Trophodynamic of endocrine disrupting compounds in the aquatic food webs: Association with hydrophobicity and biota metabolic rate

Increasing concentration of endocrine disrupting compounds (EDCs) are released into the aquatic environment, result-ing in irreversible effects on the endocrine and reproductive systems of biota. How the liver enzymes affect metabolic rate of these compounds and thus their structure-related trophic transfer in aquatic food webs remains largely un-known. In this study, the concentrations of seven common EDCs were measured in 15 species of fish, 7 invertebrate species and plankton collected from Liuxi River to Pearl River, South China. The mean sigma EDC concentrations generally were found to increase as follows: plankton (29.59 ng g-1 dw) < invertebrate species (50.69 ng g-1 dw) < fish (122.56 ng g-1 dw), with 4-nonylphenol (4-NP) and bisphenol S (BPS) as the predominant components. Trophic mag-nification factors (TMFs) values were >1.0 ranged from 1.30 (BPS) to 4.07 (4-NP), indicating trophic magnification potential. Measurement of metabolism and activities of microsomal CYP450 enzymes were performed in the fish liver microsomes of Hypophthalmichthys molitrix ([TL] = 2.27), Cirrhinus mrigala (TL = 3.87) and Odontamblyopus rubicundus (TL = 4.73). TMFs were significantly negatively correlated with the obtained in vitro biotransformation clearance rates (CL in vitro) of EDCs and CYP450 enzymes activities. A multiple linear regression model indicated that biotransformation clearance is a more powerful predictor for TMFs than the hydrophobicity (Kow) to drive changes in the studied aquatic food web trophodynamics.

Automated summary

The increasing concentration of endocrine disrupting compounds (EDCs) in the aquatic environment has irreversible effects on biota's endocrine and reproductive systems. This study measured the concentrations of seven common EDCs in fish, invertebrate species, and plankton collected from South China. The results showed that fish had the highest EDC concentrations, with 4-nonylphenol and bisphenol S being the predominant components. Trophic magnification factors (TMFs) were negatively correlated with in vitro biotransformation clearance rates (CL in vitro) and CYP450 enzymes activities, indicating that metabolism plays a significant role in the trophic transfer of EDCs.