This study assessed heavy metal(loid) pollution (As, Pb, Zn, Fe, Cd, Cu, Cr, Ni) and
the associated health risks in agricultural soils near the Menzel Bourguiba steel
smelter in northeastern Tunisia. The extent of contamination was quantified using
multiple pollution indices, including the geo-accumulation index (Igeo) and enrichment
factor. Health risks were evaluated using both deterministic and probabilistic approaches,
incorporating Monte Carlo simulation to characterize uncertainty and Sobol sensitivity
analysis to identify key influencing parameters. Mean heavy metal(loid) concentrations
(mg kg −1 ) decreased in the order of Fe (28,136) > Zn (480.73) > Cr (184.85) > Pb
(147.12) > Ni (73.5) > Cu (55.50) > As (15.97) > Cd (5.27). Pollution indices consistently
identified Cadmium (Cd) and Lead (Pb) as the primary contributors to soil contamination.
Enrichment factor analysis revealed extreme enrichment for Cd, with concentrations
exceeding background levels by up to 58 times. Probabilistic risk assessment indicated
a high potential for adverse health effects. For children, the non-carcinogenic Hazard
Index for lead exceeded the safe limit of 1 in over 50% of simulations. The Total
Carcinogenic Risk (TCR) for children surpassed the acceptable threshold (1 × 10 −4
) in over 80% of simulations for As, Cr, and Cd. For adults, the TCR for Cd exceeded
this threshold in over 70% of cases. The 95th percentile of the simulated TCR for
children reached 5.7 × 10 −3 , a value 57 times higher than the acceptable limit.
Sobol analysis identified the soil ingestion rate as the primary source of uncertainty
in the risk models (contributing 68–74%). These findings indicate that the soil contamination
poses a significant health risk to the local population, warranting targeted intervention
strategies.
