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Water quality assessments provide essential information for protecting aquatic habitats and stakeholders downstream of mining sites. Moreover, mining companies must comply with environmental quality standards and include public participation in water quality monitoring (WQM) practices. However, overarching challenges beyond corporate environmental responsibility are the scientific soundness, political relevance and harmonization of WQM practices. In this study, a mountainous watershed supporting large-scale gold mining in the headwaters, besides urban and agricultural landuses at lower altitudes, is assessed in the dry season. Conventional physicochemical and biological (Biological Monitoring Water Party-Colombia index) freshwater quality parameters were evaluated, including hydromorphological and land-use characteristics. According to the indicators used, water quality deterioration by mining was absent, in contrast to the effects of urban economic activities, hydromorphological alterations and (less important) agricultural pollutants. We argue that mining impacts are hardly captured due to the limited ecological knowledge of high-mountain freshwaters, including uncharacterized mining-specific bioindicators, environmental baselines and groundwater processes, as well as ecotoxicological and microbial freshwater quality components. Lessons for overcoming scientific and operational challenges are drawn from joint efforts among governments, academia and green economy competitiveness. Facing a rapid development of extractive industries, interinstitutional and multidisciplinary collaborations are urgently needed to implement more integrated freshwater quality indicators of complex mining impacts.

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-The Portoviejo River, located in the central western part of Ecuador, has been heavily impacted by damming, intensive agriculture and untreated wastewater discharge. Unfortunately, detailed information on the water quality and the ecological status of the Portoviejo River is not available, inhibiting decisionmaking and the development of water management plans. Therefore, the aims of this study were (1) to assess the ecological water quality, (2) to investigate the point along the environmental gradient where the most significant change in macroinvertebrate community occurs and (3) to find potential macroinvertebrate taxa that significantly change in abundance and frequency of occurrence along the Portoviejo River. To this end, macroinvertebrate and physico-chemical data were collected and hydro-morphological conditions were recorded at 31 locations during the dry season of 2015. The results showed that the ecological water quality of the sampling sites ranged from good to bad. In addition, the Threshold Indicator Taxa ANalysis was used to examine changes in macroinvertebrate communities and revealed significant community change points for sensitive taxa declining at a conductivity value of 930 (mS.cm x1 ) and nitrate-nitrogen concentrations of 0.6 mg.L x1 . In addition, the thresholds estimated for tolerant taxa were set at a conductivity value of 1430 mS.cm x1 and nitrate-nitrogen concentration of 2.3 mg.L. Atyidae, Corbiculidae, Thiaridae, Acari, Baetidae and Leptohyphidae can be considered indicator taxa, showing shifts in the community. This study suggests that values of conductivity and nitrate-nitrogen concentrations should not exceed the threshold levels in order to protect macroinvertebrate biodiversity in the Portoviejo River.

Aim:We studied the distribution of freshwater macroinvertebrate taxa and traits to distinguish ecological gradients among the mining-controlled and natural headwaters, and rural and urban economic activity influences.Location: In 2016's dry season, macroinvertebrate samples were collected at 40 locations in the Mashcon watershed, northern Peruvian Andes. Six locations were in the headwaters directly influenced by mining, eight near-pristine tributary headwaters, 14 agricultural locations at midstream and 12 urban locations downstream.Methods: Eight traits (five biological and three ecological) were selected according to data availability, and modalities scores were assigned using the weighted and the dominant-trait approaches. The traits relative abundances and abiotic conditions were compared among watershed sections. The ecological interpretability of the ungrouped data was verified with a distance-based redundancy analysis. Results:The high-altitude mining section had fewer taxa types and abundance, and distinct body forms distributions and prevalent body sizes in macroinvertebrate communities, relatable to the control of the mining headwaters. Physiological and ecological traits (respiration, mobility and attachment, food sources, feeding habits, saprobity and pH preferenda) differed among traits quantification approaches and were less informative at high altitudes. The ecological conditions from the near-pristine tributaries recovered in the vegetated midstream section, to again be affected in the downstream urban section.Main Conclusions: Our results suggest the presence of ecological impairment despite the excellent physicochemical quality of the water discharged by the mine. The obtainment of autecological information at a higher taxonomic resolution, e.g. for ubiquitous taxa like Acari and Chironomidae, would be needed to advance the freshwater quality assessment of ecologically and hydrogeochemically complex Andean mining ecosystems.