High levels of the endocrine disruptors bisphenol-A and 17 beta-estradiol detected in populations of green mussel, Perna viridis, cultured in the Gulf of Thailand

The occurrence of the endocrine disruptors bisphenol-A (BPA) and 17 beta-estradiol (E-2) in cultured populations of green mussel (Perna viridis) and water samples collected from selected fresh and marine coastal environments along the eastern coast of Thailand were investigated. Analysis found high levels of BPA in mussel tissues that correlated with levels found in coastal (maximum 37.13 ng/L) and freshwater (50.7 ng/L) sites situated near industrial and densely populated areas. By comparison, high levels of E-2 (62.99 +/- 5.03 ng/L) were found in freshwater sites near to urban areas. Higher concentrations of BPA and E-2 were found in mature green mussels (> 6 mo. old; 6.40 +/- 0.52 cm shell length) than levels determined in juveniles (< 2-3 mo. old; 2.29 +/- 0.65 cm shell length). To evaluate the potential risks associated with the consumption of green mussels, the bioconcentration factor (BCF) for BPA was determined to be 1650 for adult bivalves and 283 for juveniles. As P. viridis can accumulate BPA from the environment, this raises concerns regarding the risks posed by consuming seafood sourced from zones near to major conurbations. Whether the high levels of E-2 found in green mussels is due to accumulation or to de novo synthesis as seen in other molluscs, requires further investigation. While industrial and domestic wastewater may be important sources of BPA, E-2 contamination within the eastern part of the Gulf of Thailand has been linked to domestic waste. The study highlights the importance of the temporal and spatial monitoring of sentinel species, such green mussels, for environmental contaminants, the results of which can lead to the construction of regional risk maps helping to inform national strategies regarding aquaculture zoning and aquatic food safety.