Drug substances in urban wastewater: a pilot study

Background Drugs improve the quality of human life, but, in the production phase first and then, variously metabolized are source of unrecognized pollution with environmental and health effects. In addition, the continuous introduction on the market of new molecules makes it difficult to control their disposal. Objectives: To investigate the presence of drug molecules (DM) and their metabolites, in municipal waste of a city quantifying the differences between input and output of purifiers. Methods The survey was conducted on two purifiers (D1, D2) of a city that serve an area of 118.71 km2 with about 56,000 inhabitants. The selected DM, on the basis of a literature search and for their environmental persistence and potential impact on human health, were: ibuprofen, erythromycin, lincomycin, amoxicillin, clarithromycin, ciprofloxacin, diazepam, carbamazepine, furosemide, hydrochlorothiazide, ranitidinae, bezafibrate , atenolol, enalapril. Three samples of 1 L of waste incoming and outbound from both the purifiers were carried out, in three different times in the same day (h 12, 18 and 24). We proceeded to the extraction of the active principles analyzed by HPLC-MS. Results All sought active principles have been found, both in entry and exit from D1 and D2. The drugs found in greater concentration, inlet, were: ibuprofen (D1 7.20 mg/m3, D2 2.13 mg/m3), hydrochlorothiazide (D1 1.03 mg/m3, D2 1.17 mg/m3) , carbamazepine (D1 0.17 mg/m3, D2 0.24 mg/m3) and ciprofloxacin (D1 0.15 mg/m3, D2 0.12 mg/m3 D2). The power of pulling down the DM by the two purifiers was varied: enalapril and ciprofloxacin were the most degraded drugs, respectively, with 95.3% (D1), 97.2% (D2) and 94.4% (D1), 89.7% (D2), lincomycin and ibuprofen among the least degraded, respectively, with 3.4% (D1) and 1.4% (D2) and 9.6% (D1) and 4.2% (D2). Conclusion The results show how different substances are not degraded by current processes of purification of sewage. It will be probably necessary to standardize this type of controls and to develop abatement techniques in order to avoid the potential environmental and health damage.