RESEARCH

Prevention Measures

LEAD-SAFE GUIDE FOR HEALTH PROFESSIONALS

CONTENTS

LEAD EXPOSURE - AN OVERVIEW

Increasing awareness

Level of concern

A long history

Sources, pathways and exposures

Risk factors

Symptoms and health effects

Testing

Notification

Management and prevention

IDENTIFYING AT-RISK GROUPS

The danger of lead

Sources and pathways

Lead in the workplace

Exposures: How lead enters the body

Hand-to-mouth activities among children

The facts about pica

People at increased risk

Unsafe hobbies

Nutritional factors

Symptoms and health effects

NHMRC recommendations: The level of concern

Symptoms at a glance

Key questions

TESTING FOR LEAD

Taking blood samples

Who should be tested?

Notification

READING TEST RESULTS

Follow-up guidelines

MANAGEMENT AND PREVENTION

Medical emergency

Chelation - the last resort

Advice for parents or adults at risk

Checking the home for hazards

Lead Exposure - an Overview

Increasing AwarenessElevation of blood lead levels and lead poisoning are age-old problems still prevalent today, due to the continued presence of lead in our urban and rural environments. Children are particularly vulnerable to environmental exposure to lead, but adults engaged in various occupations and hobbies are also at risk. Over the last two decades there has been a significant increase worldwide in awareness and concern about the effects of lead on human health and the environment.

New evidence suggests that lead is harmful even when blood lead levels fall within a range previously thought to be safe. Even low lead levels can have a detrimental effect on intellectual development, as the developing brain and nervous systems of children are much more susceptible to lead toxicity than those of adults. While the effects of lead emissions have been known for many years, urban and rural communities may also experience contamination from widespread use of consumer products containing lead, including lead paint and leaded petrol.

Level of Concern

Internationally, many health authorities such as the World Health Organization and the United States Centers for Disease Control have set a "level of concern" of 0.48 m mol/L (10 m g/dl) for blood lead tests which should alert health professionals to a dangerous level of lead contamination in patients, particularly for children under six years of age. Studies show that a 0.48 m mol/L (10 m g/dl) increase in blood lead concentration is associated with a decrease of between two and three IQ points in young children, observable in children with blood levels between 0.48 and 1.2 m mol/L (10 and 25 m g /dl ). Studies have also demonstrated links between childhood lead exposure and learning disabilities, impaired growth, reduced hearing acuity and behavioral problems including hyperactivity, aggressiveness and attention deficit.

While these effects may be clinically undetectable in individual children, the effect on the distribution of IQ scores in populations of children exposed to higher blood lead levels is considerable, with the proportion of very bright children diminished and the number of children requiring special educational assistance because of lower IQs increased up to two to threefold. Effects of childhood lead exposure have been shown to persist into adolescence and adulthood. Adults are also at risk through exposure at work, while pursuing hobbies that involve lead, or by undertaking home renovations.

A long History

The deleterious effects of lead on the human body and lead poisoning have been known since ancient times. Hippocrates recognised lead poisoning in miners and the toxic effects of lead -- colic, mental weakness and lethargy -- were noted by the physician Nicander in 400 BC. Dioscorides observed "lead makes the mind give way" in 200 BC. During the industrial revolution and up to the beginning of the 20th century, lead poisoning was largely viewed as an occupational disease of adults. However the discovery of lead paint poisoning among Queensland children in 1892 demonstrated that lead exposure could cause distinct childhood illness and that contaminated households could pose a health risk. Further evidence published in the Australian Medical Gazette in 1904 linked normal childhood hand-to-mouth behavior with lead poisoning through exposure to lead dust from deteriorating lead paint.

Sources, Pathways and Exposures

This section provides a brief summary of the ways individuals may be exposed to lead so that health professionals can identify and treat illness caused by excess exposure to lead.

Lead contaminated dust is a major source of health risks to children and adults in most domestic and occupational environments. Widespread use of leaded petrol, leaded paints on vehicles, signs, and equipment and backyard or ‘cottage industries’ in ceramics, battery breaking and jewelry making will often result in contamination and expose occupants and neighboring houses to significant health risks.

Inhalation of emissions from leaded petrol cause a general exposure to lead and measurable blood lead level across the whole population, which may be higher in those near heavily trafficked urban roads, or near petrol refineries. However, reducing the use of leaded petrol and reducing amounts of lead in the petrol will result in a decline in risk, especially to people who live near main urban thoroughfares.

Lead contamination of food may occur through the deposition of lead petrol emissions on food or the use of lead-arsenate pesticides or fertilizers contaminated with lead and other heavy metals. Risk of lead contamination may occur with root vegetables grown in contaminated soil, leafy vegetables exposed to lead dust, food stored, cooked, reheated or served in pots ‘tinned’ with a lead-tin mixture, brass with leachable lead levels or ceramics using lead glazes. Foods cans joined with a lead soldered seam may also contaminate food with lead, particularly acidic foods such as pineapples, pickles and tomatoes. Spices and food coloring may also be contaminated with lead from petrol emissions, lead pigments or painted storage containers.

Drinking water also may be a source of lead. The major sources of lead in drinking water are lead piping and the corrosion of leaded plumbing materials in the water supply or household plumbing. Contamination can arise from lead connectors, lead and PVC piping, lead-soldered joints in copper and brass faucets and other fittings containing lead. Water from lead-soldered water tanks or run-off systems from roofing with lead-based paint also may pose a risk, especially in areas near mining and smelting sites where dust and emissions could add to the problem.

Regardless of the source, the most common routes of entry for lead into the human body are by inhaling or swallowing lead dust or food or drink contaminated with lead dust, or by ingesting soil, dust or materials containing or contaminated with lead. This usually happens when people put their hands or other objects coated with lead dust in their mouths, or when they breathe in lead dust.

Babies and young children aged up to 48 months and pregnant women are most at risk. Lead can cross the placenta and at low concentrations can cause problems in early neurological development. The developing brain in young children appears more vulnerable to a range of biological and environmental hazards, including lead. Normal exploratory hand-to-mouth activity in young children exposes them to higher risks of ingesting lead. The most extreme variant of this is pica. Children may deliberately swallow paint flakes or other objects or suck fingers or toys coated with lead contaminated dust or soil. Toys or other objects may have been painted with lead-based paints.

Lead inhalation, ingestion and contamination of clothing is a particular hazard for workers in lead industries including mining, smelting, battery breaking, metal repair or foundry work, automotive repairs and ceramics. People living in towns or suburbs near lead mining, smelting or lead processing industries are also at high risk

Individuals most at risk include those working in the following occupations:

  • Lead mining, smelting and processing
  • Battery breaking, recycling or manufacturing
  • Automotive body or radiator repairers
  • Brass or copper foundry work
  • Bridge, tunnel, tower and ship work (where lead paint was used)
  • Building, construction and demolition work
  • Cable repair
  • Paint, pigment or shellac manufacture
  • Plumbing/pipe fitting
  • Scrap metal industry
  • Welding/metal working
  • Ceramics and jewelry making

Risk Factors

A combination of risk factors should alert the medical practitioner to the possibility of a patient’s symptoms being attributable to excess lead.

(a) At risk populations

  • in utero
  • children 0-4 years
  • children 4-16 years
  • children of any age with developmental delay
  • pregnant and lactating women.

(b) Increased risk of high exposure

  • occupations involving lead
  • residents of communities near lead mining, processing or manufacturing industries
  • lead-related ‘cottage’ industries such as battery breaking, ceramics or jewelry making

(c) Exposure to unusual sources of lead

  • hobbies and recreational
  • Indian system medicines
  • consumer products containing lead

(d) Circulation of skeletal lead sources

  • post menopausal women
  • retired lead workers.

Symptoms and Health Effects

When ingested, inhaled or absorbed, lead can harm virtually every organ in the human body, especially the brain, kidney and reproductive systems. Most patients with increased blood lead levels show no symptoms, yet even low levels can have serious long-term effects. When symptoms do appear they are usually non-specific. Symptoms of moderate to severe exposure include lethargy, intermittent abdominal pain or constipation, irritability, headache, aggressiveness, paralysis or encephalopathy, which may lead to seizures, coma and death. Anemia may occur, but is rarely severe.

Symptomatic lead intoxication in children generally does not occur until blood lead levels reach 2.17 to 2.42 m m /L (45-50 m g /dl). Lead encephalopathy can occur at levels above

3.38 m m/L (70 m g /dl) and this constitutes a medical emergency.

Lead poisoning may develop insidiously in children, manifesting as developmental delay, learning difficulties, hyperactivity or other behavioral problems. Health care providers may need to consider lead as a contributory factor to such problems in children or adolescents. Adults may display symptoms at blood lead levels of 2.90 m m/L (60 m g/dl) and above, including peripheral neuropathy, and reproductive sequel.

Testing

As most lead exposure is not immediately apparent and may be asymptomatic, the best way to confirm exposure is by careful questioning of the patient or their guardian to identify risk factors followed by a blood test. Blood lead is most effectively measured in venous blood taken with lead-free equipment. Capillary or finger-prick samples may be contaminated by lead on the skin. Hair and urine testing are not recommended due to the potential for contamination from environmental sources.

Blood lead levels may reflect only recent exposure, within three to six weeks - the half life of red blood cells. However levels indicate whether a patient is being exposed to lead contamination and whether the medical practitioner should further investigate environmental and other risk factors. Although the less commonly used measurement of dentine (tooth) lead is considered a more accurate measure of total accumulated lead in the body, there is disagreement about what constitutes a "normal" dentine level.

Blood lead tests are recommended for children who:

  • Are aged 9-48 months and live in or visit older deteriorating houses, or who have been present during renovations of older painted houses, have siblings with elevated blood lead levels or parents who work with lead.
  • Are aged 9-48 months and live in a home engaged in battery breaking or other occupations linked with lead contamination such as ceramics, jewelry making or painting.
  • Have pica, particularly if living in lead painted houses
  • Are aged 9-48 months and live near industrial or automotive sources of lead.
  • Have developmental delay.

Testing may be appropriate for adults, who work in industries or pursue hobbies that involve lead.

Management and Prevention

The main treatment for adults and children is to avoid or reduce further lead exposure. For adults, this usually requires changes in work or hobbies or how that work is carried out. For most children, sources of lead in the home must be identified and eliminated.

Health care providers should advise people affected by lead exposure to:

(a) Reduce or remove exposure to lead. This means preventing children or adults from having access to sources of lead or hazard situations; for example, move work involving lead out of dwellings and away from food preparation and living areas, replace older cooking pots where lead/tin solder may have been used on recent repairs, moving children or pregnant women away from sources of exposure to lead.

(b) Reduce or remove the hazard. This means addressing existing contamination and removing the hazard itself; for example, washing food preparation surfaces before cooking or making meals, covering cooking spices and cookware to prevent dust accumulation, replacing or covering contaminated soil with organic materials or other covering.

(c) Prevent the creation of lead hazards. Don’t bring lead hazard activities such as battery breaking or jewelry work into living areas at home.

In patients with very high blood lead levels (2.65 m mol/L or 55 m g /dl or above), medical treatment including chelation therapy may be necessary. Check with the hospital in your area regarding specialist procedures and the availability of chelation therapy.

Identifying At-Risk Groups

The Danger of Lead

When ingested, inhaled or absorbed, lead is toxic to virtually every human organ, especially the brain, kidney and reproductive systems of both men and women. Fetuses and children are particularly susceptible to these toxic effects. Lead harms the body disrupting enzyme systems activated by other metals important to the body: iron, calcium and zinc. This is one of the reason iron and calcium deficiencies actually increase lead absorption.

Lead is readily absorbed and quickly distributed to the blood (3 per cent), where it is most commonly measured. It then circulates to other parts of the body, such as soft tissue (5 per cent), bone or teeth (90-95 per cent), where it remains an insidious source of internal exposure over extended periods (20-30 year half-life in bone) which can be mobilized back into the blood. Lead in the blood has a half-life of around 28-35 days.

Sources and Pathways

(a) Household Dust, Lead Paints and Soil

Lead contaminated dust is a major source of health risks to children and adults in most domestic and occupational environments. Widespread use of leaded petrol, leaded paints on vehicles, signs, equipment and housing and backyard or ‘cottage industries’ in ceramics, battery breaking and jewelry making will often result in contamination and expose occupants and neighboring houses to significant health risks.

Dust in and around homes may be contaminated with lead from petrol, lead paint or other products or work that may have contaminated soils. Activities that disturb lead contaminated dust, soil or paint may pose special risks as children and adults may accidentally ingest or inhale lead dusts or lead paint flakes. Sanding or burning lead-based paint releases dust to the air and contaminates surrounding soil.

(b) Petrol

Inhalation of emissions from leaded petrol causes a general exposure across the whole population. Leaded petrol emissions may also accumulate close to roadways where soil and dusts may become highly contaminated. US research has shown for every 4g/L of lead in petrol, 75% or 300 mg will be emitted in exhaust while the remaining 25% will coat engine parts and internal exhaust components or remain in engine system lubricants. Of the 300 mg of lead emitted in exhausts, 140 mg will be emitted as a fine aerosol which are very fine particles while 160 mg will be emitted as larger particles that deposit on or close to roadways.

International research has shown reductions in the use of leaded petrol and reduced amounts of lead in the petrol will result in a decline in lead in ambient air and risk to the population, especially to people who live near main urban thoroughfares.

Contamination from petrol coming into contact with the skin -- especially relevant for "petrol sniffers" -- remains a risk. People working in petrol refineries or distribution (including service station workers) are particularly exposed to lead through skin contact with petrol.

(c) Hazardous Industries

Lead inhalation and ingestion are particular hazards for workers in lead industries including mining, smelting, battery breaking, petrol refining, metal repair or foundry work, chemical manufacture, and ceramics and jewelry work. Industries which use lead or lead-based products also present hazards for workers. These include radiator and automotive repair, plumbing, panel beating and construction.

Lead particles or fumes are created through melting, sanding, scraping or burning lead surfaces or objects or lead-based paint and are common in the lead industry or maintenance or renovation work. Lead particles, dust or fumes from these activities can also contaminate the hands, face, hair and clothing of workers and may result in the contamination of food or drink being handled, or bringing lead dusts or particles from work areas to contaminate other areas.

(d) Communities at Risk

People who live in villages or cities near lead mining, smelting, processing or manufacturing industries are at particular risk through industrial emissions, industry waste disposal and contamination of soil or clothing and footwear from family members working in those industries.

Recent research in the United States found that many children with high blood lead levels were contaminated by "take home" lead dust on parents' work clothes, hair, skin and vehicles or home activities that contaminated living and eating areas.

(e) Food

Food may be contaminated in these ways:

  • Soil, pesticide or zinc fertilizer containing lead may be taken up into a root plant or deposited on leafy plants. Lead emissions from cars or industry may be deposited on plants grown in home or market gardens near main roads.
  • Foods or beverages, particularly acidic foods such as pineapples, pickles and tomatoes, may be packed in cans with lead-solder side seams or processed by equipment containing lead soldering. Foods or beverages may be stored, cooked, reheated or served in lead-glazed ceramics or porcelain, cookpots ‘tinned’ with a lead-tin mixture, brass with leaching of lead, or leaded crystal or glass. Spices and food coloring may also be contaminated with lead from petrol emissions, lead pigments or painted storage containers.

(f) Water

Lead in drinking water may not be a common source of lead in India. The major source is the corrosion of leaded plumbing materials in the water supply and household plumbing. Contamination can arise from lead connectors, lead and PVC piping, lead-soldered joins in copper and brass faucets and other fittings containing lead.

Water from lead-soldered water tanks or run-off systems from roofing with lead-based paint also pose a risk, especially in areas near mining and smelting sites where dust and emissions could add to the problem.

Exposures: How Lead Enters the Body

When ingested, inhaled or entering the body by other less common means (such as through the skin), lead may be absorbed, excreted, or both, depending on age, sex, nutritional status and time elapsed since the last meal. Ingestion is the most common route of exposure in children and adults who are not in occupations associated with lead. Inhalation plays a larger role in occupational exposure and in community exposures to leaded petrol.

Adults may ingest lead through eating, smoking, or nail-biting with lead contaminated hands, particularly after working which involve melting or casting lead, disturbance or creation of lead dusts or lead fumes such as burning, scraping or sanding lead paint or lead objects .

When particles are inhaled, large particles stop high in the respiratory tract, trapped in the protective mucus lining of the nose, throat and upper respiratory passages. This mucus is regularly moved up and out of the respiratory tract and swallowed resulting in ingestion of large inhaled lead particles. Only tiny lead particles and lead fumes reach the lower respiratory tract. Fumes can penetrate deep into the lungs and quickly transfer into the blood stream, resulting in rapid absorption of dangerously high lead doses. Absorption can also occur when leaded petrol comes into contact with the skin, a particular risk for "petrol sniffers" and others involved in solvent abuse.

Pregnant women can recirculate previously stored lead if they:

  • Had lead poisoning as children;
  • Have recently been exposed to lead; or
  • Have accumulated lead in bone stores through repeated exposure.

When the body demands more calcium for the developing fetus, it mobilizes calcium out of the bone, carrying lead with it. A similar process occurs when the body demands more calcium during lactation.

Hand-to-mouth Activities Among Children

Pre-school children frequently ingest lead by placing toys, objects or their hands in their mouths after coming in contact with contaminated soil or dust or lead paint. Children may deliberately swallow paint flakes because of their sweetish taste or suck fingers or toys coated with lead paint. Older furniture and toys may have been painted with lead paints.

Children with pica, the habitual eating of non-food substances, are particularly at risk through eating paint flakes, objects coated in lead dust or soil which may have been contaminated by airborne lead emissions or other sources.

The Facts About Pica

Pica is a "normal" temporary phenomenon in some children, which decreases with age. For example, 78 per cent of one-year old children mouth objects and 35 per cent ingest them. By four years, 33 per cent were mouthing and only 6 per cent had pica.

Estimates of the amount of soil ingested by children with pica vary from 4 to more than 200 mg/day, (average 60-100 mg/day). This varies according to mouthing behavior, dirty clothes, hands and play areas, and exposure time. Children with pica may consume up to 20 grams of soil per day. When lead is present in the soil at high concentrations, this may constitute a serious hazard.

People at Increased Risk

(a) Children and Pregnant Women

Lead can readily accumulate in and cross the placenta at low concentrations. Early exposure to lead has been shown to cause problems in early mental development of the fetus and to affect a child's development in the first few years of life.

There is also evidence of adverse pregnancy outcomes in women with lead as low as 0.72 um/L, with slightly higher risks of pre-term delivery low birth weight, and increased frequency of miscarriage and stillbirth. Pregnant and breastfeeding women risk exposure to lead from occupational or household sources.

Children under 48 months are at special risk because:

  • The developing brain is more vulnerable to a range of biological and environmental hazards, including lead.
  • The normal exploratory hand-to-mouth activity in young children (the most extreme variant of which is pica, habitual eating of non-food substances) exposes them to higher risks of ingesting lead from a contaminated environment.
  • Children absorb a much higher proportion of ingested lead than adults - up to 50 per cent compared to 10 per cent.

Children with developmental delay, regardless of age, are at increased risk.

(b) Increased Risk of High Exposures

Factors that may significantly increase a person’s exposure to lead include:

  • Occupation -- working in a lead industry or work environment contaminated with lead.
  • Location or living conditions -- proximity to lead industries; old and/or poor housing.

Unsafe hobbies

Adults may risk exposure if they pursue hobbies or do-it-yourself activities which involve working with lead or lead paint, such as:

  • Antique furniture restoration
  • Radiator repair and maintenance
  • Boat building
  • Casting lead fishing sinkers, shot or pewter
  • lead soldering of electronics
  • Lead lighting
  • Indoor shooting
  • Welding.

(c) Exposure to Unusual Sources of Lead

These may present considerable problems when attempting to locate sources of contamination and may involve intensive patient questioning and investigation of home and work environments. Examples of possible sources include:

  • Foods or beverages stored, cooked, reheated or served in lead glazed ceramics or porcelain, leaded crystal or glass, or imported cans with lead soldering.
  • Food contaminated with lead pigments or contaminated spices during festivals
  • Bone meal calcium products.
  • Certain Indian system medicines and cosmetics (including surma, kohl and sindoor).
  • Painted buttons or hair ornaments.

(d) Circulation of Skeletal Lead Sources

Recirculation of lead stored in the long bones from past exposure occurs particularly among people whose bones are demineralising as part of the aging process. This group includes menopausal women and elderly people (especially those who have worked in lead industries), as well as those suffering from chronic illnesses. Mobilization of bone lead may also occur in pregnant and lactating women.

 

Nutritional Factors

Iron deficiency: Children and adults with insufficient iron in their diets, or deficient iron stores, absorb lead more readily. Lead, through interfering with iron uptake, is likely to increase iron deficiency. Thus anemia is more likely in children who have both iron deficiency and elevated blood lead levels. Key foods and behaviors involved include:

  • Calcium: Deficiency of dietary calcium increases absorption of lead.
  • Zinc and protein: Diets deficient in zinc and protein may predispose children to increased lead absorption.
  • Fat: A very high fat diet promotes lead absorption. There is no evidence that a low fat diet minimizes absorption.
  • Frequency of eating: Frequent nutritious meals are important for children. The presence of food in the stomach decreases the absorption of lead from non-food sources.

Symptoms and Health Effects

Although most patients with increased blood lead levels remain asymptotic, even low levels can have serious effects. Some asymptomatic effects include:

  • Lowered IQ, abnormal cognitive development and behavior in children.
  • Neurological deficits in early childhood which may persist into late adolescence.
  • Elevation of hearing thresholds at 500, 1000, 2000 and 4000 Hz.
  • Decreased gestation, lower birth weight.

Recent research suggests serious health effects occur at much lower blood lead levels than previously recognised. Blood lead concentrations above 3.38 m m/L (70 m g /dl) in children have long been known to produce the classic symptoms of lead poisoning: fits, cerebral edema, brain damage and death.

Lead crossing the placenta during pregnancy or absorbed after birth can have detrimental effects on intellectual development and behavior at blood levels as low as 0.48 m m/L (10 m g/dl). Since few children show signs and symptoms of adverse effects at these and much higher levels, childhood lead poisoning has been called the "silent epidemic".

When symptoms do appear they are usually non-specific. Symptoms of moderate to severe exposure may include lethargy, intermittent abdominal pain or constipation, irritability, headache, aggressiveness, paralysis, and encephalopathy, which may lead to seizures, coma and death. Anemia may occur, but is rarely severe.

Symptomatic lead intoxication in children generally does not occur until levels are at least 2.17 to 2.42 m m/L (45-50 m g /dl ). Lead encephalopathy can occur with levels above 3.38 m m/L (70 m g/dl) and this level constitutes a medical emergency. Adults may not display signs or symptoms until they have blood lead levels of 2.90 m m/L (60 m g/dL).

Lead poisoning may also develop insidiously in children manifesting as developmental delay, learning difficulties, aggressiveness, hyperactivity or other behavioral problems. Lead exposure is a relatively uncommon cause of clinically recognizable developmental or behavioral problems.

Children exposed to chronic high lead levels in early childhood have increased risk of poor performance at school including: reading disabilities; problems with attention and fine motor skills; lower class standing; increased absenteeism and lower vocabulary and grammatical scores. These children are more likely to develop anti-social behavior, be more aggressive and destructive and less likely to graduate from high school.

Adults with high levels of lead (for example, from occupational exposure) are at increased risk of peripheral neuropathy and reproductive sequel.

Recommendations: "The level of concern"

Health care practitioners and health authorities may want to consider a range of responses to different blood levels:

  • In communities where surveys show more than 5 per cent of children aged 1-4 years have blood levels above 0.72 m m/L (15 m g/dl), lead sources in the community should be investigated and environmental management plans developed.
  • In individual children with a blood lead level greater than 0.72 m m/L (15 m g/dl), personal sources of lead exposure should be evaluated, remediated and controlled, with personal education and counseling on exposure control provided to the child and family. It may be necessary to repeat blood testing to assess the effectiveness of any action taken.

If blood lead levels are above 1.2 m m/L (25 m g/dl) a detailed medical history and examination is required including particular attention to nutritional and developmental status. Retesting after three months is recommended.

Children with blood levels above 2.65 m m/L (55 m g/dl) should be referred for urgent specialist pediatric assessment and advice regarding the need for chelation therapy.

In diagnosis, health professionals might consider elevated lead as a contributing factor in children who have intellectual disability or behavioral problems. High blood lead levels may also be a factor in children with iron deficiency anemia.

Key Questions

Key questions to help practitioners identify children exposed to hazards

Does the child:

1. Live in or visit a house with peeling or chipping paint or where occupational lead work occurs?

2. Live in or regularly visit a house (of relatives or neighbors) with ongoing renovations or remodeling or where occupational lead work occurs? Has renovation or work disturb existing lead contamination in soil or dust or created new lead dust and soil contamination through paint stripping, power sanding, welding, lead casting or battery breaking?

3. Live near heavily trafficked roads where petrol emissions may be of concern?

4. Have pica, chew or eat non-food items, or excessively suck his/her thumb?

5. Have a brother; sister, housemate or playmate with confirmed lead poisoning?

6. Live with an adult whose job or hobby involves exposure to lead?

7. Live near an active lead mine, smelter, battery-recycling plant or other industry likely to release lead?

If the answer to any of these questions is yes, a blood lead test should be carried out.

Follow-up Questions

If initial questioning indicates the potential of a person being at risk in the home environment, health professionals should probe further with questions such as:

1. Is the home on land, which may have previously been used for industrial purposes?

2. Has landfill been used in the grounds of the home?

3. Are there old sheds or outbuildings still standing, or which have been demolished, which

could have contaminated surrounding soil?

4. Does the home have areas of bare soil or sandpits where children play?

5. Does the family have pets (especially furry ones) that may bring contaminated lead dust into

living areas?

6. If renovation has taken place in the home, what kind of clean up was carried out?

7. Does the home have carpets or other soft furnishings? Could they have been contaminated

and store lead dust?

8. Is the home near a major road or traffic intersection where leaded petrol emissions may be

excessive?

9. Are car parks or garages located close to entrances or windows in the home?

10. Have older structures nearby, such as bridges, water tanks or towers that may be covered

with higher lead content primers and paints been renovated recently?

Testing for Lead

Taking Blood Samples

Because most lead exposure is asymptomatic, the best way to identify lead exposure is a blood test. Lead in blood is most effectively measured on veinous blood, taken using lead-free equipment. Capillary or finger-prick samples are not recommended because they could be contaminated by lead on the skin. However, studies have found hand washing for 15 to 20 minutes can reduce surface contamination that may compromise finger-prick tests.

A blood lead level does not reflect total body lead, only lead from recent exposure (within three to six weeks) still circulating in the blood stream. However, it does indicate to the health professional whether a patient is being exposed to lead contamination and whether there are grounds to further investigate environmental and other risk factors.

The less commonly used measurement of dentine (tooth) lead is considered a more accurate measure of total accumulated lead in the body, but there is disagreement about what constitutes a "normal" dentine level. Bone X-rays also give a more exact measure of the "body burden" of lead. Both these methods are used more for research purposes than standard diagnosis.

Urine and hair tests are not recommended as a guide to clinical management, as they do not accurately represent circulating lead levels. Where it is known or suspected that children have eaten paint flakes or have swallowed lead objects, health professionals should obtain an X-ray of the abdomen. If there is evidence of significant lead paint in the intestine, a cathartic and possibly activated charcoal should be considered (although their value has not been proven).

Who Should be Tested?

Blood lead tests are recommended for children who:

  • Are aged 9-48 months and live in or visit older dilapidated houses, or who have been present during renovations of older painted houses
  • Have siblings with elevated blood lead levels
  • Are aged 9-48 months and have parents who work with lead.
  • Are aged 9-48 months and live in a home engaged in battery breaking or other occupations linked with lead contamination such as ceramics, bidriware or jewelry making, or painting.
  • Are aged 9-48 months and live near lead mines, smelters, battery breaking yards, lead ore bodies or on highways or main roads with heavy traffic.
  • Have pica
  • Are aged 9-48 months and live near industrial or automotive sources of lead.
  • Have developmental delay.
  • Are exposed to other sources of lead, such as Indian system medicines or lead-glazed pottery used to store or cook food.

Until better epidemiological information about blood lead levels in the community is available, universal screening of all children may not be considered necessary.

Blood lead levels fall rapidly in children with a single episode of exposure but fall very slowly over months or years in a child with previous heavy or repeated exposure. In children with elevated levels, it is usually necessary to repeat tests over a period of time.

Management and Prevention

By asking questions about patients' lifestyles and living environments, correct testing, monitoring and advice, health professionals can help people at risk to control and eliminate their exposure to lead.

The main treatment for adults and children is to avoid further lead exposure. For adults, this usually requires changes in exposure and work practices through work or hobbies. For most children, sources of lead in the home must be detected and eliminated. By reducing hazards, exposure and risk are reduced.

There are many sources of lead including leaded petrol, lead paint, lead contamination of soil and dust from ‘cottage industry’ battery breaking, ceramics or jewelry making but investigation may reveal other sources.

Before older homes or living areas undergo activities that may disturb lead paint or lead contaminated dust or soil, special precautions should be taken to prevent young children and pregnant women being exposed to the dust or fumes. Ideally, children and pregnant women should be away from the area.

Medical Emergency

In patients with very high blood lead levels above 2.6 m m/L (55 m g/dl or above), medical treatment including chelation therapy may be necessary.

Chelation - the Last Resort

Chelation therapy involves the use of an oral or intravenous chemical agent which binds to all metals in the body (both toxic and beneficial) and enables the kidneys to excrete the resulting chelating agent/metal complex in the urine.

Different chelating agents (e.g. succimer and EDTA) target lead bound to tissue in different parts of the body, such as the skeleton, brain or vital organs. Thus a number of agents may be needed. Any decision to use chelation therapy on a lead-affected person must consider:

  • Chelation is not appropriate for all children or adults with seriously elevated blood lead levels.
  • It can be a painful process with serious side effects.
  • Patients must not be returned to lead-contaminated environments as the treatment increases their vulnerability to the effects of lead.
  • Multiple hospital treatments are required.
  • Dietary supplements will be needed to replace beneficial metals (especially iron and zinc) removed by the treatment.

Advice for Parents or Adults at Risk

The main treatment for adults and children is to avoid further lead exposure. For adults, this usually requires changes in exposure through work or hobbies. For most children, sources of lead in the home must be detected and eliminated. Health care providers can advise people who appear to be affected by lead exposure to take a number of specific steps to avoid exposure.

(a) Reduce or remove exposure to lead. This means preventing children or adults from having access to sources of lead or hazard situations; for example:

  • Ensure children's hands and faces are clean before they eat or have a nap.
  • Discourage children from putting dirty fingers or toys in their mouths.
  • Encourage children to play in grassy areas rather than places where dirt sticks to their fingers and toys. Plant grass or ground cover on exposed areas of soil or have clean soil and organic materials to cover contaminated soils.
  • Wash fruit and vegetables before eating.
  • Ensure children do not have access to peeling paint or chewable surfaces painted with lead-based paint, especially toys, cots, windowsills and windows.
  • Wash children's toys (especially those used outside) and dummies frequently.
  • Wash family pets frequently, especially if furry. Discourage pets from sleeping on children's beds.
  • Seal wood floors to reduce collection of dust between floor boards and provide a cleanable surface.
  • Wet-wash hard surface halls and floors, windows and child play areas with water regularly to reduce the accumulation of lead dust and lead contaminated soil that may be tracked inside.
  • Hose front steps and verandahs, remove shoes at the door, and brush pets outside.

(b) Reduce or remove the hazard. This means addressing existing contamination and removing the hazard itself; for example:

  • Move areas for work that involve lead like battery breaking, ceramics or jewelry making away from living areas or areas where children have access.
  • Remove or cover lead contaminated soil by turning over bare areas near buildings, adding clean soil or organic materials like dung or leaf litter, mulch or gravel and moving child play areas or gardens to safer yard areas.
  • Ensure children's diet has sufficient calcium and iron which help to minimize lead absorption. Sources of iron include fish, cooked legumes (beans, peas, lentils), fortified cereal, poultry, red meat, liver, dark green leafy vegetables. Sources of calcium include yoghurt, milk, cheese. Avoid high fat diets, which enhance lead absorption.
  • Ensure young children have regular, frequent meals and snacks (up to six per day), as more lead is absorbed on an empty stomach.
  • Don't store food in pottery with bright colours that might be lead-based glazes. Beware of imported foods in cans with lead soldering.
  • Remove shoes before entering homes to reduce tracking lead contaminated dust and soil into living areas.
  • Move furniture in front of painted surfaces where lead paint may present a hazard (peeling paint, friction, impact or chewable surfaces) to prevent child access.
  • Tape or cover unsafe chewable surfaces on windows.
  • Remove carpet which has been contaminated with paint dust
  • Damp or wet wipe hard surface floors and children’s play areas to reduce lead dust accumulation.

(c) Prevent the creation of lead hazards. This may include:

  • Do not allow lead hazard work in or near living areas.
  • Prevent the use of blowtorches, arc welders or high temperature heat guns where lead paint might be present as it may burn lead paint and create lead fumes.
  • Take care when renovating (if lead paint has been used) and restrict access of young children and pregnant women to work areas or seal off work areas with plastic and taping to prevent contamination with lead paint and dust. Wet all painted surfaces to minimize dust generation and ease clean-up and disposal when scraping or sanding paint
  • Prevent abrasive or water blasting and certain machine tools such as orbital sanders, except in restricted circumstances (proper training, adequate containment and drop cloths, vacant property, and thorough cleaning and debris disposal).
  • Ensure contractors clean the work area daily during renovations and thoroughly clean the dwelling and dispose of debris before allowing families to return.

Checking the Home for Hazards

Take special care if renovating lead painted homes. Seek advice about identifying

lead-based paint in the home, lead safe work practices and controlling lead-based paint flakes and dust.

  • Check the lead content in paint or assume lead paint is used.
  • Assess the risk of lead exposure, such as peeling paint and lead dust, particularly to young children or pregnant women.
  • Use lead safe work practices by working wet and reducing lead dust generation.

This material has been adapted from ‘A guide for healthcare providers’, a publication of the NSW Lead Reference Center, New South Wales, Australia.

TOP