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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

Key value for chemical safety assessment

EC50 for freshwater algae:
0.48 mg/L
EC50 for marine water algae:
0.24 mg/L
EC10 or NOEC for freshwater algae:
0.062 mg/L
EC10 or NOEC for marine water algae:
0.1 mg/L

Additional information

Many references are cited in the EU Risk Assessment DODMAC report (2002). This section cited below refers to the values used to derive the PNECwater:

"The influence of different test media on the sensitivity of Selenastrum capricornutum towards DHTDMAC was investigated by EG & G Bionomics, (Effect of X0161.01 in AAP medium on the fresh water algae Microcystis aeruginosa and Selenastrum capricornutum, Project-No. R22, internal report No. BP-81-7-113 and Effect of X0161.01 in river water on the fresh water algae Microcystis aeruginosa and Selenastrum capricornutum, Project-No. R22, internal report No. BP-81-7-117.). In laboratory water a NOEC of 0.078 mg/L and an algistatic concentration of 0.228 mg/L were derived for the reduction of cell number after 5 days (nominal concentrations of active ingredient). The corresponding values for the river water were: NOEC = 0.062 mg/L and algistatic concentration = 0.708 mg/L. The results for Microcystis aeruginosa are similar."

An other study (Kroon & van Ginkel, 1991) was carried out in accordance with the OECD 201 and properly assessed impact on growth rate but the test was not carried out in river water. The definitive algal growth inhibition test has been performed using the following nominal test concentrations: 0.04, 0.12, 0.36, 1.08 and 3.24 mg/L. The ErC50 -96 h and 72h of Quaternary ammonium compounds, di-C16 -18 -alkyldimethyl, chlorides are 0.36 and 0.48 mg/L respectively. The ErC10and EbC10(72 h) are 0.13 and 0.11 mg/L respectively.

The acute toxicity of Quaternary ammonium compounds, di-C16 -18 (even numbered) - alkyldimethyl, chlorides was also evaluated with the marine alga Skeletonema costatum in a static test over 72 hours in accordance to the procedure described in EN ISO 10253:1998. EC50 -72h was calculated to be 0.24 mg/L and the NOEC determined was < 0.1 mg/L.

The NOEC were similar between all these studies. Therefore, the lowest NOEC value (in river water) that was chosen to derive the PNEC in the EU Risk Assessment was also chosen as the key value for freshwater algae.