OCCURRENCE AND ENVIRONMENTAL RISK ASSESSMENT OF PHARMACEUTICALS IN SEWAGE SLUDGE AND SOIL - A CRITICAL REVIEW

摘要

Pharmaceuticals administered for treating and preventing numerous diseases are only partially assimilated in human body and the remaining part is excreted through urine and feces and occurs in urban wastewater. This is conveyed to a municipal wastewater treatment plant where activate sludge system is the most adopted treatment due to its simplicity and economical convenience. Unfortunately it is not able to efficiently remove these micropollutants and other persistent compounds from wastewater.Removal efficiency of pharmaceuticals has been extensively investigated in the last years with respect to the liquid phase, whereas their fate in activated sludge process and their partitioning between aqueous and solid phases has been less frequently studied. It should be very important to investigate the presence of these compounds in the sewage sludge and the potential environmental risk posed by their residues on terrestrial organisms as sludge may be applied in agriculture.This study collects and discusses available literature data on the occurrence of about 100 pharmaceuticals in untreated and treated sewage sludges derived from urban wastewater treatment plants in different countries. It was found that variability range of concentration varies depending on pharmaceuticals and on adopted treatment level. This is the case of ciprofloxacin and triclosan. Attempts to correlate pharmaceutical concentrations in sludge and pharmaceutical properties were carried out.Moreover, environmental risk posed by pharmaceuticals in sludge and soil is also evaluated through the Risk Quotient approach. Based on this study, the most critical compounds in sludge and soil are antibiotics and hormones, respectively. Finally, a comparison between risk posed by sludge, land disposal and that previously assessed by secondary effluent is reported and discussed. This allows to identify the most critical compounds in the two matrixes.