LEAD IN AIR
In the United States, emissions of lead have decreased nearly 90 percent during the last 20 years, mainly due to the phasing out of leaded gasoline. A parallel decline in blood lead levels accompanied the phase-out of leaded gasoline and the introduction of catalytic converters in 1973(figure 2). The current U.S. limit is 0.1 grams of lead per gallon (0.1 g/gal) of gasoline. Amendments to the Clean Air Act in 1990 called for a ban on manufacturing, sale or introduction of engines that required leaded gasoline after 1992, and for prohibition of all leaded gasoline for highway use after 1995.
It is estimated that the U.S. has saved over $10 for every $1 invested in phasing out leaded gasoline. These savings can be attributed to reduced health care costs, improved fuel efficiency and savings on engine maintenance (leaded gasoline causes corrosion of auto exhaust systems and requires more frequent oil and spark plug changes). Shifting gasoline production from leaded to unleaded form is also technically easy and inexpensive.
By the end of 1996, 18 countries had eliminated the use of leaded gas (Argentina, Austria, Bermuda, Brazil, Canada, Columbia, Costa Rica, Denmark, El Salvador, Finland, Guatemala, Honduras, Japan, Nicaragua, Slovak Republic, Sweden, Thailand and the U.S.)
Unfortunately, most countries still permit the use of leaded gasoline; airborne lead pollution from mobile sources remains a serious health threat in such countries. The combustion of tetraethyl lead, a gasoline additive used to prevent engine "knock", causes approximately 90% of the airborne lead pollution in cities. Lead concentrations in gasoline vary widely from country to country, and range from a low of 0.1 grams of lead per liter (g/L) of gasoline to a high of 0.84 g/L. Highly-leaded gasoline is a problem in economically developing nations, particularly in Africa. In 1993, petroleum in Benin, Barbados, Ecuador, Ethiopia, Indonesia, Phillippines, Uganda and Zimbabwe was shown to contain 0.75 or more g/L.
Additional information on lead in air is available in the following EPA documents:
* EPA/600/D-90/199 Control of Motor Vehicle Emissions--The U.S. Experience (1990)-- This document gives an historic overview of the U.S. experience in controlling emissions from motor vehicles. The evolution of vehicle emissions certification, surveillance methods, inspection, maintenance and anti-tampering programs are discussed. Also presented are changes in motor vehicle design and fuel formulation, and the corresponding changes in motor vehicle emissions. Possible directions for future improvements are also described. This publication may be ordered from EPA's National Center for Environmental Publications and Information (NCEPI).
* EPA/600/J-93/378 Human Health Effects of Air Pollution (1993) -- This report contains the results from a multi disciplinary study (epidemiology, animal toxicology and controlled human exposure studies) on the health effects from air pollution from lead, sulfur dioxide, nitrogen oxides and carbon monoxide. This publication may be ordered from EPA's National Center for Environmental Publications and Information (NCEPI).
* EPA-230-05-85-006 Costs and Benefits of Reducing Lead in Gasoline: Final Regulatory Impact Analysis (1985)-- The cost versus the benefits of slowly reducing lead levels in gasoline versus phasing it out quickly are compared. Included are an in-depth review of the costs of reducing lead in gasoline, an analysis of human exposure to lead from gasoline, and an overview of the benefits to human health following reductions in lead levels. This publication may be ordered from EPA's National Center for Environmental Publications and Information (NCEPI).
* EPA/410/R-97/002 Final Report on Benefits and Costs of
the Clean Air Act, 1970 to 1990 -- Appendix G: Lead Benefits Analysis (1997) -- Describes in detail the analysis of benefits resulting from the estimated reduction in lead in gasoline and from stationary sources achieved pursuant to the Clean Air Act. This report is available [in PDF] on the EPA web site at:
* EPA-68-02-1375; EPA-450/2-77-012-A Control Techniques for Lead Air Emissions, Volume I, Chapters 1-3 -- This report documents atmospheric emissions of lead and its compounds from various sources, methods for controlling these emissions and approximate costs for implementing these control methods. Estimates of energy and environmental impacts are given for specific model plants. This publication may be ordered from EPA's National Center for Environmental Publications and Information (NCEPI).
* EPA-68-02-1375; EPA-450/2-77-012-B Control Techniques for Lead Air Emissions, Volume II: Chapter 4--Appendix B -- This publication describes the numerous sources of atmospheric lead emission in the United States and deals with the methods and estimated costs of emission control. This publication may be ordered from EPA's National Center for Environmental Publications and Information (NCEPI).
* EPA/450/3-90/024 Risk Assessment for Toxic Air Pollutants: A Citizen's Guide (1990)-- Risk assessment is the process used to estimate the risk of illness from a specific human exposure to a toxic air pollutant. This brochure from EPA's Air Risk Center gives an overview of the 4-step assessment process. This document is available on-line at:
LEAD IN PAINT
In the United States, as exposures from air, food and drinking water have declined, the relative importance of exposure from leaded paint has increased. Currently, leaded paint is viewed as the main cause of blood lead levels over the limit of 10 micrograms per deciliter (10 ug/dL). Over 80% of US homes built before 1978 contain lead paint. Although lead-based house paint has not been sold in the U.S. for 20 years, children living in older homes may be exposed to chips of peeling old paint and, subsequently, to lead-contaminated dust, both indoors and outdoors. Families renovating older structures and low-income families living in dilapidated housing are especially at risk.
* EPA/540/F-94/045 Guidance on Residential Lead-Based Paint, Lead-Contaminated Dust, and Lead-Contaminated Soil (1994)-- This guide is used to help decision makers prioritize primary prevention activities to reduce hazards from lead in and around residences. It is intended for use by decision makers (risk assessors, risk managers, etc.) to identify lead-based paint hazards, other sources of lead exposure, and the need for control actions in residential environments where children may be present. This publication may be ordered from the National Technical Information Service (NTIS).
INDUSTRIAL SOURCES OF LEAD
Many developing countries engage in high levels of lead smelting and lead-acid battery production and recycling. Lead-acid battery production is technically straightforward, and batteries are an important, inexpensive and portable source of electricity. However, the manufacturing process generates air-borne lead dust and problems arise when the factories are improperly vented and when residences are too close to the plant. Also, workers in these industries might accidentally expose their families to lead particles by bringing hazardous dusts home on work clothing.
LEAD IN FOOD
Lead particles can enter the food supply through a number of routes. Lead-containing particles in air can deposit onto vegetables and fruits during harvesting, processing and distribution. Some agricultural pesticides also contain lead-based compounds which might remain as residues on crops. Lead solder in canned goods can also result in food contamination. In the U.S., the largest source of lead in food, though, is lead-glazed ceramic ware such as mugs, plates and bowls. Foil on wine bottles and bottled water, food additives and leaded crystal ware are other (lesser) sources of lead in food.
LEAD IN DRINKING WATER
Drinking water contamination occurs primarily from lead-containing components in plumbing. Lead and lead compounds show a wide range of solubility and are highly persistent in water, with a half-life (the time for half of a chemical to degrade) of over 200 days. While source water seldom contains high amounts of lead, chemical reactions between the water and lead connectors, water pipes, and materials including solder, brass and some plastics may result in lead leaching into the distribution system and into homes. The EPA has estimated that 20 to 40 percent of the average blood lead in U.S. children may come from lead in drinking water.
For additional information on lead in drinking water, refer to the following EPA documents:
* EPA/812/B-92/002 Lead in Drinking Water Regulation: Public Education Guidance (1992) -- This document contains information on conducting a community-based public education program, including organizing a community task force, developing an action plan, preparing public education materials, developing a water-testing program, and program implementation. Sample public education materials are included. This publication may be ordered from EPA's National Center for Environmental Publications and Information (NCEPI).
* EPA/600/A-93/035 Corrosion Control Principles and Strategies for Reducing Lead and Copper in Drinking Water Systems (1993) -- This paper gives an overview of plumbing and corrosion issues and discusses the impact of water softeners on corrosion. Water sampling methods and the trade-offs in water quality associated with different methods of corrosion control are discussed. This publication may be ordered from EPA's National Center for Environmental Publications and Information (NCEPI).
* EPA/625/R-93/001 Seminar Publication: Control of Lead and Copper in Drinking Water (1993)-- This publication discusses five topics: (1) Regulation of drinking water in the United States; (2) the corrosive effects of water on lead and copper-containing materials; (3) design and implementation of a corrosion-monitoring program; (4) corrosion control assessment, including methods to measure corrosion; (5) an overview of control strategies and secondary effects.
* EPA/812/K-93/001 Lead in Drinking Water: An Annotated List of Publications (1993)-- List of documents published by the EPA and other organizations for a variety of audiences.
The EPA also publishes seven documents which provide guidance on lead and copper monitoring for water systems serving communities of various sizes. These publications contain specific information on conducting a materials evaluation to identify lead and copper sampling sites, how and when to collect tap water samples for lead and copper, water quality parameter sampling, and source water sampling. Also included are sample forms and worksheets. Each of these publication is available from EPA's National Center for Environmental Publications and Information (NCEPI):
* EPA 812/B-92-003 Lead and Copper Monitoring Guidance for Water Systems Serving < 100 persons
* EPA 812/B-92/004 Lead and Copper Monitoring Guidance for Water Systems Serving 101 to 500 persons
* EPA 812/B-92/005 Lead and Copper Monitoring Guidance for Water systems Serving 501 to 3,300 persons
* EPA 812/B-92/006 Lead and Copper Monitoring Guidance for Water Systems Serving 3,301 to 10,000 Persons
* EPA 812/B-92/007 Lead and Copper Monitoring Guidance for Water Systems Serving 10,001 to 50,000 Persons
* EPA 812/B-92/008 Lead and Copper Monitoring Guidance for Water Systems Serving 50,001 to 100,000 Persons
* EPA 812/B-92/009 Lead and Copper Monitoring Guidance for Water Systems Serving Over 100,000 Persons
Some additional information on the problem of lead in drinking water may be found on the following web site maintained by EPA's Office of Water:
LEAD IN DUST AND SOIL
Lead concentrations of 500-1000 parts per million (ppm) in soil have been shown to correspond to increases in blood lead. Young children may ingest high levels of lead from soil and dust, but actual absorption of ingested lead (bioavailability) depends on both the chemical and physical characteristics of the lead-containing compound and the physiology and metabolism of each child. Industrial and mobile sources are significant sources of lead in soil in urban areas. For additional information, refer to:
* EPA/747/R-95/001 Residential Sampling for Lead: Protocols for Dust and Soil Sampling [Final Report] (1995)-- This report contains finalized protocols for dust and soil sampling for lead in U.S. residential areas. It gives guidance for necessary equipment and supplies, sampling procedures and quality control for both dust and soil lead sampling. This publication may be ordered from EPA's National Center for Environmental Publications and Information (NCEPI).
* EPA/747/R-95/007 Sampling House Dust for Lead: Basic Concepts and Literature Review (1995)-- This report contains an extensive literature review of sampling methods for measuring lead in house dust. The report outlines issues related to dust in homes, defines terms, explains basic concepts, summarizes numerous house dust sampling methods and sampling strategies.
This publication may be ordered from the National Technical Information Service (NTIS).
In the United States, a striking decline in the lead levels in air was observed from 1975 to 1988, concurrent with the phase out of leaded gasoline. Increased health concerns over the health effects of lead also resulted in dramatic reductions of lead in paints, ceramics, caulking and pipe solder over the past 15 years; in addition, the use of lead solder in canned food was eliminated in the U.S. in the 1980's.
The control of lead exposure in the U.S. is now focused on risk reduction from drinking water, lead-based paint, household dust and contaminated soil. Efforts to reduce multimedia exposure pathways from pollutant sources (e.g. smelter emissions) are conducted through the tightening of regulatory controls, and by increasing voluntary and cooperative risk reduction efforts.
A broad perspective on lead issues is required to avoid undesirable trade-offs between different segments of the environment or the population. The EPA published a "Lead Strategy" in 1990 that specifies specific objectives for the United States: (1) To significantly reduce the number of children with concentrations exceeding 10 micrograms of lead per deciliter of blood (ug/dL). (2) To reduce the amount of lead released into the environment by 50% by 1995 (focusing on voluntary pollution reduction, beyond the level of existing regulatory requirements). To reach these goals, the EPA has focused on developing detection and abatement methods to tackle existing lead contamination. Another focus has been reduction of lead production and consumption (about 50% of lead used in the U.S. comes from recycled products), and on preventing further pollution using market-based incentives, regulation, and technology enhancement.
In many industrializing countries, childhood lead poisoning and occupational exposure to lead are typically more severe because of inadequately controlled industrial emissions, unregulated cottage industries, the use of leaded gasoline and the use of folk remedies and cosmetics containing lead. The average blood lead levels of many populations studied around the world was much higher that currently acceptable levels. Using preventive measures to address the problem is preferable since cleaning up contamination once lead has dispersed into the environment is difficult, costly and slow.
* EPA/540/2-91/014 Selection of Control Technologies for Remediation of Lead Battery Recycling Sites (1991)-- This report discusses remedial action, waste treatment and waste management at lead battery recycling sites in the U.S. Treatment alternatives and cleanup services are presented, and the advantages and disadvantages of the different technologies are discussed. This document may be ordered from the National Technical Information Service (NTIS).
* EPA/450/2-79/002 Guideline Series: Development of an Example Control Strategy for Lead (1979)-- This guide presents a method for developing a control strategy for lead. The guide covers the following topics: development of baseline emissions inventory and air quality data; projection and allocation of emissions; application of models and analysis of modeling results; and the testing, evaluation and selection of strategies.
* EPA/452/R-93/009 EPA Lead Guideline Document and Appendix (1993)-- This document is intended as a guide on lead policy; it compiles currently available policy and guidance for lead programs in the United States, reflecting statutory and regulatory sources such as the Clean Air Act. Each chapter summarizes relevant policy and guidance and provides detailed references for more comprehensive information sources. Topics include air quality status, air quality monitoring and modeling, and control strategies. This publication may be ordered from EPA's National Center for Environmental Publications and Information (NCEPI).
U.S. EPA. 1997. Executive Summary: Laboratory Study of Lead-Cleaning Efficacy. (EPA/747/R-97/002)
U.S. EPA. 1995. Review of Studies Addressing Lead Abatement Effectiveness. (EPA/747/R-95/006)
U.S. EPA. 1996. Executive Summary: Comparative Abatement Performance Study, Volumes 1 and 2. (EPA/230/R-94/013a + 013b)
OPPT LEAD PAGE
EPA's Office of Pollution Prevention and Toxics (OPPT) Lead Page contains many electronic links to lead poisoning prevention documents. These documents include EPA residential lead hazard guidance and standards, technical reports, and public education materials; links to EPA offices including the Office of Water and Office of Air; links to non-EPA resources including the Department of Housing and Urban Development (HUD), the Centers for Disease Control and Prevention (CDC), the Occupational Safety and Health Administration (OSHA) and the National Lead Information Center. To access the OPPT Lead Page, use the following Internet address:
NATIONAL LEAD INFORMATION CENTER
This site is produced and maintained by the National Lead Information Center (NLIC). NLIC operates under a cooperative agreement with the U.S. EPA, with funding from the EPA, the Centers for Disease Control and Prevention, and the Department of Housing and Urban Development. NLIC provides the general public and professionals with information about lead poisoning and its prevention. Users may access the NLIC web site at:
Inquiries to NLIC may also be made through the organization's hotline or by mail. The hotline is staffed Monday through Friday from 8:30 a.m. to 5:00 p.m. Eastern Standard Time. Call 1-800-424-5323 to speak with an information specialist. Specialists can answer (in English or Spanish) specific questions on lead-related issues. To reach the NLIC by fax, dial 1-202-659-1192. To reach the NLIC by email, send messages to: [email protected]
AGENCY FOR TOXIC SUBSTANCES AND DISEASE REGISTRY
The Agency for Toxic Substances and Disease Registry is part of the Unites States Public Health Service. The web site listed below contains detailed information on the health effects of lead exposure:
HOUSING AND URBAN DEVELOPMENT LEAD PROGRAM
The Office of Lead Hazard Control at the U.S. Department of Housing and Urban Development (HUD) maintains this web site. The site contains general technical information on lead, but concentrates on lead-based paint issues: