Reclaimed water irrigation: Accumulation of contaminants of emerging concern in food crops

Irrigated agriculture is a predominant economic activity in many areas of the Mediterranean region.  However, water scarcity and restrictions on the use of fresh water resources in high agricultural production regions, endangers sustainable agricultural development.  So, alternative water resources are necessary.

The use of reclaimed water for agriculture irrigation makes available a low-cost water source, providing an additional source of nutrients for the plants, helping to reduce the amount and costs associated with the consumption of synthetic fertilizers in agriculture. However, this practice is not a remedy for water scarcity free of disadvantages. Among them, the presence of contaminants of emerging concern (CECs) is one of the most worrying to the scientific community. The problem with these compounds is that they are not completely removed during wastewater treatment, which makes their long-term consequences unpredictable. On the other hand, the absorption and bioaccumulation of CECs in food crops is a matter still to be clarified.

In this work, the absorption capacity, accumulation and persistence of a selected group of CECs in real crops (baby lettuce) irrigated with reclaimed water from a WWTP were evaluated. Results showed different behaviors depending on CECs properties and concentrations, indicating a progressive accumulation when the culture time increased. So, the chemical quality of reclaimed water is a key issue in safe agricultural irrigation.