Acidic, metal-rich waters from mines flow into Prince
This story entered on 18th Oct, 2004 07:00:00 AM PST
Groundwater and surface water associated
with the former copper mines on Latouche Island, Prince William
Sound, have been documented to contain elevated levels of acid and
dissolved metals, which result from weathering of copper sulfide
tailings. However, determining the presence of these acids and metals
in the nearby marine environment, by analysis of seawater, has been
difficult to establish due to their rapid dispersal into the Sound's
bays and fords.
A NURP-sponsored study utilized a novel approach to determine whether
metals leached from Prince William Sound mines flow to the marine
environment. The study results indicate that plumes of acidic,
metal-rich groundwater originating from mines are indeed discharging
into the intertidal zone of Prince William Sound.
Rather than studying samples of seawater, Drs. Randy Koski and Pat
Shanks of the USGS and Dr. Lee Ann Munk from the University of Alaska
Anchorage analyzed the gravel and water of subsurface beach sands
in the zone of mixing between groundwater and seawater. The researchers,
funded by NURP's West Coast and Polar Regions Center, concluded
that acidic water containing elevated levels of iron, barium, lead,
mercury, thallium, zinc and copper entered the bay.
Establishing that mines contribute acidic water containing dissolved
metals to Prince William Sound is new scientific information that
can be useful to coastal managers. While it is known that elevated
levels of some metals can be toxic, the impact of acidic metal-rich
water on the ecology of Prince William Sound is largely unknown.
Building upon the findings of this study, future research may investigate
the fate of dissolved metals in the Prince William Sound ecosystem.
Name: Jennifer Reynolds
Tel: (907) 474-5871