Toxicological and biochemical responses of the earthworm Lumbricus rubellus to pyrene, a non-carcinogenic polycyclic aromatic hydrocarbon P.J. Brown, S.M. Long, D.J. Spurgeon * , C. Svendsen, P.K. Hankard Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire PE28 2LS, UK Received 27 August 2003; received in revised form 6 May 2004; accepted 23 May 2004 Abstract The effects of the polycyclic aromatic hydrocarbon (PAH) pyrene on earthworms were investigated in contact and soil tests. In addition to measuring toxic effects on survival and reproduction, Ethoxyresorufin-o-deethylase (EROD) activity and catalase activity were also studied as possible biomarkers of toxic stress. The survival data indicated that LC 50 values were 0.0068 mg/ml for the contact test, and 283 mg/kg in the soil test. Cocoon production rate was signifi- cantly reduced compared to controls at 160, 640 and 2560 mg/kg in the soil test. No EROD activity could be detected in preliminary studies using control and exposed animals from the contact test, so this assay was not used to the soil test. Catalase activity was shown to be significantly lower at 640 mg/kg in the soil test compared to all other treatments and the control. When compared to toxicological data for other soil invertebrates, Lumbricus rubellus has an intermediate sensitivity in respects of survival and a lower sensitivity for reproductive effects, although the soil used in this study had a higher organic content than previous studies, meaning that the sensitivity of this species may be underestimated in comparison to previous published data for other soil invertebrates. Ó 2004 Elsevier Ltd. All rights reserved. Keywords: Polycyclic aromatic hydrocarbon; Pyrene; Reproduction; EROD; Catalase 1. Introduction The presence of PAHs in the environment is a result of industrial, accidental, or deliberate release usually occurring through the incomplete combustion of organic material (Van der Wal, 2003). These released PAHs can accumulate in surface waters and soil, where they can pose a toxicological risk to aquatic and terrestrial inver- tebrate species. Of the PAHs, benzo[a]pyrene (B[a]P), because of its known mammalian carcinogenicity, has been extensively studied in invertebrates. Effects on spe- cies such as mussels (Akcha et al., 2000) and marine polychaetes (Fries and Lee, 1984) have been investi- gated. In contrast to B[a]P, pyrene is considered to be non-carcinogenic by the International Agency for Re- search on Cancer and the US Environmental Protection Agency. Toxicities for this PAH are, thus, thought to re- sult principally through non-polar narcosis (Jensen and Sverdrup, 2003). The ability of soil organisms such as earthworms, to survive in the presence of both carcinogenic and 0045-6535/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2004.05.041 * Corresponding author. Tel.: +44 1487 772 561; fax: +44 1487 773 467. E-mail address: dasp@ceh.ac.uk (D.J. Spurgeon). Chemosphere 57 (2004) 1675–1681 www.elsevier.com/locate/chemosphere