An Integrative Approach to Assess the Environmental Impacts of Gold Mining Contamination in the Amazon

Abstract

As the number of legal and illegal mining sites increase, integrative methods to evaluate the effects of mining pollution on Andes-Amazonia freshwater ecosystems are paramount. Here, we sampled water and sediments in 11 sites potentially affected by mining activities in the Napo province (Ecuador). The environmental impacts were evaluated using four lines of evidence (LOEs): water physico-chemical parameters; metal exposure concentrations; macroinvertebrate community response (AAMBI); and toxicity by conducting bioassays with Lactuca sativa and Daphnia magna. Overall, dissolved oxygen and total suspended solids were, under (<80%) and above (>130 mg/Ls) quality standards. Ag, Al, As, Cd, Cu, Fe, Mn, Pb and Zn in water and V, B and Cr in sediments were detected above quality standards. Nine out of eleven sites were classified as having bad environmental quality based on the AAMBI. Ranges of L. sativa seed germination in both water (37% to 70%) and sediment (0% to 65%), indicate significant toxicity. In 5 sites, neonates of D. magna showed a 25% reduction in survival compared to the control. Our integrated LOEs index ranked sites regarding their environmental degradation. Given the importance of the Andes-Amazon region, we recommend environmental impact monitoring of the mining expansion using multiple LOEs.

Negative effects of mining conflicts on the Amazon ecosystem. Amazonian Ecosystem. A systematic review between the years 2012-2022

“…Alberga grandes bosques tropicales, quienes estabilizan el terreno para que las precipitaciones sigan su curso, evitando inundaciones [3]. La biodiversidad de la región permite la conservación de los ecosistemas, proporcionando diversos bienes y servicios [4]. Desafortunadamente, el desarrollo de las actividades económicas extractivas genera la vulneración de los ecosistemas.…”

“…Por ello, se requiere un trabajo en conjunto entre los gobiernos y agencias de desarrollo, respecto a la inversión para que las actividades mineras ilegales se formalicen y sean fiscalizadas según la normativa establecida en cada país [14]. Realizando diferentes análisis como físicoquímicos, toxicológicos y monitoreos rutinarios, para prevenir posibles impactos negativos en los ecosistemas [4]; teniendo en cuenta que para la formalización es importante conocer las limitaciones y fortalezas de la zona de estudio [15].…”