Environmental Health Officer Guidance Material for the Investigation of Environmental Sources of Excessive Lead Exposure

This Guidance Material was kindly provided to The LEAD Group by one of the state health departments, in the hope that it is useful throughout Australia and overseas

INTRODUCTION

This document has been developed as a resource for use by environmental health officers in the investigation of cases of excessive lead exposure of non-occupational origin.  It identifies common environmental sources of lead exposure that should be considered in an investigation. Each section finishes with some prompt questions that should be considered by an environmental health officer during the investigation of a case.

The other aspect of follow-up is the provision of advice to cases or parents of cases about measures which need to be taken to reduce exposure to lead and the need for and suitable timing of further blood lead testing.

ASSESSING LEAD EXPOSURE IN THE HOME ENVIRONMENT

Natural levels of lead in environmental media such as air, water and soil are generally very low. However, many industrial and other activities over many years have resulted in contamination of the environment. Lead in the environment is both persistent and cumulative. Once contamination has occurred, it is difficult and often expensive to mitigate it.

The following are aspects to consider when assessing the possible sources of lead exposure for an individual case with an elevated blood lead level.

1. Ambient Air

Consider

• How far is the home from a major road?
• Are there any lead industries close to the home?
• Are local lead industries likely to be emitting significant lead to the air?

2. Paint

The major cause of notifications of excessive blood lead levels in children is exposure to lead-based paint. This most commonly occurs when their home is undergoing renovation involving the mechanical sanding or stripping of lead-based paint. These activities generate large quantities of lead contaminated dust, which may be inhaled or ingested. Lead-based paint which is flaking or peeling is also a significant hazard for young children prone to pica behaviour ie. the eating of non-food items. The percentage absorption of ingested lead is greatest in young children and, in view of their tendency to mouth toys and their general hand-to-mouth behaviour, the dust from lead-based paint poses a major hazard. Other possible paint sources which might contain lead are toys which are frequently mouthed or played with, and bedroom furniture, especially old cots.

Consideration should also be given to the likelihood of lead exposure at a previous residence of the child, particularly if the move to the current home was recent eg. in the last 6-12 months.

The key factors in regard to the hazard posed by lead-based paint on homes are the age of the home and the type of material of which it is constructed. Homes built before the 1920s typically were painted with lead-based paint, some of which may still be present. Even if it has been stripped, the removal may have contaminated the house considerably. However, homes built up to the 1960s could well be painted with lead-based paint also. Naturally, the use of lead-based paint on brick and other earthen based homes would be less substantial, though the paint of window sills, doors etc. can be lead-based.

Consider

• How old is the house?
• Is it likely to have been painted with lead-based paint?
• What is the condition of the paintwork?
• Has there been any sanding or stripping of paint recently?
• Does the child chew on any painted objects (eg. cot, toys)?
• In the last 2 years, has the child lived at another home which might have been the source of the lead exposure?
• Has any neighbouring property been substantially sanded or stripped of paint recently?

3. Soil and Dust

In smelter communities, soils may contain very high levels of lead from the spread of tailings or from natural mineralisation of the region.

Lead in household dusts (ie. indoor dust) is derived primarily from soil, paint and deposition from use of leaded petrol.

Lead in soil and dust is an important source of exposure for young children because of the frequency of their hand-to-mouth activity and their closer contact with soil through play.

Consider

• Was the land ever used for industrial purposes?
• Has fill been brought onto the property?
• Where did the fill come from?
• Could the fill be contaminated by lead eg. tailings?
• Are there areas of bare dirt in the yard?
• Does the child play there regularly?
• Does the child regularly eat dirt?
• Has the child been observed eating dirt?
• Does the sandpit contain contaminated sand?

4. Water

Lead levels in drinking water can vary considerably from house to house, depending on the nature of the plumbing systems.

Use of lead in pipes, fittings or in solder used to seal joins, will increase lead concentrations in water depending on a number of factors including water pH and hardness, and the standing time of the water. Higher levels of lead are found in 'first flush' water, that is water that has been standing in the pipes overnight, compared to water from pipes that have been fully flushed.

Some people may collect and drink rainwater in which case sources of lead from roofs, guttering, downpipes and tanks may increase lead levels in the water.

Consider

• Is there a source of drinking water other than the reticulated supply?
• Are there possible sources of lead contamination of this water?
• How old is the plumbing system in the house?
• Are there any lead pipes or lead-soldered joins?

5. Food

Deposited airborne lead can contaminate fruit and vegetables. Produce grown in lead contaminated soil can also become contaminated, largely through particles on the surface rather than through lead uptake into the plants. Direct contact with contaminated soil presents a greater risk of lead exposure to children who play in it than to children who eat vegetables grown in it.

The replacement of lead solder in cans by welded seams has markedly reduced the lead content of canned food. Lead levels in food in soldered cans vary depending on the acidity of the food. Australian produced canned foods are nearly always in welded cans, thus limiting this as a source of lead exposure. Lead may leach into food from lead crystal or from tableware, such as earthen ware, china and porcelain with lead glazes.

• Does the case eat imported canned food regularly?
• Does the case use a particular glazed pottery cup or bowl?
• Having regard to deposition of lead from air, or the possibility of contaminated soil, are home grown vegetables eaten by the case?

6. Occupational Exposure

Children of lead workers can incur significant lead exposure if the worker returns home contaminated by lead. This lead may be on work clothing, on the skin or perhaps deposited in the family car. Sometimes, a lead worker may have access to lead contaminated material which is brought home and used as landfill or in children’s sandpits.

Consider

• Are any adults at the residence exposed to lead at work?
• Do any adults who work with lead return home with contaminated clothing or skin?

7. Cosmetics

Surma or kohl are eye cosmetics used in Israel, Middle Eastern countries and India. They can contain substantial quantities of lead. In addition, lead acetate is used in some hair dyes.

Consider

• Are any suspect cosmetics used by/on the case for cultural reasons?

 8. Traditional Medicines

On occasions, it has been found that the use of traditional medicines, in particular among Asian immigrants, has resulted in substantial lead exposure and toxicity. Often, these preparations are imported directly by the affected person or a relative or friend.

Consider

• Is the case taking any suspect or nondescript medicines or tonics?

9. Hobby Activities

Hobbies including making and repairing lead-light windows, use of lead glazes in pottery, casting lead weights (sinkers) for fishing, furniture finishing and shooting in indoor firing ranges can be sources of lead exposure. Particular attention should be placed on any hobbies or activities in the home environment which involve the melting of lead, particularly if fumes containing lead are produced.

Consider

• Does any person engage in a hobby involving the melting of lead at home?

CASE MANAGEMENT ACTIVITIES

To ensure that ongoing exposure is reduced, the investigating officer may provide the following information to the exposed individual:

• Lead education on environmental and dietary factors
• Results of investigations identifying the source of exposure
• Lead hazard reduction advice
• Advice on follow up blood lead monitoring within three months
• Lead Safety information to homeowners