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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

EC10 (16h) = 250 mg/L for growth inhibition of Pseudomonas putida (DIN 38412, part 8)
EC50 (3h) > 10000 mg/L for respiration inhibition of activated sewage sludge (OECD 209), read across

Key value for chemical safety assessment

EC50 for microorganisms:
10 000 mg/L

Additional information

One study for Zinc O,O,O',O'-tetrabutyl bis(phosphorodithioate) is available (Hansonis-Jouleh, 1992). In this study the impact on growth of Pseudomonas putida was investigated according to German national standard guideline DIN 38412 part 8 (Hansonis-Jouleh, 1992). After 16 hours of exposure of the test organisms an EC10 value for growth inhibition of 250 mg/L (nominal) is reported.

A further study is available for the analogue substance (Phosphorodithionic acid, mixed O,O-bis(1,3 -dimethylbutyl and iso-Pr) esters zinc salts (CAS 84605-29-8), assessing the influence on the respiration of activated sewage sludge according to OECD guideline 209 (Goodrich, 1994). There was almost no impact on the respiration rate. The EC50 value after 3 hours of exposure was above the highest test concentration of 10000 mg/L (nominal). The result of the respiration inhibition test is considered as more appropriate for assessing the toxicity towards aquatic microorganisms and was consequently used for the PNEC derivation.