Effects of a gadolinium-based contrast agent detected in wastewater on the clam Ruditapes decussatus: a multi-marker approach

The present study is an in-vivo evaluation of the toxicity of Dotarem (DOTA) for marine clam Ruditapes decussatus . Three concentrations of DOTA ( C1 = 12.5 µg.L ^− 1 , C2 = 25 µg.L ^− 1 , C3 = 50 µg.L ^− 1 ) were used for exposure on 7 days. Responses of R. decussatus after its exposure, were monitored using filtration rate, oxidative stress, lipo-peroxidation, neurotoxicity and histopathological markers. Four biomarkers were measured at the gills and digestive gland: two defense biomarkers catalase (CAT) and glutathione-S-transferase (GST), a cellular damage biomarker (MDA) and a neurotoxicity biomarker acetylcholinesterase (AChE). The filtration rate was significantly decreased by exposure to DOTA rising from 8.18 ± 4.22 mg.h ^− 1 .ind ^− 1 in the control to 2.03 ± 0.6 mg.h ^− 1 .ind ^− 1 in the clams after 7 days of exposure. The results showed that the activities of antioxidant enzymes (CAT, GST) and the cellular damage status (MDA) revealed concentration and organ-dependent responses for DOTA. Acetylcholinesterase activity (AChE) showed a highly significant decrease in the gills, independent of the DOTA exposure concentration, and in the digestive gland depending of dose exposure ( p  < 0.0001). This contamination causes histopathological changes in both organs, marked by infiltrations, vacuolizations and cell necrosis. The intensity of these lesions depends on the concentration of this pollutant.