| dc.description.abstract | Red Mountain Creek is located in the rich mineralized San Juan Mountains of
Southwestern Colorado, where mining from the mid 1800s through the late 1970s
occurred. Sampling of the Uncompahgre River in the late 1970s, which is downstream of
the five tailings ponds, showed high levels of heavy metals. It was assumed the
remaining mine tailings were responsible for the high concentrations of heavy metals in
the waters down-valley from the deposits. Thus, in 1983, remediation began with the use
of direct re-vegetation of the deposits. This remediation was required as a result of
National laws, which mandated the state of Colorado and the Idarado Mining Company
develop a Remedial Action Plan (RAP). Interestingly, the tailings were assumed to be
the sole source.
Studies over the past twenty years, have suggested for site-specific locations, the
highly mineralized zones may be additional sources of inputting heavy metals into
streams. We assumed that heavy metal concentrations found in the streams come from
the weathering of highly complex mineral assemblages, as well as from mining
activities. It was our objective to establish the geochemistry in streams in the areas above
and below mining activity and remediated areas and to evaluate the impact of
remediation. Water quality data were collected for Aluminum (Al), Cadmium (Cd),
Copper (Cu), Iron (Fe), Lead (Pb), Magnesium (Mg), Manganese (Mn), Zinc (Zn), and
temperature, specific conductance, pH and dissolved oxygen.
Twenty-seven samples were filtered with a 0.45μm membrane filter and twenty-seven
were left unfiltered. Samples were collected in-stream after determining discharge
for each stream. The samples of RMC were evaluated by using a Shapiro-Wilks test.
There is a definitive difference between pH and dissolved metal concentrations when
comparing streams on the east side to west side. In addition, there were five distinct
confluences with Red Mountain Creek that provided significant changes in water
quality. This was due to hydrothermally altered bedrock, which had and had not been
mined. | en |
