Lead (inorganic) - Health Surveillance – Guide for medical practitioners

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Appointed Medical Practitioners (AMP) undertaking health surveillance should have an understanding of the potential adverse health effects of inorganic lead, and use their clinical knowledge to advise on health surveillance of workers in the workplace.

Lead is a cumulative toxic substance. Exposure to high levels of lead dust or fumes may cause anaemia, peripheral nerve damage (weakness), and kidney and brain damage (encephalopathy).

Lead enters the body through inhalation and ingestion. Ten percent of ingested lead is absorbed in the gut. Fifty to eighty percent of inhaled lead is absorbed through the lungs. Lead is excreted predominantly by the kidneys (70%).

Lead is distributed in the body to three compartments:

  1. blood (binds quickly to red blood cells, to blood protein, and as free plasma lead; half-life of 35 days)
  2. soft tissues (kidneys, brain, liver, bone marrow; half-life of 40 days)
  3. bone (half-life of 6.7 years; range 3.4-15 years).

Ninety percent of the total body lead is stored in bone. Lead is released from bone in osteoporosis, pregnancy and from fractures, thus raising the lead levels in blood.

Lead inhibits enzymes (including ALA dehydratase, ferrochelatase) which are involved in the synthesis of haem, an essential component of haemoglobin in red blood cells. Lead shortens the lifespan of red blood cells. Anaemia develops when the lifespan has been reduced from 128 days to 30 days. Affected red cells are more fragile and their removal from circulation stimulates bone marrow production (stippled red cells).

Young children (under 5 years) are more vulnerable to encephalopathy as their brains are rapidly developing. Blood lead levels greater than 10 µg/dL may potentially be harmful with reports of impact on IQ, and behavioural disturbance. Ingested lead is absorbed at a higher rate in children. Hence, personal hygiene of the worker is vital to avoid contamination of the home environment.

Pregnant and breast-feeding women must be removed from lead-risk work (OSH regulation. 5.63). Lead is released from bone stores during pregnancy. Lead crosses the placental barrier and can be transferred to breast milk.

Symptoms are non-specific and may be absent or mild in adults. For blood lead levels greater than 10 ug/dL there may be adverse health effects on the body’s digestive, cardiovascular, renal, reproductive and neurological functions. Severe health effects including abdominal pain, convulsions or death are now extremely rare in Australia. 

Table 1 Adverse effects of lead
Blood lead level (µg/dL) Symptoms may include:
10-20 Increased blood pressure, abnormal kidney function
20-40 Reduced kidney function, reduced nerve conduction and postural balance
60 Neurobehavioural affects - tiredness, moodiness, headache and vague aches
80   Anaemia develops
70-90 Encephalopathy in children (headache, vomiting, ataxia, seizures, paralysis, stupor, coma)
100 Abdominal colic, peripheral nerve palsies, muscle wasting and encephalopathy
150 Encephalopathy in adults

Blood lead thresholds

The average background blood lead level among Australians is less than 5 µg/dL (NHMRC, 2015; NHMRC, 2016). Levels above 5 µg/dL are considered to be consistent with exposure above the background level, e.g. from work activities, hobby, home renovation.

Surveillance guidelines

The AMP completes the WorkSafe Health Surveillance Notification Form – Lead (inorganic) which guides the AMP through the health surveillance process.

A baseline health surveillance is recommended prior to commencement of work, then at 2 and 6 months after the initial test. Thereafter, the frequency of testing is determined by the blood lead levels as outlined in the tables below.

The nature and duration of the exposure including the year of first exposure; work environment controls; personal hygiene and smoking history are important considerations in the assessment of risks and potential for elevated blood lead levels.

Monitoring blood lead levels enables early intervention by the AMP. Early intervention includes:

  • education (lead hazard and health effects)
  • counselling (safe work practices, personal hygiene)
  • temporary removal from lead work
  • re-reinstatement when appropriate
  • feedback to the employer for remedial measures (to improve safety controls).

Workplaces should provide amenities for hot water, hand washing and showering. Personal hygiene must be strict (washing face and hands before eating; not smoking, eating or drinking in lead work area; laundry provisions, showering and changing into clean clothes before leaving work). It is important for workers not to bring lead dust home from work.

Threshold actions

The removal level of females (of reproductive capacity) is 10 µg/dL.

The removal level for males and females (not of reproductive capacity) is 30 µg/dL.

Table 2 Male workers, and female workers (not of reproductive capacity)
Blood Lead Level (BLL) Actions
Less than 10 µg/dL Re-test six monthly.
10 to below 20 µg/dL
  • Counsel worker and review personal hygiene/work practice.
  • Liaise with employer regarding remedial measures (review personal hygiene, investigate workplace exposure and safety controls).
  • Re-test at three months.
20 to below 30 µg/dL
  • Counsel worker and review personal hygiene/work practice.
  • Consider removal from lead work when BLL exceeds 25 µg/dL.
  • Liaise with employer regarding remedial measures (as above).
  • Re- test in 6 weeks.
  • Consider medical review.
30 µg/dL or higher
  • Remove from lead work and notify all parties including WorkSafe without delay.
  • AMP to conduct medical examination within 7 days.
  • Counsel employee and review personal hygiene/work practice.
  • Liaise with employer regarding remedial measures (as above).
  • Re-test in one month and so forth.
  • AMP may certify suitable to return to lead work when BLL is less than 20 µg/dL.
  • Medical review at least annually.

 

Table 3 Female workers (of reproductive capacity)

Pregnant and breast-feeding women must be removed from lead-risk work (reg. 5.63).

Blood lead level Actions
Less than 5 µg/dL Six monthly testing.
5 to below 10 µg/dL
  • Counsel worker and review personal hygiene/work practice.
  • Liaise with employer regarding remedial measures (review personal hygiene, investigate workplace exposure and safety controls).
  • Re-test at 6-8 weeks.
  • Consider medical review.
10 µg/dL or greater
  • Remove from lead work and notify all parties including WorkSafe without delay.
  • AMP to conduct medical examination within seven days.
  • Counsel worker and review personal hygiene/work practice.
  • Liaise with Employer regarding remedial measures (as above).
  • Re-test at one month and so forth.
  • AMP may certify suitable to return to lead work when BLL is below
  • 5 µg/dL.
  • Medical review at least annually.

 

Health counselling

  • Inform workers of potential adverse health effects from lead exposure.
  • Counsel all workers to stop smoking.
  • Be clean shaven for effective respiratory protection.
  • Reinforce safe work practice (effective local exhaust ventilation, not to conduct dry sweeping, cleaning work area with HEPA filter vacuum cleaner, respirators with appropriate level of protection, etc.).
  • Reinforce personal hygiene and cleanliness, including:
    • washing face and hands before eating or drinking
    • no eating, drinking or smoking in the workshop
    • shower and change into clean clothes and footwear before leaving work.

Removal from lead-risk work

The AMP has a duty to recommend the removal of the worker from lead-risk work prior to the threshold being reached when they see the blood lead level rising over the course of the testing.

The AMP notifies the employer to arrange the removal of the employee from lead work immediately. The AMP conducts a medical examination of the employee within seven days of the removal.

The frequency of blood lead level testing is at the discretion of the AMP. The employee must not return to lead work until:

  • the blood lead level is less than 20 µg/dL for male employees and female employees not of reproductive capacity, or
  • the blood lead level is less than 5 µg/dL for female employees of reproductive capacity:

and the AMP has examined the employee, and certified the employee is suitable to return to lead work.

Legislative requirements

Health surveillance results from lead-risk work are to be sent to WorkSafe Western Australia by the AMP using the WorkSafe Health Surveillance Notification Form (Lead) together with the corresponding pathology report (blood lead levels reported in µg/dL).

The AMP is required to explain the results of the health surveillance to the worker, and provide feedback to the employer to enable remedial action (i.e. review and improve safety controls in the workplace).

Where the blood lead level is at or above the removal level, the AMP should report to WorkSafe promptly, and consider referral to the appropriate physician or toxicologist for clinical management and advice.

The AMP is expected to keep WorkSafe informed of the outcome of the employee who has been removed from lead work. 

References

Refer to the WorkSafe WA guidelines for health surveillance when planning and implementing health surveillance.

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