Harvard University



LEAD SMELTING

International Review

Presented by

Nicole Fobi, MD

Internal Medicine Residency Program

Morehouse School of Medicine, Atlanta, GA

May 15th, 2007

Mary Jean Brown, PhD

Peter Kowalski, MPH

NCEH/ATSDR/CDC, Atlanta, GA

ABSTRACT

Lead is the most abundant of the heavy metals in the Earth’s crust. It has been used since prehistoric times, and has become widely distributed and mobilized in the environment. Exposure to and uptake of this non-essential element have consequently increased. Both occupational and environmental exposures to lead remain a serious problem in many developing and industrializing countries, as well as in some developed countries. In most developed countries, however, introduction of lead into the human environment has decreased in recent years, largely due to public health campaigns and a decline in its commercial usage, particularly in petrol. Acute lead poisoning has become rare in such countries, but chronic exposure to low levels of the metal is still a public health issue, especially among some minorities and socioeconomically disadvantaged groups. At high levels of human exposure there is damage to almost all organs and organ systems, most importantly the central nervous system, kidneys and blood, culminating in death at excessive levels. The demand for Lead is steadily increasing world wide. Many communities are still exposed to lead from past and present lead smelting activities. In developing countries, awareness of the public health impact of exposure to lead is growing but relatively few of these countries have introduced policies and regulations for significantly combating the problem. Much work needs to be done to identify and treat children with elevated blood lead levels and reduce lead exposure in the community. Screening, monitoring, intervention and evaluation are critical for the development of rational, cost-effective and science-based public health policies aimed at achieving these goals.

This article reviews the nature and importance of environmental exposure to lead

in developing and developed countries as well as policies and guidelines

from Stakeholders.

Lead Mining and Smelting

Lead metal is described as being either primary or secondary. Primary lead is produced directly from mined lead ore. Secondary lead is produced from scrap lead products which have been recycled.

The most common lead ore is galena or lead sulphide. Other elements frequently present include zinc and silver. In fact lead ores constitute the main sources of silver, contributing substantially towards the world's total output.

Lead is obtained from galena by a process called smelting. This involves roasting the ore to remove the sulphur and to obtain lead oxide which is then reacted with coke in a furnace. The resulting lead bullion contains many impurities such as silver and gold (hence the name bullion) as well as antimony, arsenic, copper, tin and zinc. These impurities are then removed by various refining steps to obtain pure lead.

The process is extremely costly financially and to the environment.

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A typical primary lead smelting and refining

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Lead in Galena

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Lead Mine pit

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Blast operation to form mine pit

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Galena is taken to a mill and crushed in a rod and ball machine

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Crushed Galena from lead mine

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Large, uncovered trucks transport crushed galena to the lead smelting plant

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Crushed galena put in suspension tank with water and dithiophosphate chemical. Chemical reaction creates froth separating lead from ores (sulfides). Lead clings to froth which hardens and is skimmed off resulting in 90% lead concentrate

DEMOGRAPHICS, STATISTICS and USES

Around 3 million tonnes of lead are mined in the world each year. Lead is found all over the world but the largest mining countries are Australia, China and the United States, which between them account for more than 50% of primary production.

| | Mine production |Reserves |Reserve base |

| | | | | |

|  |2005 |2006 |  |  |

|United States |426 |430 |8,100 |20,000 |

|Australia |776 |780 |15,000 |28,000 |

|Canada |73 |79 |2,000 |9,000 |

|China |1,000 |1,050 |11,000 |36,000 |

|India |58 |60 |NA |NA |

|Ireland |64 |65 |NA |NA |

|Kazakhstan |44 |55 |5,000 |7,000 |

|Mexico |130 |140 |1,500 |2,000 |

|Morocco |31 |42 |500 |1,000 |

|Peru |319 |320 |3,500 |4,000 |

|Poland |48 |60 |NA |5,400 |

|South Africa |42 |50 |400 |700 |

|Sweden |61 |61 |500 |1,000 |

|Other countries |198 |170 |19,000 |30,000 |

|World total (rounded) |3,270 |3,360 |67,000 |140,000 |

US Geological Survey, Mineral Commodity Summaries, January 2007

Data in thousand metric tons of lead content

|Top Mining Countries |Largest Lead Producers |

|Australia |654,000 |China |1,533,000 |

|China |618,000 |USA |1,338,000 |

|USA |464,000 |Germany |352,000 |

|Peru |308,000 |UK |338,000 |

|Mexico |152,000 |Australia |304,000 |

|Major Users of Lead |Main Recyclers of Lead |

|USA |1,488,000 |USA |1,098,000 |

|China |1,050,000 |Germany |222,000 |

|Germany |392,000 |Japan |190,000 |

|Korea Rep |342,000 |UK |176,000 |

|UK |330,000 |Italy |153,000 |

KEY WORLD STATISTICS 2003 (Values shown in tones)

Lead –Major Uses

Batteries largest use by far (78%) for motor vehicles and back up power generators

Lead compounds (8%)

–petrol anti-knock additives

–stabilizers for PVC, crystal glass, ceramic glazes

–pigments

Rolled sheets for construction (5%)

Use of lead in petrol has been largely discontinued and is being phased out where use continues

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ENVIRONMENT AND HEALTH

Material left over after mining is called tailings which are composed of waste water, dithiophosphate, zinc ore and sulfides. Garbage from mine workers is discarded on landscape as well. Tailings accumulate and are dumped along with waste water into tailing ponds. Heavy metals and chemicals leech into the soil and migrate into the water supply especially when it rains. The amount of waste dumped into pond could be outrageous. Doe Run Mine alone in 1998 generated 4.9 million metric tons of process water into unlined surface impoundments. Even after mine/smelters close waste continue to contaminate the land and remains a source of exposure in the community. This leads to tremendous geological damage. Contaminated water flows into streams and wells. Animals drink the water, humans use it for recreation and fishing. The aquatic life becomes contaminated.

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Leftovers called tailings

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Lead contaminating nearby system

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Waste water

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Man-made lake filled with contaminated water

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Exposure Pathway

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Health impacts on Adults and Children

Lead in the body

Health consequences are more devastating in children especially those less than 6yrs of age. They are more exposed as a result of picking up lead from playgrounds/soil and ingesting (hands to mouth). Even trace amounts can damage a child’s still developing body (affects nervous system, stunt growth, attention span, behavioral problems etc). Fetuses exposed suffer low birth weight and altered gestation age.

STAKEHOLDERS GUIDELINES AND POLICIES

These include multinational organizations (e.g. WHO, World bank), NGOs, country health agencies, lead industries and communities.

In developing countries, awareness of the public health impact of exposure to lead is growing but relatively few of these countries have introduced policies and regulations for significantly combating the problem.

Much work needs to be done to identify and treat children with elevated blood lead levels and reduce lead exposure in the community. Screening, monitoring, intervention and evaluation are critical for the development of rational, cost-effective and science-based public health policies aimed at achieving these goals.

The most immediate priority is to reduce exposure to lead and other contaminants. This is best accomplished by building the environmental public health infrastructure needed to develop and implement a comprehensive and integrated intervention plan. Stakeholders need to unite and collaborate systemically to reduce emissions, remediate soil contamination, and operate a sustainable monitoring system

A.WHO

Public health measures to reduce and prevent exposure to lead by reducing the use of the metal and its compounds and by minimizing lead-containing emissions that result in human exposures. This can be achieved by:

1. Phasing out lead additives in fuels and removing lead from petrol as soon as is practicable.

2. Reducing and phasing out the use of lead-based paints.

3. Eliminating the use of lead in food containers.

4. Identifying, reducing and eliminating lead used in traditional medicines and cosmetics.

5. Minimizing the dissolving of lead in water treatment and water distribution systems.

6. Improving control over exposure to lead in workplaces.

7. Improving identification of populations at high risk of exposure on the basis of monitoring systems.

8. Improving procedures of health risk assessment.

9. Improving promotion of understanding and awareness of exposure to lead.

10. Increasing emphasis on adequate nutrition, health care and attention to socioeconomic conditions that may exacerbate the effects of lead.

11. Developing international monitoring and analytical quality control programmes (36).

Environmental lead exposure: a public health problem of global dimensions

Bulletin of World Health Organization, 2000, 78 Refs No. 0686

Lead Air Quality Guidelines

Guidelines for lead in air will be based on the concentration of lead in blood. Critical effects to be considered in the adult organism include elevation of FEP, whereas for children cognitive deficit, hearing impairment and disturbed vitamin D metabolism are taken as the decisive effects. All of these effects are considered adverse. A critical level of lead in blood of 100 μg/l is proposed. It should be stressed that all of these values are based on population studies yielding group averages, which apply to the individual child only in a probabilistic manner.

1. Currently measured “baseline” blood lead levels of minimal anthropogenic origin are probably in the range 10–30 μg/l.

2. Various international expert groups have determined that the earliest adverse effects of lead in populations of young children begin at 100–150 μg/l. Although it cannot be excluded that population effects may occur below this range, it is assumed to be prudent to derive a guideline value based on the lowest value of this range (100 μg/l).

3. It can be assumed that inhalation of airborne lead is a significant route of exposure for adults (including pregnant women) but is of less significance for young children, for whom other pathways of exposure such as ingested lead are generally more important.

4. It appears that 1 μg lead per m3 air directly contributes approximately 19 μg lead per liter blood in children and about 16 μg per liter blood in adults, although it is accepted that the relative contribution from air is less significant in children than in adults. These values are approximations, recognizing that the relationships are curvilinear in nature and will apply principally at lower blood lead levels.

5. It must be taken into account that, in typical situations, an increase of lead in air also contributes to increased lead uptake by indirect environmental pathways. To correct for uptake by other routes as well, it is assumed that 1 go lead per m3 air would contribute to 50 μg lead per liter blood.

6. It is recommended that efforts be made to ensure that at least 98% of an exposed

population, including preschool children, have blood lead levels that do not exceed

100 μg/l. In this case, the median blood lead level would not exceed 54 μg/l. On this

basis, the annual average lead level in air should not exceed 0.5 μg/m3. This proposal is based on the assumption that the upper limit of non-anthropogenic lead in blood is 30 μg/l. These estimates are assumed to protect adults also.

7. To prevent further increases of lead in soils and consequent increases in the exposure of future generations, air lead levels should be kept as low as possible.

Since both direct and indirect exposure of young children to lead in air occurs, the air guidelines for lead should be accompanied by other preventive measures. These should specifically take the form of monitoring the lead content of dust and soils arising from lead fallout. The normal hand-to-mouth behavior of children with regard to dust and soil defines these media as potentially serious sources of exposure. A specific monitoring value is not recommended. Some data indicate that lead fallout in excess of 250 μg/m² per day will increase blood lead levels.

Chapter 6.7 Lead Air Quality Guidelines - Second Edition

WHO Regional Office for Europe, Copenhagen, Denmark, 2001 13

B.WORLD BANK

Lead and Zinc Smelting – Industry Sector Guidelines

Key Issues

The key production and control practices that will lead to compliance with emissions requirements can be summarized as follows:

1. Give preference to the flash-smelting process where appropriate.

2. Choose oxygen enrichment processes that allow higher SO2 concentrations in

Smelter gases to assist in sulfur recovery, use the double-con-tact, double-absorption

process.

3. Improve energy efficiency to reduce fuel usage and associated emissions; use

Low NOx burners; give preference to natural gas as fuel.

4. Reduce air emissions of toxic metals to acceptable levels.

5. Maximize the recovery of dust and minimize fugitive emissions; use hoods and

doghouse enclosures.

6. Reduce effluent discharge by maximizing wastewater recycling.

7. Avoid contamination of groundwater and surface waters by leaching of toxic metals

from tailings, process residues, slag, and other wastes.

Monitoring and Reporting

Frequent sampling may be required during startup and upset conditions. Once a record of consistent performance has been established, sampling for the parameters listed in this document should be as described below.

Air emissions should be monitored continuously for sulfur dioxide and particulate matter. Other air emissions parameters should be monitored monthly. Fugitive emissions should be monitored annually.

Liquid effluents should be monitored daily for pH and total suspended solids and at least weekly for all other parameters.

All solid waste, tailings, and leachates should be monitored for toxic metals. Contamination of groundwater and surface waters should be avoided.

Monitoring data should be analyzed and reviewed at regular intervals and compared with the operating standards so that any necessary corrective actions can be taken. Records of monitoring results should be kept in an acceptable format. The results should be reported to the responsible authorities and relevant parties, as required

Pollution Prevention and Abatement Handbook

WORLD BANK GROUP Effective July 1998

Environmental, Health, and Safety Guidelines

Base Metal Smelting and Refining

1. Environmental

1.1 Air Emissions and Ambient Air Quality

1.2 Energy Conservation

1.3 Wastewater and Ambient Water Quality

1.4 Water Conservation

1.5 Hazardous Materials Management

1.6 Waste Management

1.7 Noise

1.8 Contaminated Land

2. Occupational Health and Safety

2.1 General Facility Design and Operation

2.2 Communication and Training

2.3 Physical Hazards

2.4 Chemical Hazards

2.5 Biological Hazards

2.6 Radiological Hazards

2.7 Personal Protective Equipment (PPE)

2.8 Special Hazard Environments

2.9 Monitoring

3. Community Health and Safety

3.1 Water Quality and Availability

3.2 Structural Safety of Project Infrastructure

3.3 Life and Fire Safety (L&FS)

3.4 Traffic Safety

3.5 Transport of Hazardous Materials

3.6 Disease Prevention

3.7 Emergency Preparedness and Response

4. Construction and Decommissioning

4.1 Environment

4.2 Occupational Health and Safety

4.3 Community Health and Safety

World Bank Group, April 2007

C. ILZRO - The International Lead Zinc Research Organization

ILZRO's sponsors include most of the major producers of lead, zinc and silver, and significant numbers of end-users of these metals from among the steel, automotive, die casting, battery, galvanizing and other industries.

ILZRO's R&D portfolio for 2007 encompasses the primary applications of lead, zinc and silver, as well as significant work in the areas of the environment and human health. The results of ILZRO R&D efforts are communicated through a variety of forums, including research reports, technical seminars, expert consulting, internet sites and printed publications.

D. ILZSG - The International Lead Zinc Study Group

The International Lead and Zinc Study Group (ILZSG) is an intergovernmental organization which regularly brings together twenty-eight member countries in an international forum to exchange information on lead and zinc. ILZSG provides a unique and globally recognized source of industry statistics and organizes twice yearly meetings between producing and consuming countries, industry and government representatives.

The International Lead and Zinc Study Group (ILZSG) represents one of the few international forums for the lead and zinc business where Governments and Industry can exchange views through its Economic and Environmental Committee and its Secretariat, on the consequences of international environmental and health related initiatives on the trade in lead and zinc. Moreover, the ILZSG Secretariat may attend committee meetings of relevant international organizations such as the OECD, the European Commission and the World Bank, as well as private industry associations.

The ILZSG's Economic and Environment Committee follows all environmental aspects relevant to lead and zinc mines and smelters and end uses. This entails:

• monitoring of environmental issues

• Informing Study Group member countries on particular issues relating to

- ecotoxicity

- transboundary movements of waste

- transboundary air pollution

- international co-ordination of activities on chemicals

ILZSG has already released environmental studies such as “Environmental and Health Controls on Lead 2007"

E. ILMC - The International Lead Management Center

The ILMC, LLC, is a lead risk reduction project administered by the International Lead Zinc Research Organization (ILZRO).

The international lead industry recognizes that exposure to lead can result in

risk to human health and the environment. The industry is committed, through

the International Lead Management Center (ILMC), to work with

governments, industries and the international community to manage the risk of

lead exposure.

The International Lead Management Center is thus charged with the implementation

of a voluntary Industry Lead Management Project.

ILMC complements and supports existing international risk management

activities and responds to the individual needs of countries who wish to

introduce such projects in either industry or their local communities.

The Center welcomes inquiries and requests for either advice or assistance.

The Center is sponsored by the following major mining and lead-producing

corporations:

• Aberfoyle Ltd., Australia

• ASARCO, Inc., United States of America

• Boliden, Sweden

• Cominco Ltd., Canada

• Doe Run Company, United States of America

• Met-Mex Pen˜oles S.A. de C.V., Mexico

• Mount Isa Mines Holdings, Australia

• Noranda Mining and Smelting, Inc., Canada

• Pasminco Ltd., Australia

• Union Miniere, Belgium

Guidance and direction on priorities, project feasibility and action programs

are provided by a Policy Advisory Group that includes independent experts

with international experience and expertise in:

• Lead mining, smelting, refining and recycling

• Occupational and public health

• Risk reduction programs

• Technology transfer

• Social policy and economic issues

Activities of the ILMC

Pilot Programs

ILMC will assist and cooperate with government agencies interested in

assessing and reducing the risk of lead exposure.

These Pilot Programs address distinct lead exposure issues unique to each

country’s cultural, technical, geographic and socio-economic circumstances

Pilot Programs:

ILMC and the Philippines

ILMC and Mexico

ILMC and Russia

ILMC and Peru

Risk Management Teams

When ILMC receives a request for assistance from a government agency or

industry sector wishing to initiate a lead risk management program, a “Risk

Management Team” will be assigned to collect, collate and analyze all the

available data.

Worker Health and Hygiene Training Programs

Good operating practices and hygiene

procedures are the most important factors in reducing occupational lead

exposure. Experience has shown that those companies with the lowest levels

of exposure have invariably the highest operating standards and the best

hygiene procedures.

Outreach To Consumer Industries

ILMC has established liaison with relevant industry and consumer

organizations in order to ensure a cooperative approach to minimize exposure

Information Resources and Databases

ILMC has established an extensive database covering

such issues as:

• International inventory of standards and best practice - for

occupational exposure

• Occupational and environmental case studies - for risk

management projects

• Usage, properties, risks and options - for lead bearing products

• International inventory of standards and control - for industrial

emissions

• Research results assessing risk reduction benefits - for exposure

reduction

• Exposure assessments and environmental sampling - for

abatements

• Material collection systems, recycling technology - for recycling

• Community-based risk management programs - an inventory of

risk reduction experience

Internet Services

Information is available electronically on the Internet at

on the following:

• Risk Management and Control Protocols

• Environmental Management Systems

• International Lead Exposure Standards

• Testing Methods and Procedures

• Product Definitions

• Codes of Practice

• News Casting

• Pilot Programs

• Fact Sheets

• Diary of ILMC Activities

• An electronic inquiry and comment hotline to the ILMC office.

News Casting

News Casting is the quarterly bulletin of ILMC and features articles covering

all the international activities of the Center.

There are regular Pilot Program updates and features explaining the role and

achievements of the lead industry’s voluntary risk management strategy.

Product and Application Information

Risk Management Information for products

and applications are available for the following:

• Ceramics - Pottery and Glass

• Communication and Power Cables

• Fishing Sinkers

• Lead Coatings, Piping and Sheet

• Lead Pigments - including paints and children’s toys

• Lead Shot

• Lead Solder – food cans and electronics

• Leaded Gasoline

• Life Cycle Inventory for Lead-Acid battery

• Miscellaneous - including modeling and wheel weights

• Noise Insulation

• Plumbing

• Radiation Shielding

• Stabilizers

F. LDAI - Lead Development Association International

LDAI is dedicated to encouraging the responsible use of lead and its compounds.

Objectives:

1. Promote the responsible use of lead throughout its life cycle

2. Increase lead's competitiveness with alternative materials

3. Provide cost-effective co-ordination of sustainable initiatives for the benefit of the lead

industry and society

4. Contribute to the identification of appropriate ways to manage risks to health or the

environment attributable to lead

5. Address legislative or other scientific issues which may affect the lead industry

6. Communicate with members and with outside parties as appropriate on issues of

relevance to the lead industry.

G. The Green Lead Project

As lead acid batteries account for about 75% of lead consumption, it seemed logical to initially focus on the stewardship of lead acid batteries.

In principle, this means that a Green Lead Program would direct all sectors in the life cycle of a Lead Acid Battery, that is, the Mines, the Smelters, the Battery manufacturers, Consumers and the Recyclers in practices and procedures that minimize or negate any potential adverse impacts on either the environment or the population.

Green Lead Cycle

Firstly, primary lead is dispatched to the battery manufacturer and subsequently Lead Acid Batteries are delivered to the retailer. As we know, the bulk of battery sales are to the automotive sector, but some will be sold for other uses.

Used batteries are usually returned to the retailer for either a refund or a purchase discount and in turn, the retailer will send the ULAB to a collection center for sorting and packaging. Some consumers will also send their ULAB directly to a collection center.

The collection center ships ULAB in bulk to a secondary smelter for recycling and the refined ingots will be sold to the battery manufacturer for the cycle to begin again.

In those instances where there are unregulated smelters or “informal” battery reconditioners operating, there is the distinct possibility that by offering a premium for a ULAB above that offered under a deposit/refund scheme, that ULAB will find there way into the “informal in the informal sector, where possible, the ULAB will be reconditioned and returned to customers looking for a cheap battery.

Used battery plates and those ULAB deemed beyond repair will be recycled without much recourse to environmental and health controls. In many cases, the lead bullion produced is often marketed to battery manufacturers for use as terminal posts.

It is envisaged that under a Green Lead license, battery manufacturers will only be able to purchase lead ingots from a primary or secondary Green Lead supplier and an outlet for the informal sector will be eliminated.

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Green Lead™ Standards Currently Available

1. Medical surveillance – Blood Leads

2. Solid Waste Management

3. Effluent treatment and discharges

4. Emission Control Systems

5. ULAB Collection, transport and shipping

6. Battery Labels

7. Public Communications and awareness

8. Site Sustainability

9. Community Outreach

It is anticipated that in this way those working in the informal sector will either get out of the ULAB business or become legitimate collectors of ULAB.

So a Green Lead regime has tremendous potential in the developing world (already in Salvador, Philippines and Venezuela) as model to assist in the elimination of poor recovery practices.

The Green Lead initiative, once in place, will facilitate the development of environmentally sound practices, safe working conditions and create a level of product stewardship at the forefront of any commodity.

Summary

The demand for lead is increasing worldwide

Communities need to be educated about exposure and health effects of Lead

Communities are still exposed to lead from present and past mining and smelting activities worldwide (esp. in developing countries.

Multinational companies appear to be taking some positive steps but more needs to be done to prevent continuous exposure

Stakeholders need to unite and collaborate systemically to reduce emissions, remediate soil contamination, and operate a sustainable monitoring system.

Because of their experience, many international bodies are well equipped to provide assistance with tackling the various dimensions of exposure to lead in the environment. Concerted efforts on a worldwide basis can overcome this menace.

Screening, monitoring, intervention and evaluation are critical for the development of rational, cost-effective and science-based public health policies aimed at achieving these goals.

Success in this endeavor requires government commitment, incentive policies, a broad consensus among stakeholders and public understanding, acceptance and support.

References

1. Pollution Prevention and Abatement Handbook: Lead and Zinc Smelting

WORLD BANK GROUP, Effective July 1998

2. Smith MA. Lead in history. In: Lansdown R, Yule W, eds. Thelead 7. Winder C. The developmental neurotoxicity of lead. Lancaster, debate: the environmental toxicology and childhealth. London, England, MTP Press, 1984. Croom Helm, 1984: 7–24. 8.

3. Inorganic lead. Geneva, World Health Organization, 1995

The Centers for Disease Control and Prevention. Atlanta, GA,

(Environmental Health Criteria, No. 165).

4. Development of an integrated Intervention plan in La Oroya, Peru



5. Lead: Statistics and Information



6. Lead Production and its uses:



7. US Geological Survey



8. Base Metal smelting and Refinery: World bank

Environmental Health and Safety Guidelines: April 2007

9. International Lead Management Center



10. The Green Lead Initiative -

11. Chapter 6.7 Lead Air Quality Guidelines - Second Edition

WHO Regional Office for Europe, Copenhagen, Denmark, 2001 13

13. Health Impacts of Lead Poisoning

E:\who\Health Impacts of Lead Poisoning.htm

14. Lead Development Association International



15. International Lead Zinc Research Organization



16. World Health Organization - who.int

17. The world bank -

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