Microplastics and contaminants emerging in surface waters: watersheds uses and impacts on the environment

Abstract

Microplastics are solid polymer particles <5mm in size and can be classified as primary or secondary microplastics. These particles are present in several environmental compartments and have effects on the organisms that live in these environments, such as reproductive performance, energy metabolism and the physiology of the biota liver at different trophic levels. Emerging contaminants are substances of anthropic or natural origin, detected in all environmental matrices and which are not commonly monitored. The presence of these contaminants in the environment can cause adverse effects on humans and biota due to chronic exposure to residual concentrations of the compounds or mixture of them, with studies reporting the ability to cause changes in the endocrine system, abnormal physiological effects and reproductive impairment, increase cancer incidence, among others. The development of new analytical techniques has made microplastics and emerging contaminants more evident in the scientific environment over the past few years and could be studied in greater detail, facilitating the understanding of this, which is considered a very complex environmental dynamic to be elucidated. In Brazil, there are studies on emerging contaminants in some regions of the country, with an emphasis on the south and southeast regions, but research on the occurrence of microplastics in freshwater bodies is still scarce. Thus, studies related to the presence, characterization and quantification of these contaminants that can be associated with the uses of hydrographic basins are necessary, in order to trace the real anthropogenic impacts in specific regions, considered critical from the environmental point of view, for example, those with high water demand and that face serious shortage problems in some periods of the year. The Atibaia River basin is comprised of an industrial and densely urbanized area, while the Turvo/Grande basin comprises a predominantly agricultural region. Given these different uses of the basins, these regions were chosen as strategic to outline a case study on the occurrence of microplastics and emerging contaminants considered relevant to the State of São Paulo, in order to explore together with the commonly monitored physical-chemical parameters, bringing an innovative look to the quality management of water resources in the state. (AU)