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Biological Monitoring in Occupational Health

What is biological monitoring?

Biological monitoring is a method of chemical exposure assessment of toxic compounds, elements, or their metabolites, in biological substances. Often, these measurements involve the analysis of blood, urine, hair, or exhaled breath and are undertaken in both environmental health, occupational health and safety as a means of exposure assessment and workplace health surveillance.

The aim of biological monitoring is to detect hazardous substances in the body before adverse health effects occur. Biological monitoring helps employers estimate past exposure and assessing individual susceptibility to hazards in the workplace. Identification of biomarkers may enable timely intervention to prevent disease. It is also an adequate tool in the assessment of the efficacy of PPE, ventilation, and other workplace hygiene measures.

How do I know what to test my employees for?

This will depend upon your risk assessment and method statement relating to the processes which you undertake in the workplace. Biological monitoring guidance values (BMGVs) provide clear criteria for interpreting the results of biological monitoring and are essential to their effective use in exposure assessment. The HSE have established a system of non-statutory BMGVs to provide an authoritative guide to the interpretation of biological monitoring results.

There is no requirement in the COSHH Regulations for compliance with BMGVs. Their purpose is as guidance in the interpretation of biological monitoring data. In the absence of BMGVs in place by the HSE, other biological values can be used as a guide to interpretation.

Do I have to undertake biological monitoring?

In the UK it is not a statutory requirement to carry out biological monitoring (with exception to Lead – see below) and the control of lead at work (CLAW) regulations. ISBN 978 0 7176 2565 6 (CLAW)). So these biological guidance values are used a benchmark to assess the effectiveness of PPE, ventilation, and other hygiene measures, as mentioned above.

What are the CLAW regulations?

The Control of Lead at Work (CLAW) Regulations 2002 detail how employers should manage the risk of lead in their workforce they came into force on 21 November 2002 and revoked the previous CLAW Regulations (1998). The new Regulations have been extended by the health requirements of the European Union’s Chemical Agents Directive (98/24/EC), the aims of which are to:

(a) protect the health of people at work by preventing or, where this is not reasonably practicable, adequately controlling their exposure to lead; and

(b) monitor the amount of lead that employees absorb so that individuals whose work involves significant exposure (as defined by the regulations) to lead at work can be taken off such work before their health is affected.

Further information about the CLAW regulations can be found at

Where can I find out more information about biological monitoring?

The HSE have information on how to set up and manage a biological monitoring program.

The main steps involve:

Step 1 Define the purpose of the programme.

Step 2 Appoint a competent person to manage the programme.

Step 3 Define the monitoring strategy.

Step 4 Consult on the programme with employees or their representatives

Step 5 Discuss and agree the programme with the individual employees concerned.

Step 6 Establish procedures for sample collection, storage, transportation, analysis, and quality assurance.

Step 7 Establish procedures for feedback, including interpretation or results.

Step 8 Ensure arrangements are in place for acting on the results and evaluating the effectiveness of the programme.

Further information visit the HSE website

Additional information about guidance values

Different countries and governing boards will use the following values as guidance. The International Commission on Occupational Health (ICOH) and The European Scientific Committee on Occupational Exposure Limits (SCOEL) use a Biological Limit Value (BLV) this is a reference value for the evaluation of potential health risk in the practice of occupational health.

Biological Tolerance Values or Biologischer Arbeitsstoff-Toleranzwert (BAT values) in Germany. BAT (biological tolerance) values are based either on the relationship between external exposure and internal dose, or between the internal dose and the resulting effect of the substance, using the average of internal dose.

Biological Exposure Indices (BEI®) of the American Conference of Governmental Industrial Hygienists (ACGIH) are indirect guidance values based mainly on the correlation between the biomarker concentration and the airborne concentration of the original substance.

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