Dr. Michael Young
Associate Director for Environmental Systems
Bureau of Economic Geology
Scarcity of potable water in arid and semi-arid environments has led to the wider use of recycled water for irrigating agricultural fields, parks, golf courses, and other areas. One concern using recycled water as a source of irrigation has been the presence of pharmaceuticals and personal care products (PPCPs), and their fate and transport in water that percolates below the rootzone of plants and potentially toward groundwater; however, very few multi-year field studies have been reported on this topic in the peer-reviewed literature. In this study, we assessed mass flux of 13 target pharmaceutical compounds over a 2-yr field study, using drainage flux gages installed in the fairway of three active golf courses in California and one in Nevada. The gages contained a soil column 60-cm thick. The sites varied by climate, soil type, and depth to groundwater, but were similar in their turfgrass management and length of study. The results showed the presence of at least one pharmaceutical compound in nearly all samples collected, though their concentrations were substantially lower than in source water. Mass fluxes were below 0.1 g/ha for all compounds during the 2-yr study, and often less than 1 mg/ha. Carbamazepine, meprobamate, and sulfamethoxazole were most commonly found in drainage water, representing nearly 80% of all detections. The other six compounds identified in drainage water (diclofenac, gemfibrozil, ibuprofen, naproxen, triclosan, and trimethoprim) occurred between one and nine times; four compounds (atenolol, atorvastatin, diazepam, and fluoxetine) were not detected in any drainage samples. Results show substantial removal efficiency through only 60 cm of soil, and highlighted the benefits of the turfgrass/soil system for removing these compounds.