Bioaccumulation of Selected Pharmaceuticals and Personal Care Products between Primary Producers and Consumers in the Tidal Freshwater Potomac River
Abstract
Increased concentrations of pharmaceuticals and personal-care products (PPCPs) and their metabolites flow into our waterways every year and pose a threat to aquatic ecosystems. This study examined the bioaccumulation and trophic transfer of PPCPs within a lower trophic level food web in a tidal freshwater environment: water, sediment, biofilm on the macrophyte (Hydrilla verticillata) and invertebrate snail grazers (Cipangopaludina japonica). Two Virginian embayments, Hunting Creek and Gunston Cove, that feed into the Potomac River and are downstream from wastewater treatment plants were sampled once a month for four months during the summer of 2018. Concentrations (ng/g) of 150 contaminants were calculated and statistically analyzed to compare across sites and food web stage following solid-phase extraction, QuEChERS, and liquid chromatograph triple-quadrupole mass spectrometry (LC-MS/MS). Nine PCPPs, including diuretics, beta blockers, antidepressants, SSNRIs, antihistamines, and steroids, were found consistently each month across both sites and food web stages and were selected for further analyses. The highest levels of PCPPs corresponded to the diuretic drug triamterene (169.9 ng/g wet weight in Hunting Creek and 152.2 ng/g in Gunston Cove) in snails and the antihistamine fexofenadine (127.8 ng/g in Hunting Creek and 269.1 ng/g in Gunston Cove) in water. Compounds either showed significant differences in concentrations in the site x food web stage interaction (diphenhydramine hydrochloride, venlafaxine, fexofenadine), site only and food web stage only (propranolol, desvenlafaxine, budesonide), or food web stage only (metoprolol, triamterene, DEET). Site differences may be due to anthropogenic activities and outflow from wastewater treatment plants, which are likely the main sources of PCPPs at these locations. Additionally, bioaccumulation factors (BAFs), biota to sediment accumulation factors (BSAF) and trophic accumulation factors (TAF) were calculated for the nine selected PPCPs. The snail showed the highest bioaccumulation capability (BAF) for the antihistamine diphenhydramine hydrochloride, which was significantly higher (p<0.05) than either the beta blocker metoprolol or fexofenadine. There were no significant differences between the PCPPS for the calculated BSAFs. The snail also showed the highest TAF for triamterene, which was significantly higher (p<0.05) than the insect repellant DEET. While the snails bioaccumulate certain PCPPs, it is unlikely they receive these chemicals through the grazing process on biofilm; rather, it is more likely that snails are exposed to PCPPs through behaviors that place them in direct contact with the sediment (e.g., burrowing or grazing on the sediment surface). While we have documented the presence of nine different PCPPs throughout the lower level food chain of a tidal freshwater system, further bioaccumulation of these chemicals to higher level vertebrates (i.e., fish) is of interest given the possible ingestion of contaminated fish.
Description
This thesis has been embargoed for 5 years and will not be available until July 2024 at the earliest.
Keywords
PPCPs, Bioaccumulation, Freshwater, Tidal, Biofilm, Trophic transfar