Sulfate-reducing biochemical reactors (BCRs) were installed to provide a basis for substrate selection for a final treatment remedy for mining influenced water (MIW) from the National Tunnel adit. Black Hawk, CO. The MIW was characterized by elevated metal and SO 4 2concentrations as well as pH fluctuations from 4.8-6.4. Three pairs of BCRs were installed in 2006, each of which contained a different mixture of solid or liquid-phase substrates. The above-ground BCRs partially froze during the first winter, prompting a redesign of the hydraulic system in May 2007 and the installation of heating and insulation in preparation for the following winter in October 2007. During the hydraulic system re-design, a fourth pair of reactors that contained CHITOREM ® SC-20 chitin complex was added to provide data on an alternative solid-phase substrate.Results from 2007 suggest that nearly all of the reactors removed greater than 95% of the Fe and Zn and 50-95% of the sulfate from the MIW during September through December 2007. Copper removal was typically above 95%. In addition, chitin complex reactors demonstrated high Mn removal (average removal was 80%) and high alkalinity (average of 4200 mg/L as CaCO 3 ) during the same period. The high alkalinity was partially due to high concentrations of ammonium (up to 450 mg/L as nitrogen). Operational challenges due to winter conditions in November and December 2007 caused significant temperature and flow fluctuations; however, effective removal of metals was still observed. The BCRs will be monitored through summer 2008 and the data will be evaluated in late-summer 2008 to determine which substrates (CHITOREM ® SC-20, ethanol or solid phase organic mixture) are best suited for long-term treatment of the National Tunnel MIW by BCRs.
Releases of mine waste, contaminated water and sediments with elevated levels of metals have impaired productivity of agricultural land adjacent to the Arkansas River and downgradient from the historic mine districts of Leadville, Colorado. Historically irrigated agricultural meadows outside the floodplain contaminated by low pH, metal enriched irrigation water were sampled. The resultant depositional pattern shows the influence of irrigation ditches in conveying contaminated materials as expressed by bare ground and sparse vegetation cover dominated by metal tolerant species. The co-occurence of phytotoxicity with acidic soil was described during pre-treatment sampling.
<p>Heavy metals in the marine environment are a worldwide issue due to their toxicity, non-biodegradability and their ability to accumulate and magnify in organisms. Increased human activity has caused higher inputs of heavy metals, resulting in escalated pressures on delicate coastal ecosystems. A means of assessing the natural environment and how it is changing in response to pollution and other environmental degradation is through the use of biological indicator or biomonitor species. These organisms provide information on the bioavailability of metals present in the environment. In recent years amphipods, a diverse order of small crustaceans, have been increasingly used as bioindicators of disturbed aquatic communities. They are widespread and important components of many food webs, and likely to be frequently exposed to metal contamination through both sediment and seawater. The aim of this research was two-fold: 1) to use amphipods to examine variation across sites and species in concentration of 20+ trace elements and 2) to examine whether the uptake of two metals, copper (Cu) and neodymium (Nd), is mediated by the presence of the other metal or an elevated seawater temperature. To investigate variation of trace element concentrations across sites, the amphipod Eusiroides monoculoides was collected from three sites in the Wellington region, approximately 5 km apart: Oriental Bay, Evans Bay and Point Halswell. To investigate differences amongst species comparisons were made between Eusiroides monoculoides, Apohyale papanuiensis and Sunamphitoe mixtura when they occurred at the same site. Analysing the trace element concentrations of 36 metals was done using an Inductively Coupled Mass Spectrometer (ICPMS). Overall, although these sites were not greatly distant from each other, there were differences among sites. Evans Bay in general had the highest concentration of trace elements. Further, there were also species-specific differences and S. mixtura was the species with the highest concentration of trace elements. There was also a size effect, where the average dry weight of S. mixtura was negatively related to the concentration of trace elements in the body. To assess the effects of heavy metals Cu and Nd in both an ambient (14 °C) and elevated (20 °C) temperature, an experiment was run at Victoria University’s Coastal Ecology Lab (VUCEL). Sand hoppers, Bellorchestia quoyana, were collected from a single site in Wellington (Scorching Bay) and assigned to eight treatments: ambient and warm controls in raw seawater and ambient and warm seawater doped with Cu, Nd and Cu and Nd together. Amphipods from treatments with Cu and Nd added had significantly higher concentrations of these metals from the controls, however temperature had no effect, and neither was there an interaction between the metals. Similar to S. mixtura from the field study, dry weight of B. quoyana was negatively related to the concentration of trace elements in the body. Results from this work demonstrate that when using amphipods as bioindicator species it is important to consider species and size specific effects. This thesis also provides baseline data for 20+ elements from three Wellington sites and demonstrates that there can be unexpected variation across relatively small spatial scales. The laboratory experiment did not yield results that coincided with the consensus of the literature. The experiment showed that at least in this case, temperature did not mediate the uptake of metals and there was a negative relationship between size and metal uptake.</p>
<p>Heavy metals in the marine environment are a worldwide issue due to their toxicity, non-biodegradability and their ability to accumulate and magnify in organisms. Increased human activity has caused higher inputs of heavy metals, resulting in escalated pressures on delicate coastal ecosystems. A means of assessing the natural environment and how it is changing in response to pollution and other environmental degradation is through the use of biological indicator or biomonitor species. These organisms provide information on the bioavailability of metals present in the environment. In recent years amphipods, a diverse order of small crustaceans, have been increasingly used as bioindicators of disturbed aquatic communities. They are widespread and important components of many food webs, and likely to be frequently exposed to metal contamination through both sediment and seawater. The aim of this research was two-fold: 1) to use amphipods to examine variation across sites and species in concentration of 20+ trace elements and 2) to examine whether the uptake of two metals, copper (Cu) and neodymium (Nd), is mediated by the presence of the other metal or an elevated seawater temperature. To investigate variation of trace element concentrations across sites, the amphipod Eusiroides monoculoides was collected from three sites in the Wellington region, approximately 5 km apart: Oriental Bay, Evans Bay and Point Halswell. To investigate differences amongst species comparisons were made between Eusiroides monoculoides, Apohyale papanuiensis and Sunamphitoe mixtura when they occurred at the same site. Analysing the trace element concentrations of 36 metals was done using an Inductively Coupled Mass Spectrometer (ICPMS). Overall, although these sites were not greatly distant from each other, there were differences among sites. Evans Bay in general had the highest concentration of trace elements. Further, there were also species-specific differences and S. mixtura was the species with the highest concentration of trace elements. There was also a size effect, where the average dry weight of S. mixtura was negatively related to the concentration of trace elements in the body. To assess the effects of heavy metals Cu and Nd in both an ambient (14 °C) and elevated (20 °C) temperature, an experiment was run at Victoria University’s Coastal Ecology Lab (VUCEL). Sand hoppers, Bellorchestia quoyana, were collected from a single site in Wellington (Scorching Bay) and assigned to eight treatments: ambient and warm controls in raw seawater and ambient and warm seawater doped with Cu, Nd and Cu and Nd together. Amphipods from treatments with Cu and Nd added had significantly higher concentrations of these metals from the controls, however temperature had no effect, and neither was there an interaction between the metals. Similar to S. mixtura from the field study, dry weight of B. quoyana was negatively related to the concentration of trace elements in the body. Results from this work demonstrate that when using amphipods as bioindicator species it is important to consider species and size specific effects. This thesis also provides baseline data for 20+ elements from three Wellington sites and demonstrates that there can be unexpected variation across relatively small spatial scales. The laboratory experiment did not yield results that coincided with the consensus of the literature. The experiment showed that at least in this case, temperature did not mediate the uptake of metals and there was a negative relationship between size and metal uptake.</p>
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