Assessing hospital impact on pharmaceutical levels in a rural ‘source-to-sink’ water system

Abstract

It is widely recognised that inadequate removal of pharmaceuticals in wastewater may lead to their presence in surface waters. Hospitals are key point-sources for pharmaceuticals entering municipal waterways, and rural hospitals are of concern as receiving wastewater treatment plants (WWTPs) may be smaller, less advanced and thus less efficient. While most research has focused on urban settings, here we present results from a rural ‘'source-to-sink’' study around a hospital. The aim was to determine the contribution of pharmaceuticals discharged to a municipal wastewater system, and, to assess pharmaceutical removal efficiency in the WWTP. Samples were collected daily for one month to assess water quality and pharmaceuticals in the broader water cycle: (i) raw water supply; (ii) treated hospital tap water; (iii) hospital wastewater discharge; (iv) combined WWTP influent; and (v) final WWTP effluent. Target compounds included analgesics/antiinflammatories, antibiotics, psychiatric drugs, and a synthetic estrogen hormone. Concentrations ranged from: 3 ng/L (carbamazepine) to 105,910 ng/L (paracetamol) in hospital discharge; 5 ng/L (ibuprofen) to 105,780 ng/L (paracetamol) in WWTP influent; and 60 ng/L (clarithromycin) to 36,201 ng/L (paracetamol) in WWTP effluent. WWTP removal ranged from 87% (paracetamol) to <0% (carbamazepine and clarithromycin), and significant correlations with water quality characteristics and WWTP flow data were observed for some compounds. Results suggested that the hospital is an important source of certain pharmaceuticals entering municipal wastewater, and associated water quality parameters are impacted. Pharmaceutical persistence in the WWTP effluent highlighted the direct pathway these compounds have into receiving surface water, where their impact remains uncharacterised. Rural regions may face future challenges mitigating environmental risk as WWTP infrastructure ages, populations grow and pharmaceutical use and diversity continue to increase.