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National Drinking Water Database
Lead (total) in Maryland
Lead is a metal that enters water by corrosion of household plumbing systems, discharge of industrial pollution and erosion of natural deposits. [read more]
Lead is a very toxic heavy metal that can cause permanent neurological and behavioral problems. Lead toxicity is manifested in virtually every system in the body. The U.S. Environmental Protection Agency (EPA) recommends a Maximum Contaminant Level Goal (MCLG) for lead in drinking water of zero - this is the level of lead in drinking water below which there is no known or expected risk to health (USEPA 2009b). The state of California lists lead as a developmental and reproductive toxicant because of its potential for causing infertility and spontaneous abortion in adults and developmental defects in children. Some studies also suggest a relationship between blood lead levels and pre-term delivery, low birth weight and fetal growth retardation (Agency for Toxic Substances and Disease Registry (ATSDR) 1999b, 2007b).
Lead can affect children at extremely low levels, and there is no evidence of a threshold dose below which developmental effects do not occur. Levels as low as 10 micrograms per deciliter (mg/dL), currently considered by the Centers for Disease Control and Prevention as the threshold for elevated blood lead level, have been associated with decreased intelligence and impaired neurobehavioral development (ATSDR 1999b). Lead is "reasonably anticipated" to be a human carcinogen by the National Toxicology Program (NTP), based on kidney and nervous system tumors in laboratory animals (NTP 2002a).
Most recently, lead contamination of drinking water has been reported due to tap water treatment with the disinfection agent chloramine (USEPA 2007a). In 2009, Virginia Polytechnic Institute and State University (Virginia Tech) scientists reported shockingly high lead levels in the blood of young Washington, D.C. children tested between 2001 and 2004, when the District of Columbia's drinking water was contaminated with lead from aging pipes (Edwards 2009). Unfortunately, this situation is not unique: similar results have been reported in Greenville, North Carolina, according to studies by Duke University researchers (Miranda 2007). Other areas in the country with lead-based service pipes distributing municipal water may be similarly affected.
Even after lead has been removed from gasoline and food containers, lead-based house paint has remained a common source of lead exposure, especially for children. About 10 billion pounds of lead paint were used in the United States between its introduction in 1889 and the imposition of federal restrictions in the U.S. in 1970 - 61 years after France, 48 years after Australia and 44 years after Great Britain. House dust is often contaminated by lead-based paint that is peeling or deteriorating, or is disturbed during renovation or the preparation of painted surfaces for repainting without proper safeguards. Soil contamination can be traced to deteriorating exterior paint or the past widespread use of leaded gasoline (ATSDR 2007b).
Lead was a major ingredient in most interior and exterior oil house paint before 1950 and was still used in some paints until 1978, when the residential use of lead paint was banned. The Department of Housing and Urban Development (HUD) estimates that three-quarters of pre-1980 housing units contain some lead-based paint, and that the likelihood, extent, and concentration of lead-based paint increase with the age of the building. In 1995, a federal task force on lead-based paint in the U.S. estimated that 6 to 16 percent of the nation's housing units contain lead-based paint hazards.
According to the U.S. EPA's Toxics Release Inventory (TRI), in 2002, industries released an estimated 441.8 million pounds of lead. Lead releases are spread out over every single state, with the highest levels in Kansas, Alabama and Idaho. High levels are also seen in Texas, Illinois, Iowa and Ohio. The largest industrial releases are from steel and iron industries and lead production and processing operations (USEPA 2009i). Additionally, urban runoff and atmospheric deposition are significant indirect sources of lead pollution (ATSDR 1999b).
The Most Polluted Communities in Maryland
26 water utilities reported detecting Lead (total) in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies
Ranked by highest average Lead (total) level
|Rank||System||Population Served||Positive test results of total reported tests||Average Level|
|1,600||2 of 5||9.42 ppb|
(0 to 40 ppb)
|2||Naylor Mill Village Mobile Home Park|
|180||1 of 1||7.86 ppb|
|3||City of Frostburg|
|11,000||3 of 3||6.89 ppb|
(1.75 to 15.25 ppb)
|4||Klondike Water Company|
|195||1 of 1||6 ppb|
|5||Mount Carmel Woods|
La Plata, MD
|180||1 of 1||5.7 ppb|
|6||Gateway Village Mobile Home Park|
|60||1 of 1||5.66 ppb|
|7||Baltimore City Department of Public Works|
|1,600,000||21 of 24||5.16 ppb|
(0 to 19.33 ppb)
|8||Lyons Creek Estates|
|750||1 of 1||5 ppb|
|9||Westside Mobile Home Park|
|300||2 of 2||4.59 ppb|
(1.12 to 8.05 ppb)
|10||City of Aberdeen|
|14,500||1 of 1||4 ppb|
Health Based Limits for Lead (total)
|Maximum Contaminant Limit Goal (MCLG)||A non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.||0 ppb|
|California Public Health Goals||Defined by the State of California Office of Environmental Health Hazard Assessment (OEHHA) as the level of contaminant that is allowed in drinking water. For acutely toxic substances, levels are set at which scientific evidence indicates that no known or anticipated adverse effects on health will occur, plus an adequate margin-of safety. PHGs for carcinogens or other substances which can cause chronic disease shall be based solely on health effects without regard to cost impacts and shall be set at levels which OEHHA has determined do not pose any significant risk to health.||0.2 ppb|
Violation Summary for Lead (total) in Maryland
There are no violations reported for this contaminant in Maryland