Health risk assessment on a low-cost water desalination and sensor technology compact module - DESERT

The continued use of reclaimed water resources for irrigation may put the agrosystems and the environment at toxicity and health risk. The main aim of the DESERT project is to create an innovative concept as a smart system combining sustainable technology on water treatment and water quality sensors, tuned to the local situation. DESERT project introduces a new approach and vision of agriculture. Reclaimed DESERT-prototype water (PW), as well as the secondary effluent (SW) from a wastewater treatment plant and conventional irrigation water (CW), were used to cultivate mini-romaine lettuce in a greenhouse in Murcia region, Spain. The three waters were drip and sprinkler-irrigated; thus, six treatments were established. To assess the water reclamation potential of the DESERT-prototype, physicochemical and microbiological quality of waters, agricultural and microbiological quality of produce of all treatments, and health risks related to their consumption were analyzed and compared against relevant Spanish/European standards and guidelines. PW irrigated lettuces, unlike SW and CW ones, did not present any detectable pathogenic presence, thereby rendering them in safely consumable leafy greens. Deterministic and stochastic manager-oriented QMRA models, whose results showed negligible risks of infection in all PW exposure scenarios, confirmed this safety level. Contrariwise, some sprinkler-irrigated SW and CW scenarios presented unacceptable risks of infection. However, public acceptance of using reclaimed water, as well as its tolerable risks, rely on factors that are beyond mere risks estimations, such an appropriate risk communication and management.