Aquatic macroinvertebrate assemblages in rivers influenced by mining activities

Axel Eduardo Rico-Sánchez,Jacinto Elías Sedeño-Díaz,Andrea Sundermann,Alexis Joseph Rodríguez-Romero,Eugenia López-López

doi:10.1038/s41598-022-06869-2

Abstract

Mining is one of the major pollution sources worldwide, causing huge disturbances to the environment. Industrial and artisanal mining activities are widespread in Mexico, a major global producer of various metals. This study aimed to assess the ecological impairments resulting from mining activities using aquatic macroinvertebrates assemblages (MA). A multiple co-inertia analysis was applied to determine the relationships between environmental factors, habitat quality, heavy metals, and aquatic macroinvertebrates in 15 study sites in two different seasons (dry and wet) along two rivers running across the Central Plateau of Mexico. The results revealed three contrasting environmental conditions associated with different MAs. High concentrations of heavy metals, nutrients, and salinity limit the presence of several families of seemingly sensitive macroinvertebrates. These factors were found to influence structural changes in MAs, showing that not only mining activities, but also agriculture and presence of villages in the basin, exert adverse effects on macroinvertebrate assemblages. Diversity indices showed that the lowest diversity matched both the most polluted and the most saline rivers. The rivers studied displayed high alkalinity and hardness levels, which can reduce the availability of metals and cause adverse effects on periphyton by inhibiting photosynthesis and damaging MAs. Aquatic biomonitoring in rivers, impacted by mining and other human activities, is critical for detecting the effect of metals and other pollutants to improve management and conservation strategies. This study supports the design of cost-effective and accurate water quality biomonitoring protocols in developing countries.

Highlights

Efforts to protect and preserve biological diversity are usually focused on protected natural areas (PNAs), which are the cornerstone of conservation strategies worldwide[16]
There are more than 140 active mines in the Sierra Gorda region (Central México), 60% of which are located inside the Sierra Gorda Biosphere Reserve (SGBR) polygon[21]; the impacts of mining on aquatic life in PNAs have not been documented until now
This study aimed to identify how anthropogenic pollutants, those associated with mining, agriculture, and villages, affect aquatic macroinvertebrate assemblages in rivers with a high mineral content and different metal composition running across a PNA in Central Mexico

Summary

Introduction

Efforts to protect and preserve biological diversity are usually focused on protected natural areas (PNAs), which are the cornerstone of conservation strategies worldwide[16]. Environmental disturbances can modify the structure of macroinvertebrate assemblages in response to several stressors These modifications include changes in species composition and abundance in impacted areas with the predominance of tolerant species, while sensitive species occur only in areas with minimally disturbed conditions or negligible impacts[24]. Additional information is needed to fully understand the response of macroinvertebrates to heavy metals and other minerals from geological strata to assess the disturbances caused by human impacts on aquatic wildlife, especially in a PNA affected by mining a ctivities[30]. This study aimed to identify how anthropogenic pollutants, those associated with mining (metals), agriculture (nutrients), and villages (wastewater), affect aquatic macroinvertebrate assemblages in rivers with a high mineral content and different metal composition running across a PNA in Central Mexico. We examined the impact of organic pollution on aquatic macroinvertebrate assemblages

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