The Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area of the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) has presented the 2018 List of Maximum Workplace Concentrations and Biological Tolerance Values. The list, which has now been submitted to the German Federal Minister of Labour and Social Affairs, includes 95 supplements and new entries and is available in printed form and as a digital open-access resource. The list is prepared in fulfillment of the DFG’s mandate to provide scientific policy advice as stipulated in its statutes.
The maximum workplace concentration (MAK value) for polytetrafluoroethylene is a new addition to the list. Known by a number of names, including Teflon and Gore-Tex, this substance is used to coat cookware and functional clothing and is essentially non-toxic. The MAK value therefore applies only to the fine particles of polytetrafluoroethylene dust produced in the workplace during production or processing, some of which can enter the alveoli. If a person is exposed to this dust in high concentrations over a prolonged period of time, the dust particles can cause inflammation in the lungs and the resulting tissue changes can lead to the formation of tumors.
The Commission takes a wide range of different factors into account when assessing chemicals of relevance to the workplace. As an example, a biological reference value (BAR) of 15 μg/g of creatinine in the urine has been determined for aluminum. This will help to describe the background level in the general population, not just in those who are exposed to the metal in the workplace. Exposure to higher levels of the substance does not necessarily represent a health risk, but the value does serve as an indicator of additional aluminum load and as such requires investigation into the cause. How aluminum affects the body is not yet fully understood. The BAT value for aluminum was determined by the Commission in 2017.
For women of childbearing age and pregnant women, the Commission reviewed the maximum plasma concentration up to which chlorinated biphenyls (also known as polychlorinated biphenyls or PCBs) may be safely assumed not to be toxic to reproduction. Once used as plasticizers and in sealants, the production and sale of these compounds have been banned in Germany since 1989. However, they are still found in older buildings and appliances. After reviewing the relevant studies, the Commission concluded that there is no reason to expect reproductive toxicity up to a concentration of 3.5 μg of PCB indicator congeners – which indicate the overall level of chlorinated biphenyls in the body – per liter of plasma.
In addition to the eponymous maximum workplace concentrations (the amount of a substance that may be present in the workplace in the form of a gas, vapour or aerosol without causing long-term damage), the list of MAK and BAT values contains information about which substances are carcinogenic, damage germ cells or harm a developing foetus, sensitise the skin or respiratory tract, or are absorbed through the skin in toxic amounts. It also reports the concentration of a substance in the body to which a person can be exposed for a working lifetime without experiencing adverse health effects (the biological tolerance value). Furthermore, it describes biological guidance values (BLW values) and biological reference values (BAR values). For each of the reviewed substances, there is detailed scientific documentation that makes the Commission’s decision-making processes transparent. The proposals for the supplements and the new entries are available for discussion until 31 December 2018. New data and scientific comments can also be submitted to the Commission’s Scientific Secretariat up to that date.
In all, the Commission determined MAK values for 14 substances, changed the value for eight substances, and confirmed the existing value for 13 substances following a careful assessment of the most recent literature. One MAK value was deleted. In addition, the 35 substances with a revised or new MAK value were reviewed with regard to the limitation of short-term peak exposure and risks during pregnancy.
The Commission also examined all of the substances included in the list for their ability to sensitize the skin or respiratory tract; the skin-sensitizing effect of azinphos-methyl, 1-butanethiol and isobornyl acrylate was newly indicated. A warning that not only inhalation but also absorption through the skin can significantly contribute to health risks was added to five substances; this warning has been retained for 12 other substances. Experts have included ten supplements and new entries in the “BAT values, BLW, EKA and BAR” section. Amendments were made, for example, to the BAT values for chlorobenzene, dimethylformamide, methanol and 1,1,1-trichloroethane. The biological reference value for benzene was amended and new values were determined for aluminum and molybdenum. A new biological guidance value was determined for lead.
The digital version of the list of MAK and BAT values is available in German and English, and, as of last year, in Spanish as well. The data published by the Senate Commission provides an independent, scientifically sound source of information for many emerging nations in Latin America, which often lack the resources to establish evidence-based occupational safety limits and guidelines for preventive medical check-ups. The Commission is, therefore, contributing to the process of ongoing development and active occupational safety in countries with increasingly global economic links.