To the Journal editor:

Numerous news reports over the past few years have quoted Eagle Mine personnel saying that the mine’s treated discharge water protects the environment because it meets the EPA’s “drinking water standards.”

Drinking water standards are set based on known effects of contaminants on human health. By comparison, discharge concentration limits of contaminants from mining, industrial and agricultural facilities are usually set based on known effects of potential contaminants on health of aquatic species in nearby surface waters.

My concern here is focused on only one contaminant (copper) and only on aquatic species belonging to the salmon family (which includes all trout).

For humans, copper is an essential race element. Since most of us live in residences with copper plumbing, the drinking water standard for copper is set relatively high: 1.3 mg/liter (1.3 ppm) – this value from USEPA website. For many fish species (including trout), copper is a toxic element at trace levels (People keeping exotic fish in homes with copper plumbing quickly realize they cannot use untreated tap water to replenish their tanks). As an example from the mining industry, the discharge limited at an iron mine discharging to a trout stream was set at 1.0 ppb (0.001 ppm) copper.

Particular circumstances in a receiving steam can affect the set limit somewhat, but my point here is that because of trout in a receiving stream, the discharge limit for copper is typically on the order of 1,000 times lower that the corresponding “drinking water standard.”

Based on these factors, I challenge the statement in the May 22 front page article that “discharging water that meets or exceeds drinking water quality … protects the environment.”

Because Eagle Mine processes copper minerals, I believe mine personnel need to be more complete in their characterization of treated discharge water than simply saying “it meets drinking water standards.”

An additional local concern is that the mine’s watershed (Salmon Trout River) is supposedly one of only a few remaining Lake Superior watersheds still hosting a population of the “Coaster Brook Trout.” I realize there is some controversy about whether this is a unique trout species, but I believe this situation requires utmost care in the water-related operations of the mine.

I believe that Marquette County residents deserve better assurance than they are now receiving that our environment is being sufficiently protected.

Bob Railey

Marquette