Pharmaceutical Footprint in Domestic Wastewater: Case Study in Malaysia

Increasing pharmaceutical consumption usage today has contributed to the rising frequency of occurrence and detectable concentration of pharmaceuticals in domestic sewage. Current sewage treatment technologies were not designed and, thus, will not thoroughly remove this pollutant, therefore discharged along with the effluent to the waterways, leading to potential ecological risk. The current study investigates the occurrence of various classes of pharmaceuticals (analgesic and anti-inflammatories, antibiotics, antifungals, antihistamines, antihypertensives, beta-blocker, lipid regulators and psychiatric drugs and antidepressants) in three different sewage treatment plants with varying catchments areas, denoted as STP 1 (mixed development), STP 2 (majority residential) and STP 3 (commercial residential) using liquid chromatography time-of-flight mass spectrometry (LC-TOF/MS). The consumption trend of each compound in each STP was evaluated based on their footprint in domestic wastewater and their ecotoxicology risk to the environment. Thirteen compounds were detected, while others were absent in either influent or effluent of the STPs. High pharmaceutical concentration is found dominantly in STP 1, which is expected due to socio-demographic residential factors. Ciprofloxacin was detected in all samples with the highest concentration at 965.89 ng/L in the influent and 2285.90 ng/L in the effluent, showing the possibility of being invulnerable to the treatment process. The second dominant compound is the antidepressant medicine of venlafaxine and citalopram, where high concentration was measured in all samples up to 325.49 ng/L and 607.96 ng/L in the influent and effluent, respectively. The current detected concentration found is consistent and within the range of reported values around the globe. Ecotoxicological risk assessment indicated two high-risk compounds, venlafaxine and sulfamethoxazole, while others were medium to no risk. The study provides a preliminary baseline scenario of the current presence of pharmaceutical compounds in our waterways, particularly identifying high-risk elements that pose a potential ecological risk to humans and the environment.