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Mining activities, including prospecting, exploration, construction, operation, maintenance, expansion, abandonment, decommissioning and repurposing of a mine can impact social and environmental systems in a range of positive and negative, and direct and indirect ways. Mining can yield a range of benefits to societies, but it may also cause conflict, not least in relation to above-ground and sub-surface land use. Similarly, mining can alter environments, but remediation and mitigation can restore systems. Boreal and Arctic regions are sensitive to impacts from development, both on social and environmental systems. Native ecosystems and aboriginal human communities are typically affected by multiple stressors, including climate change and pollution, for example.
Mining activities, including prospecting, exploration, construction, operation, maintenance, expansion, abandonment, decommissioning and repurposing of a mine can impact social and environmental systems in a range of positive and negative, and direct and indirect ways. Mine exploration, construction, operation, and maintenance may result in land-use change, and may have associated negative impacts on environments, including deforestation, erosion, contamination and alteration of soil profiles, contamination of local streams and wetlands, and an increase in noise level, dust and emissions (e.g. [1,2,3,4,5]). Mine abandonment, decommissioning and repurposing may also result in similar significant environmental impacts, such as soil and water contamination [6,7,8]. Beyond the mines themselves, infrastructure built to support mining activities, such as roads, ports, railway tracks, and power lines, can affect migratory routes of animals and increase habitat fragmentation [9, 10].
Mining can also have positive and negative impacts on humans and societies. Negative impacts include those on human health (e.g. ) and living standards , for example. Mining is also known to affect traditional practices of Indigenous peoples living in nearby communities , and conflicts in land use are also often present, as are other social impacts including those related to public health and human wellbeing (e.g. [14,15,16,17]. In terms of positive impacts, mining is often a source of local employment and may contribute to local and regional economies [18, 19]. Remediation of the potential environmental impacts, for example through water treatment and ecological restoration, can have positive net effects on environmental systems . Mine abandonment, decommissioning and repurposing can also have both positive and negative social impacts. Examples of negative impacts include loss of jobs and local identities , while positive impact can include opportunities for new economic activities , e.g. in the repurposing of mines to become tourist attractions.
Mitigation measures designed to alleviate the negative impacts of mining on social and environmental systems may not always be effective, particularly in the long-term and across systems, e.g. a mitigation designed to affect an environmental change may have knock on changes in a social system. Indeed, the measures may have unintentional adverse impacts on environments and societies. To date, little research appears to have been conducted into mitigation measure effectiveness, and we were unable to find any synthesis or overview of the systems-level effectiveness of metal mining mitigation measures.
Many topics relating to mining and its impacts on environmental and social systems are underrepresented in the literature as illustrated by the following example. The Sami people are a group of traditional people inhabiting a region spanning northern Norway, Sweden, Finland and Russia. Sami people are affected by a range of external pressures, one of which pertains to resource extraction and land rights, particularly in relation to nomadic reindeer herding. However, there is almost no published research on the topic .
The literature on the environmental and social impacts of mining has grown in recent years, but despite its clear importance, there has been little synthesis of research knowledge pertaining to the social and environmental impacts of metal mining in Arctic and boreal regions. The absence of a consolidated knowledge base on the impacts of mining and the effectiveness of mitigation measures in Arctic and boreal regions is a significant knowledge gap in the face of the continued promotion of extractive industries. There is thus an urgent need for approaches that can transparently and legitimately gather research evidence on the potential environmental and social impacts of mining and the impacts of associated mitigation measures in a rigorous manner.
We will include all impacts (positive, negative, direct and indirect) associated with any aspect of metal mining and its mitigation measures. We will include research pertaining to all stages of mining, from prospecting onwards as follows: prospecting, exploration, construction, operation, maintenance, expansion, abandonment, decommissioning, reopening and repurposing. Eligible mines will include those of gold, iron, copper, nickel, zinc, silver, molybdenum and lead.
Iron limitation led to a 65 % decline in growth rate in C. simplex cells compared to those grown under replete conditions (Table 2). Reduced growth rates are commonly observed in Fe-limited phytoplankton (Timmermans et al. 2001; Alderkamp et al. 2012; Strzepek et al. 2012). In line with this, POC quotas were also reduced in +DFB cultures (Table 2), which suggests lower carbon fixation capacities. Along with these changes, several aspects of photophysiology were impacted by the differences in iron availability in C. simplex. In the +DFB-treated cells, for instance, an increased disconnection of antennae from PSII reaction centers is supported by our data, as Jcon was strongly reduced (Table 3). Congruently, also a shift from α-dominant PSII to a β-dominant PSII structure was observed under these conditions (Table 3), which indicates reorganization of the light-harvesting antenna systems into more isolated units (Lavergne and Briantais 1996). Consequently, the transfer of excitons to the PSII reaction centers is hindered, and thus, the efficiency of PSII is reduced, causing a decline in the F V/F M in C. simplex grown in the +DFB medium (Table 3). This finding is consistent with general photosynthetic responses to iron limitation in phytoplankton (Greene et al. 1991, 1992; Vassiliev et al. 1994). Reduced F V/F M in +DFB-treated cells of C. simplex was countered by an increase in σPSII (Table 3). Similar responses in σPSII were also observed for various iron-limited Southern Ocean diatoms (Timmermans et al. 2001; Van Oijen et al. 2004; Alderkamp et al. 2012; Strzepek et al. 2012). An increase in σPSII corresponds to an increase in the ratio of antenna complexes relative to the reaction center core complexes (Greene et al. 1992). Strzepek et al. (2012) suggested that a larger size of σPSII compensates for fewer iron-rich photosynthetic reaction centers in Southern Ocean phytoplankton species.
Consequently, many important questions have been raised on the fate and speciation of As and Hg in the environment and how to limit their toxicity. However, due to their reactivity towards aquifer components, it is difficult to clearly dissociate the biogeochemical processes that occur and their different impacts on the fate of these TE.
Thus, a better understanding of the impact of iron and sulfate cycling on the fate of TE, such as Hg and As, could help us to better manage contaminated sites and maintain soil and water quality. Data could also contribute to reinforcing existing metal-mobility models. Microbial Fe(III)-reduction16,17,18 can cause the desorption of TE. Theoretically, the indirect reduction of iron (oxy)hydroxides by sulfide produced by the microbial reduction of sulfate could also impact TE mobility. However, the extent and kinetics of these reactions are generally studied in batch homogenous systems or batch microcosms16,18,19,20. The drawback of batch experiments is the lack of dissociation of the occurring phenomena; indeed, activity is based on and limited by the resources present in the batch and only gives a final result of the shifts in speciation and adsorption. Using a column approach enables the renewal of inflowing media and the monitoring of the fate of TE over time and space. These conditions are more realistic when compared to an aquifer, where real phenomena are closely linked to continuous percolation conditions. Moreover, heterogeneous iron (oxy)hydroxide occurrence in aquifer sediments is common21,23, and the spatial changes in the mineralogical and chemical composition of the solid phases certainly drives microbial activities.
For this experiment, two columns were setup identically. The first was inoculated with an iron-reducing bacterial community and supplied with both molybdate (0.40 mmol L-1), to inhibit sulfate reduction, and glucose, to favor iron-reducing bacteria (IRB column). Another column was inoculated with a sulfate-reducing bacterial community and fed with sulfate to create a sulfate reducing zone in the sandy lower half of the column as well as sodium lactate as a substrate (SRB column).
During a recent high-throughput screen for compounds that exhibited enhanced activity against intracellular Mtb, we identified a compound, sAEL057, which had enhanced activity against intracellular Mtb in comparison to rich broth. Mode of action (MOA) analyses indicated that the compound dysregulates iron acquisition through the chelation of Fe. While synthetic iron chelators are approved for clinical use to prevent iron-induced disease progression and to control inflammation25,26, the long-term administration of anti-TB drugs required for effective treatment likely limits the usefulness of such compounds for TB treatment. Nonetheless, sAEL057 has proven to be a useful tool in revealing that iron plays a hitherto unappreciated role in the assimilation of cholesterol. Our data indicate that dysregulation of iron homeostasis caused by sAEL057 differentially impacted Mtb growth on specific carbon sources, most notably cholesterol. This finding builds on an extensive body of work stressing the importance of cholesterol utilization for Mtb survival in vivo and demonstrates that both survival and cholesterol utilization can be dysregulated through iron limitation. 2b1af7f3a8