New Mexico Geological Society Annual Spring Meeting — Abstracts

Endocrine disruptor chemicals (EDC), including pharmaceutical and personal care products (PPCP), are contaminants of significant concern found in aquatic environments worldwide. Numerous EDC and PPCP have been measured in treated and non-treated sanitary sewage effluent throughout the United States and Europe during the past two decades. Since the mid-1940s, Los Alamos National Laboratory (LANL) and Los Alamos County, New Mexico have released sewage effluent to three watersheds that provide recharge to groundwater beneath the Pajarito Plateau. The regional aquifer at Los Alamos is a sole-source aquifer providing high-quality drinking water to the public and LANL. Sampling stations located across the Pajarito Plateau were analyzed for 32 EDC and PPCP with detection limits in the low nanogram/liter range. These include wells screened in alluvial and perched intermediate-depth groundwater and wells and springs pumping or discharging from the regional aquifer. Surface-water sampling locations were selected in two watersheds currently receiving treated sewage and cooling-tower effluent from NPDES outfalls. Analytical results showed EDC and/or PPCP at most of the sampling locations, with variable types and frequency of detections. Commonly detected pharmaceuticals include acetaminophen, caffeine, carbamazepine, DEET, Dilantin, meprobamate, methadone, salicylic acid, and sulfamethoxazole. Acetaminophen, caffeine, and sulfamethoxazole were detected at the highest frequency. Several of the wells containing pharmaceuticals also contain contaminants associated with treated sewage, cooling tower, and industrial-derived effluents such as nitrate, boron, chromate, and tritium. Presence of EDC and PPCP in groundwater at Los Alamos refines the conceptual model for fate and transport of mobile contaminants migrating through the deep vadose zone (305 meters thick) to the regional aquifer.