## 2 Environmental and Human Health Impacts of Short-Chain Chlorinated Paraffins  
Short-chain chlorinated paraffins were historically manufactured in numerous countries, including the United States, Canada, and several European nations [11]. While precise global production figures are elusive due to data limitations and inconsistent reporting standards, estimates suggest a significant surge in SCCP production, particularly during the mid-20 th century, primarily driven by Chinese manufacturing. Cumulative global production between 1935 and 2012 is estimated to have exceeded 25,000,000 metric tons. More recent modeling studies suggest cumulative global CP production of approximately 32.5 million metric tons between 1930 and 2020, with SCCPs constituting roughly 28% of this total [12]. As of 2020, approximately 1.6 million metric tons of historically produced SCCPs have been released into the environment [12]. Sources of SCCP emissions include the production, storage, and transportation of SCCP-containing products, as well as their use in industrial and consumer applications. Some studies demonstrate that many consumer products, such as toys, sports equipment, and kitchen appliances, contain SCCPs, leading to their release into the air or migration into food [13]. Additional sources are the disposal and burning of waste and the landfilling of products [14]. The primary sink for these emissions is soil, followed by air and fresh water. The spatial distribution of SCCPs in soil samples [15; 16; 17] exhibits a clear urban-rural gradient, with higher concentrations observed in urban areas, particularly near industrial and waste disposal facilities and sewage treatment plants. The extensive and largely unregulated utilization of SCCPs across diverse industrial sectors has resulted in their omnipresence in atmospheric samples, underscoring their persistence and potential for long-range atmospheric transport [18; 19; 20]. The magnitude and distribution pattern of SCCP levels exhibit significant variability, primarily influenced by the production and consumption of SCCPs, as well as their physicochemical properties and meteorological variables. SCCPs preferentially partition into the gas phase during summer and favor binding to particles during winter [21]. Surface runoff, municipal and industrial wastewater effluents, and leachate originating from waste disposal sites introduce SCCPs into freshwater environments, where they can be present in significant concentrations [22; 23; 24; 25]. For example, evaluations of levels of SCCPs in water and sediment samples from various regions of China and assessments of the potential ecological risks have identified elevated ecological risks, especially in sediments [26]. Moreover, the results indicate that eating aquatic products and drinking water in some regions could produce non-carcinogenic health risks to human health. SCCPs have also been detected in other matrices: indoor environments [27; 28; 29], sewage and sewage sludge [30; 31; 32], seawater [33; 34; 35], sediments [36; 37; 38], biota [39; 40; 41; 42], and food [43; 44; 45; 46]. Diet is the primary human exposure route for SCCPs [47]. The occurrence and distribution of CPs in food samples have been reviewed by [PERSON] et al. [48]. SCCPs have been found in oils, milk and dairy, ready-made meals, sediments, noodles, bread, wine, tea, meats, aquatic foods, shellfish, fish, cereals, legumes, eggs, vegetables, and fruits. Based on available data, the authors stated that the consumption of SCCP-contaminated food does not appear to pose a significant health risk. However, SCCPs in breast milk and infant formula may pose health concerns for infants [49]. A recent study revealed that all breast milk samples collected in Shanghai from 2016 to 2017 contained high levels of SCCPs (median concentrations up to 771 ng/g lipid weight) [50]. A Monte Carlo simulation-based risk assessment showed the potentially high risks to breastfed infants. Other routes of exposure include dust ingestion, inhalation, and dermal contact [51; 52; 53; 27].