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Ecotoxicological information

Endpoint summary

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No studies on the toxicity of LAS-TEA to soil organisms were available. The toxicity of LAS-TEA to soil organisms may be described by the toxicity of LAS-Na and TEA according to the read-across statement in which full dissociation of the LAS-TEA in the environment is supported.

For LAS-Na a large number of terrestrial toxicity studies are available. No studies on terrestrial toxicity of TEA were available. The following data waiver for TEA was provided: 2,2',2''-nitrilotriethanol (TEA) is readily biodegradable and has a low adsorption potential (Koc= 17 L/kg, logKow = -2.3), therefore soil exposure via sewage sludge as an agriculture fertilizer is low. It does not have the potential to bioaccumulate nor is it considered as a PBT/vPvB substance. 2,2',2''-nitrilotriethanol is expected to rapidly degrade in soil, as indicated by a half-life of 1.8d determined in a degradation test in soil. Hence, soil is not expected to be a compartment of concern, therefore toxicity testing of soil macroorganisms, terrestrial arthropods and terrestrial plants can be waived.

A PNECsoil for LAS-NA was derived in the European Union (EU) Risk Assessment of LAS (Jensen et al , 2007). The EU undertook a review of studies on the toxicity of LAS to soil macro-organisms and terrestrial plants in order to determine a predicted level of no adverse effects (PNEC) in soil. Nine invertebrate studies and 12 plants studies were used to calculate the PNEC. Full references for all studies are provided in the dossier. In all the plant experiments, LAS was added as an aqueous solution, and the most sensitive endpoint - growth - was used in the PNEC calculation. In cases where an NOEC or EC10value was not reported, the original data or graphical estimations were used to calculate the EC10value. This was considered more appropriate than using an arbitrary extrapolation factor. Invertebrate data were based on 9 chronic studies. In cases where there was more than one study on a particular species, a geometric mean of the data was used. The data for both sets of studies were merged as the sensitivity of both types of species were similar. This was confirmed by the Kolmogorov-Smirnov test. The species sensitivity distribution was then calculated. From this, the concentration that would exceed NOEC or EC10 for 5% of species was calculated (HC5).   Based on this information, the HC5was determined to be 35.3 mg/kg soil. The 95% confidence interval was 18.6-50.0 mg/kg. The PNEC for soil was determined to be 35 mg/kg. For completeness, the PNECsoil of 35 mg/kg is proposed for LAS-TEA.

PNEC-soil for LAS-TEA was derived on the basis of equilibrium partitioning method , and was as such considered to be less acurate than a PNEC derived from toxicity data as was done for LAS-Na. The PNEC-soil for TEA was not taken into account and the PNEC-soil derived for LAS-Na was used as estimate for the PNEC-soil for LAS-TEA. Differences in molar weight of LAS-Na and LAS-TEA were not taken into consideration.