Geochronologies of pharmaceuticals in a sewage-impacted estuarine urban setting (Jamaica Bay, New York).

Pharmaceuticals are active substances found in sewage effluents and can negatively impact aquatic systems even at low concentrations. A fraction of these chemicals can be attached onto suspended solids and end up in sediments. This research shows concentrations of a wide group of pharmaceuticals in sediments from an urban estuarine setting (Jamaica Bay, New York). Highest concentrations (>75 ng g(-1)) were measured in surface sediments from the inner part of the bay, directly affected by sewage discharges and where water circulation is more restricted. Only 16 out of 61 target compounds were detected, and those positively charged (e.g., metoprolol) and/or highly hydrophobic (e.g., tamoxifen) were predominant. Their sediment-pore water partition coefficients were also calculated for the first time and were in a range between 11 and 2041 L/kg depending on the compound. Analysis of dated sediment cores revealed that pharmaceuticals were well preserved along the sedimentary column, a highly reducing environment. There was an increase in the concentration of most target compounds over the last five decades correlated with the increase in their usage, with some exceptions such as sulfamethazine (now used only for veterinary purposes). Thus, overall concentration of pharmaceuticals in sediment cores showed a doubling time of 9.2 years. Vertical distribution profiles for selected compounds also allowed reconstructing the history of contamination at Jamaica Bay by pharmaceuticals. The use of some of these chemicals as sewage molecular markers was also investigated.