Uptake and Accumulation of Pharmaceuticals and Hormones in Vegetables after Irrigation with Reuse Water

The widespread occurrence of pharmaceutical and personal care products (PPCPs) and steroid hormones in watersheds has been recognized as an emerging environmental issue. The potential uptake and accumulation of these emerging contaminants by food plants that are irrigated with contaminated water could be a food safety issue. In the present project, uptake, translocation, accumulation, and depuration of seven PPCPs and three steroid hormones in lettuce and tomato plants were investigated using hydroponic cultures with compound concentrations of 0.5, 50, or 500 μg L-1 and several exposure scenarios. An isotopic dilution method was developed for the analysis of trace levels of PPCPs and hormones in food plants using liquid chromatography-tandem mass spectrometry (LC-MS/MS), combined with ultrasonication-shaking extraction and solid phase extraction (SPE) cleanup. For lettuce plants, all targeted PPCPs and hormones were detected in the roots. The bioaccumulation factors (BAFs) of PPCPs and hormones in lettuce roots were more than 1, indicating these emerging contaminants can be bound to or taken up by the plant roots. In lettuce leaves, only caffeine (CAF), carbamazepine (CBZ), and sulfamethoxazole (SMO) showed very high BAF values compared to other targeted PPCPs and hormones, indicating that these three compounds can easily translocate from lettuce roots to leaves and thereby accumulate in plant leaves. For tomato plants, all PPCPs and hormones were detected in the roots. By contrast, the translocation factor (TF) values of all targeted compounds except CAF and CBZ were very small in tomato plants, implying their poor translocation from roots to above-ground plant parts following uptake. The BAFs of all targeted hormones in tomato fruits were much less than 1, suggesting that hormone contamination of tomato fruits after irrigation with contaminated water could be negligible. In addition, exposure study showed that accumulation of PPCPs and hormones may rapidly reach a steady level (< 1 week) in lettuce plants with exposure through contaminated water. Lettuce plants also appear to have a potential to metabolize accumulated PPCPs, with the exception of triclosan (TCS) in roots and sulfamethoxazole (SMO) in leaves. Hormones did not exhibit any tendency to depurate. Comparing protective estimates of human exposure in lettuce leaves and acceptable daily intake (ADI) values suggests that CBZ and ethinylestradiol (EE2) could exceed their ADIs under some circumstances.