Assessment of arsenic and its associated health risks due to mining activities in parts of North-central Nigeria: Probabilistic approach using Monte Carlo

Highlights: • The As in soil, water and guinea corn samples are high for most of the mining sites. • The Hazard Indices estimated for the soil and grain samples are 1. • The Hazard Indices estimated for the well waters are ≈1. • The cancer risks are beyond than the acceptable range of 1.00E-6 and 1.00E-4.. This study evaluates health risks associated with Arsenic due to mining activities in parts of North-central Nigeria. 306 samples of soil, water and guinea corn were collected for analysis using Atomic Absorption Spectrometry. The analysis reveals varying concentration of Arsenic that is in most cases, above the acceptable limits of consumption, signifying evidence of pollution. The estimated pollution evaluation indices indicates evidence of pollution due to the mining activities. The estimated values of the bioaccumulation factors are very low. The Average Daily Intake reveals that ingestion pathway is the dominant pathway of exposure. While most of the Hazard Index (HI) estimated for the soil and grain samples are « 1, the HI estimated for the water is ≈1. This therefore, means that the probable non-cancerous effect of Arsenic in the drinking water is high. Based on the Delphii method of classification, the Incremental Lifetime Cancer Risk ranges between level II and level III for the soil and grain samples and between level VI and level VII for the water samples within the study sites. This high cancer risks was confirmed by the mean, 5th and 95th percentiles of the cumulative probabilities using the Monte Carlo simulation.