LEAD HEALTH SURVEILLANCE

Lead is a well known poison. Health surveillance organised by the employer is required by law where there is a risk of significant lead exposure. As a general rule, lead health surveillance is advisable:

  • If workers are required to wear respiratory personal protective equipment (PPE) to control lead exposure

  • If workers are at risk of returning blood lead levels of 5 ug/dL or higher due to an occupational source

Ability OPN's occupational physicians are AMPs (appointed medical practitioners). We offer:

Code of practice

National code of practice for the control and safe use inorganic lead at work NOHSC: 2015 (1994)

The code of practice outlines the employers' duties in providing a safe lead workplace with a focus on risk assessment, induction and training, control measures, PPE and health surveillance. 

Information for workers

This Worksafe bulletin provides effective understandable information including a FAQ. Also see Common Questions about Lead.

Download the Worksafe Prevention of Lead Poisoning information bulletin

Health surveillance guidelines for Appointed Medical Practitioners contains a useful summary of the health effects of lead and the rationale behind health surveillance.

Health effects of lead

Lead enters the body through breathing it in (lead dust and fume) and ingestion (typically through hands contaminated with lead touching food, the mouth and cigarettes).

Once lead is absorbed, it is stored in blood and body tissues, particularly bone where it is only very slowly removed from the body. Lead can damage various body organs and in many cases the damage is irreversible or only partially reversible. 

Therefore, it is very important to minimise any lead absorption in the first place through good workplace controls and safe work practices. 

Lead exerts toxicity on the nervous system, cardiovascular system, gastrointestinal system, kidneys and blood making organs. 

Problems associated with lead include:

  • Peripheral nerve damage - weak wrist or foot extension (levels over 80 ug/dL)

  • Raised blood pressure (levels above 10 ug/dL)

  • Anaemia (levels over 50 ug/dL)

  • Increased cancer risk - lung, stomach and bladder cancer

  • Kidney damage (levels over 50 ug/dL)

  • Reproductive problems - infertility, miscarriage, stillbirths

  • Effects on the developing brain of the fetus and children leading to behavioural problems and reduction in IQ

Symptoms associated with higher lead levels (more than 40-60 ug/dL) include:

  • Fatigue

  • Feeling generally unwell

  • Headaches

  • Memory problems

  • Generalised aches & pains
  • Loss of appetite, abdominal pain, diarrhoea, constipation

  • Depression

  • Sexual dysfunction

At lower levels, symptoms are often absent but if present are typically minor and non-specific:

  • Not feeling right

  • Low in energy

  • Mood changes

  • Irritability

The developing fetus and children are particularly sensitive to the effects of lead. 

Acute symptomatic lead poisoning (abdominal pain, weakness, constipation) very rarely occurs when blood lead levels are kept below 80 ug/dL. 

As more scientific evidence has accumulated about the health effects of lead, the regulatory blood lead level threshold for removal from lead work for males has progressively lowered from 80ug/dL to the current 30 ug/dL. The reasoning behind the lower thresholds is to protect against 'subclinical' health effects ie. adverse health effects which may not have obvious symptoms. 

Graph showing the prevalence of different adverse health effects at increasing lead levels. 

 

ALAD and ZPP are enzymes in the blood forming process.  

Source: Evans and Elinder as adapted from Elinder et al monograph on biological monitoring (WHO)

Common questions
Does drinking milk help?

No. Many decades ago it was observed that the health of lead workers was improved by a pint of milk a day but that was due to their very poor diet at that time. The calcium in milk will not reduce lead absorption or reduce its toxic effects. 

Is there anything I can take to reduce lead absorption such as chelating agents?

No. Chelation is not recommended unless there is acute poisoning (pain, weakness) from very high lead levels. There is no evidence that chelation is of long term benefit in the absence of poisoning and the agents themselves can be associated with adverse reactions.

 

One paper suggested that taking Vitamin C may reduce the toxic effects of lead but this remains speculative.  

How long does it take to get rid of lead from my body?

When lead enters the body it is distributed into red blood cells, soft tissues and bone. Elimination of lead from these different storage areas differs from a half-life of 30 days for blood to 27 years for bone. Half-life is the time it takes for the amount of lead to halve. In adults, over 90% of the total body burden of lead is stored in the bones. 

Once lead exposure stops, the blood lead level will fall quickly over months. If there is a high body burden of lead from chronic exposure then the blood level may drop much more slowly over many months due to leaching of lead from the bones back into the blood. 

Nature and frequency of lead health surveillance

Lead health surveillance involves biological monitoring (blood lead tests) and medical examinations. Health surveillance is an adjunct and not a substitute for other control measures. 

 

Regulation 5.59 of the Occupational Safety and Health Regulations 1996 (WA) states the following blood testing frequency:

  • Within the first month of commencing employment (ie baseline test)

  • 2 months after the first test

  • 6 months after the first test

  • then at the discretion of the supervising doctor (AMP). This is usually 6 monthly. The frequency of testing increases at higher blood lead levels

Additionally it is recommended in the code of practice that the AMP medically examine employees:

  • Prior to an employee commencing lead risk work (some medical conditions may exclude a worker from a lead risk job)

  • When blood lead levels indicate the need for medical removal from the workplace

  • Routinely between 1-5 years as determined by the AMP​

For employees considered at risk of developing adverse effects from lead due to higher levels the AMP may recommend additional pathology tests including full blood picture, ZPP, kidney function tests and urine analysis and microscopy as part of the medical examination.

For convenience Ability OPN can provide on-site medical examinations. 

Medical removal from lead work

SafeWork Australia is currently examining whether to lower the threshold for removal from lead work to further protect worker health. Current legislated blood lead thresholds for removal from lead work are:

  • 10 ug/dL for females of reproductive capacity 

  • 30 ug/dL in all other cases

By legislation, workers can also be medically removed from lead work if:

  • Pregnant or breast-feeding

  • There is a belief that the employee has had excessive lead exposure or is suffering adverse health effects

References
  1. C.-G. Elinder, L. Friberg, T. Kjellstorm, G. Nordberg, et al. Biological Monitoring of Metals: Chemical Safety Monographs: International Programme on Chemical Safety, World Health Organization, Geneva, Switzerland (1994)

  2. Committee on Potential Health Risks from Recurrent Lead Exposure of DOD Firing-Range Personnel; Committee on Toxicology; Board on Environmental Studies and Toxicology; Division on Earth and Life Studies; National Research Council. Potential Health Risks to DOD Firing-Range Personnel from Recurrent Lead Exposure. Washington (DC): National Academies Press (US); 2012 Dec 3. 4, Noncancer Health Effects.

  3. Kathuria P et al. Lead nephropathy. Medscape Jan 2016.

  4. OSHA Medical surveillance guidelines standard 1926.62 App C. 

  5. Safe Work Australia. (2014). Review of hazards and health effects of inorganic lead – implications for WHS regulatory policy. Canberra: Safe Work Australia.

  6. Kim H-C, Jang T-W, Chae H-J, et al. Evaluation and management of lead exposure. Annals of Occupational and Environmental Medicine. 2015;27:30. doi:10.1186/s40557-015-0085-9.

  7. Hunter's Diseases of Occupations, Tenth Edition 2010, Chapter 23 - Lead. 

 
 

© 2019 by Ability OPN.