Bioaccumulation of antibiotics in wild freshwater invertebrates

Occurrence and bioaccumulation of 20 antibiotics, including fluoroquinolones (FQs), sulfonamids (SAs), macrolids (MLs), tetracyclins (TCs),diaminopyrimidins (DPs) and nitro-imidazols (NIs) in an amphipod crustacean (Gammarus pulex) inhabiting in the small river, downstream of effluent from a wastewater treatment plants in Ile-de-France (France) and in shrimps (Lipopenaeus vannamei) inhabiting in the rivers surrounding of intensive shrimp farmingsfarming in the Delta Mekong - Vietnam were investigated. Surface water, sediment and invertebrates samples were analyzed by HPLC-MS/MS. Sulfamethoxazole, ciprofloxacine, ofloxacine and norfloxacine, were found in all surface water samples in both research studied areas. However, in France, SAs were the predominant antibiotics in surface water with the maximum concentration of 2780 ng/l for sulfamethoxazole, while, in Vietnam, FQs were the predominant antibiotics with the maximum concentration of 200 ng/l for ciprofloxacin. In sediment samples of both research areas, FQs were the most frequently detected with concentrations from a few to several hundreds µg/kg. The high concentrations and detection frequencies of FQs in sediments indicate that sediments are an important reservoir for FQs as they are strongly adsorbed on to sedimentsit. In the Gammarus pulex, six antibiotics (nalidixic acid, ciprofloxacin, ofloxacin, norfloxacin, flumequin and trimethoprim) were detected with the concentration rangedge from 2 - to 106 µg/kg (dry weight). Concentration in juvenile were higher than in adult and a seasonal effect was observed during the study period, this variation is however of lower amplitude in juvenile. In the shrimps Lipopenaeus vannamei, ciprofloxacin, norfloxacin, erythromycin and sulfamethoxazole were detected with the concentrations ranged from 4 - to 160 µg/kg. These results shown that antibiotics are weakly bioaccumulated with respect to environmental contamination and that , there is a correlation between the adsorption of antibiotics in sediments and their accumulation in wild freshwater invertebrates. The molecular profiles and the concentrations in the invertebrates were depending on species and habitat.