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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

An analysis of the growth rate of the algal population within the 72 h exposure period (by probit analysis and Williams Multiple Sequential t-test Procedure) gave the following results: ErC10 = 149 mg/L; ErC50 = >149 mg/L; NOEC [r] = ≥149 mg/L and LOEC [r] = >149 mg/L.

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater algae:
149 mg/L

Additional information

In order to test acute toxicity of thiophosphoryl trichloride to algae (Desmodesmus subspicatus) was exposed to the test solution of nine nominal concentatrions of thiophosphoryl trichloride ( 0.01, 0.032, 0.1, 0.32, 1.0, 3.2, 10, 32 and 100 mg/L) and control solution for a period of 72 hours under static conditions. The cell densities were measured at 24 hour intervals. Inhibition of the algal population was measured as reduction in growth rate (index r), relative to control grown under identical conditions. The measured concentrations confirmed that deviation from the nominal concentrations was less than 30 % (measured concentrations were in range of 96.6 % to 147.1 % of nominal concentrations). An ErC10 of 149 mg/L and an ErC50 of >149 mg/L were determined, a NOEC [r] of ≥149 mg/L and a LOEC [r] of >149 mg/L were calculated. This toxicity study is classified as acceptable and satisfies the guideline requirement for the acute algae study.