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Ecotoxicological information

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The acute toxicity to fish was investigated according to EU Method C.1 (which is equivalent to OECD Guideline 203) (Kanne, 1993). Danio rerio (Zebra fish) was used as test organisms and was exposed for 96 hours to the test substance. A LC50 of 6.5 mg/L was determined by the geometric mean. The environmental impact of wastewater, and thereby the acute toxicity of the test substance towards Danio rerio was investigated by Broroson et al. (1994). Based on the reported LC50(96h) value of 2100 mg/L (> 0.21 %), it is considered as disregarded study since the procedure is not described in detail.

The QSAR program ECOSAR v1.00 (EPIWIN software by US-EPA) was used to predict the acute and chronic toxicity towards fish, daphnids and algae using an extensive set of structure-activity relationships (SARs). The mode of toxic action for most neutral organic chemicals is narcosis, and many chemical classes present toxicity to organisms via narcosis (i.e. ethers, alcohols, ketones). However, some organic chemical classes have been identified as having a more specific mode of toxicity. These are typically organics that are reactive and ionizable and that exhibit excess toxicity in addition to narcosis (i.e. acrylates, epoxides, anilines). The short-term results are based on the SAR for Vinyl / Allyl Ketones, whereas for long-term predictions only the so-called Chronic Value (ChV) is available. This value is defined as the geometric mean of the Lowest Observed Effect Concentration (LOEC) and the No Observed Effect Concentration (NOEC) and can classify the chemical only according to a low, moderate or high toxicity concern. Due to this, these values are not taken into account for the derivation of Predicted No Effect Concentrations (PNECs) for the aquatic compartment.

The following acute results were obtained for freshwater fish, daphnids and green algae: LC50(96h): 137.87 mg/L, LC50(48h): 89.87 mg/L and EC50(96h): 63.73 mg/L, respectively. The Chronic Values (ChVs) are based on neutral organics SARs (baseline toxicity) and were predicted as 9.93 mg/L for fish, 5.64 mg/L for Daphnia and 9.68 mg/L for green algae, respectively, indicating a moderate toxicity for all three trophic levels.

Beside these supporting QSAR predictions, experimental data are also available for aquatic microorganisms in sewage treatment plants (STP). Following ISO 8192, which corresponds in most parts to OECD Guideline 209, an EC50 of 383 mg/L (nominal) was obtained concerning toxicity to microorganisms in waste water treatment plants (Kanne, 1993). A Microtox test with Photobacterium phosphoreum resulted in an EC50(15min) of 0.21 % (2100 mg/L), indicating a low toxicity.