DISTRIBUTION OF PHARMACEUTICALLY ACTIVE COMPOUNDS ALONGSIDE WASTEWATER TREATMENT. ENVIRONMENTAL RISK OF WASTEWATER DISCHARGES AND SLUDGE DISPOSAL

摘要

In the present work, the distribution of sixteen pharmaceutically active compounds in wastewater and sewage sludge alongside wastewater treatments have been evaluated. Pharmaceuticals selected belong to seven different therapeutic groups. The environmental risks to the aquatic associated to effluent wastewater discharges to the receiving streams and to terrestrial ecosystems due to the application of sewage sludge onto soils have been also evaluated. Twelve of the Pharmaceuticals evaluated were detected in wastewater at mean concentration levels from 0.10 to 32.0 ug/L All the compounds found in wastewater were also found in sewage sludge at mean concentration levels from 8.1 to 2206 ug/kg dry matter, except the anti-inflammatory drug diclofenac. The anti-inflammatory drugs ibuprofen and salicylic acid, the lipid regulator gemfibrozil and the nervous stimulant caffeine, were the Pharmaceuticals at the highest concentration levels in both wastewater and sewage sludge. The solid-water partition coefficients (K_d) of the pharmaceutically active compounds were determined. Log K_d values were in the ranges between 1.17 (naproxen) and 3.48 (carbamazepine), respectively. K_d values obtained were used to evaluate the removal rates of these compounds from the aqueous phase in wastewater treatment plants by sorption onto sludge particles. Environmental risk assessment revealed a significant decrease of the ecotoxicological risk to aquatic and terrestrial ecosystems (risk quotients between 1-10~(-4)-0.1 and 2-10~(-5)-2.7, respectively) after effluent wastewater is discharged to the receiving streams and sewage sludge is disposed as fertilizer onto soils.