Chlorinated Paraffins in Sediments from the Pearl River Delta, South China: Spatial and Temporal Distributions and Implication for Processes

Abstract

b S Supporting Information ' INTRODUCTION Chlorinated paraffins (CPs) with the formula (C n H 2n+2-z Cl z ) are subdivided into short-chain (C 10 ÀC 13 , SCCPs), mediumchain (C 14 ÀC 17 , MCCPs) and long-chain (C > 17, LCCPs) according to their carbon chain length, where chlorine content ranges from 10% to 72%. 1 Because of their chemical and thermal stability, CPs were widely used as additives in lubricants, as cutting fluids for metal working, as plasticizers and flame retardants in plastics, sealants, and leather. 2 As high production volume chemicals, CPs are inevitably released into the environment during their production, transportation, and usage. CPs have been detected in various environmental matrices including water, sediment, air, soil, biota ,and human beings. 1 It is also suggested that CPs are bioaccumulated and biomagnified in food webs. 3 CPs, especially SCCPs, have attracted increasing attentions in the past decade as they represent a potential "new" category of persistent organic pollutants (POPs). 4 The European Union restricted the usage of SCCPs via the Water Framework Directive based on the SCCP risk assessment. 5,6 Furthermore, SCCPs have been banned for use in Germany since 2003. 1

Short-chain chlorinated paraffins in marine organisms from the Pearl River Estuary in South China: Residue levels and interspecies differences

“…Regarding the chlorine content, Cl 7 and Cl 8 were the dominant congeners with the average percentages ranging from 25%-30% (27%, average) and from 21%-33% (26%, average) of the total SCCPs, respectively. This patterns of SCCPs were generally consistent with those in Indo-Pacific humpback dolphins from the study region in recent years (2012)(2013)(2014) (Zeng et al, 2015); but different from those reported in the surface sediment samples with higher abundance of short carbon chain (C 10 and C 11 ) in the Pearl River Estuary, although homologue groups with 7-8 chlorines dominated in the sediments (Chen et al, 2011). However, it was not clear whether this finding suggested selective accumulation of longer carbon chain SCCPs in these organisms; because Zeng et al (2015) found a more significant temporal shift trend in the SCCP homologue pattern from shorter-to longer-chain groups in dolphin from the Pearl River Estuary between 2004 and 2014.…”

“…China is the largest producer of CPs in the world, and the production volume has rapidly increased from 24.2 kt/year in 1990 to about 1000 kt/year in 2009 (Chen et al, 2011;Zeng et al, 2011a). As high production volume chemicals, CPs can be inevitably released into the environment during the production, storage, transportation, usage, and disposal or recycling of CPs and CP-based products.…”

“…Many studies demonstrate that the Pearl River Delta region have become a hotspot area for persistent halogenated compound contamination due to rapid industrialization and urbanization, and intensive e-waste recycling activities (Fu et al, 2003;Mai et al, 2005aMai et al, , 2005b. High levels of ∑SCCPs were observed in various environmental matrices such as sediment (320-6600 ng·g − 1 dry weight, dw), soil (18 ng·g − 1 dw, average), and air samples (18 ng·m − 3 , average) obtained from this region (Chen et al, 2011;Wang et al, 2013). Luo et al (2015) reported that ∑SCCP concentrations in terrestrial bird species inhabiting an e-waste recycling site in the Pearl River Delta, South China ranged from 620 to 17,000 ng·g −1 lipid weight (lw).…”

Short- and Medium-Chain Chlorinated Paraffins in Air and Soil of Subtropical Terrestrial Environment in the Pearl River Delta, South China: Distribution, Composition, Atmospheric Deposition Fluxes, and Environmental Fate

“…The high M/S ratios also indicated a shift to the use of formulations containing more MCCPs in the PRD. Chen et al 15 also suggested a shift to more use of MCCPs in recent years. Wide spatial variation of CP concentrations revealed that the gradient decreasing trend of CPs from more to less industrialized areas was also found in soils (Figure 2b).…”

“…22 Meanwhile, atmospheric transport is said to be the major pathway for SOCs transport to rural areas. 23 Despite increasing attention over CPs over the past decade, there is still lack of insight on the environmental partition and fate of CPs in different matrixes, especially in the developing countries like China, 13,15,23,24 where the largest production and export of CPs in the world takes place without restriction. 25 Consequently, the extensive production (600 000 tons in 2007) and usage of CPs suggest that the potential for contamination and impact to humans and the environment is very high, rendering the need for such studies in China imperative.…”