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

Pharmaceuticals have recently gained attention as emerging contaminants in surface waters throughout the United States.  The majority of these contaminants enter these surface waters via discharged treated sewage effluent. An environmentally acceptable alternative is to use treated sewage effluent as an irrigation source, such as on large turfgrass areas (golfcourses, parks). However, such contaminants may be mobile in soil plant systems. This study was designed to explore the fate and transport of several target pharmaceuticals after recycled water was applied as irrigation.  A controlled lysimeter study was conducted at the Center for Urban Horticulture and Water Conservation in North Las Vegas.  To explore the mobility of pharmaceuticals under different soil-plant-irrigation conditions, lysimeters were constructed and filled with two different soil types (Sandy Loam or Loam), left bare or covered with turfgrass (hybrid bermudagrass/ryegrass) and then irrigated to impose two different leaching fractions (drainage volume/irrigation volume = 0.25 or 0.05)  A hydrologic balance was closed on each lysimeter on a weekly basis to estimate evapotranspiration by measuring soil water in storage (volumetric water content with depth) and irrigation and drainage volumes. Soil water in storage was used to estimate the number of unsaturated pore volume passing through the soil columns.  Redox potential was measured on a weekly basis at depths of 15 and 105 cm to assess the aeration status within the soil profile.  Irrigation and drainage water was analyzed for electrical conductivity, cations, anions and 17 targeted pharmaceuticals. Experimental treatments were imposed for a two year period. Experimental results will be discussed.