This research was funded by Cienciactiva, an initiative of CONCYTEC (grant contract No. 002-2016-FONDECYT, and by a VLIR-TEAM programme ZEIN2013PR395: ‘Impact on surface water resources and aquatic biodiversity by opencast mining activities in Cajamarca, Peru’.

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 MonitoringWater Party-Colombia index) freshwater quality parameters were evaluated, including hydromorphological and land-use characteristics. According to the indicators used, water quality deterioration by m...