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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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Description of key information

1) Key study: Chronic (56 days) toxicity to eartworms (Eisenia fetida); K1; 2010; OECD 222; GLP; NOEC = 1000 mg/kg dry soil (mortality, growth and reproduction)
2) Supporting study: Acute (14 days) toxicity to earthworms (Eisenia fetida); K2; 2010; OECD 207; non-GLP; no toxicity determined up to 1000 mg/kg dry soil (mortality and growth).

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for soil macroorganisms:
1 000 mg/kg soil dw

Additional information

In a first range finder study, the acute toxicity towards earthworms (Eisenia fetida) exposed to chemically-treated artificial soil at levels of 0.1, 1.0, 10, 100 & 1000 mg/kg dry soil for 14 days was evaluated (McCormac, 2010). This study was performed according to OECD guideline 207, but not according to GLP guidelines. Adult worms were monitored for lethality and body weight changes during the exposure period. No effects were observed on either one of these endpoints. The NOEC (14d) was determined at 1000 mg test chemical/kg dry soil (nominal values) for both endpoints (growth and mortality).

 

Subsequent to the acute toxicity study (OECD 207), a 56 -day chronic toxicity study (OECD 222; McCormac, 2010) was performed to assess the impact of DAPD levels on the earthworm Eisenia fetida. This study was compliant to both the OECD and GLP guidelines. Compound levels added to soil were 125, 250, 500, and 1000 mg test chemical/kg dry soil (nominal values). No chemical analysis was performed in this study due to the high degree of adsorption of this chemical to soil shown by the OECD 121 study (Koc > 4.3) (Drake, 2010) and the low degree of chemical migration shown in a soil field study (McLaughlin, 1997). Earthworm mortality and body weight changes were monitored after 28-day exposure period. Egg cocoons that were observed at Day 28 were returned to the treated soil to allow hatching. Numbers of juveniles appearing by Day 56 were recorded as unhatched cocoons. There were no statistically significant changes resulting from DAPD exposures towards worm mortality, body weight changes, appearances of juveniles or unhatched cocoons during the 56 day study. Therefore, the NOEC was determined at 1000 mg test chemical/kg dry soil (endpoints: mortality, growth, reproduction).