Assessing the Vertical Distribution and Health Risks of Trace Metal Elements in Phosphogypsum-Enriched Agricultural Soils of Typical Peri-Urban Areas in Southwestern Tunisia

Large quantities of phosphogypsum originate from accumulated Tunisian industrial waste each year. Thus, mining effluents that do not comply with Tunisian discharge standards affect the hydrographic network and cause not only soil contamination of trace metal elements but are also considered a source of toxicity in the food chain and ultimately in the human body organs. In a bid to determine the contamination status and assess heavy metal pollution and the health risk of agricultural soils in a typical peri-urban area in southwestern Tunisia-M'Dhilla Basin, sex samples subdivided into 17 sub-samples from three different depths (0-60 cm), (0-80 cm), and (0-200 cm) were collected with a stainless steel auger. This study is based on physic-chemical analysis using standard laboratory procedures, X-ray fluorescence technique, and multivariate statistical analysis. Results showed that trace metal element concentration ranged as follows: Sr > Zn > Cr > Cd > Pb. A significant contamination was discovered in the study area that indicated a high Cr and Zn topsoil contamination and a homogenous pattern in Cd and Pb (p < 0.05). Assessment of the trace metal element pollution was determined with calculations of the contamination factor and the pollution load index. Our finding proved that the study area was highly polluted with Cd, Sr, and Zn. Accordingly, high concentrations of trace metal elements cause serious environmental problems to the atmosphere, soil, and water. Carcinogenic health risks worsen and affect most of the inhabitants in the mining basin of M'Dhilla.

Automated summary

Large quantities of phosphogypsum from Tunisian industrial waste have a negative impact on the hydrographic network and pose a risk to soil contamination and human health due to toxicity in the food chain. A study conducted in the M'Dhilla Basin of southwestern Tunisia revealed high levels of trace metal element pollution, particularly with Cd, Sr, and Zn, which exacerbate environmental problems and increase the carcinogenic health risks for inhabitants in the mining basin.