Investigating the potential for microbially induced carbonate precipitation to treat mine waste.

In this study, the feasibility of promoting microbially induced carbonate precipitation (MICP) in mine waste piles by using an environmental bacterial enrichment is explored, with goals to reduce metals and acid leaching. MICP has been explored for remediation applications and stabilization of mine waste. Here, we utilize a native bacterial enrichment to promote MICP on seven mine waste samples with variability in acid production and extent of toxic metal leaching.

Influence of copper recovery on the water quality of the acidic Berkeley Pit lake, Montana, U.S.A.

The Berkeley Pit lake in Butte, Montana, formed by flooding of an open-pit copper mine, is one of the world's largest accumulations of acidic, metal-rich water. Between 2003 and 2012, approximately 2 × 10(11) L of pit water, representing 1.3 lake volumes, were pumped from the bottom of the lake to a copper recovery plant, where dissolved Cu(2+) was precipitated on scrap iron, releasing Fe(2+) back to solution and thence back to the pit.

Rates of arsenopyrite oxidation by oxygen and Fe(III) at pH 1.8-12.6 and 15-45 degrees C.

The oxidation rate of arsenopyrite by dissolved oxygen was measured using a mixed flow reactor at dissolved O2 concentrations of 0.007-0.77 mM, pH 1.

Diel changes in water chemistry in an arsenic-rich stream and treatment-pond system.

Arsenic concentrations are elevated in surface waters of the Warm Springs Ponds Operable Unit (WSPOU), located at the head of the upper Clark Fork River Superfund site, Montana, USA. Arsenic is derived from historical deposition of smelter emissions (Mill and Willow Creeks) and historical mining and milling wastes (Silver Bow Creek). Although long-term monitoring has characterized the general seasonal and flow-related trends in As concentrations in these streams and the pond system used to treat Silver Bow Creek water, little is known about solubility controls and sorption processes that influence diel cycles in As concentrations.

Diel cycling of zinc in a stream impacted by acid rock drainage: initial results from a new in situ Zn analyzer.

Recent work has demonstrated that many trace metals undergo dramatic diel (24-h) cycles in near neutral pH streams with metal concentrations reproducibly changing up to 500% during the diel period (Nimick et al., 2003). To examine diel zinc cycles in streams affected by acid rock drainage, we have developed a novel instrument, the Zn-DigiScan, to continuously monitor in situ zinc concentrations in near real-time.

Diel mercury-concentration variations in streams affected by mining and geothermal discharge.

Diel variations of concentrations of unfiltered and filtered total Hg and filtered methyl Hg were documented during 24-h sampling episodes in water from Silver Creek, which drains a historical gold-mining district near Helena, Montana, and the Madison River, which drains the geothermal system of Yellowstone National Park. The concentrations of filtered methyl Hg had relatively large diel variations (increases of 68 and 93% from morning minima) in both streams. Unfiltered and filtered (0.

Mercury concentrations of fish, river water, and sediment in the Río Ramis-Lake Titicaca watershed, Peru.

This study reports the first set of data on the concentration of mercury in muscle tissue of several varieties of fish from Lake Titicaca, including the pejerrey (Basilichthyes bonariensis), the carachi (Orestias), and 2 types of indigenous catfish (Trichomycterus). Approximately 27% of the pejerrey and 75% of the carachi exceeded the US EPA fish tissue-based water quality criterion level of 0.30 microg g(-1).

Biogeochemical controls on Diel cycling of stable isotopes of dissolved O2 and dissolved inorganic carbon in the Big Hole River, Montana.

Rivers with high biological productivity typically show substantial increases in pH and dissolved oxygen (DO) concentration during the day and decreases at night, in response to changes in the relative rates of aquatic photosynthesis and respiration. These changes, coupled with temperature variations, may impart diel (24-h) fluctuations in the concentration of trace metals, nutrients, and other chemical species. A better understanding of diel processes in rivers is needed and will lead to improved methods of data collection for both monitoring and research purposes.