Ancient Roman lead water valve from Pompeii / Valve Magazine

Lead is a naturally-occurring inert metal that has been used by humans since about 9000 years ago.  It has been used widely in plumbing applications since the time of the Romans.  It has physical properties such as softness and ductility that have made it a key material or additive in many industrial processes as well as in paints, cosmetics, ammunitions, glass, glazes, electrical parts, fuels, batteries and more.  Unfortunately, it is also a potent neurotoxin that is extremely unhealthy for humans and wildlife.

Humans ingest lead though inhalation of dusts, by skin absorption, and through drinking and eating contaminated products.  Lead in the environment can be a significant problem, particularly in industrial areas where lead mining or smelting and battery production or demolition has taken place.  Before they were banned in the 1970s, leaded gasoline additives contributed to widespread airborne lead exposure in the USA. In Maine, lead pollution occurs in lakes and streams where lead fishing gear is left behind.

Lead-bearing minerals such as galena (PbS) are common in Maine, but are seldom sources of drinking water pollution. Lead in drinking water is most often a result of lead solders or pipes used in household plumbing leaching into water sitting in the pipes.

Lead was also frequently used in household paints in the USA prior to 1978, presenting exposure risks from inhalation and touch that persist today. MEL does test for lead in paint chips and other items. Although the EPA sets limits for drinking water exposure to lead, there is no safe level for lead exposure.

Many household materials and products still contain lead, particularly if the products come from countries with lower consumer manufacturing standards than the US (see

Drinking Water Exposure Limits

Maine Maximum Exposure Guideline for Drinking Water limit: 0.010 mg/L

USA Primary Drinking Water Standard limit: 0.015 mg/L



Wikipedia, "Lead"

Maine DEP, "Lead Hazard Prevention" (webpage)

US EPA, "Lead" (webpage - exhaustive)

CDC Toxic Substances Portal, "Lead" (website)

USA Centers for Disease Control: "About Lead in Drinking Water" (webpage)

EPA, "Protect Your Family from Exposure to Lead" (webpage), "Lead" (non-profit mining information website)


Galena, a primary ore for lead mining, is found all over Maine:

Lead-bearing galena from North Castine (ME) mine /

MEL Test Methods for Lead

Drinking Water - EPA 200.5 Rev. 5.2 , 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

Drinking Water:
Container: plastic
Volume: more then 1 L
Hold time: 2 weeks
Preservation: n/a


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" Lead Water Sample