Integration of soil magnetometry and geochemistry for assessment of human health risk from metallurgical slag dumps

The main objective of the study was an assessment of the pollution level of agricultural land located close to dumps of industrial waste remaining after former Zn and Pb ore processing in Poland. The integrated geophysical-geochemical methods were applied for assessment of soil quality with respect to trace element pollution. Additionally, human health risk induced by the contaminated arable soil and dusting slag heap was estimated. The investigations pointed out that soils in the vicinity of the metallurgical slag dump in Piekary were heavily polluted. Spatial distribution of magnetic susceptibility corresponding well with distribution of the content of potentially toxic elements indicated the local "pollution hotspots." Proper geophysical and geochemical data interpretation supported by statistical factor analysis enabled identification of three different sources of pollution including metallurgical slug dump as a main source, but also traffic pollution influencing the area located along the busy road and relatively strong influence of the geochemical background. Computed health hazard index revealed no adverse health effect to the farmers cultivating arable soil, but in the direct vicinity of dusting, slag dump health risk occurred, caused mostly by very toxic elements as As and Tl. In the future, investigation should be focused on contribution of different sources to the heavy metal pollution in soil-crop system in this area. It should be highlighted that a site-specific approach should be taken in order to redevelop this kind of area in order to reduce ecological and human health threat. The study proved the integrated two-stage geophysical-geochemical method to be a feasible, reliable, and cost-effective tool for identification of the extent of soil pollution and areas at risk.