Quaternary ammonium compounds, di-C16-18-alkyldimethyl, chlorides

Long-term toxicity to aquatic invertebrates

Description of key information

Toxicity figure based on river water testing with DSDMAC.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.38 mg/L

Additional information

The no observed effect concentration (NOEC) for daphnids exposed to 14C-labeled DSDMAC in river water was determined to be 0.38 mg/L by Lewis and Wee in 1983. Length, total young and mean brood size of adults exposed to mean concentrations of >= 0.76 mg/L DSDMAC were significantly less (p <= 0.05) than the same parameters for adults in the controls and in the remaining test waters. For example, total young produced at the 0.76 mg/L concentration was approximately 38% less than that for adults exposed to 0.38 mg/L. Mean brood sizes reflected these differences in young production, generally declining at concentrations > 0.38 mg/L. Reproductive performance was more sensitive than mortality: the 21-d LC50 was 1.72 (95%CI = 1.31-2.49) mg/L.

Based on the toxicity data for daphnids in river water, the acute to chronic ratio or application factor is 0.12 (NOEC/LC50=0.38/3.1).

In another semistatic 21d-study (OECD 202 carried out by Hooftman in 1991) with Daphnia magna DHTDMAC was emulsified in reconstituted ground water by treatment for 30 minutes in an ultrasonic vibration bath. The most sensitive endpoint was the reproduction rate with a NOEC of 0.18 mg/L (nominal concentration of active ingredient). The NOEC for adult mortality was 0.56 mg/L. Test substance was analyzed at the end of the test only for concentrations of 0.56 mg/L and higher showing that they had not decreased in the course of the test.