Chemical pollution can be a significant environmental issue. Many countries attempt to asses and limit the risk of chemical pollution, e.g., by introducing regulatory frameworks and  requiring the registration of chemicals. However, there is a variety of these registries, some focused on single industries, and they often have a significant overlap. This can make it difficult to asses the number and amount of chemicals in use globally.

Zhanyun Wang, Swiss Federal Institute of Technology (ETH) Zurich, Switzerland, and colleagues have analyzed all available national and regional inventories of industrial chemicals to further the global understanding of chemical pollution and to point out deficits in the current knowledge of produced chemicals. The team found 22 inventories from 19 countries and regions. They assigned Chemical Abstracts Service Registry Numbers to the registered compounds where possible, removed duplicates, and verified the resulting unified dataset. 

The researchers found over registered 355,000 chemicals in the combined dataset, a much higher number than previously estimated. There were significant variations in the number and types of chemicals registered in different countries and regions. This indicates a need for greater international cooperation. The team points out that are uncertainties regarding the total numbers of chemicals in use globally due to, e.g., the registration of complex mixtures, substances of unknown or variable composition, or compounds whose identity is considered to be confidential business information. According to the researchers, there needs to be better information on chemicals on the global market to understand the risks and impacts of chemical pollution.

• Toward a Global Understanding of Chemical Pollution: A First Comprehensive Analysis of National and Regional Chemical Inventories,
  Zhanyun Wang, Glen W. Walker, Derek C. G. Muir, Kakuko Nagatani-Yoshida,
  Environ. Sci. Technol. 2020.
  https://doi.org/10.1021/acs.est.9b06379