Behaviour of Pharmaceutically Active Compounds in contact with Reactive Media in Simulated Ground Water

Abstract

Water treatment approaches for pharmaceutically active compounds (PhACs) are restricted by the chemically-variable nature of the PhACs themselves, each successful in treating only a small number; or the adaptability or expense of the treatment system. Minimal study has taken place concerning novel, affordable, amendable treatment media that can be employed on numerous scales and water types, with the potential to treat a variety of PhACs and other water contaminants. This study evaluates the removal of a suite of environmentally relevant pharmaceuticals from water in response to contact with reactive media and/or natural organic matter. Experiments were conducted with batch samples containing a media of interest in simulated ground water spiked with carbamazepine, caffeine, naproxen, gemfibrozil, ibuprofen, sulfamethoxazole and clofibrate, each at an environmentally relevant concentration of 2-2.5 µg l-1. Media investigated included: Stelco-BOF slag (STB), woodchips (WC), Borden sand (BDS), zero valent iron (ZVFe), and granular activated carbon (GAC). Water samples were analyzed for basic water quality parameters and pharmaceutical concentrations were calculated by internal and external calibration of HPLC-MS/MS results. Calculated pharmaceutical removal efficiencies were based upon percent changes in concentration between initial and final measurements. Pharmaceutical removal was observed for all investigated media, with success varying between media and pharmaceutical types. The greatest percent removal, of >99.88% was observed for all PhACs, with concentrations dropping below the limits of detection (LOD) of 3-189 ng l-1, in GAC and ZVFe-GAC mixtures; the smallest percentage removal when considering all media, of 0.0%, was exhibited by ibuprofen and naproxen in STB, BDS and WC samples. The greatest removal was observed within the first 24 hours for the majority of the drugs that showed measurable removals. Results also indicated that the addition of activated carbon to zero valent iron may enhance the reactivity and/or lifespan of the media.