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Ecotoxicological information

Toxicity to soil microorganisms

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Description of key information

The studies of Schulz (2010) and Lemnitzer (2010) were used in a weight of evidence approach to cover this endpoint as both studies are performed according to standardized guidelines and under GLP. The lowest NOEC and EC50 were reported by Lemnitzer (2010) for the toxicity of lanthanum (added as LaCl3) on microbial nitrate formation in soil. The 28-d NOEC and EC50 were determined to be 283 and > 566 mg La/kg soil dw, respectively. These values were considered as key values and correspond to a NOEC and EC50 of 644 and > 1288 mg lanthanum triacetate/kg soil dw.

Key value for chemical safety assessment

Long-term EC10 or NOEC for soil microorganisms:
283 mg/kg soil dw

Additional information

Three studies were identified containing relevant and reliable information on the toxicity of lanthanum to soil microorganisms. Two studies were used in a weight of evidence approach to cover the endpoint as performed according to standardized guidelines (OECD 216 and OECD 217) and under GLP. The third study was flagged as a supporting study

Schulz (2010) studied the effect of lanthanum (added as LaCl3) on microbial respiration rate (C) in soil during 28 days. The NOEC and EC50 were determined to be 298 and > 595 mg La/kg soil dw, respectively. Finally, Lemnitzer (2010), in a similar study, investigated the effect of lanthanum on microbial nitrate formation in soil. The NOEC and EC50 were determined to be 283 and > 566 mg La/kg soil dw, respectively. These values were considered as the key values for this endpoint and, when expressed as lanthanum acetate, correspond to a NOEC and EC50 of 644 and > 1288 mg/kg soil dw.

In the supporting study of Chen et al. (2002), a natural soil was spiked with LaCl3 at varying concentrations and microbial ATP, soil dehydrogenase activity and soil urease activity were monitored for up to 16 weeks. The lowest EC50 values obtained were 1086.5 La mg/kg soil dw for microbial ATP, 897.8 mg La/kg soil dw for soil dehydrogenase activity and 1054.3 mg La/kg soil dw for soil urease activity.