DNA damage

Organic chemistry

Enzyme

Superoxide dismutase

Oxidative stress

Phthalic acid

Comet assay

Eisenia fetida

Reactive oxygen species

Chemistry

Antioxidant

Lipid peroxidation

Malondialdehyde

Glutathione peroxidase

Catalase

Glutathione

Phthalate

Toxicity

Food science

Biochemistry

Environment International

Phthalates (phthalic acid esters) have been widely applied as plasticizers. They are ubiquitous contaminants in soils, thereby posing a threat to human health. In this study, ecotoxicological effects of three typical PAEs (dimethyl phthalate-DMP, di-n-octyl phthalate-DOP and butyl benzyl phthalate-BBP) were investigated. As a biological indicator, earthworms (Eisenia fetida) were exposed to phthalates at various doses (0, 0.1, 1, 10 and 50 mg/kg) for different times (7, 14, 21, and 28 d). We evaluated the effects of phthalates on reactive oxygen species (ROS) generation, antioxidant enzymes (superoxide dismutase-SOD, peroxidase-POD and catalase-CAT) activities, glutathione S-transferase enzyme (GST) activity, malondialdehyde (MDA) content and DNA damage. Results showed that ROS content increased with increasing phthalates, whereas ROS content generally increased and then decreased with exposure time. However, antioxidant enzymes activities in earthworms displayed different trends. The GST activity in high-dose treatment group was significantly activated. For DMP and DOP, lipid peroxidation mainly occurred between 14 and 28 d, while for BBP, it primarily existed after 7 d and then disappeared after 28 d. Besides, comet assay indicated that there was a dose-response relationship between the DNA damage and phthalate dose, following DMP > DOP > BBP. Given their toxicity, it is important to understand the mechanisms associated with their eco-toxicity and to reduce their adverse impacts on the environment.

Phthalate induced oxidative stress and DNA damage in earthworms (Eisenia fetida)