Biomarker Responses in Earthworms Lumbricus Terrestris L. (Annelida: Lumbricidae) to Artificial Soils Contaminated with Dimethyl Phthalate
In ecotoxicological studies, oxidative damages and antioxidant defense responses in earthworms have been used as hallmarks for assessing the environmental pollution. Phthalates, which are esters of phthalic acid (PAEs) are primarily used to enhance plasticity of industrial polymers, and are an unavoidable part of modern life. In the present study, ecotoxicological effects of dimethyl phthalate (DMP) were investigated in the earthworms Lumbricus terrestris L., at different concentrations (0,
... 1, 10 and 50 mg kg-1) on the 7th and 14th days of exposure in artificial soils. We evaluated the effects of DMP on oxidative stress (OS) biomarkers including malondialdehyde (MDA/LPO) level and the activities of antioxidant enzymes catalase (CAT) and glutathione S-transferase (GST), and carbonylated proteins (CP) content in earthworm's whole body extract. The neutral red retention (NRR)-time of coelomocytes and total antioxidant capacity (TAC) were also measured in the earthworm's coelomic fluid (ECF). Upon exposure to DMP, OS status was induced in a time and concentration-dependent manner. The MDA level, CAT and GST activities, and CP content were found to be increased, but the TAC value and NRR-times were decreased in all DMP-treated groups on 7th and 14th days of exposure. The toxicity of DMP was generally greater in the groups with 14 day toxicant exposure. Briefly, our resultes defined that DMP is a source of oxidative damages in the earthworms. However, for detailed elucidation of the mechanisms associated with DMP ecotoxicity and its adverse impacts in the soli organisms, further unraveling is needed.