Fate and Transport of Pharmaceuticals In Soil Turfgrass Systems Irrigated with Reclaimed Water.

Treated sewage effluent (reuse water) is used in communities throughout the United States to augment existing water resources. Using reuse water allows communities to diversify their water resource portfolios while at the same time utilizing such water in an environmentally acceptable and responsible fashion. In Las Vegas NV, over 30 of the existing 53 golfcourses utilize reuse water to irrigate fairways and greens. However, such water contains elevated soluble salts that require an irrigation management strategy that incorporates effective leaching to maintain soil salinity below threshold levels. Such leaching is critical for the maintenance of favorable long term salt balances but also provides an opportunity for other soluble compounds to be leached from the soil profile. This has long been a concern with nitrates in reuse water but more recently with pharmaceuticals and personal care products (PPCP). We conducted a lysimeter study in which we investigated the fate and transport of 14 PPCP compounds over a 745 day monitoring period. Reuse water from the Clark County, NV treatment facility was used to irrigate lysimeters which were packed with either a loamy sand or sandy loam soil, planted to bermudagrass/ryegrass or left bare in which a leaching fraction of 0.05 or 0.25 was imposed.  Results from the lysimeter study would suggest that most PPCP compounds are not very mobile. However, after a 745 day period, nine of the fourteen compounds were detected in the drainage. Of these compounds, only three revealed a consistent pattern, which was correlated with the number of unsaturated pore volumes being displaced from the 120 cm soil profiles. These three compounds were primidone, sulfamethoxazole and carbamazepine. In the case of primidone, 94% of the variation in the amount leached could be described by the number of unsaturated pore volumes drained, the % sand in the soil and the average redox potential at the 105 cm depth.