Polychlorinated Naphthalenes Concentrations Research Articles

Polychlorinated naphthalene concentrations in human serum caused by unintentional production and emissions, and potential effects of polychlorinated naphthalenes on thyroid hormones

The concentrations of 75 polychlorinated naphthalene (PCN) congeners in 95 human serum samples from the Fengjiang electronic waste dismantling area and Huangyan District in Taizhou City (Zhejiang Province, China) were determined. Thyroid hormone (FT3, FT4, TSH, and TRH) concentrations in the samples were also determined. The total PCN concentrations in the samples from Fengjiang and Huangyan were 1.29 × 104–4.28 × 105 and 8.29 × 102–6.45 × 105 pg/g lipid, respectively. The less-chlorinated (Cl1–3) PCN concentrations were relatively high in all of the samples, and the concentrations in the samples from the two areas were not significantly different. The sums of the combustion-related PCN congener concentrations were significantly higher in the samples from Fengjiang than in the samples from Huangyan, and the sums of the more-chlorinated (Cl4–8) PCNs were slightly higher in the samples from Fengjiang than in the samples from Huangyan. The relationship between the PCN concentration and age indicated that electronic waste controls have decreased human exposure to PCNs but that attention should still be paid to exposure to less-chlorinated PCNs. The main PCN congeners that contributed to the toxic equivalent concentrations were markedly different for the samples from Fengjiang and Huangyan. CN-66/67 was dominant for the Fengjiang samples and CN-10 was dominant for the Huangyan samples. Attention should be paid to the risks posed by less-chlorinated PCNs to human health. CN-1, CN-2, and CN-20 concentrations are related to human thyroid hormone levels, and the relationships between less-chlorinated PCN concentrations and thyroid hormone concentrations should be further studied.

Partitioning and potential sources of polychlorinated naphthalenes in water-sediment system from the Yangtze River Delta, China

Spatial trends, partitioning behavior, and potential sources of polychlorinated naphthalenes (PCNs) in water-sediment system from the Yangtze River Delta (YRD) were investigated in this study. The total concentrations of 75 PCNs in water and sediment samples were 0.022–0.310 ng/L and 0.01–1.59 ng/g dry weight, respectively. The homolog patterns in the sediment and water samples were somewhat different. Di-to tetra-CNs made larger contributions in the sediment, while the mono-to tri-CNs were dominant homologs in the water. Overall, the low-chlorinated naphthalenes (mono-to tetra-CNs) were found to be the dominant homologs in the YRD water and sediment samples, and the homolog group contributions to the total PCNs concentrations decreased as the number of chlorine atoms increased. CN-5/7 and CN-24/14 were found at high concentrations in both the water and sediment. Partitioning and transfer of PCNs between water and sediment were assessed by calculating the partition coefficients and fugacity fractions. The partition coefficients showed that PCNs were not in equilibrium status in the water–sediment system, and hydrophobicity played an important role in PCNs partitioning. The fugacity fractions indicated that mono- to tri-CNs had stronger tendencies to escape from the sediment into the water, while the high-chlorinated naphthalenes close to equilibrium. Principal component analysis and correlation analysis indicated that industrial thermal processes and the use and disposal of products containing PCNs industrial products are sources of PCNs in the YRD water-sediment system.

Distributions of Polychlorinated Naphthalenes in Sediments of the Yangtze River, China.

The pollution status of polychlorinated naphthalenes (PCNs) in the sediment of the Yangtze River Basin, Asia’s largest river basin, was estimated. The total concentrations of PCNs (mono- to octa-CNs) ranged from 0.103 to 1.631 ng/g. Mono-, di-, and tri-PCNs—consisting of CN-1, CN-5/7, and CN-24/14, respectively, as the main congeners—were the dominant homolog groups. Combustion indicators and principal component analysis showed that the emissions from halowax mixtures were the main contributor to PCNs in sediment, among most of the sampling sites. The mean total toxic equivalent (TEQ) was calculated to be 0.045 ± 0.077 pg TEQ/g, which indicates that the PCNs in sediments were of low toxicity to aquatic organisms. This work will expand the database on the distribution and characteristics of PCNs in the river sediment of China.

Using Polychlorinated Naphthalene Concentrations in the Soil from a Southeast China E-Waste Recycling Area in a Novel Screening-Level Multipathway Human Cancer Risk Assessment.

Polychlorinated naphthalene (PCN) concentrations in the soil at an e-waste recycling area in Guiyu, China, were measured and the associated human cancer risk due to e-waste-related exposures was investigated. We quantified PCNs in the agricultural soil and used these concentrations with predictive equations to calculate theoretical concentrations in outdoor air. We then calculated theoretical concentrations in indoor air using an attenuation factor and in the local diet using previously published models for contaminant uptake in plants and fruits. Potential human cancer risks of PCNs were assessed for multiple exposure pathways, including soil ingestion, inhalation, dermal contact, and dietary ingestion. Our calculations indicated that local residents had a high cancer risk from exposure to PCNs and that the diet was the primary pathway of PCN exposure, followed by dermal contact as the secondary pathway. We next repeated the risk assessment using concentrations for other carcinogenic contaminants reported in the literature at the same site. We found that polychlorinated dibenzodioxins and dibenzofurans (PCDD/Fs) and PCNs caused the highest potential cancer risks to the residents, followed by polychlorinated biphenyls (PCBs). The relative importance of different exposure pathways depended on the physicochemical properties of specific chemicals.

Factors affecting multiple persistent organic pollutant concentrations in the air above Japan: A panel data analysis

Numerous reports have elucidated different statistical approaches to identify temporal trends in atmospheric persistent organic pollutant (POP) time series. However, the correlation of industrial activity with concentrations of atmospheric POPs in Japan has not yet been determined. Herein, a panel data analysis of a 16-year monitoring program (2003–2018) conducted by the Japanese Ministry of Environment was used to investigate a range of POPs in the atmosphere above Japan. This work focuses on polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB), and pentachlorobenzene (PeCBz) collected each year at 53 sites across Japan. The panel analysis revealed that PCB, PCN, and PBDE concentrations were influenced by a combination of factors including year, industrial activity (municipal and industrial waste incinerators, cement kilns, steel industry, and secondary zinc production), population, temperature, and atmospheric boundary layer. However, HCB and PeCBz were not significantly affected by these factors. Industrial activity showed stronger positive correlations with all homologues of PCBs, PCNs, and PBDEs as compared to those demonstrated by population. Significant decreasing trends were identified for the atmospheric ∑PBDEs (half-life t1/2 = 9.4 years), ∑PCNs (t1/2 = 8.9 years), and ∑PCBs (t1/2 = 13.5 years) concentrations, while HCB and PeCBz showed slightly increasing or steady levels. As a statistical tool, panel data analysis can contribute to the assessment of spatial and temporal trends of POPs at a national scale, while elucidating different behavioral responses to numerous environmental variables.

Polychlorinated Naphthalenes across the Great Lakes: Lake Trout and Walleye Concentrations, Trends, and TEQ Assessment-2004-2018.

Polychlorinated naphthalenes (PCNs) were measured in lake trout and walleye over the period 2004-2018, utilizing isotope dilution techniques with high-resolution gas chromatography/high-resolution mass spectrometry to assess concentrations and toxic equivalence (TEQ). An age-trend model was applied to mitigate the effect of a changing lake trout age structure. Most Great Lakes Fish Monitoring and Surveillance Program sampling sites demonstrated significant half-life and percent decreases for lake trout total PCNs and total TEQ over the 2004-2018 period, the exceptions being Lake Erie lake trout and walleye which illustrated increasing concentrations. Great Lakes total PCN concentrations ranged between 5701 and 100 pg/g ww, whereas total PCN TEQ concentrations ranged between 8.89 and 0.13 pg-TEQ/g ww. Based on the average number of chlorines per naphthalene, we determined that the overall lake trout and walleye PCN congener distribution has significantly shifted to a lower-chlorinated composition in the Great Lakes (5.33 to 4.48 Cl/CN) and has resulted in a substantial 59.1% reduction of the overall total PCN TEQ burden. A prominent PCN concentration trend breakpoint was observed in Lake Ontario lake trout over the 2012-2016 period likely associated with hazardous waste cleanups, channel dredging, and spoils disposal in the Detroit River and western-basin of Lake Erie.

Preliminary investigation on the occurrence of PCNS in ambient air of Ho Chi Minh City, Vietnam

Polychlorinated Naphthalenes (PCNs) were included as the new Persistent Organic Pollutants (POPs) under the Stockholm Convention and forced to terminate the production and use in any application due to their toxicity, bioaccumulation, persistence and adverse effects to the environment and humans. However, no study on the occurrence of PCNs in the environment in Vietnam has been conducted so far. Therefore, it is necessary to carry out an investigation on the presence of these pollutants in Vietnam. In this study, ambient air samples were collected at 5 different sites in the urban area of Ho Chi Minh City to investigate the occurrence of PCNs. Fourteen air samples (both gas and particulate phases) were collected using large volume samplers. Totally, 75 PCNs in gas and particulate phases were analyzed using HRGC/HRMS following isotope dilution method. Total concentrations of PCNs measured at five sites ranged from 60.4 pg/m3 to 264 pg/m3 (mean 134 pg/m3), which was significantly higher than those reported by similar studies around the world. The result also indicated that gaseous PCNs predominated in total atmospheric concentration (99.7 – 100%); while particulate PCNs only contributed minor faction. Based on the characteristics of the analyzed PCNs, the samples were divided into 2 groups, group 1 is characterized by TetraCN as the main contributor, while group 2 is dominated by low-chlorine homologues (1 to 3 chlorines). The results also revealed that the PCNs in the air samples in HCMC were mainly derived from evaporation of PCNs from products containing PCNs and combustion-related sources. However, evaporation of PCNs from products containing PCNs seemed to be the dominant source.

Atmospheric pressure ionization for gas chromatography-high resolution mass spectrometry determination of polychlorinated naphthalenes in marine sediments

In this work, the performance of the atmospheric pressure chemical ionization (APCI) and photoionization (APPI) was assessed to develop a new selective and sensitive gas chromatography-high resolution mass spectrometry (GC-HRMS) method for the determination of polychlorinated naphthalenes (PCNs) in sediment samples. The capability of both APCI and APPI sources for the ionization of PCNs was investigated, showing the formation of the molecular ion and the [M‒Cl+O]‒ ion in positive and negative ion modes, respectively. Positive ion APCI provided high responses using high corona ion current, while the use of high vapour pressure dopant-solvents, such as toluene in positive mode and diethyl ether in the negative mode, was required to achieve high ionization efficiencies in APPI. The performance of the two API sources in the PCN determination by GC-HRMS were compared and the best results were achieved using the GC-APPI(+)-HRMS (Orbitrap) system. The GC-APPI(+)-HRMS (Orbitrap) method was applied to the characterization of Halowax mixtures and the analysis of marine sediments collected near to the coastal area of Barcelona (NE, Spain), demonstrating a great detection capability with low method limits of detection (0.2–1.6 pg g−1 dry weight), good precision (RSD <15%) and trueness (relative error <13%). Total PCN concentrations ranged from 0.35 to 5.0 ng g−1 dry weight and the presence of related compounds, such as polychlorinated biphenyls (PCBs), was also detected by combining positive and negative ion modes, providing complementary information to better monitor of all PCN congener groups. The results presented here show the feasibility of the GC-APPI-HRMS method for the suitable determination of PCNs.

Reduction of polychlorinated naphthalenes (PCNs) emission from municipal waste incinerators in Taiwan: Recommendation on control technology

Emission factor and removal efficacy of PCNs are evaluated via the flue gas sampling of two MWIs equipped with different air pollution control devices (APCDs) in Taiwan. MWI-A is equipped with ESP, wet scrubber (WS) and selective catalytic reduction (SCR), while cyclone (CY), semi-dry absorber (SDA), activated carbon injection (ACI) and baghouse (BH) are employed in MWI-B. The average concentrations of PCNs measured at stacks of MWI-A and MWI-B are 2.1 ng Nm−3 (0.218 pg TEQ Nm−3) and 23.2 ng Nm−3 (0.425 pg TEQ Nm−3), respectively. The emission factors of PCNs calculated from feeding rates of waste and stack sampling results range from 6.7 to 6.95 μg t−1 (0.790–1.45 ng TEQ t−1). PCNs are formed in ESP via chlorination, while SCR and SDA + ACI + BH are effective in removing PCNs with the overall efficacies of 97.6% and 94.3%, respectively. PCN removal efficiencies achieved with SCR and SDA + ACI + BH increase as chlorination level increases. Specifically, around 72% and 82% of Mono-CN are removed by SCR and SDA + ACI + BH, respectively. The removal efficacies of other homologues achieved with SCR are consistently high (96–100%). Dominances of Mono-to Tri-CNs in scrubbing liquid collected from WS and higher removal efficacies of these homologues achieved with WS + ESP compared with ESP alone indicate that WS can capture low chlorinated PCNs to some extent. The results suggest that CY + SDA + ACI + BH should be equipped in MWI for effective removal of PCNs, while ESP, WS and SCR should be utilized with precaution to eliminate PCNs formation and enhance the PCNs removal efficiency.

Polychlorinated Naphthalene Congener Profiles in Common Vegetation on the Tibetan Plateau as Biomonitors of Their Sources and Transportation.

Polychlorinated naphthalenes (PCNs) are globally transported, carcinogenic, persistent organic pollutants (POPs) that were recently added to the Stockholm Convention with 184 parties. The Tibetan Plateau plays an important role in the global transportation and distribution of POPs. Knowledge of PCN sources and transportation on the Tibetan Plateau is important for their control globally. In this study, we quantified the congener-specific concentrations of PCNs in lichen, moss, soil, and air samples collected on the Tibetan plateau and found that common lichens were effective biomonitors for predicting atmospheric PCNs in this area. The physiochemical properties of the PCNs, the temperatures, and the lichen lipid contents were identified as important factors influencing PCN partitioning between lichens and air. Lichen-air partitioning equations were established and used to predict PCN concentrations in air in Southeast Tibet. The lichens could be used as PCN biomonitors to clarify their spatial variations, sources, and transportation in the southeast of the plateau. PCN concentrations in lichens increased with altitude, suggesting that high-mountain cold-trapping influenced the PCN transportation behavior. Principal component analysis and linear discriminant analysis showed that the major source of PCNs in this region was long-range atmospheric transportation via the Indian monsoon in summer and wind from Southwest Asia in winter. This study provides a novel method using PCN congener profiles as fingerprints and statistical models for studying the geochemical effects of conditions in high-mountain regions on the contamination behaviors of 75 congeners of the notorious PCNs.

Exposure of polychlorinated naphthalenes (PCNs) to Pakistani populations via non-dietary sources from neglected e-waste hubs: A problem of high health concern

To date limited information’s are available concerning unintentional productions, screening, profiling, and health risks of polychlorinated naphthalenes (PCNs) in ambient environment and occupational environment. Literature reveals that dust is a neglected environmental matrix never measured for PCNs. To our knowledge, this is the first study to investigate the concentrations and health risks of PCNs in indoor dust, air, and blood of major e-waste recycling hubs in Pakistan. Indoor air (n = 125), dust (n = 250), and serum (n = 250) samples were collected from five major e-waste hubs and their vicinity to measure 39 PCN congeners using GC-ECNI-MS. ∑39PCN concentrations in indoor air, dust, and serum (worker > resident > children) samples ranged from 7.0 to 9583 pg/m3, from 0.25 to 697 ng/g, and from 0.15 to 401 pg/g lipid weight, respectively. Predominant PCN congeners in indoor air and dust were tri- and tetra-CNs, while tetra- and penta-CNs were dominant in human serum samples. The higher PCNs contribution was recorded at the recycling units, while the lower was observed at the shops of the major e-waste hubs. Higher contribution of combustion origin CNs in air, dust and human samples showed combustion sources at the major e-waste hubs, while Halowax and Aroclor based technical mixture showed minor contribution in these samples. Mean toxic equivalent (TEQ) concentrations of PCNs were 2.79E+00 pg-TEQ/m3, 1.60E−02 ng-TEQ/g, 8.11E−01 pg-TEQ/g, 7.14E−01 pg-TEQ/g, and 6.37E−01 pg-TEQ/g for indoor air, dust, and serum samples from workers, residents, and children, respectively. In our study, CNs- 66/67 and −73 in indoor air, dust, and human serum were the great contributors to total TEQ concentrations of PCNs. This first base line data directs government and agencies to implement rules, regulation to avoid negative health outcomes and suggests further awareness in regard of provision of proper knowledge to the target population.

Polychlorinated naphthalenes, polychlorinated dibenzo-p-dioxins and dibenzofurans, and polychlorinated biphenyls in soils in an industrial park in Northwestern China: Levels, source apportionment, and potential human health risks

Seventeen soil samples collected in an industrial park located in Ningxia Province, Northwestern China were analyzed for polychlorinated naphthalenes (PCNs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polychlorinated biphenyls (PCBs). The PCN, PCDD/F, and PCB concentration ranges were 183–3340, 7.00–215, and 45.1–355 pg/g, respectively. Positive matrix factorization showed that secondary ferrous metal smelters and cement kilns contributed more than 70% of the total PCN concentration. Historical use of Halowax 1051 also affected the PCN concentrations in soil. Principal component analysis indicated that the PCDD/F concentrations in soil in the study area were mainly affected by thermal processes in secondary ferrous metal smelters. CB-209 was an important contributor to total PCBs in the study area, and likely originated from the phthalocyanine-type pigments used in a local recycled paper mill. Samples S10, S1, S17, and S6 had high ∑TEQ (PCDD/Fs + PCNs + PCBs) concentrations, and the carcinogenic risks of PCDD/Fs, PCNs, and PCBs for workers from these samples were 0.487 × 10−6, 0.234 × 10−6, 0.230 × 10−6, and 0.210 × 10−6, respectively. According to our results, the health risks of PCDD/Fs, PCNs, and PCBs for workers in this area should be given more attention.

Polychlorinated naphthalene (PCN) emissions and characteristics during different secondary copper smelting stages

The amounts and characteristics of polychlorinated naphthalenes (PCNs) emitted by a secondary copper smelter were investigated. Differences in the amounts and characteristics of PCNs emitted during different smelting stages were investigated, and the main stage during which PCNs were emitted was identified. PCN concentrations in stack gases emitted during secondary copper smelting were 477.0–762.5 ng/m3 (4.4–8.3 pg toxic equivalents/m3). The contributions of the different stages to total PCN emissions decreased in the order feeding–fusion stage (65% of total PCN emissions) > oxidation stage (27%) > deoxidation stage (8%). The main contributor to PCN emissions during secondary copper smelting was the feeding–fusion stage. PCN concentrations and profiles in stack gas, fly ash, and deposit ash collected during different smelting stages were determined. PCNs in stack gases were mainly less-chlorinated homologs, and fly ash and deposit ash were dominated by highly-chlorinated homologs. These results will help improve strategies for decreasing and eliminating PCN emissions during secondary copper production.

Temporal trends in polychlorinated naphthalene emissions from sintering plants in China between 2005 and 2015

The Chinese Government has established stringent policies since 2005 to control SO2, particulate matter, and NOx emissions from sintering plants with the aim of tackling severe air pollution in China. Notably, sintering is also important sources of polychlorinated naphthalenes (PCNs), but it is not clear whether the air pollution control policies have led to decreased PCN emissions. In this study, the PCN concentrations in 144 stack gas, 87 discarded fly ash, and 24 desulfurization by-product samples from 24 Chinese sintering plants were determined. This study revealed that desulfurization processes decreased PCN emissions by 47.2%–72.2%. However, these PCNs were not completely eliminated, and transformed to desulfurization by-product. PCN emission in such previously ignored solid residues, including of desulfurization by-product and fine particles, produced in the process of cutting down air pollutants emissions from Chinese sintering plants between 2005 and 2015 was found contained 324 kg, and these residues therefore need to be managed better than currently. Furthermore, PCN concentrations were higher from produced in old plants than produced in new plants, so it is necessary to increase the rate at which out-of-date sintering plants are eliminated. Phasing out old sintering processes decreased total PCN emissions in China by 1549 kg between 2005 and 2015.

Polychlorinated naphthalenes in human serum samples from an industrial city in Eastern China: Levels, sources, and sex differences

Polychlorinated naphthalenes (PCNs) in the environment in China have been studied extensively. However, there have been no reports on PCNs in human serum samples from China. In this context, we collected 480 serum samples from an industrial city in Eastern China. The concentration range for the sum of the mono-to octa-CNs was 14300–50700 pg/g lipid. The most predominant congener was CN-5/7, which accounted for 21.6%–51.1% of the total PCN concentration. Further analysis indicated that residues of PCN industrial technical products in the local environment appear to be the main source of CN-5/7 in the serum samples. On the other hand, the sum of the tetra-to octa-CNs concentration was obviously higher in males (1390 ± 929 pg/g lipid) than in females (267 ± 25 pg/g lipid). Moreover, the concentrations of combustion-related PCNs in the male 20–24, 25–29 and 30–34 years groups were obviously higher than those in the female samples. Therefore, industrial thermal processes are important sources of PCNs in male serum in addition to PCN products. The toxic equivalent (TEQ) concentrations of PCNs in the pooled serum samples ranged from 0.12 to 0.40 pg/g lipid. CN-10 and CN-66/67 were the dominant TEQ congeners in male serum, and CN-10, CN-1, and CN-2 were the main TEQ congeners in female serum.

Thermochemical formation of multiple unintentional persistent organic pollutants on metallurgical fly ash and their correlations

Metallurgical processes are currently the predominant anthropogenic sources of multiple unintentional persistent organic pollutants (POPs), including polycyclic aromatic hydrocarbons (PAHs), chlorinated and brominated PAHs (Cl-PAHs and Br-PAHs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), and polybrominated diphenyl ether (PBDEs). Understanding the formation of multiple POPs is important for source control. These POPs could be formed through fly ash-mediated heterogeneous reactions. In this study, we comprehensively investigated the thermochemical (150–450 °C) formation of these POPs on fly ash samples collected from a secondary aluminum smelter, secondary lead smelter, and iron ore sintering plant. The maximum concentrations of PCNs and PCBs were 154.5 and 181.3 times those in the original fly ash, respectively. Formation variations of PAHs, Cl-PAHs and Br-PAHs, and PBDEs were different from that of PCBs and PCNs. The PAHs concentration, which was the highest among the POPs in the original fly ash, decreased sharply by 95% at 150 °C. The ∑19Cl-PAHs and ∑19Br-PAHs increased marginally at 250 °C before decreasing slightly at 350 °C. The PBDE concentrations decreased under 250 °C and increased at 350 °C. PCNs, PCBs, and PCDD/Fs showed good correlations, all of which had a negative relationship with the PAHs. There were no significant correlations between PAHs and Cl/Br-PAHs. Low brominated congeners could be formed by destruction of higher brominated congeners because of thermal instability of the PBDEs.

Polychlorinated naphthalene emissions to the atmosphere from typical secondary aluminum smelting plants in southwestern China: concentrations, characterization, and risk evaluation.

Secondary aluminum smelting industry, as an important source of polychlorinated naphthalene (PCN) in environment, has been concerned in recent years. To figure out the emission characteristics of PCNs and the potential influence on surrounding environment, two typical secondary aluminum smelting plants were selected and PCNs were determined in flue gas, fly ash, aluminum slag, soil, and air samples collected at and around the plants by GC-MS coupled with DFS. PCN emission factors from the flue gas of the two plants (mean 0.006ng toxic equivalents/t) were found obviously decreased compared with similar smelting process detected in 2010. The stage of feeding material was still the major PCNs discharge period during the whole smelting process. The total PCN concentrations in air were found to be ranked as following: workshops (290-1917pg/m3), the area near the workshops (62.3-697pg/m3), and the surrounding areas (29.9-164pg/m3, mean 64.5pg/m3). Similar high concentrations of PCNs were found in soil from by the workshop door (983ng/g dry weight). Soil-air exchange calculations indicated that mono-CN to tetra-CN would volatilize but hepta-CN and octa-CN would be deposited to the soil. Exposure of plant workers and local inhabitants to PCNs through inhalation was found to be acceptable but higher (especially for workers in the workshops) than living areas. The workshop and the nearby area are potential PCNs polluted areas and should be paid attention during the practical operation.

The occurrence and distribution of polychlorinated naphthalenes (PCNs), focusing on tissue-specific bioaccumulation in crucian carp in South Korea

The occurrence and distribution of 41 congeners of polychlorinated naphthalenes (PCNs) were investigated in major tissues of crucian carp (muscle, gonad, liver, and blood) and in river sediment to assess the bioaccumulation potential of PCNs. The total PCN concentrations in sediment ranged from 4.37 to 19.5 pg/g dry weight (dw), mainly comprising CN-13, CN-33/34/37, and CN-38/40. Among fish tissues, higher PCN concentrations were observed in the gonads (29.6 ± 10.3 pg/g wet weight, ww) and liver (25.7 ± 4.35 pg/g ww) of crucian carp than in the muscle (2.17 ± 0.68 pg/g ww). CN-28/43, CN-33/34/37, CN-42, CN-52/60, CN-53/55, and CN-66/67 congeners were detected most frequently and had the highest concentration among all crucian carp tissues. We investigated the association between the PCN concentration in each tissue (muscle, liver, and gonad) and the size of the fish (total length and weight) and found positive correlations between the PCN concentration in the gonads and the total length and weight (p < 0.05, Spearman correlation).

Small-scale waste incinerators in rural China: Potential risks of dioxin and polychlorinated naphthalene emissions

Abstract Rapid development has led to a tremendous increase in the volume of solid waste produced in rural China. The annual amount of solid waste produced from Chinese rural areas is approximately 110 million tons. Many small-scale solid waste incinerators have been built in Chinese rural areas. It was speculated that the emissions and potential risks of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs, commonly known as dioxins) and polychlorinated naphthalenes (PCNs) from these incinerators could be serious. A preliminary case investigation on PCDD/F and PCN emissions from a small-scale waste incinerator was performed. The stack gas samples were collected using auto isokinetic sampling techniques and PCDD/F and PCN congeners were identified and quantified by high resolution gas chromatography combined with high resolution mass spectrometry. Concentrations and toxic equivalents of PCDD/Fs emitted from the small-scale waste incinerator were 153 ng m−3 and 5.6 ng TEQ m−3, respectively, which was much higher than the regulatory level for municipal solid waste incinerators permitted in China and the European Union Directive. PCNs have similar toxicological effects with PCDD/Fs, and the relative potency factors (RPFs) of some PCN congeners (dioxin-like PCNs) to 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD) were previously proposed to evaluate the dioxin-like toxicity of PCNs. The mass concentrations of PCNs and dioxin-like PCNs from the small-scale solid incinerator were 2927 ng m−3 and 1137 ng m−3, much higher than that of dioxins. However, much less attention has been paid to the small-scale incinerators compared with municipal solid waste incinerators. Here, we proposed that there should be a growing need to focus on the emissions and potential risks of dioxins and dioxin-like pollutants from these small-scale waste incinerators in rural China.

Preliminary investigation of polychlorinated dibenzo-p-dioxin and dibenzofuran, polychlorinated naphthalene, and dioxin-like polychlorinated biphenyl concentrations in ambient air in an industrial park at the northeastern edge of the Tibet–Qinghai Plateau, China

Ambient air samples collected in an industrial park at the northeastern edge of the Tibet–Qinghai Plateau (China) were analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated naphthalenes (PCNs), and dioxin-like (dl) polychlorinated biphenyls (PCBs). The PCDD/F, PCN, and dl-PCB concentrations were 1.18–2.18, 21.9–75.1, and 0.49–0.90 pg/m3, respectively. The concentrations of these compounds were clearly higher than that observed at a remote site and were comparable with those found in ambient air in industrial areas in other locations. A principal component analysis indicated that emissions from local industrial sites (a secondary aluminum smelter, a cement kiln, and a lead–zinc smelter) at which thermal processes are performed were the sources of PCDD/Fs to the air. The combustion-related PCN congener profiles suggested that industrial thermal processes strongly affect PCN concentrations in ambient air at the industrial park. The results clearly indicated that the industrial park is a source of environmental PCDD/Fs and PCNs at the northeastern edge of the Tibet–Qinghai Plateau.