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Background > Government Regulation
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Government Regulation
Occupational Health Standards
The exposure limits for workers exposed to mercury vary with the governmental jurisdiction. Until recently, a typical value (NIOSH) was 50 ug/m3 average air concentration for an 8 hour shift. In 1994, the WHO (World Health Organization) reduced their exposure limit for total inorganic mercury (including elemental mercury) from 50 to 25 ug/m3. (Ref: ACGIH 1996 TLV's and BEI's. ISBN: 1-882417 13-5) In the province of Ontario, Canada, dentists and dental workers are exempted from these occupational health limits since they are considered impossible to meet. This is due to the mercury used in the preparation of amalgam dental fillings.
These levels are sufficiently high that they fall outside the working range of the Model 2537A. Several manufacturers make portable, high level mercury vapor analyzers. The detection limit and operating range of these products is typically four orders of magnitude (10,000 times) higher than Tekran products.
Ambient Air Standards
Most jurisdictions have not yet developed ambient air criteria. There appear to be two major reasons for this.
1) There was no practical way to measure these small concentrations until recently. It is neither advisable nor practical for a government to set a standard that cannot be measured and enforced.
2) The deleterious effects of low levels of mercury on the environment have only recently become known. Older standards considered only direct toxicological effects of emissions on humans.
The few jurisdictions that have standards generally set them many years ago in response to the potential health problems of high level emissions from industrial sources. For example, the Ontario ambient air standard is 5 ug/m3 (5000 ng/m3) for an hour average.
Many governments have recently instituted ambient air monitoring programs in response to concerns about mercury.
Government Approvals
Air Standards
The question is often raised if Tekran® products are EPA approved or approved in some other jurisdiction. Unfortunately, no government has yet approved a methodology for ultra-low level ambient air measurement, let alone approved a particular instrument. Many government organizations (including the US EPA) have already bought the Model 2537A for their own use. The Canadian federal government has purchased several dozen units, which are being used in a wide variety of applications. Tekran products are widely used in Europe and Asia as well as North America.
Water Standards
The USEPA has approved a method (Method 1631) that uses fluorescence for low level water analysis. The Tekran Series 2600 is a suggested supplier for the equipment used in this method. This system is also compliant with alternative low level methods. (eg: Method 245.7)
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