Growth inhibition and DNA damage in the earthworm (Eisenia fetida) exposed to perfluorooctane sulphonate and perfluorooctanoic acid

An artificial soil method was applied to study the effects of perfluorooctane sulphonate (PFOS) and perfluorooctanoic acid (PFOA) on earthworms (Eisenia fetida). Survival, growth inhibition and damage to DNA of earthworms were detected after 14 d acute exposure. The 14 d-LC50 of PFOS and PFOA was 478.0 mg·kg−1 dw and 759.6 mg·kg−1 dw, respectively, indicating that they were of low toxicity. Both PFOS and PFOA could significantly inhibit the growth of earthworms after 14 d exposure, and growth inhibition rates increased with the greater concentrations of PFOS or PFOA, showing a dose–response relationship (PFOS: r = 0.951, P < .01; PFOA: r = 0.962, P < .01). PFOS or PFOA were shown to damage earthworm coelomocytes DNA, the indicators of treatments exposed to PFOS or PFOA, tail length (TL), comet length (CL), head DNA content (HD) and olive tail moment (OTM) were significantly different (P < .05) from the control treatments, and the indicators and concentration of PFOS or PFOA had a strong dose–response relationship. 14 d-LC50 of PFOS was lower than that of PFOA, the growth inhibition rate of earthworm exposed to PFOS was higher than that exposed to PFOA at the same concentration level, and the median values of TL, CL and OTM in PFOS treatments were also higher than those in PFOA treatments. In conclusion, both these fluorine compounds were moderately toxic to earthworms, but the PFOS effect was greater than that of PFOA.