LSU FIELD WORK IN THE AMAZON

A research project led by Leo Guerrero focused on understanding the impacts of extensive gold mining in the Amazon, specifically on the Madre de Dios river system in southern Peru.

Work included:

• Excavation Mining in the Andes Mountains: This involved using heavy machinery to extract gold from the slopes and tributaries feeding into the Madre de Dios River.
• Suction mining in the river floodplain: Smaller-scale operations use suction excavators to pull sediment from the riverbed and floodplain, sifting out the gold and leaving behind large piles of coarse gravel and sediment.
• Physical Impacts: The team used a combination of field measurements, including bathymetric mapping, velocity surveys, and sediment sampling, to quantify how the mining activities are altering the river's hydrology, sediment transport, and morphodynamics. This included documenting increased erosion, channel widening, and disruption of natural bedforms.
• Mercury Contamination: In addition to the physical changes, the mining operations are introducing mercury into the river system, which can bioaccumulate aquatic species and pose risks to human health. Researchers are tracking the fate and transport of this mercury contamination.
• Ecosystem Impacts: The fieldwork also examined the broader ecological implications of the mining, including changes to aquatic habitats and the potential impacts on biodiversity within the Madre de Dios watershed.

OBJECTIVE & IMPACT

The collaborative project, involved local stakeholders and a diverse research team, all working to provide a comprehensive understanding of the significant and long-term impacts of mining activities on the Madre de Dios river ecosystem. By investigating these effects, the project seeks to inform sustainable management practices for the watershed and similar Amazon River systems facing the dual challenges of resource exploitation and environmental preservation.

The findings highlight the profound effects of mining on vulnerable habitats and species, offering critical insights into the complex interactions between human activities and river systems. These insights can guide efforts to mitigate environmental damage, protect fragile ecosystems, and develop more sustainable mining practices that balance local economic needs with broader ecological considerations. Ultimately, the research contributes to actionable strategies for conservation and sustainable resource management, with implications that extend to other Amazon River basins experiencing similar pressures.

PARTICIPATION & ROLES

The field research team included over 10 members, led by PhD student Leo Guerrero. The team collaborated with local NGOs and Peruvian government agencies that have been monitoring the mining impacts since 2020. Leo's expertise and on-the-ground experience in the region have been crucial to the project. The team also included Dr. Kory Konsoer, Associate Professor, Graduate Advisor, and Associate Director for the LSU Center for River Studies, who contributed his expertise in fluvial geomorphology and river dynamics.

METHODS & TOOLS

The fieldwork utilized a variety of techniques and equipment, including:

• Boat-based surveys using hydroacoustic instruments to map the riverbed bathymetry and measure flow velocities
• Suspended sediment sampling to quantify changes in sediment concentrations
• Riverbed sediment sampling to analyze the composition and potential contaminants
• Drone surveys to capture high-resolution aerial imagery and video of the mining sites and river system

KEY FINDINGS

The main findings from the fieldwork indicate that the extensive mining activities are significantly disrupting the natural processes and dynamics of the Madre de Dios River system:

• Increased erosion and channel widening in areas with concentrated mining operations
• Altered sediment routing and deposition, leading to the formation of anthropogenic bed forms that disrupt natural flow patterns
• Elevated suspended sediment concentrations, which can transport mercury and other contaminants through the system
• Challenges in predicting the long-term response of the river to these disturbances, as the mining impacts are complex and variable across the watershed