A comparison of pre‐ and post‐remediation water quality, Mineral Creek, Colorado

Abstract

Abstract:Pre-and post-remediation data sets are used herein to assess the effectiveness of remedial measures implemented in the headwaters of the Mineral Creek watershed, where contamination from hard rock mining has led to elevated metal concentrations and acidic pH. Collection of pre-and post-remediation data sets generally followed the synoptic mass balance approach, in which numerous stream and inflow locations are sampled for the constituents of interest and estimates of streamflow are determined by tracer dilution. The comparison of pre-and post-remediation data sets is confounded by hydrologic effects and the effects of temporal variation. Hydrologic effects arise due to the relatively wet conditions that preceded the collection of pre-remediation data, and the relatively dry conditions associated with the post-remediation data set. This difference leads to a dilution effect in the upper part of the study reach, where pre-remediation concentrations were diluted by rainfall, and a source area effect in the lower part of the study reach, where a smaller portion of the watershed may have been contributing constituent mass during the drier post-remediation period. A second confounding factor, temporal variability, violates the steady-state assumption that underlies the synoptic mass balance approach, leading to false identification of constituent sources and sinks. Despite these complications, remedial actions completed in the Mineral Creek headwaters appear to have led to improvements in stream water quality, as post-remediation profiles of instream load are consistently lower than the pre-remediation profiles over the entire study reach for six of the eight constituents considered (aluminium, arsenic, cadmium, copper, iron, and zinc). Concentrations of aluminium, cadmium, copper, lead, and zinc remain above chronic aquatic-life standards, however, and additional remedial actions may be needed. Future implementations of the synoptic mass balance approach should be preceded by an assessment of temporal variability, and modifications to the synoptic sampling protocol should be made if necessary. Published in

Rare earth and trace element signatures for assessing an impact of rock mining and processing on the environment: Wiśniówka case study, south-central Poland

“…Unfavorable localization of the Wiśniówka mining area, i.e., a dismembered mountain range reaching 100 m in relative elevation and the proximity of villages, makes it difficult to utilize abiotic or biotic remediation strategies (e.g., Banks et al 1997; Plumlee and Logsdon 1999; Coulton et al 2003; Johnson and Hallberg 2005; Runkel et al 2009). In addition, the lack of flat areas for construction of large biotic aerobic ponds or wetlands and (an) aerobic plots has forced the mining company to use other options of AMD water remediation, including anoxic limestone drains, impermeable barriers to potential acid seeps, lime addition, and revegetation of some tailings piles.…”

Use of Natural and Applied Tracers to Guide Targeted Remediation Efforts in an Acid Mine Drainage System, Colorado Rockies, USA

“…Much of the southwestern USA, including the San Juan Mountains, can be characterized by bimodal precipitation patterns, i.e., spring snowmelt and summer monsoon rains [24]. Previous mine drainage studies in the region have demonstrated that consistent low-flow conditions are most attainable in late summer (August-October) after monsoon rains have subsided and prior to freezing conditions during the winter months [15,25,26]. To quantitatively and qualitatively assess individual components of the hydrologic system, a series of independent environmental and applied tracers were applied and/or sampled at discrete locations within the study area.…”

Ecotoxicity of Purified Industrial Waste Water

“…Elevated aquatic Cu +2 concentrations are primarily occurring near copper mining, smelting facilities and in urbanized areas [21,25]. Higher Cu +2 concentrations are observed in mine-impacted Mineral Creek Colorado, where they were approximately 410 ppb [55] and around the mine impacted Copperas Brook in Vermont where they were around 4600 ppb [8]. Sansalone et al [56] documented Cu +2 concentrations of 325 ppb in urban storm water run-off, such copper concentrations are lethal to fish and aquatic life [25].…”