Spatial distribution, partitioning, and ecological risk of short chain chlorinated paraffins in seawater and sediment from East China Sea

Human exposure to polychlorinated alkanes (C8-36) in soil and dust from Nigerian e-waste sites: Occurrence, homologue pattern and health risk assessment

Electronic waste (e-waste) dismantling and dumpsite processes are recognized as significant sources of chlorinated paraffin (CP) exposure. This study aims to investigate the environmental occurrence and distribution of polychlorinated alkanes (PCAs-C8-36), specifically in soil and outdoor dust samples collected from e-waste dumpsites and automobile dismantling and resale sites in Nigeria. The results revealed a widespread occurrence of PCAs across all sampled locations. For the PCAs homologue groups ∑PCAs-C10-13, ∑PCAs-C14-17, and ∑PCAs-C18-20, the median concentrations were 1150 ng/g dry weight (dw), 1180 ng/g dw, and 370 ng/g dw in the dust samples, and 2840 ng/g dw, 1820 ng/g dw, and 830 ng/g dw in the soil samples, respectively. Notably, the homologue distribution patterns of PCAs-C8-36 were similar in both dust and soil samples. However, PCAs-C10-13 was found to be higher in the soil samples, likely due to the wet and/or dry deposition effect of the aerosols, given these chemicals' volatile nature and ease of atmospheric dispersion. Pearson correlation analysis further revealed a co-occurrence of contaminants in the soil samples, supporting the hypothesis that soil acts as a sink for persistent organic pollutants (POPs). Additionally, lower molecular weight polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) showed reduced correlation with the PCAs. Health risk assessments indicated that working on e-waste sites could potentially pose a risk to the workers' health. This study highlights the urgent need for mitigating occupational exposure to PCAs, especially in informal e-waste processing environments where personal protective measures are often lacking.

Acute and chronic detrimental effects induced by short-chain chlorinated paraffins in the marine mysid Neomysis awatschensis

To determine the potentially detrimental impacts of short-chain chlorinated paraffins (SCCPs), we conducted assessments of acute effects on 96-h survival rate and biochemical markers, as well as chronic and multigenerational impacts on growth and reproduction over three generations in the marine mysid, Neomysis awatschensis. Dose-dependent increase of mortality was measured in both juvenile and adult mysids for 96 h. Exposure to the LC10 value (derived from the 96-h acute toxicity value) significantly reduced feeding activity in juveniles, accompanied by a significant elevation in oxidative stress and a reduction in acetylcholinesterase activity. When juvenile and adult mysids were exposed to 1/10 of the NOEC and NOEC values for four weeks, mortality significantly increased in juveniles. Furthermore, mysids subjected to constant exposure to 1/10 of the NOEC and NOEC values across three generations, F0-F2, displayed more pronounced growth retardation, an extended intermolt duration, and a reduced rate of reproduction. These results collectively indicate that even sublethal concentrations of SCCPs can have harmful effects on the health status of mysid populations when they are consistently exposed.

Investigating the research landscape of chlorinated paraffins over the past ten decades

Chlorinated paraffins (CPs) are classified as emerging persistent organic pollutants (POPs). Due to their associated environmental and health impacts, these groups of chemicals have been a subject of interest among researchers in the past decades. Here we used a scientometric approach to understand the research landscape of CPs using literature published in the Web of Science and Scopus database. RStudio and VOSviewer programs were employed as scientometric tools to analyze the publication trends in global CP-related research from 1916 to 2024. A total of 1,452 articles were published over this period, with a publication/author and co-author/publication ratio of 0.43 and 5.49, respectively. China ranked first in publication output (n = 556, 43.3%), and the highest total citations (n = 12,007), followed by Sweden (n = 90), Canada (n = 77), and Germany (n = 75). Publications from developing countries were limited, with most contributions from Africa originating from Egypt (n = 7), South Africa (n = 5), and Nigeria (n = 3), primarily through international collaborations. The average annual growth rate of 4.3% suggests a significant future article output. This scientometric analysis allowed us to infer global trends in CPs, identify tendencies and gaps, and contribute to future research. Despite having similar toxicity to short-chain chlorinated paraffin (SCCP), long-chain chlorinated paraffin (LCCP) has received less attention. Therefore, future research should prioritize studying LCCP bioaccumulation and toxicity in diverse food webs, focusing on aquatic species vulnerable to CPs and effective toxicological models. Additionally, collaborative research with developing countries should be encouraged to enhance meeting the Stockholm Convention's demand.

Acute and multigenerational effects of short-chain chlorinated paraffins on the harpacticoid copepod Tigriopus japonicus

Although the measurement of short-chain chlorinated paraffins (SCCPs) in aquatic ecosystems has increased, limited information is available on their toxic effects on aquatic animals. To evaluate the harmful effects of SCCPs, we assessed their acute impact on 24-h survival and biochemical parameters, as well as their chronic effects on growth and reproduction over three generations in the harpacticoid copepod Tigriopus japonicus. Dose-dependent increases in mortality were observed, with an LC50 value of 74.6 μg L-1 for 24 h. Acute exposure to the LC10 value for 24 h significantly reduced feeding behavior, accompanied by a notable decrease in acetylcholinesterase enzymatic activity. Simultaneously, the intracellular levels of reactive oxygen species increased, along with elevated malondialdehyde contents. Glutathione level was increased by the LC10 value of SCCPs with the induction of enzymatic activities of antioxidant defense components, including glutathione S-transferase, catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase. When T. japonicus was continuously exposed to 1/10 of the NOEC and NOEC values for 12 days across three generations (F0-F2), growth retardation was observed in the F2 generation, with delay in the developmental periods from nauplius to adult. Although the total number of nauplii per brood was not significantly altered across generations, a significant delay in the onset of reproduction was observed in the F2 generation. Our findings suggest that even sublethal concentrations of SCCPs can negatively affect the health of copepod populations with consistent exposure.

Spatial distribution and air-soil exchange of short and medium chain chlorinated paraffins in Lahore, Pakistan

This study provides the first systematic data on the distribution of short- (SCCPs) and medium chlorinated paraffins (MCCPs) in the atmosphere and surface soils of Lahore, Pakistan. The spatial distribution of SCCPs and MCCPs in air (n = 12) and soil (n = 15) was investigated from industrial, residential, commercial, conventional e-waste burning and background areas of Lahore. The concentrations ranged from below the limit of detection ( Collapse

Key Words

• Exchange flux
• Fugacity fraction
• Land-use
• Risk assessment
• TOC

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MESH Headings

• Pakistan
• Environmental Monitoring
• Paraffin/analysis
• Soil Pollutants/analysis
• Air Pollutants/analysis
• Hydrocarbons, Chlorinated/analysis
• Soil/chemistry

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Grants Collapse

Affiliation(s)

Areej Tahir College of Earth and Environmental Sciences, University of the Punjab, Lahore 54590, Pakistan.
Naeem Akhtar Abbasi College of Earth and Environmental Sciences, University of the Punjab, Lahore 54590, Pakistan.
Chang He Queensland Alliance for Environmental Health Science, The University of Queensland, Brisbane 4102, Australia; Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, PR China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
Sajid Rashid Ahmad College of Earth and Environmental Sciences, University of the Punjab, Lahore 54590, Pakistan

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Spatial distribution and ecological risk assessment of short and medium chain chlorinated paraffins in water and sediments of river Ravi, Pakistan

Short (SCCPs) and medium (MCCPs) chain chlorinated paraffins being the emerging organic pollutants have raised serious concerns due to their widespread use and related human health risks. However, their occurrence in aquatic bodies like rivers and associated damage to ecological integrity is yet unknown in some regions of the world. The current study is the first ever assessment of SCCPs and MCCPs in sediment and water of river Ravi, Pakistan. Spatial occurrence and associated ecological risks were investigated from sediments (n = 16) and composite water samples (n = 8) collected at eight locations along the stretch of river Ravi. The concentrations of SCCPs and MCCPs varied from below limit of detection ( Collapse

Key Words

• Aquatic body
• Partitioning coefficient
• Risk assessment
• Source identification
• Total organic carbon

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MESH Headings

• Humans
• Animals
• Chlorine
• Hydrocarbons, Chlorinated/analysis
• Paraffin/analysis
• Rivers
• Pakistan
• Environmental Monitoring
• Risk Assessment
• Carbon
• China

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Grants Collapse

Affiliation(s)

Areej Tahir College of Earth and Environmental Sciences, University of the Punjab, Lahore 54590, Pakistan
Naeem Akhtar Abbasi College of Earth and Environmental Sciences, University of the Punjab, Lahore 54590, Pakistan.
Chang He Queensland Alliance for Environmental Health Science, The University of Queensland, Brisbane 4102, Australia; Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, PR China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
Sajid Rashid Ahmad College of Earth and Environmental Sciences, University of the Punjab, Lahore 54590, Pakistan
Mujtaba Baqar Sustainable Development Study Centre, Government College University, Lahore 54000, Pakistan
Abdul Qadir College of Earth and Environmental Sciences, University of the Punjab, Lahore 54590, Pakistan

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Investigating the levels, spatial distribution, and trophic transfer patterns of short-chain chlorinated paraffins in the Southern Bohai Sea, China

The marine environment of the southern Bohai Sea is severely polluted by short-chain chlorinated paraffins (SCCPs). To improve understanding of how SCCPs occur and of how they migrate, are transformed, and transferred in this area, we collected seawater, sediment, and organism samples, and determined the SCCP contents using a new approach based on high-resolution mass spectrometry. The ΣSCCP concentrations in the seawater, sediment, and organism samples ranged from 57.5 to 1150.4 ng/L, 167.7-1105.9 ng/g (dry weight), and 11.4-583.0 ng/g (wet weight), respectively. Simulation of the spatial distribution of SCCPs using Kriging interpolation showed that SCCPs were markedly influenced by land-based pollution. Substantial quantities of SCCPs were transported to the marine environment via surface runoff from rivers that passed through areas of major SCCP production. Once discharged from such rivers into the Bohai Sea, these SCCPs were further dispersed under the influence of ocean currents. Furthermore, the logarithmic bioaccumulation factor that varied from 2.12 to 3.20 and the trophic magnification factor that reached 5.60 (r2 = 0.750, p < 0.01) suggest that organisms have the ability to accumulate and biomagnify SCCPs through the food chain, which could potentially present risks to both marine ecosystems and human health.

Chlorinated Paraffin Pollution in the Marine Environment

Chlorinated paraffins (CPs) are ubiquitous in the environment due to their large-scale usage, persistence, and long-range atmospheric transport. The oceans are a critical environment where CPs transformation occurs. However, the broad impacts of CPs on the marine environment remain unclear. This review describes the sources, occurrence and transport pathways, environmental processes, and ecological effects of CPs in the marine environment. CPs are distributed in the global marine environment by riverine input, ocean currents, and long-range atmospheric transport from industrial areas. Environmental processes, such as the deposition of particle-bound compounds, leaching of plastics, and microbial degradation of CPs, are the critical drivers for regulating CPs' fate in water columns or sediment. Bioaccumulation and trophic transfer of CPs in marine food webs may threaten marine ecosystem functions. To elucidate the biogeochemical processes and environmental impacts of CPs in marine environments, future work should clarify the burden and transformation process of CPs and reveal their ecological effects. The results would help readers clarify the current research status and future research directions of CPs in the marine environment and provide the scientific basis and theoretical foundations for the government to assess marine ecological risks of CPs and to make policies for pollution prevention and control.

Short- and Medium-Chain Chlorinated Paraffins in the Sediment of the East China Sea and Yellow Sea: Distribution, Composition, and Ecological Risks

Chlorinated paraffins (CPs), a class of complex mixtures synthesized from polychlorinated n-alkanes, are widely used as flame retardants, plasticizers, lubricant additives, coolants, metalworking cutting fluids, and sealants. This study investigated the spatial distribution, the potential pollution sources, and ecological risk of 24 short-chain CPs (SCCPs) and 24 medium-chain CPs (MCCPs) from 29 surface marine sediment samples from the East China Sea and Yellow Sea in September 2019. All of the 48 CPs were detected. The concentrations of SCCPs and MCCPs ranged from 0.703 to 13.4 ng/g dw and 0.0936 to 4.19 ng/g dw, respectively. C₁₀ congeners showed the highest abundancy. The median concentrations of the SCCPs and MCCPs declined gradually with carbon atoms and chlorine atoms, except for Cl₅ congeners. Spatial variations showed that all CP congeners in the East China Sea were larger than in the Yellow Sea and displayed a point-source-type distribution, which is consistent with the industrial park distribution. Although the potential ecological risk was at a relatively low level, bioaccumulation and trophic magnification could amplify the risk to marine organisms. Our results provide data support and theoretical assistance for SCCP and MCCP pollution control and sewage outlets in the East China Sea and Yellow Sea.

Source toxicity characteristics of short- and medium-chain chlorinated paraffin in multi-environmental media: Product source toxicity, molecular source toxicity and food chain migration control through silica methods

Short and medium-chain chlorinated paraffin (SCCP/MCCP) have been widely studied because of their extensive environmental hazards. In this study, product source toxicity, molecular source toxicity and food chain migration of SCCP and MCCP in multi-environmental media were comprehensively considered. The additive combination of SCCP and MCCP in the air, water and soil environment was adjusted, and PVC, PU and rubber products with the lowest source toxicity were screened. The source toxicity of SCCP and MCCP in the water environment was inhibited by design of the feed additive addition scheme (highest inhibition was 16.29 %), and the source toxicity of SCCP and MCCP in the soil environment was affected by different field management measures (highest inhibition was 38.22 %). A forage fertilizer addition plan, a cattle feed addition plan and a special population healthy complementary food regulation plan were developed to prevent the migration step by step and absorption of SCCP and MCCP in the terrestrial food chain. In addition, by means of density functional theory and analysis of key amino acid residues, the mechanism of toxicity difference between SCCP and MCCP was analyzed from the level of chemical interaction, and rationality of the inhibition scheme designed in this study was verified.

The potential health risks of short-chain chlorinated paraffin: A mini-review from a toxicological perspective

Short-chain chlorinated paraffins (SCCPs) are ubiquitously distributed in various environmental matrics due to their wide production and consumption globally in the past and ongoing production and use in some developing countries. SCCPs have been detected in various human samples including serum, milk, placenta, nail, and hair, and internal SCCP levels were found to be positively correlated with biomarkers of some diseases. While the environmental occurrence has been reported in a lot of studies, the toxicity and underlying molecular mechanisms of SCCPs remain largely unknown. The current tolerable daily intakes (TDIs) recommended by the world health organization/international programme on chemical safety (WHO/IPCS, 100 μg/kg bw/d) and the UK Committee on Toxicity (COT, 30 μg/kg bw/d) were obtained based on a no observed adverse effect level (NOAEL) of SCCP from the repeated-dose study (90 d exposure) in rodents performed nearly 40 years ago. Importantly, the health risks assessment of SCCPs in a variety of studies has shown that the estimated daily intakes (EDIs) may approach and even over the established TDI by UK COT. Furthermore, recent studies revealed that lower doses of SCCPs could also result in damage to multiple organs including the liver, kidney, and thyroid. Long-term effects of SCCPs at environmental-related doses are warranted.

Bioaccumulation of emerging persistent organic pollutants in the deep-sea cold seep ecosystems: Evidence from chlorinated paraffin

Persistent organic pollutants (POPs) are highly toxic and can accumulate in marine organisms, causing nonnegligible harm to the global marine ecosystem. The Cold seep is an essential marine ecosystem with the critical ecological function of maintaining the deep-sea carbon cycle and buffering global climate change. However, the environmental impact of emerging POPs in the deep-sea cold seep ecosystem is unknown. Here, we investigated the potential pollution of chlorinated paraffins (CPs) and their bioaccumulation in the cold seep ecosystem. High concentrations of CPs were detected in the cold seep ecosystems, where CPs bioaccumulated by the keystone species of deep-sea mussels can be released into the surface sediment and vertically migrate into the deeper sediment. Furthermore, more toxic CPs were accumulated from transforming other CPs in the cold seep ecosystem. Our study provides the first evidence that high concentrations of POPs are bioaccumulated by deep-sea mussels in the cold seep ecosystem, causing adverse ecological effects. The discovery of CPs bioaccumulation in the deep-sea cold seep ecosystem is a crucial mechanism affecting deep-sea carbon transport and cycling. This study has important guiding significance for revealing the deep-sea carbon cycle process, addressing global climate change, and making deep-sea ecological and environmental protection policies.

Characterization of chlorinated paraffin-degrading bacteria from marine estuarine sediments

This study explored chlorinated paraffin (CP)-degrading bacteria from the marine environment. Aequorivita, Denitromonas, Parvibaculum, Pseudomonas and Ignavibacterium were selected as the dominant genera after enrichment with chlorinated paraffin 52 (CP52) as the sole carbon source. Eight strains were identified as CP degraders, including Pseudomonas sp. NG6 and NF2, Erythrobacter sp. NG3, Castellaniella sp. NF6, Kordiimonas sp. NE3, Zunongwangia sp. NF12, Zunongwangia sp. NH1 and Chryseoglobus sp. NF13, and their degradation efficiencies ranged from 6.4% to 19.0%. In addition to Pseudomonas, the other six genera of bacteria were first reported to have the degradation ability of CPs. Bacterial categories, carbon-chain lengths and chlorination degrees were three crucial factors affecting the degradation efficiencies of CPs, with their influential ability of chlorinated degrees > bacterial categories > carbon-chain lengths. CP degradation can be performed by producing chlorinated alcohols, chlorinated olefins, dechlorinated alcohols and lower chlorinated CPs. This study will provide valuable information on CP biotransformation and targeted bacterial resources for studying the transformation processes of specific CPs in marine environments.