Análise química de solos e água para caracterização ambiental de um antigo lixão no município de Caçapava do Sul – RS

Abstract

The impact on human health by water, rocks and minerals has been known for several years, but in Brazil there is still a shortage of systematic and multidisciplinary studies on the relationship between geological processes and human health, especially in the field of Medical Geology. However, in recent years there has been a resurgence of interest in this field of study. Together, geologists and public health professionals, have made important contributions to understanding of new exposure pathways of exposure and causes of environmental health problems, such as: exposure to toxic levels of chemical elements, trace element deficiencies, exposure to dust/pollution and chemical compounds in drinking water. In Brazil, especially in interior cities, such as Caçapava do Sul – RS, control and scientific knowledge about the disposal of household solid waste, which can generate several consequences for the environment and man, is scarce or nonexistent. The lack of previous studies and constant monitoring can lead to continuous pollution of soil, air, surface and ground water. Knowledge about soil characteristics allows us to predict, evaluate and characterize its health. The anomalous concentrations, superior or inferior to the current Brazilian legislation of some chemical elements can be harmful to the regional biota and, consequently, to human being. Thus, periodic monitoring of sites prone to pollution is necessary. This work aims to characterize the geochemistry of the soil in an area in Caçapava do Sul – RS, from samples collected in a landfilled dumping ground that has been in use for 14 years. Despite the effort to landfill the deposited waste, the action of time caused remobilization of the overlapped material. That created escape surfaces that carried part of the soil, leaving the old residue exposed locally in some areas. From the collection and analysis of 17 soil samples trough X-ray Fluorescence Spectroscopy with Inductive Dispersion (EDXRF), some elements such as Fe, Al, and Cd were found to be related to anthropogenic sources. The acquisition of 5 samples of water from the proximal slopes of the study area and analysis of their hydrochemical characteristics identified small variations of pH, total hardness, electrical conductivity and alkalinity of the regional water resources, which may be related to the old dumping ground. Although showing evidences of correlation, it is necessary to carry out more specific analyses to ascertain the water and soil quality of the region.