Assessment of pesticide contamination in groundwater bodies in the Jucar River Basin (Spain) and its spatial distribution

Abstract

Exposure to the pesticides used in agriculture is a threat to human health and the environment. Nowadays, the world experiences a number of global changes, such as anthropogenic climate change and agricultural expansion which are associated to an increased consumption of water, fertilisers, and pesticides. This has increased the risk of soil and groundwater contamination. In this study, the model Pesticide Root Zone Model 5 (PRZM 5) has been applied to model the behaviour of pesticides in groundwater bodies within the Júcar River Basin (JRB) in Spain. We consider a groundwater body to be at risk of contamination if pesticide estimated concentrations exceed the Maximum Concentration Levels (MCL) and two additional indicators. We identified that Mancha Oriental groundwater body presents a high risk of Atrazine contamination. In the case of the Bromacil risk indicators, Castellón groundwater body was the most likely to be contaminated. Regarding Terbuthylazine risk maps, the probability of exceeding the threshold is low, thus posing a minimal risk in the studied area. Conversely Terbumeton risk maps, showed a high risk of contamination, detecting new areas of contamination that had not been studied for contamination for any pesticide. The spatial distribution of pesticides corresponds to areas mostly dedicated to irrigated agriculture which are associated to regular pesticide applications. Therefore, it can be concluded that the amount of pesticide applied on the field is the most important factor influencing pesticide concentration in groundwater bodies.