Establishing cost effective methods to analyze a wide range of pharmaceutical compounds through laboratory scale experiments aimed at assessing fate and transport mechanisms in groundwater
Pharmaceutical and organic wastewater contaminants have been increasingly detected in drinking water and groundwater supplies. A stepwise approach was used to determine a simple and cost effective method for testing various classes of pharmaceutical compounds. A robust, accurate method was developed and validated using two commonly detected pharmaceuticals in water resources; sulfamethoxazole (SMX) and carbamazepine (CMP). Tandem solid-phase extraction in conjunction with high performance liquid chromatography (HPLC) analysis was effective for quantifying concentrations of analytes under environmentally relevant laboratory-scale scenarios. Using predetermined standards and known concentrations, an average recovery percentage of 96.25% was achieved in validation efforts. Batch tests consisting of streambed sediment and known concentrations of the study analytes were conducted over a 96-hour period to determine Freundlich adsorption isotherm coefficients (KF) and retardation factors (R). The results of these tests demonstrate that CMP had a greater affinity to adsorb to the sediment (K_F=8.79) compared to SMX (K_F=4.22) with corresponding retardation factors (R) of 49.3 and 20.7, respectively. In addition to the development of a promising cost-effective analytical method to quantify different types of pharmaceutical compounds in groundwater, this work also demonstrates that SMX (compared to CMP) may pose higher risk for entering drinking water supplies, as natural retention processes will be less under most conditions. Limits of detection using the SPE/SPE HPLC-UV method was 0.48 μg/L for SMX and 0.60 μg/L for CMP.