Short-chain chlorinated paraffins (SCCPs) in a freshwater food web from Dianshan Lake: Occurrence level, congener pattern and trophic transfer

Occurrence, sources, partitioning and ecological risk of short- and medium-chain chlorinated paraffins in river water and sediments in Shanghai

The characteristics of regional environmental pollution of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) in river system from Shanghai were comprehensively investigated in this study for the first time. The total concentrations of SCCPs and MCCPs ranged from 15.0 to 1640 ng L^-1 (median: 278 ng L^-1) and 40.3 to 3870 ng L^-1 (median: 939 ng L^-1) in water, and from not detected (ND) to 2020 ng g^-1 (median: 89.3 ng g^-1) and 10.1 to 10,800 ng g^-1 (median: 947 ng g^-1) in sediments, respectively. The higher levels of SCCPs and MCCPs were found in water from Jinhui and Yexie rivers, and in sediments from Huangpu River, respectively. The concentrations of MCCPs were higher than those of SCCPs in both water and sediments, suggesting that the river system was mainly contaminated by MCCPs. Compared with other areas around the world, the concentrations of SCCPs and MCCPs were at medium to high levels in water and sediments. Factor analysis results revealed that SCCPs and MCCPs had different sources in both water and sediments. The log K_oc values of CPs were significantly correlated with carbon chain lengths (p < 0.01), but not with chlorine number for both SCCPs and MCCPs (p > 0.05). A significant second-order polynomial relationship was observed between log K_oc values and molecular weights of homologue groups of SCCPs (p < 0.001) and MCCPs (p < 0.01), respectively. SCCPs in water posed a low ecological risk at all sampling sites, and MCCPs in water posed a moderate ecological risk to aquatic life at nearly a fifth of sampling sites. SCCPs and MCCPs in sediments posed a low ecological risk to sediment dwelling organisms at most sampling sites.

Concentrations and congener group profiles of short- and medium-chain chlorinated paraffins in animal feed materials

Chlorinated paraffins (CPs) are ubiquitous environmental pollutants that are lipophilic and can accumulate in the food chain. Animal-derived products are predominant contributors to human CP exposure. CPs in animal feed might accumulate in domestic animals through dietary exposure, leading to potential contamination of animal-derived food products and human health risks. However, information on the presence of CPs in animal feed materials is scarce. In this study, 16 animal feed material samples were collected in China in 2016. Thirteen of the samples were of animal origin and three were of plant origin. The concentrations and carbon and chlorine congener group profiles of shortchain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in these animal feed materials were investigated. The concentrations of SCCPs were higher than those of MCCPs in all of the samples. The SCCP concentration range was 120 to 1700 ng/g (mean 640 ng/g), and the MCCP concentration range was 6.4 to 260 ng/g (mean 78 ng/g). Fish meal had the highest SCCP and MCCP concentrations. The lowest SCCP and MCCP concentrations were detected in peanut meal and whey powder, respectively. The concentrations of SCCPs and MCCPs varied among the types of animal feed materials. SCCP and MCCP concentrations also varied among samples of the same type of animal feed material. Relatively high concentrations of SCCPs and MCCPs were detected in feed materials of animal origin. The predominant congener groups in the animal feed materials were C10-11Cl6-7 for SCCPs and C14Cl7 for MCCPs. The carbon and chlorine congener group profiles of SCCPs indicated that SCCP contamination in the animal feed materials might arise from commercial CP mixtures.

Validation of a HRGC-ECNI/LRMS method to monitor short-chain chlorinated paraffins in human plasma

Short-chain chlorinated paraffins (SCCPs) are produced in high volume and have the high potential to pose a threat to human health. However, little information is available for SCCP contamination in human blood/plasma/serum, mainly due to the difficulty of sample preparation and quantitative analysis. A method using high resolution gas chromatography coupled with electron capture negative ionization low resolution mass spectrometry (HRGC-ECNI/LRMS) was developed and validated to measure SCCPs in human plasma. The pretreatment process included protein denaturation and lipid elimination, liquid-liquid extraction with a mixture of n-hexane/dichloromethane (1:1, V/V), and cleanup on a multi-layer silica column. The blank controls, including procedural blank, vacuum blood collection tube blank, and instrumental blank, were the most pivotal points for the reliable analysis of SCCPs. The average value of procedural blanks was 9.0ng/g; and the method detection limit (MDL), calculated as the sum of the average procedural blank value and 3 times of the standard deviation of the procedural blanks, was 12.6ng/g plasma. The validated method was applied to measure the concentrations of the total SCCPs (∑SCCPs) in 50 plasma samples from a general population. The measured plasma concentrations of ∑SCCPs ranged from <MDL to 203ng/g wet weight (ww), with an average value of 32.0ng/g ww. The relative abundance profiles of SCCPs in plasma samples were dominated by C₁₀- and C₁₁-CP congener groups centered on Cl_6-7. The developed method can be used for the comprehensive and large-scale investigation of SCCP levels in human plasma.

Combined Effects of Dust and Dietary Exposure of Occupational Workers and Local Residents to Short- and Medium-Chain Chlorinated Paraffins in a Mega E-Waste Recycling Industrial Park in South China

Four types of dust samples and nine categories of locally produced staple foods were collected from a mega e-waste recycling industrial park and its surrounding regions, and simultaneously analyzed for short-chain and medium-chain chlorinated paraffins (CPs) to estimate dust and dietary exposure and their combined effects on occupational workers and local residents. All samples related to e-waste activities contained considerably high concentrations of CPs. The highest dust concentration was found in e-waste workshops. CPs were highly accumulated in local plant and animal origin foods, most markedly in fish, vegetables, and rice. The main contribution to CP intake under a median exposure scenario was from the diet, and vegetables, fish, and rice were the three largest dietary intake sources. Only the combined dust and food exposure from the present study has approached or even exceeded the highest tolerable daily intake (TDI) set up by the International Program on Chemical Safety (IPCS). However, due to lack of official threshold values for CP exposure on adverse human health, there are limitations on accurate risk assessment. Considering the presence of other exposure pathways, CPs' endocrine disrupter properties, as well as the multicomponent chemical "cocktails" effects, potential high risks from CP exposure may be posed to e-waste workers and local residents.

Bioaccumulation of organic pollutants in Indo-Pacific humpback dolphin: A review on current knowledge and future prospects

Indo-Pacific humpback dolphin (Sousa chinensis) are chronically exposed to organic pollutants since they inhabit shallow coastal waters that are often impacted by anthropogenic activities. The aim of this review was to evaluate existing knowledge on the occurrence of organic pollutants in Indo-Pacific humpback dolphins, identify knowledge gaps, and offer recommendations for future research directions. We discussed the trends in the bioaccumulation of organic pollutants in Indo-Pacific humpback dolphins focusing on sources, physicochemical properties, and usage patterns. Furthermore, we examined factors that influence bioaccumulation such as gender, age, dietary intake and tissue-specific distribution. Studies on bioaccumulation in Indo-Pacific humpback dolphin remain scarce, despite high concentrations above 13,000 ng/g lw we previously detected for PFOS, ∑PBDE and chlorinated paraffins. The maximum concentration of organochlorines detected was 157,000 ng/g wt. Furthermore, variations in bioaccumulation were shown to be caused by factors such as usage patterns and physicochemical properties of the pollutant. However, restrictions in sampling inhibit investigations on exposure pathway and toxicity of organic pollutants in Indo-Pacific humpback dolphin. We proposed the use of biopsy sampling, predictive bioaccumulation and toxicity modeling, and monitoring other emerging contaminants such as microplastics and pharmaceuticals for future health risk assessment on this critically endangered marine mammal species.

Short-, Medium-, and Long-Chain Chlorinated Paraffins in Wildlife from Paddy Fields in the Yangtze River Delta

Short-chain chlorinated paraffins (SCCPs) were added to Annex A of the Stockholm Convention on Persistent Organic Pollutants in April, 2017. As a consequence of this regulation, increasing production and usage of alternatives, such as medium- and long-chain chlorinated paraffins (MCCPs and LCCPs, respectively), is expected. Little is known about the environmental fate and behavior of MCCPs and LCCPs. In the present study, SCCPs, MCCPs, and LCCPs were analyzed in nine wildlife species from paddy fields in the Yangtze River Delta, China, using atmospheric pressure chemical ionization-quadrupole time-of-flight mass spectrometry. SCCPs, MCCPs, and LCCPs were detected in all samples at concentrations ranging from <91-43 000, 96-33 000, and 14-10 000 ng/g lipid, respectively. Most species contained primarily MCCPs (on average 44%), with the exception of collared scops owl and common cuckoo, in which SCCPs (43%) accumulated to a significantly (i.e., p < 0.05) greater extent than MCCPs (40%). Cl₆ groups were dominant in most species except for yellow weasel and short-tailed mamushi, which contained primarily Cl₇ groups. Principal components analysis, together with CP concentrations and carbon stable isotope analysis showed that habitat and feeding habits were key factors driving CP accumulation and congener group patterns in wildlife. This is the first report of LCCP exposure in wildlife and highlights the need for data on risks associated with CP usage.