Fate of pharmaceuticals during ground water recharge

Pharmaceuticals and personal care products (PPCPs) have recently. been detected in the aquatic environment. Many studies have identified domestic waste water discharge as the source for detectable concentrations of PPCPs in surface water. PPCPs are a concern for the aquatic environment when production and use are sufficiently large and physicochemical properties are appropriate. Hydrophilic PPCPs present in surface water or waste water may also affect ground water quality where water is used to recharge ground water. However, less is known about how efficiently PPCPs are removed during percolation, through the subsurface. The scope of this study was to. examine the fate of selected PPCPs during ground water recharge at two water reuse sites where secondary and tertiary treated waste water is used for subsequent ground water recharge. The ground water recharge sites selected differ in aboveground treatment and geohydrological settings. The selected pharmaceutials represent blood lipid regulators, analgesics/anti-inflammatories, blood viscosity agents, and antiepileptics. Organic iodine was used as a surrogate parameter for X-ray contrast agents. Composite samples of treated waste water and from ground water monitoring wells were collected and, analyzed for pharmaceuticals using gas chromatography with mass spectroscopic,detection. The study revealed that the stimulant caffeine, analgesic/anti-inflammatory drugs such as diclofenac, ibuprofen, ketoprofen, naproxen, and fenoprofen, and blood lipid regulators such as gemfibrozil were efficiently removed to concentrations near or below the detection limit of the analytical method after retention times of less than six months during ground water recharge. The antiepileptics carbamazepine and primidone were not removed during ground water recharge under either anoxic saturated or aerobic unsaturated flow conditions during travel times of up to eight years. Organic iodine showed a partial removal only under anoxic, saturated conditions as compared to aerobic conditions and persisted in the recharged ground water.