on long-term effects to aquatic invertebrates are not available for diethylene glycol, therefore, the read-across approach with the structurally similar substances was performed.

The study with ethylene glycol (CAS 107 -21 -1) was conducted according to EPA guideline 600/4-89/001 with Ceriodaphnia dubia as a test specie. This test was terminated when 60% of the control organisms had produced three broods. After a test duration of 7 days the NOEC for reproduction was determined to be 8590 mg/L for ethylene glycol (nominal, Pillard, 1995).

No analytical monitoring was performed during the test study; however, the test substance is expected to be stable in water based on its physicochemical properties:

The Substance has a sufficiently high water solubility (miscible, cited in HSDB Database). Adsorption is not expected based on the low log Kow (-1.36, cited in HSDB Database) and log Koc (log Koc = -1.03; estimated; EPI Suite v4.11, KOCWIN v2.00, BASF SE, 2021). The Substance is not expected to evaporate from the test solution based on its low Henry's Law Constant (HLC = 0.1327 Pa m³/mol, 25 °C, estimated; EPI Suite v4.11, HENRYWIN v3.20; in applicability domain; BASF SE, 2021) and its low vapor pressure (VP = 0.123 hPa, cited in HSDB Database).

For the structurally similar substance triethylene glycol (CAS 112 -27 -6) two key studies and one supporting study are available.

One key and one supporting studies measured the effect of triethylene glycol on the reproduction of Daphnia magna (Adams & Heidolph, 1985; LeBlanc & Surprenant, 1983). One study was conducted according to the national standard ASTM (E 47.01, Draft No. 1, "Draft proposed standard practice for conducting renewal life cycle toxicity tests with Daphnia magna"). In this test the Daphnids were exposed to triethylene glycol for 21 days. Based on reproduction the reported NOEC is > 15000 mg/L triethylene glycol (nominal, Adams & Heidolph, 1985).  Supporting reproduction study was conducted under standartised test conditions. The 21 -d NOEC was determined to be > 6120 mg/L (converted from 5500 µL/L, nominal, LeBlanc, 1983).

The second key study with the saltwater shrimp Mysidopsis bahia was conducted according to the standard of ASTM (E-47.01, Draft No. 2, 1982 (Standard Practice for Conducting Life-Cycle Toxicity Tests With Saltwater Mysid Shrimp). The test organisms were exposed to triethylene glycol in a flow-through system for 23 days. Up to the highest test concentration of 1000 mg/L no effect on the reproduction of the saltwater shrimps were observed (nominal, analytically verified, Montgomery et al., 1985).

Additionaly, for the test substance the long-term toxicity to aquatic invertebrates was determined using a valid QSAR model (ECOSAR v2.0; BASF SE, 2022). The ChV for the test substance was predicted to be 4512 mg/L. The substance is within the applicability domain of the model.

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 aquatic invertebrates are not to be expected.