Coal Geochemistry and Potential Environmental Pollution: A Case Study of the Guaíba Coalfield in the Southern Paraná Basin, Brazil

Geochemical studies of coal mining projects in Environmental Impact Studies (EIS) are often limited to economic characterization of the mineral resource, resulting in a gap in the understanding and assessment of the potential environmental impact caused by coal exploration. A set of analytical techniques were carried out with the general objective of measuring the potential impact of the possible exploitation of coal from the Guaíba Coalfield located in the southernmost region of Brazil. The results indicate coal deposition in a lacustrine environment with a significant continental contribution from a fan delta and a little marine influence. Most of the analyzed chemical elements present higher contents in the samples than the world average. When associated with organic matter and clay minerals, these elements become more readily available to the environment than sulfides. Among the analyzed elements, arsenic (As), zinc (Zn), and fluoride (F) are the most critical due to their enrichment levels (> 10 times for As and Zn) and potential impact on human health.