Copper-bearing malachite from the Callahan Mine in Maine /

Copper is a metallic element that occurs naturally in Maine bedrock.  Historically, it was the first metal to be mined and smelted into objects by human beings, in about 8000BC.  The search for copper-bearing rocks to mine was one of the motives for early exploration of the mediterranean and near east.  Today, of relevance to homeowners with drinking water issues,  is used widely in plumbing pipes and fixtures.

Although copper has been mined in Maine and New Hampshire since the 1800s, high copper concentrations in local drinking water is almost always a result of corrosive water (acidic/low pH) leaching copper from plumbing lines. Blue-green deposits on porcelain fixtures, or blue or green tinted hair or laundry may be an indication of this copper piping deterioration.  Many Maine wells have naturally acidic well-water that must be neutralized to prevent this unwanted copper leaching.  While copper is not poisonous to humans in trace amounts, it can taste bad, and expensive copper pipes will eventually develop leaks if they continue to be eroded from the inside.


Exposure Limits

Maine Maximum Exposure Guideline for Drinking Water limit: .5 mg/L  (aka 500 ppb)

USA Primary Drinking Water Standard limit: 1.3 mg/L  (aka 1300 ppb)

USA Secondary Drinking Water Standard limit: 1.0 mg/L (nuisance level - staining and bad taste)



Wikipedia, "Copper"

Toxic Substances Portal, "Copper" (website)

USA Centers for Disease Control: "Copper and Drinking Water from Private Wells", "Copper" (non-profit mining information website)

FUN PROJECT: "Prehistoric copper smelting in a pit!" (video, 5:43)

Maine's 1970's era open-pit copper mine in Harborside.

MEL Test Methods for Copper

Drinking Water - EPA 200.5 Rev. 4.2, 200.7 Rev. 4.4 (SDWA Compliant)
Wastewater - EPA 200.7  Rev. 4.4 (NPDES Compliant)
Solids - EPA 6010C Rev. 3  (SW846) (RCRA Compliant)

Sample Requirements


Container: plastic, glass
Volume: 250mL
Hold Time: 6 months if preserved with HNO3 to pH<2, otherwise 2 weeks
Preservation: HNO3 to pH<2


Container: plastic, glass, baggie
Volume: a least 150g
Hold Time: 6 months
Preservation: n/a


How to Take a "First Draw" Copper Water Sample