Fate and effects of waterborne contaminants of emerging concern in the soil-plant system : impact of biochar soil amendment to mitigate their plant uptake

Open Access

Abstract

Water scarcity is an issue of global concern due to the increase of the population and the climate change, which both increase the water demand. Many arid and semiarid countries are facing high water stress and the use of reclaimed water becomes a valuable resource. Many countries' economy is based on the agro-food sector, with amounts ca. the 70% of water demand. For this reason, reclaimed water represents an important component of wise water management. Wastewater treatment plants (WWTP) are designed to remove efficiently some biodegradable compounds, however, they are not able to remove a number of recalcitrant organic coñtamina0nts known as chemical oxygen demand (COD). There are many sources of water pollution, and contaminants of emerging concern (CECs) including many compounds that they are not legislated and recently some effects to the environment have been observed. For example, pharmaceuticals, personal care products, flame retardants, microplastics, etc. Consequently, plants are exposed to a huge number of chemical contaminants that are present not only in water, but also in air or soil. For this reason, it is important to understand the dynamics involved in the plant uptake of these CECs and more specifically in crops. In this Thesis, the uptake of some CECs, chosen by their occurrence in the environment and their physical-chemical properties, has been assessed. To elucidate the factors that are involved in the uptake of these contaminants, three different experiments were performed in a greenhouse. Therefore, this Thesis is divided in the three experiments. In the first one, the plant uptake of some CECs with a perlite:sand mixture and its modelling were assessed. Moreover, a mass balance was performed to evaluate the persistence of the CECs in the substrate. Then, by inverse modelling, the half-lives of CECs in the soil-plant system were estimated. In the second experiment, most of the CECs that were added in the irrigation water were taken up by lettuce. Hence, in this experiment, biochar, which ...