Comparative uptake and translocation of pharmaceutical and personal care products (PPCPs) by common vegetables

Reuse of treated wastewater to irrigate agricultural crops is increasing in many arid and semi-arid areas around the world. The presence of numerous pharmaceutical and personal care products (PPCPs) in treated wastewater and their potential transfer into food produce such as vegetables poses an unknown human health risk. The goal of this study was to identify PPCPs that have a comparatively high potential for plant uptake and translocation. A total of 20 frequently-occurring PPCPs were compared for their accumulation into four staple vegetables (lettuce, spinach, cucumber, and pepper) grown in nutrient solutions containing PPCPs at 0.5 or 5μgL(-1). Triclocarban, fluoxetine, triclosan, and diazepam were found at high levels in roots, while meprobamate, primidone, carbamazepine, dilantin, and diuron exhibited more active translocation from roots to leaves. Root uptake of neutral PPCPs was positively correlated with the pH adjusted log Kow(i.e., log Dow), and was likely driven by chemical adsorption onto the root surfaces. In contrast, translocation from roots to leaves was negatively related to log Dow, suggesting hydrophilicity-regulated transport via xylems. Compounds preferentially sorbed to roots should be further evaluated for their uptake in tuber vegetables (e.g., carrot, radish) under field conditions, while those easily translocated into leaves (e.g., carbamazepine, dilantin) merit focused consideration for leafy and other vegetables (e.g., lettuce, cucumber). However, estimation of dietary intake by humans suggested the implied risks from exposure to PPCPs via wastewater irrigation to be negligible.