Ecological risk assessment of pharmaceuticals and endocrine disrupting compounds in Brazilian surface waters

Pharmaceuticals and endocrine disrupting compounds are organic micropollutants that can cause adverse effects at low concentrations. Their occurrence in surface waters has been reported in several countries, including Brazil, at concentrations on the order of ngL^-1, while the concentrations at which toxic effects are observed are often in the range of mg.L^-1 to μg.L ^-1, however few studies have been undertaken to characterize risks they represent in Brazilian surface waters. Thus, the objective of this study was to evaluate the ecological risk to Brazilian surface waters caused by the presence of pharmaceuticals and natural and environmental estrogens. Twenty-nine pharmaceuticals, hormones and environmental estrogens were included in the risk assessment while twelve were discarded due to insufficient data availability. The endocrine disrupting compounds were the most frequently detected (39.8% of the reported concentrations), followed by non-steroidal anti-inflammatory drugs (16.3%), antibiotics (6.6%), antiseptics (5.1%), analgesics (5.1%), antihypertensives (4.6%), and to a lesser extent, lipid controllers, anticonvulsants, antidepressants, antihistamines, antivirals and corticosteroids. Bisphenol-A was the most frequently detected compound, followed by diclofenac, 17-β-estradiol, 17-α-ethynilestradiol, naproxen, triclosan and 4-n-nonylphenol. Acute ecological risk was predicted in two thirds and chronic risk in one third of the water bodies surveyed. The presence of diclofenac or triclosan was determinant for acute risk while estrogenic hormones proved to be decisive for chronic risk. In addition to natural and synthetic endocrine disruptors, the pharmacological groups estimated to have the highest average associated risks were non-steroidal anti-inflammatory drugs, followed by anticonvulsants. No discharge limits exist for most of the compounds found to contribute to ecological risks, indicating the need for regulatory action by the proper Brazilian authorities.