Distribution and Emission Estimation of Short- and Medium-Chain Chlorinated Paraffins in Chinese Products through Detection-Based Mass Balancing.

Short- and medium-chain chlorinated paraffins (SCCPs and MCCPs, respectively) have raised environmental concern due to their potential for persistence, long-range transport, bioaccumulation, and toxicity. However, little is known about the production, use, and environmental emissions of SCCPs and MCCPs in China, the world's largest producer and consumer. In this study, we estimated the amounts of SCCPs and MCCPs produced and used in China in 2018-2019 based on a nationwide survey and measurements of concentrations in products, from which we estimated the environmental emissions of SCCPs and MCCPs in China. Our results show that 225.2 and 236.4 metric kilotons (kt) of SCCPs and 428.5 and 450.2 kt of MCCPs were used in China in 2018 and 2019, respectively, with poly(vinyl chloride) (PVC) products dominating SCCP and MCCP usage. Moreover, a total of 3.9 and 4.2 kt SCCPs and 3.8 and 4.1 kt MCCPs were emitted into China's environment in 2018 and 2019, respectively. Although less MCCPs are released into the air relative to SCCPs, their level exceeds the emission of SCCPs into soil. Finally, detailed mass balance calculation indicates that, although emissions from the use of PVC products dominate SCCP and MCCP inputs into the air, emissions from the use of polyurethane foam adhesives are more closely related to input into surface waters for SCCPs and MCCPs. For input into soil, the main emission sources are the use of polyurethane foam adhesives (for SCCPs) and rubber products (for MCCPs). This study provides a preliminary overview of the distributions of SCCPs and MCCPs in products and insight into the mass balance of SCCPs and MCCPs from their production and use to emission in China. This assessment also provides an important foundation for better understanding the environmental risks and fates associated with SCCPs and MCCPs in China and around the world.