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

ABSTRACT

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.

KEYWORDS:

• Perfluorooctane sulphonate (PFOS)
• perfluorooctanoic acid (PFOA)
• Eisenia fetida
• LC₅₀
• growth inhibition
• DNA damages

Acknowledgments

The authors are grateful for the support provided by the National Natural Science Foundation of China [Grant No. 41272487], and the International S&T Cooperation Program of China [Grant No. 2012DFA91150]

Disclosure statement

No potential conflict of interest was reported by the authors.