Ecotoxicological and pre-remedial risk assessment of heavy metals in municipal solid wastes dumpsite impacted soil in morocco

Abstract

Study related to heavy metal pollution and subsequence health risk assessment adjacent to landfills region is indispensable since landfills are a convergence point for hazardous elements which have adverse impacts on the soil and subsoil in the surrounding area with a threat to human health and ecosystem. In this view, assessing the spatial distribution of heavy metals, and evaluating their associated hazards on public health in the areas surrounding open dumpsites in Morocco using pollution indicators, multivariate statistics, and health risk assessment are the main objectives of the current work. The results of this paper indicated that the average concentrations of Zn, Cd, Fe, Cu, Ni, Pb, and Cr were well above their geochemical background. The enrichment of soils by heavy metals was confirmed by the analysis of available fractions of metals using DPTA and CaCl2. Values of pollution indexes (Geo-accumulation index, Pollution Load Index) indicated that soils in the vicinity of the landfill had moderate to high contamination level (PLI = 1.84), especially due to the enrichment by Cd and Pb. Multivariate statistical analysis and Enrichment Factor showed that heavy metals mainly originated from anthropogenic sources related to disposing practices of Municipal Solid Wastes. As well as, the results of the non-carcinogenic risk showed that daily intake for ingestion pathway was higher than for inhalation and dermal contact. Values of hazard index (HI) for trace elements exceeded the safe level (HI > 1), for children. Likewise, the total carcinogenic risk of Pb and Cd in both groups is less than the EPA threshold (10−6), indicating an acceptable carcinogenic risk. This pre-remedial assessment provides useful tools and guidelines, to propose the appropriate remediation technique for this kind of open dumpsites.