Micropollutant accumulation in edible plants irrigated with reused wastewater

Wastewater reuse for irrigation purposes is a quite popular trend nowadays because it is an environmental-friendly practice that helps relieving water-stress in locations where water availability is limited. Regulations and guidelines have set the water quality limits for reusing wastewater, but micropollutants’ fate is currently not sufficiently studied when it comes to uptake by edible crops and the implications of it. For this study, we applied hydroponic cultivation of garden cress seeds, using cotton as growing medium and irrigating them with the secondary effluent from a full-scale wastewater treatment plant. An analysis for a spectrum of 46 micropollutants was made to samples of the secondary effluent, the remaining water in the greenhouse, the growing medium and the plant tissues. 37 compounds were present in the water samples. Nine of them were found in the plant tissues, in which seven had much higher concentrations in the roots than in the stems and leaves. The concentrations in the plant tissue were very low, however, dealing with edible plants there are many aspects that need to be characterized and further studied; like the uptake of these compounds by other vegetables with longer growing periods and the use of soil as growing media.