Transport behavior of the pharmaceutical compounds carbamazepine, sulfamethoxazole, gemfibrozil, ibuprofen, and naproxen, and the lifestyle drug caffeine, in saturated laboratory columns.

Despite the large number of pharmaceutically active compounds found in natural environments little is known about their transport behavior in groundwater, which is complicated by their wide range of physical and chemical properties. The transport behavior of five widely used and often detected pharmaceutical compounds and one lifestyle drug has therefore been investigated, using a set of three column experiments. The investigated compounds were the anticonvulsant carbamazepine, the lifestyle drug caffeine, the antibiotic sulfamethoxazole, the lipid regulator gemfibrozil, and the nonsteroidal anti-inflammatories ibuprofen and naproxen. The columns were filled with three different types of sand. The substrates consisted of artificially prepared iron-coated sand, artificially prepared organic carbon sand (with 5% leaf compost), and natural aquifer sand from Long Point, Ontario (Canada). The experiments were conducted simultaneously under the same hydraulic conditions and with the same input solution of about 1µg·L-1 of each compound. The transport behavior of the organic compounds differed significantly between both the different columns and the different compounds. A strong correlation was observed between the retardation factors for carbamazepine, gemfibrozil, and ibuprofen and the organic carbon content of the substrate. While the retardation increased with increasing organic carbon content, no direct relationship was observed between the organic carbon content and the removal of these compounds. In contrast, the retardation factors for sulfamethoxazole and naproxen showed no correlation with the organic carbon content but these compounds were significantly removed in the presence of organic matter. The influence of the Fe3+ surfaces in the iron-coated sand was less significant than expected, with all compounds except for sulfamethoxazole having retardation factors <1.8. Caffeine was so strongly removed during transport through those substrates containing organic carbon that no reliable retardation factor could be determined.

Acesulfame-K and pharmaceuticals as co-tracers of municipal wastewater in a receiving river.

Wastewater treatment plant (WWTP) effluents are important sources of emerging contaminants at environmentally-relevant concentrations. In this study, water samples were collected from a river downstream of two WWTPs to identify practical tracers for tracking wastewater. The results of the study indicate elevated concentrations of Cl(-), nutrients (NH3-N and NO2(-)), the artificial sweetener acesulfame-K (ACE-K), and the pharmaceuticals carbamazepine (CBZ), caffeine (CAF), sulfamethoxazole (SMX), ibuprofen (IBU), gemfibrozil (GEM), and naproxen (NAP) in the river close to the WWTPs that decreased with distance downstream. A correlation analysis using the Spearman Rank method showed that ACE-K, CBZ, GEM, NAP, and Cl(-) were strongly correlated with each other over a 31 km stretch of the river in the study area. The strong correlations of these target compounds indicate that the artificial sweetener ACE-K and the pharmaceuticals CBZ, GEM, and NAP can potentially be used as co-tracers to track wastewater.