Even at very low levels, exposure to lead can impair a child’s IQ, learning capabilities, memory and behavior, the agency said in a statement last week announcing the revision.
The agency is proposing to require air quality monitoring around sources that emit a half ton or more of lead a year, lowering the current threshold from one ton a year to include more sources.
The proposal also modifies the current requirement for monitoring in larger urban areas. Monitors would be placed at each of the multi-pollutant monitoring stations being established in urban and rural areas.
The Doe Run lead smelter in Herculaneum, Missouri (Photo by Wampa-One)
These changes would allow monitoring at the largest sources of lead emissions and would more accurately track long-term trends and assess typical lead levels in communities throughout the country.
The EPA says the changes would improve the lead monitoring network to better assess compliance with the tighter National Ambient Air Quality Standards for lead established in 2008.
In November 2008, the EPA gave notice that the federal air quality standard for lead emissions would become 10 times more stringent – from 1.5 micrograms of lead per cubic meter of air to 0.15 micrograms per cubic meter.
EPA is not reconsidering nor delaying the implementation of these new lead standards.
States will still need to deploy lead monitors around sources emitting at least one ton of lead a year by January 1, 2010.
This proposal to monitor more sources of lead is in response to a petition requesting EPA to reevaluate the air monitoring requirements finalized in 2008 along with the tightened national air quality standards for lead.
In January 2009, EPA received a petition to reconsider the lead monitoring requirements from the Missouri Coalition for the Environment Foundation, Natural Resources Defense Council, the Coalition to End Childhood Lead Poisoning, and Physicians for Social Responsibility.
EPA granted the petition to reconsider on July 22, 2009. This proposal represents the results of the EPA’s reconsideration of the lead monitoring requirements.
Under the Clean Air Act, EPA sets and reviews national air quality standards for lead. Air quality monitors measure concentrations of lead throughout the country, and the EPA, state, tribal and local agencies use this data to ensure that lead is at levels that protect public health and the environment.
People can be exposed to lead emitted into the air by inhaling it or ingesting it after it settles on dust, drinking water or food. Ingestion is the main route of human exposure. Children are the most susceptible because they are more likely to ingest lead, and their bodies are developing rapidly. "There is no known safe level of lead in the body," the EPA says.
Today, industrial processes, primarily metals processing, are the major source of lead emissions to the air. The highest air concentrations of lead are usually found near lead smelters. Other stationary sources are waste incinerators, utilities and lead-acid battery manufacturers.
In the past, motor vehicles were the major contributors of lead emissions to the air.
In the United States, where lead had been blended with gasoline, primarily to boost octane levels, since the early 1920s, standards to phase out leaded gasoline were first implemented in 1973.
By 1995, leaded fuel accounted for only 0.6 percent of total gasoline sales. From January 1, 1996, the Clean Air Act banned the sale of leaded fuel for use in on-road vehicles, yet fuel containing lead may still be sold for off-road uses, including some aircraft and marine engines, race cars and farm equipment.
Commercial aircraft do not use leaded fuel, but fuel used for piston-engine aircraft still contains lead. As a result, the EPA is proposing to treat airports identically to other sources of lead when determining if source-oriented lead monitoring is needed. The agency is requesting comments on the availability of data that may be useful in setting an alternative emission threshold for airports.
Lead poisoning is the number one environmental hazard threatening children throughout the United States, affecting an estimated 310,000 children under the age of six, according to the Coalition to End Childhood Lead Poisoning.
"Children are frequently poisoned by ingesting lead dust that has accumulated on their hands, fingers, toys, or clothing from lead hazard sources like floors and windowsills. It takes only small amounts of lead to harm a child," the coalition says.
Once taken into the body, lead is accumulated in the bones. Depending on the level of exposure, lead can adversely affect the nervous system, kidney function, immune system, reproductive and developmental systems and the cardiovascular system, the EPA warns.
Lead exposure also affects the oxygen carrying capacity of the blood. The lead effects most commonly encountered are neurological effects in children as well as high blood pressure and heart disease in adults. Some studies also link childhood lead blood levels to violence later in life.
The only way to know for sure if a child is being exposed to lead hazards is through a blood lead test.
Copyright Environment News Service (ENS) 2009. All rights reserved.