Abstract
Coral reef fishes are about 10% of commercial fishes worldwide. Their pollution is close to human’s health. Antibiotics are one group of emerging organic pollutants in the marine environment. However, little data is available on the bioaccumulation and dietary risks of antibiotics in coral reef fish from the South China Sea (SCS) or any other parts of the global coral reef environment. In this study, we examined 19 antibiotics in 18 species of coral reef fish collected from coastal and offshore regions in the SCS. The results revealed that 17 antibiotics were detected in the fishes. Their average concentrations ranged from 1.3 _ 10_5 to 7.9 _ 10_1 ng/g ww, which were at the lower end of the global range about antibiotic levels in fish. The average total antibiotic concentrations (P19ABs) were significantly higher in the offshore fish (1.2 ng/g ww) than in the coastal fish (0.16 ng/g ww). Different fish species or the protection of mucus produced by coastal fish at severe environmental stress may cause the differences. Fluoroquinolones (FQs) accounted for 89% and 74% of the average P19ABs in the offshore and coastal fish, respectively. It may relate to their relative high aqueous solubility and adsorption ability to particles. The log BAFs (bioaccumulation factors) of the antibiotics ranged from _0.34 to 4.12. Norfloxacin, dehydrated erythromycin (DETM), and roxithromycin were bioaccumulative in some offshore fish samples with their log BAFs higher than 3.7. The results of trophic magnification factors (TMFs) demonstrated that DETM underwent significant trophic dilution while enoxacin underwent trophic magnification in the food web of coral reef fishes. The estimated daily intakes of antibiotics via fish consumption by China residents ranged from 2.0 _ 10_4 to 2.7 ng/kg weight body/day, which was 3 to 8 orders of magnitude lower thanthe respective acceptable daily intakes.
