Dibutyl phthalate

Toxicity to soil macroorganisms except arthropods

Additional information

The effect of DBP on the earthworm, Eisenia fetida, was tested in a short-term contact test (Neuhauser et al., 1985). DBP was within 10 least toxic compound among 44 tested. This result indicates that DBP is not very harmful to soil organisms. In the test condition DBP applied via a filter paper to Eisenia fetida during 48h showed a LC 50 = 1,36 mg/cm² (CI 1,05 - 1,75 mg/cm2). But as the results was obtained with an exposure via paper filter, this exposure is not enough representative for environmental exposure, therefore this study is considered as unreliable for risk assessment and to derive a PNEC soil. However for substance dimethyl phthalate both test were performed (contact test and artificial soil test). Seeing that dibutyl phthalate has LC50 for contact test higher than dimethyl phthalate, we could also estimate that the LC50 value for dibutyl phthalate in artificial soil test would be also higher (more than 3160 mg/kg soil dw).

Ohtani at al., 2000 investigated whether the toxicity of DBP alters the process of gonadal sex differentiation in genetically maleR. rugosa tadpoles. Genetically male tadpoles were exposed to DBP during days 19–23 after fertilization. 10 and 1 μM DBP induced complete or partially developed ovaries in the gonads of 17% and 7% of tadpoles, respectively (not statistically significant; NOEC = 10 μM DBP (2.8 mg/L)). The level of gonadal alteration induced by 10 μM DBP is similar to that brought about by 0.01 μM E2 (positive control). This result indicates that DBP is about 1,000-fold less potent than E2. Presented study was performed using tadpoles in water compartment and therefore this study is considered as unreliable for risk assessment and to derive a PNEC soil.