Screening for PBT chemicals among the "existing" and "new" chemicals of the EU.

Under the European chemicals legislation, REACH, industrial chemicals that are imported or manufactured at more than 10 t/yr need to be evaluated with respect to their persistence (P), bioaccumulation potential (B), and toxicity (T). This assessment has to be conducted for several 10,000 of chemicals but, at the same time, empirical data on degradability, bioaccumulation potential and toxicity of industrial chemicals are still scarce. Therefore, the identification of PBT chemicals among all chemicals on the market remains a challenge. We present a PBT screening of approximately 95,000 chemicals based on a comparison of estimated P, B, and T properties of each chemical with the P, B, and T thresholds defined under REACH. We also apply this screening procedure to a set of 2576 high production volume chemicals and a set of 2781 chemicals from the EU's former list of "new chemicals" (ELINCS). In the set of 95,000 chemicals, the fraction of potential PBT chemicals is around 3%, but in the ELINCS chemicals it reaches 5%. We identify the most common structural elements among the potential PBT chemicals. Analysis of the P, B, and T data for all chemicals considered here shows that the uncertainty in persistence data contributes most to the uncertainty in the number of potential PBT chemicals.