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Ecotoxicological information

Toxicity to soil microorganisms

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Description of key information

For microbial assays, in total 108 individual high quality NOEC/EC10s  represent 4 nitrogen transformation processes, 5 carbon transformation processes and 8 enzymatic processes and range from 17 mg Zn/kg dw for respiration  to 2623 mg Zn/kg dw for phosphatase.

Key value for chemical safety assessment

Additional information

For microbial assays, in total 108 individual high quality NOEC/EC10s are selected for the PNEC derivation. These values represent 4 nitrogen transformation processes, 5 carbon transformation processes and 8 enzymatic processes and range from 17 mg Zn/kg dw for respiration (Chang and Broadbent, 1981 and Lighthart et al., 1983) to 2623 mg Zn/kg dw for phosphatase (Doelman and Haanstra, 1989).

Information on the background Zn concentration, allowing correction for differences in bioavailability among soils, is only available for 76 NOEC or EC10 values, representing 13 microbial processes (4 for N cycle, 5 for C cycle and 4 enzymatic processes). The total range in NOEC/EC10 values for the dataset with results for background Zn concentration is the same as for the total dataset for micro-organisms.

All toxicity data are expressed as added Zn concentration in soil, based on either the nominal dose added or on measured, background corrected soil Zn concentrations.