Homologue Composition of Technical Chlorinated Paraffins Used in Several Countries over the Last 50 Years─SCCPs Are Still Out There.

Chlorinated paraffins (CPs) are widely produced chemicals, with certain CP subgroups facing global restrictions due to their environmental dispersion, persistence, bioaccumulation, and toxicity. To evaluate the effectiveness of these international restrictions, we assessed the homologue group contribution and the mass fraction of short-chain CPs (SCCPs: C 10 -C 13 ), medium-chain CPs (MCCPs: C 14 -C 17 ), and long-chain CPs (LCCPs: ≥C 18 ) in 36 technical CP mixtures used worldwide over the last 50 years. Using low-resolution mass spectrometry (LC-ESI-MS/MS), we quantified 74 CP homologue groups (C 10 Cl 4 -C 20 Cl 10 ). Additionally, high-resolution mass spectrometry (LC-ESI-QTOF-MS) screening was employed to identify unresolved CP contents, covering 375 CP homologue groups (C 6 Cl 4 -C 30 Cl 30 ). Overall, 1 sample was mainly composed of <C 10 -CPs, 10 of SCCPs, 13 of MCCPs, and 12 of LCCPs. Specific homologue group contributions and mass fractions of CP subgroups varied considerably. However, the predominance of C 11 Cl 6 - and C 14 Cl 6 -CP homologue groups was in good agreement with that of the dominant homologue groups in environmental matrices and manufactured products. SCCP yields are still high in some technical CP mixtures, and three technical CP mixtures currently produced failed the Stockholm Convention restrictions on SCCPs. This study sheds light on significant challenges in implementing international CP restrictions effectively.