A multi-dimensional approach to assessing source-oriented health risks from heavy metals in coal mining regions

Area of Science:

• Environmental Science
• Geochemistry
• Toxicology

Background:

• Soil contamination with heavy metals (HMs) in coal mining regions presents significant environmental and health risks.
• Traditional methods struggle to differentiate natural from anthropogenic HM sources.
• Limited understanding exists on factors influencing source-oriented health risk assessments.

Purpose of the Study:

• To develop and apply a multi-dimensional framework for quantifying source-specific heavy metal risks in a Chinese mining area.
• To identify the primary sources of soil heavy metal contamination.
• To assess human health risks associated with identified HM sources.

Main Methods:

• Integrated geochemical baseline analysis, Positive Matrix Factorization (PMF), Pearson correlation, GIS mapping, Pb isotope analysis (MixSIAR), and Monte Carlo simulations.
• Quantified enrichment of HMs (Cd, Hg, As, Pb, Cr, Cu, Ni, Zn) against local and national baselines.
• Utilized a Bayesian mixture model and health risk assessment to attribute risks to identified sources.

Main Results:

• Extensive HM enrichment found, with Cd, Hg, As, Pb, and Cr exceeding local backgrounds in over 70% of soils.
• Four main sources identified: natural parent materials (29%), transported parent material (24%), coal mining (27%), and agriculture (20%).
• Unacceptable total carcinogenic risks were observed, with non-carcinogenic risks dominated by coal mining and carcinogenic risks by agriculture and natural sources.

Conclusions:

• The integrated methodology effectively quantifies source-specific HM risks in mining regions.
• Coal mining and agricultural activities are significant contributors to health risks, alongside natural sources.
• Prioritizing control of Hg, As, and Cd linked to mining and agriculture is crucial for targeted interventions and protecting human health and ecosystems.