The Impact of Metal-Rich Sediments Derived from Mining on Freshwater Stream Life

Assessing the Freshwater Quality of a Large-Scale Mining Watershed: The Need for Integrated Approaches

“…As shown in the supplementary KML file (see online version), a reforested mining waste center known as San Jose [43] is near the headwaters of streams corresponding to the highest sampling points (top-right corner in Figure 3a). Since these high-altitude brooks have a near-pristine hydromorphology, the moderate biological quality at site 23 and the iron peak at site 25 could be the result of leachates or groundwater inflows altering microhabitat quality [44], besides the fact that heavy rain and flooding events are able to mobilize contaminated mineral grains by eroding and resuspending mining tailings into fluvial systems [45]. Nonetheless, two acidic brooks in the mine subsystem are likely of natural origin, since their topographical situation is unrelatable to mining drainage or legacies (sites 30 and 34).…”

“…Furthermore, the distribution of Acari macroinvertebrates confirms the need to investigate their potential as ecological indicators in mountainous and mining watersheds [50]. Therefore, mining impacts on freshwater habitats are hardly captured due to the incomplete characterization of site-specific bioindicators, ecological networks and abiotic conditions (e.g., hydrological, geochemical, physical composition or physicochemical patterns) [45] of the Mashcon catchment. Overall, the lack of an environmental baseline hinders the discernment between mining impacts and natural causes of ecological gradients…”

Looking back, looking forward: a review of the new literature on diatom teratological forms (2010–2020)

“…The presence of trace metals in the environment strongly influences diatom health, so that either deficiency or excess of certain elements can lead to the cell death (see Masmoudi et al, 2013;Jones et al, 2018 for a review). In general, trace metal excess has Fig.…”

“…When exposed to water and air, these wastes release acid leaches (due to the transformation of sulphides into sulphuric acid) and trace metals, which easily percolate over and through the soil to reach watercourses. As a consequence, the sites affected by AMD present very low pH values (pH 2-4), very high ionic strength and high dissolved metal loads, which can induce the production of diatom teratological forms (Luís et al, 2011(Luís et al, , 2013(Luís et al, , 2016Jones et al, 2018). In order to quantify AMD impact, in 2018 Fernández et al developed a new index based on diatom community (namely ICM, Índice de Contaminación por Metales), starting from the statement that AMD promotes the same pool of species independently of the geographical location of the studied area.…”

Accumulation of trace metals in freshwater macroinvertebrates across metal contamination gradients

“…However, and crucially, these models are based on the chemical speciation of trace metals in solution, and do not capture the significant role of trace metal uptake from fine-grained sediments by biota particularly obtained through diet (Adams et al, 2011;Luoma and Rainbow, 2008;Rainbow, 2018). The development and testing of tools that can capture dietary trace metal uptake which provide a realistic measure of bioavailability is still needed (Jones et al, 2020). Use of aquatic invertebrates as biomonitors is frequently advocated because they accumulate trace metals in their tissues.…”