Pharmaceuticals in a temperate forest-water reuse system.

Forest-water reuse systems infiltrate municipal, industrial, and agricultural wastewaters through forest soils to shallow aquifers that ultimately discharge to surface waters. Their ability to mitigate regulated nutrients, metals, and organic chemicals is well known, but the fate of non-regulated chemicals in these systems is largely unstudied. This study quantified 33 pharmaceuticals and personal care products (PPCPs) in soils, groundwaters, and surface waters in a 2000-hectare forest that receives ~1200mm/year of secondary-treated, municipal wastewater in addition to natural rainfall (~1300mm/year). This forest-water reuse system does contribute PPCPs to soils, groundwater, and surface waters. PPCPs were more abundant in soils versus underlying groundwater by an order of magnitude (5-10ng/g summed PPCPs in soil and 50-100ng/L in groundwater) and the more hydrophobic chemicals were predominant in soil over water. PPCP concentrations in surface waters were greater at the onset of significant storm events and during low-rainfall periods when total summed PPCPs were >80ng/L, higher than the annual average. With few exceptions, the margins of exposure for PPCPs in groundwater and surface waters were several orders of magnitude above values indicative of human health risk.