Multipath diffusion process and spatial accumulation simulation of Cd in lead-zinc mining areas

Area of Science:

• Environmental Science
• Geochemistry
• Mining Engineering

Background:

• Lead-zinc mining areas are significant sources of heavy metal pollution, particularly cadmium (Cd).
• Understanding the multipath diffusion and spatial accumulation of Cd is crucial for environmental risk assessment and mitigation.

Purpose of the Study:

• To develop and validate a multipath diffusion and spatial accumulation model for Cd in a lead-zinc mining area.
• To quantify the contribution of different pathways, such as atmospheric deposition and runoff, to Cd accumulation.
• To provide a scientific basis for preventing heavy metal diffusion in mining regions.

Main Methods:

• Combined process simulation with actual field measurements.
• Utilized accuracy and Root Mean Square Error (RMSE) analysis for model validation.
• Employed two sub-watersheds with varying runoff directions for model verification.

Main Results:

• Cadmium diffusion showed a quadratic inverse proportional relationship with distance from the pollution source.
• Average annual atmospheric Cd sedimentation was 0.71 × 10^-6 g, with runoff diffusion contributing over 80% to Cd pollution.
• Model accuracy reached 75% when the concentration range of Cd in runoff sediment (k) was between 10% and 90%.

Conclusions:

• The developed model accurately simulates spatial Cd accumulation in lead-zinc mining areas.
• Runoff is the dominant pathway for Cd diffusion and accumulation.
• The findings support the development of effective strategies for heavy metal pollution control in mining environments.