Beta-Blockers and Antidepressants: Contributions to Municipal Wastewaters from Hospitals and Residential Areas
Emerging contaminants in wastewater are of increasing concerns due to identification of previously undetected chemicals now being identified in wastewater treatment plant (WWTP) effluents, and subsequently, in surface waters. This paper provides monitoring results for selected beta-blockers (atenolol, sotalol, metoprolol, and propranolol) and antidepressants (venlafaxine, o-desmethylvenlafaxine, citalopram, desmethyl citalopram and carbamazepine) hospitals and residential neighborhoods in three different cities of Ontario, Canada. The average concentrations of compounds studied were determined for atenolol, metoprolol, propranolol and sotalol from the hospitals were 1291 ng/L, 848 ng/L, 71 ng/L and 274 ng/L respectively. The average observed concentrations of venlafaxine, o-desmethyl venlafaxine, citalopram and desmethyl citalopram from the hospitals were 1756 ng/L, 2878 ng/L, 650 ng/L and 356 ng/L respectively. The results show significant variability in the concentrations of beta-blockers and antidepressants from hospital to hospital. Results comparing these hospital effluents to wastewater treatment plant influents show that hospitals, on average, contributed 0.87% of the total load for the indicated emerging contaminants, with a range from hospitals varying between 0.25% and 1.79%. The findings also include the effects of short hospital stays indicate patients taking pharmaceuticals at home, as being evident from the monitoring results. Ninety-five percent upper confidence limits for individual beta blockers and anti-depressants are provided, as computed from available technical literature and monitoring results from this research, as a means of providing reasonable upper bounds on the magnitudes of the individual compounds.
Edward A McBean, Hamid Salsali, Munir A Bhatti, Jinhui Jeanne Huang