Antibiotics are of particular concern because of their ubiquity in aquatic environment and
long-term adverse effects on aquatic organisms and humans. However, there is no information about the bioaccumulation and trophic magnification of
antibiotics in subtropical environments. In this study, we determined the concentrations of 22
antibiotics to investigate their occurrence, bioaccumulation and trophic magnification in a subtropical food web from the Beibu Gulf. The total concentrations of target
antibiotics ranged from 52.94-77.76 ng/L in seawater, 9.69-15.43 ng/g dry weight (dw) in sediment, and 0.68-4.75 ng/g wet weight (ww) in marine organisms, respectively.
Macrolides were the predominant
antibiotics in water, while
fluoroquinolones were more abundant in sediment and biota samples. The total concentrations of target
antibiotics in examined marine taxa descended in the order: crustacean > cephalopod > fish, with
antibiotic profiles displaying distinct difference among taxa. Log BAFs (bioaccumulation factor) for
antibiotics in all organisms ranged from -0.50 for erythromycin-H2O (ETM-H2O) to 2.82 for
sulfamonomethoxine (SMM). Significantly negative correlation was observed between the log Dow and log BAF values (p < .05), indicating that log Dow is a good predictor of
antibiotics bioaccumulation potential in marine organisms. The trophic magnification factors (TMFs) for
sulfadiazine (SDZ) and
enoxacin (ENX) were greater than unity, suggesting the trophic magnification of these chemicals through the food web. In contrast,
enrofloxacin (ENR),
ciprofloxacin (CIX),
ofloxacin (OFX),
norfloxacin (NOX), ETM-H2O and
trimethoprim (
TMP) were biodiluted in the food web from the Beibu Gulf. This study provides substantial information on the fate and trophic transfer of
antibiotics in a subtropical marine ecosystem.