Assessing Environmental Risks Across the Bolivian Altiplano Through Mapping
Mining Legacy and Environmental Challenges
Stretching across a vast high-altitude plateau between the eastern and western Andes ranges, the Bolivian Altiplano has long served as one of South America’s most significant mining regions. Precious metal extraction, initiated during the Inca period and greatly expanded under Spanish colonial administration, continues to play a central role in the country’s economy today. Over centuries of intensive resource exploitation, however, mining and smelting operations have generated extensive environmental contamination, including the release of heavy metals into air, soils, and water systems.
To help address these long-standing environmental impacts, the Bolivian Ministry of Mining and Metallurgy collaborated with HydroQual to develop a geographic information system (GIS) application designed to evaluate health risks associated with mining activity and to guide remediation planning.
Integrating GIS with Environmental Modeling
The system was built on the ESRI ArcView 3.x platform and relied heavily on AVENUE scripting to connect the GIS interface with established environmental modeling tools. These models—implemented as compiled FORTRAN routines—simulate the transport and behavior of pollutants across environmental media. After running the simulations, results are exported as ASCII files and incorporated directly into GIS layers for visualization and analysis, allowing decision-makers to interpret complex environmental outputs spatially.
The combined GIS–modeling workflow enables authorities to identify areas exposed to contamination, compare mitigation strategies, and evaluate their likely effectiveness within a unified analytical environment.
Data Structures and Analytical Approach
To optimize performance and analytical efficiency, the application primarily relies on point, line, and raster data structures rather than polygon datasets. Raster-based modeling, performed using ESRI Spatial Analyst tools, allows rapid computation of pollution dispersion patterns and environmental exposure levels.
Different environmental factors are represented using appropriate spatial formats:
- Point features: Pollution sources such as smelters or discharge locations
- Line features: Rivers and streams that both carry contaminants and may themselves be affected by pollution
- Raster datasets: Airborne contaminant plumes and other spatially continuous environmental effects
Automated scripting handles the formatting of model inputs and outputs, simplifying workflow requirements so that users can concentrate on interpretation rather than technical processing.
Example Analysis: Air Pollution Around Oruro
In heavily mined regions such as the area surrounding Oruro, aging smelting facilities release significant atmospheric pollutants. Air-quality models simulate how emissions disperse across the plateau, influenced by factors such as wind direction and stack height. The resulting plume distributions are displayed as raster layers within the GIS, allowing analysts to visualize exposure zones and assess potential risks to nearby settlements, agricultural land, and water bodies.
Standard thematic layers—including settlements, lakes, mining areas, and river networks—provide contextual reference for interpreting these environmental outputs.
Building the Data Foundation
Developing the system required substantial effort to assemble and prepare the necessary datasets. Air-quality modeling demanded detailed meteorological records and high-resolution elevation models, while hydrological analysis required complete digital stream networks. Although some source data existed, many datasets needed extensive refinement or conversion.
For example, geological maps available in CAD format lacked the attributes necessary for GIS analysis and contained numerous discontinuities. Similarly, contour-based elevation files required careful processing to generate usable digital elevation models. Significant data cleaning, attribution, and reconstruction were therefore undertaken to produce the reliable baseline layers supporting the final application.
Decision Support and Policy Implementation
At the core of the system is a structured analytical framework in which GIS data layers form the foundation, environmental models generate higher-level risk assessments, and decision-support tools evaluate potential mitigation strategies. Once contamination impacts are identified, the application can perform basic cost–benefit comparisons of remediation alternatives, assisting policymakers in selecting effective response measures.
The completed system was distributed across multiple government ministries responsible for mining and environmental oversight and deployed at field offices throughout mining districts of the Altiplano. By combining spatial analysis, environmental modeling, and decision-support capabilities, the application provides authorities with a practical tool for managing long-term environmental risks associated with historic and ongoing mining activity.
