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Seven studies are available in order to determine the acute toxicity of substances belonging to the stilbene fluorescent whitening agents category to daphnids. All of those studies prove that the substances belonging to the category are with a high probability acutely not harmful to daphnids. Therefore, reading across, it is assumed that the substance CAS 371756 -75 -1 is considered with high probability acutely not harmful to daphnids.

Various studies are available in order to determine the toxicity of the stilbene fluorescent whitening agents category to microorganisms. All of those studies show that the substances belonging to the category do not inhibit the degradation activity of activated sludge in concentrations lower or equal than 100 mg/L. Therefore, reading across, it is assumed that also the substance CAS 371756 -75 -1 does not inhibit the degradation activity of activated sludge in concentrations lower or equal than 100 mg/L.

Several studies are available in order to determine the acute toxicity of the stilbene fluorescent whitening agents category to fish. Seven of those studies demonstrate that the substances belonging to the category are with a high probability acutely not harmful to fish. In one study, the LC50 values determined were significantly lower than in the studies mentioned before (CIBA-GEIGY G09304, 1991). Due to the number of studies that demonstrated that the category members are not harmful to fish, this study was considered as an outlier and not regarded for classification. Therefore, reading across, also the substance with CAS 371756 -75 -1 is considered with high probability acutely not harmful to fish.

Furthermore, five studies are available in order to determine the toxicity of the category to algae. Four of those studies demonstrate that the substances belonging to the category are with high probability acutely not harmful to aquatic algae. In one study, the EC50 value determined was determined to be 80.59 mg/L (CAS 16090-02-1, CIBA-GEIGY G09304, 1991). Since the tested compound is known to be an optical brightener, it is supposed that this result can be traced back to a physical effect (akin to dyestuff) based on the substances fluorescent properties. However, according to the four studies mentioned before there were no effects recognized on the test organisms at test concentrations of 100 mg/L. Based on the entire information of the available data the result of the RCC study is considered as an outlier. Therefore, reading across, also the substance with CAS 371756 -75 -1 is with high probability acutely not harmful to aquatic algae.

Two studies with two different substances (CAS 16470-24-9 and CAS 16090-02-1) of the category are available in order to assess its chronic toxicity to aquatic invertebrates: The NOECs of a prolonged toxicity test on daphnids were found to be 10 mg/L and 1 mg/L, respectively. Since the substances belonging to the stilbene fluorescent whitening agents category and also the substance with CAS 371756 -75 -1 are not considered as hazardous for the environment, and for reasons of animal welfare, chronic tests on fish are not provided.