Under the enormous pressure of water scarcity, municipal treated wastewater is increasingly viewed as a valuable water resource for agricultural irrigation in many parts of the world. However, treated wastewater contains numerous so-called contaminants of emerging concern (CECs), including bisphenols, steroids, and pharmaceutical and personal care products. Many CECs can cause adverse ecotoxicological effects at environmentally relevant levels. However, their potential for accumulation into higher plants such as crops and the subsequent human exposure is poorly understood. We have carried out greenhouse and field studies to evaluate uptake of common CECs into vegetables. Plant uptake was closely related to the physico-chemical properties of CECs, and further varied among plant species. 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 root surfaces. Translocation from roots to leaves was negatively related to log Dow, suggesting that transpiration-driven transport via xylems. Under field conditions, 9 out of 20 PPCPs were frequently detected in edible parts of vegetables. However, the overall accumulation was low, with the total concentrations ranging 0.01�7.3 ng/g. These levels would translate to smaller than 0.1% of a single medical dose from the consumption of these vegetables for an entire year, suggesting a limited risk from dietary uptake of vegetables irrigated with treated wastewater. This presentation will provide an overview of occurrence of CECs in treated wastewater, adverse ecological effects of CECs, accumulation into plants, and future research needs.

Treated wastewater irrigation: Emerging chemical contaminants and food safety

248th National Meeting (2014)

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