Biological Monitoring

What is biological monitoring?
Many jobs involve using chemicals that can be harmful to health if not properly controlled. For some chemicals biological monitoring can be used to indicate how good control is and how much of the chemical has entered the body. It is a way of assessing exposure and health risks and involves measuring the chemical or its breakdown products in urine, blood or breath.

  Click here for details of biological monitoring tests available from HSL

Why carry out biological monitoring?
Biological monitoring has a number of benefits when compared with other types of exposure monitoring:

• it can help to show whether personal protective equipment (e.g. gloves, masks) and engineering controls (e.g. extraction systems) are effective in controlling exposure;
• it measures exposure to a chemical via all routes - breathing in, ingestion and absorption through the skin;
• it can tell you what has actually been absorbed into the body;
• it can show how effective any improvements in controls have been in reducing exposure; and
• it can provide reassurance to workers that their personal exposure is under control.

Biological monitoring can be used to good effect on its own or alongside other monitoring techniques, such as air and surface contamination measurements, to provide important information on chemical exposures in the workplace.

Why use HSL?
HSL has provided biological monitoring services for over 25 years. During that time we have developed robust and well validated methods that enable us to monitor exposure to over 100 chemicals or classes of chemical. We have helped HSE to set and interpret Biological Monitoring Guidance Values. This experience gives us a unique knowledge base and provides a firm foundation for the interpretation of results - a key component in any biological monitoring strategy.

  HSL also runs training courses in Biological Monitoring, please click here for further information

Additional benefits of HSL's service
Our analytical services are underpinned by an extensive research programme aimed at providing continuous improvement to the services we offer.

Where possible HSL has developed non-invasive techniques to avoid the need to take blood samples from workers. We are continuing to develop improved non-invasive methods, in particular in the field of breath analysis where we have developed a simple-to-use breath sampler.

HSL can help on a day-to-day level by providing sample collection kits, packaging materials and supplying full instructions for sending samples through the post in accordance with legal requirements - all included in the price of the analysis. We also offer a range of air and surface monitoring services for chemicals that can be used with biological monitoring to provide a comprehensive monitoring strategy.

  To contact the Sample Reception, please click here.

HSL Biological Monitoring Services
HSL can provide analysis of a wide range of substances in blood, breath or urine.

  Click here for a list of biological monitoring tests available from HSL

Biological Monitoring Guidance Values (BMGV)
The Health and Safety Executive (HSE) have introduced biological monitoring guidance values into their publication Guidance Note EH40 - 'Occupational Exposure Limits'. These guidance values are intended to assist in the interpretation of biological monitoring results with respect to occupational exposure.

Prior to 2005, there were two types of guidance values: health guidance values and benchmark guidance values.

Health Guidance Values
Health guidance values are set at a level at which there is no indication from the scientific evidence available that the substance being measured is likely to be injurious to health. These are often 'biological equivalents' of occupational exposure limits.

Benchmark Guidance Values
Benchmark guidance values are practicable, achievable levels set at the 90th percentile of available biological monitoring results collected from a representative sample of workplaces with good occupational hygiene practices. They are not health based.

Since 2005 there has been only one list of BMGVs which now has entries for 16 chemicals. Each one has an information sheet outlining the monitoring method to be used and other details. These information sheets can be supplied by HSL, on behalf of HSE, on request. Alternatively they may be downloaded by clicking on the list below:

Biological Monitoring Guidance Values:
  2,2'-Dichloro-4,4' methylene dianiline (MbOCA) in urine
  2-Butoxyacetic acid in urine (metabolite of butoxyethanol)
  4,4' Methylenedianiline (MDA) in urine
  4-Methylpentan-2-one (MIBK) in urine
  Butan-2-one (MEK) in urine
  Monitoring carbon monoxide by breath carbon monoxide
  Chromium in urine
  Cyclohexanol (a metabolite of cyclohexanone) in urine
  Dichloromethane by monitoring breath carbon monoxide
  1-Hydroxypyrene (as a marker of polycyclic aromatic hydrocarbons) in urine
  Isocyanate metabolites in urine
  Lindane in plasma
  Mercury in urine
  Methyl hippuric acid (a metabolite of xylene) in urine
  Nitroglycerin (GTN) and 1,2- and 1,3-glycerol dinitrate (GDN) in urine
  N-methylacetamide (a metabolite of N, N' - dimethylacetamide) in urine

Internationally, the American Conference of Governmental Industrial Hygienists has set guidance values for over 45 substances in the US, and the Deutsche Forschungsemeinschaft in Germany has introduced values for over 86 chemicals. As a laboratory with a world-wide reputation and network in the field of biological monitoring, HSL is able to use these values and other authoritative sources to provide additional help with the interpretation of results.

Biological Monitoring Case Studies

Are you controlling exposure to asthmagens?
Biological monitoring (BM) at a motor vehicle repair company showed all staff, even administrators, at the premises had detectable traces of isocyanate from spray paint in their urine. This prompted an investigation that found that the spray booths (which had just passed their annual inspection and test) were leaking vapours into the building's ventilation system. The spray booths were repaired and subsequent BM showed that the control measures were working properly. In addition BM highlighted training issues as booths were not used properly. Follow up BM has been recommended for ongoing checks on the adequacy of controls.

  Biological monitoring for isocyanates in the motor vehicle repair industry

How to control exposure to MbOCA
Methylene bis 2-chloroaniline (MbOCA) is a substance used in the manufacture of some polyurethane products. It is a suspected carcinogen and is readily absorbed through the skin, therefore BM of workers is recommended to measure exposure via all routes. HSL has been monitoring the majority of UK MbOCA workers since 1977.

The graph shows that there has been a steady decrease in their urinary MbOCA levels over this period. This reflects the fact that BM has enabled poor working practices to be identified and improved, with the result that MbOCA exposures have been reduced dramatically.

Further Details
Contact our Business Development Group by telephone (+44) 01298 218218, fax (+44) 01298 218822 or email hslinfo@hsl.gov.uk.

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