Assessing and Managing Impact of Pharmaceuticals in Irrigation Water on Fresh Produce Safety.

Pharmaceuticals are emerging contaminants that have bene widely detected in surface water, groundwater, soil, and sediment worldwide. Concerns are heightened over their potential impact on food safety. Because consuming pharmaceutical-tainted food is a direct human exposure pathway, it is critical to investigate the pharmaceutical residue levels in food crops grown in contaminated soils or irrigated with reclaimed water. In particular, fresh produce is often minimally processed and thus has a shorter time for dissipation prior to consumption. Therefore, we have studied the uptake and accumulations of pharmaceuticals in greenhouse-grown lettuce under overhead or surface irrigations. Our results indicate that pharmaceuticals of large molecular weight and low water solubility had greater concentrations in lettuce shoots under overhead irrigation than surface irrigation. Pharmaceuticals of low molecular weight and high water solubility are less clearly influenced by irrigation methods. These results suggest that irrigation scheme can be optimized to reduce the food safety impact, when using the reclaimed water for crop irrigation. We have also investigated the removal efficiency of pharmaceuticals from contaminated fresh produce by varying washing time and wash water chemistry. Our results suggest that washing practice can be better designed to reduce the pharmaceutical residue levels in fresh produce. In summary, better assessment of pharmaceutical fate in fresh produce production system can help develop management practices to reduce the impact of waterborne pharmaceuticals on food safety.