Occurrence, distribution, ecological and resistance risks of antibiotics in surface water of finfish and shellfish aquaculture in Bangladesh

The present study for the first time reports the occurrence, distribution, ecological and resistance risks of antibiotics in the surface water of freshwater finfish and brackish water shellfish aquaculture in Bangladesh. Among the nine targets, seven antibiotics were detected in finfish aquaculture, whereas four in shellfish aquaculture. The concentrations (ranges) and overall detection frequency of sulfamethoxazole (SMX) (nd-20.02 ng L−1 and 73%), trimethoprim (TMP) (nd-41.67 ng L−1 and 60%), tylosin (TYL) (nd-39.34 ng L−1 and 60%), sulfadiazine (SDZ) (nd-17.97 ng L−1 and 53%), sulfamethazine (SMT) (nd-11.71 ng L−1 and 33%), sulfamethizole (SMZ) (nd-10.81 ng L−1 and 40%) and penicillin G (PC_G) (nd-7.83 ng L−1, 7%) were found in finfish aquaculture. In case of shellfish aquaculture, the concentrations (ranges) and overall detection frequency were for SMX (nd-16.77 ng L−1 and 67%), TMP (nd-11.39 ng L−1 and 20%), TYL (nd-0.16 ng L−1 and 20%) and erythromycin-H2O (ERY-H2O) (nd-3.91 ng L−1 and 20%). The present findings revealed that finfish aquaculture is more contaminated with the higher numbers and concentrations of antibiotics. The preliminary ecological and resistance risks assessment showed that the calculated risk quotients (RQs) were lower than one (RQs