Biological limit value

The first step is to identify the substances present at the workplace. As a starting point, knowledge of the process is needed in order to formulate a list of all chemical agents used in the establishment. The list should include not only primary products but also intermediate and final products, as well as reaction products and by-products. For the chemical agents in the list, it is necessary to know their chemical properties, especially hazardous ones their OEL values, including biological limit values and, where these are not available, other technical criteria that can be used to evaluate the risk. It is also helpful to include any information on the safety and health risks of those substances provided by the supplier or other readily available sources. This information on dangerous substances and preparations, in the form of safety data sheets, is intended primarily for industrial users, to enable them to take the measures necessary to ensure the safety and health of workers. 

Furthermore, whereas biologic limit values are set for workers exposed 8 hours/day, 5 days/week for a working lifetime, the potential exposure of the general population is generally assumed to be 24 hours/day, 7 days/ week for an entire lifetime. ACGIH (2003) addresses that point as follows ... 

Morgan, M.S., and K.H. Schaller. 1999. An analysis of criteria for biological limit values developed in Germany and in the United States. Int. Arch. Occup. Environ. Health... 

Control parameters e.g. occupational exposure limit values or biological limit values. 

Within this guidance the term occupational exposure limit(s) refers to limits in the air of the workplace or biological limit values. In addition, for the purposes of this document exposure control means the full range of specific protection and prevention measures to be taken during use in order to minimize worker and environmental exposure. Engineering control measures that are needed to minimize exposure to, and risks associated with the hazards of, the substance or mixture should be included in this section. 

In a rayon production factory, exposure to carbon disulfide was measured by personal air sampling and the excretion of TTCA in urine (Meuling et al. 1990). Based on the personal air-sampling, the TWA exposure level for carbon disulfide was 12.6 mg/m3 (4 ppm). The study authors established a calculated biological limit value of 0.77 mg TTCA/g creatinine (0.57 mmol/mol creatinine) to correspond with 95% confidence, to a TWA air concentration lower than the threshold limit value (TLV) of 30 mg/m3. 

Biological limit values. Maximum value for the content of the substance or of one of its metabolites in biological media (i.e. blood, urine). 

Valeurs limites biologiques - biological limit values. 

Finland - sitovat raja-arvot HTP -arvot biological limit values." skin notations ("Skin" or Iho ) Provisions on how to calculate the limit values... 

Occupational Exposure Limit Values. Biological Limit Values. 

Biological limit value means the limit of the concentration in the appropriate biological medium of the relevant agent, its metabolite, or an indicator of effect . 

Binding Biological Limit Values and Health Surveillance Measures... 

The biological limit values, according to directive 98/24/EC, are intended as binding limit values similar to the binding occupational limits for air exposure (BOELV) discussed in the previous Section. They have to be brought into force by the member states. National values must not exceed the community values. 

At present, only one biological limit value has been set in Europe. For lead and its ionic compounds a level of 70 pg/100 mb blood has been determined (aimex II to directive 98/24/EC). Medical surveillance is required if the lead level in blood is greater than 40 pg/100 mb or if the concentration of lead in the air has been found to exceed 0.075 mg m, calculated as a time-weighted average over 40 h per week. 

Though there exists only one single biological occupational limit value, in many European member states limit values have been set on a national basis. In Germany, as an example, the technical rule for hazardous substances TRGS 905 contains biological limit values (called BAT values) for 51 chemical substances [6-50]. 

Table 15.2.1.2. Characteristics of styrene and tetrachloroethylene (PERC). [Information compiled from ACGIH, Documentation of Threshold Limit Values and Biological Limit Values, 1991 ]...

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