Predominant Congener Research Articles

Short- and medium-chain chlorinated paraffins in imported commercial dry cat and dog food in China: Concentrations, distributions and risk assessment

Chlorinated paraffins (CPs) are produced in large amounts and used worldwide. Dietary intake is the primary pathway for the exposure of pets to CPs, but limited information is available concerning the potential contamination of pet food by CPs. In the present study, the concentrations and congener group profiles of short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) were assessed in 35 imported commercial dry cat and dog foods collected in China, and the estimated daily intakes of SCCPs and MCCPs for cats and dogs through the consumption of such foods was calculated. The concentrations of SCCPs and MCCPs in the cat and dog foods were determined to be in the ranges of 108–45,300 ng/g (median: 1340 ng/g) and 3.8–52,700 ng/g (median: 11 ng/g), respectively. The predominant congener groups were C10Cl6 for SCCPs and C14Cl7-8 for MCCPs. The high levels of CPs found in certain pet foods suggest the potential for adverse health effects.

Dietary intake of legacy and emerging halogenated flame retardants using food market basket estimations in Nanjing, eastern China

Food products are inevitably contaminated by flame retardants throughout their lifecycle (i.e., during production, use, and disposal). In order to evaluate the dietary intake of legacy and emerging halogenated flame retardants (HFRs) in typical market food in China, we investigate the distribution and profile of 27 legacy polybrominated diphenyl ethers (PBDEs) and 16 emerging HFRs (EHFRs) in 9 food categories (meat, poultry, aquatic food, eggs, dairy products, cereals, vegetables, nuts and fruits, and sugar). A total of 105 food samples collected from three markets in Nanjing, eastern China were included for evaluation. The highest concentrations of PBDEs and EHFRs were found in aquatic foods (means of 0.834 ng/g wet weight (ww) and 0.348 ng/g ww, respectively), and the lowest concentrations were found in sugar (means of 0.020 ng/g ww for PBDEs and 0.014 ng/g ww for EHFRs). 2,2′,4-tribromodiphenyl ether (BDE-17), a legacy HFR, and hexabromobenzene (HBBz), an EHFR, were the predominant pollutants in the investigated food samples. Concentrations of HBBz and 2,3-dibromopropyl tribromophenyl ether (DPTE) were comparable to those of some PBDEs in certain food samples. The concentrations of the total EHFRs and total PBDEs found in animal-based food samples were significantly greater than those in plant-based food samples. Comparison of the estimated total dietary intake of HFRs and their corresponding non-cancer reference dose (United States Environmental Protection Agency) suggests a low overall health risk. To the best of our knowledge, the present study is the first to simultaneously determine 27 PBDEs and 16 EHFRs in representative foods from Chinese markets. BDE-17, HBBz, and DPTE were the predominant congeners among the 43 investigated HFRs and meat and aquatic foods were the primary sources of PBDEs and EHFRs to the total local dietary intake.

Biosynthesis of rhamnolipid by a Marinobacter species expands the paradigm of biosurfactant synthesis to a new genus of the marine microflora

BackgroundIn comparison to synthetically derived surfactants, biosurfactants produced from microbial culture are generally regarded by industry as being more sustainable and possess lower toxicity. One major class of biosurfactants are rhamnolipids primarily produced by Pseudomonas aeruginosa. Due to its pathogenicity rhamnolipid synthesis by this species is viewed as being commercially nonviable, as such there is a significant focus to identify alternative producers of rhamnolipids.ResultsTo achieve this, we phenotypically screened marine bacteria for biosurfactant production resulting in the identification of rhamnolipid biosynthesis in a species belonging to the Marinobacter genus. Preliminary screening showed the strain to reduce surface tension of cell-free supernatant to 31.0 mN m−1. A full-factorial design was carried out to assess the effects of pH and sea salt concentration for optimising biosurfactant production. When cultured in optimised media Marinobacter sp. MCTG107b produced 740 ± 28.3 mg L−1 of biosurfactant after 96 h of growth. Characterisation of this biosurfactant using both HPLC–MS and tandem MS showed it to be a mixture of different rhamnolipids, with di-rhamnolipid, Rha-Rha-C10-C10 being the most predominant congener. The strain exhibited no pathogenicity when tested using the Galleria mellonella infection model.ConclusionsThis study expands the paradigm of rhamnolipid biosynthesis to a new genus of bacterium from the marine environment. Rhamnolipids produced from Marinobacter have prospects for industrial application due to their potential to be synthesised from cheap, renewable feed stocks and significantly reduced pathogenicity compared to P. aeruginosa strains.

Occurrence of phthalate esters in the eastern coast of Thailand.

In this work, we investigated possible contamination of phthalates in seawater and sediment around the eastern coast of Thailand in the area of Chonburi, Rayong, and Chanthaburi. The main focus was on Pradu Bay east of Map Ta Phut, a well-known industrial and economic hub in Thailand. Among six selected phthalates of interest, diethyl phthalate (DEP), and benzyl butyl phthalate (BBP) were not found in any sample, while the concentrations of dimethyl phthalate (DMP) and dioctyl phthalate (DnOP) were very low or undetectable in most samples. In December 2014, the concentration of dibutyl phthalate (DBP) and diethylhexyl phthalate (DEHP) in Pradu Bay were 0.23-0.77 and 0.31-0.91 μg L-1 in seawater, respectively and non-detected (ND)-0.80 and ND-1.65 μg g-1 for 11 out of 20 sediment samples. DBP and DEHP were considered as the predominant congeners. A surface mapping system provided us an overview concentration distribution of DBP and DEHP congeners in seawater and sediment in Pradu Bay, showing a correlation between water and sediment and allowing a prediction of a possible point source. A comparison with the EU standard concentration limit in surface water confirmed that the phthalate concentration in this area was acceptable. However, continuous monitoring of phthalate congeners in the matrices should be done to detect a possible increase in their concentrations. To the best of our knowledge, this is the first study to determine concentrations of phthalates in seawater and sediment along the east coast of Thailand.

Retardantes de llama bromados en peces comestibles del embalse de las Tres Gargantas, China

Brominated flame retardants (BFRs) have attracted increasing attention in recent decades because of their persistence, distribution, bioaccumulation, and biotoxicity in the environment. In the present study, the levels and distribution of polybrominated diphenyl ethers (PBDEs) and polybrominated biphenyl (PBBs) in twenty-four samples of twelve fish species collected from the Three Gorges Reservoir (TGR) were analyzed. The results indicated that ∑PBDE concentrations in fish muscle ranged from 22.62 pg g -1 by wet weight (ww) (yellowcheek carp) to 217.75 pg g -1 ww (yellow catfish). BDE47 and BDE209 were the most predominant congeners, with their sum accounted for 23.62–68.16% of ∑PBDEs. ∑PBB concentrations ranged from 27.83 pg g -1 ww (silver carp) to 155.75 pg g -1 ww (topmouth culter); BB49 and BB209 were detected in all samples, with concentrations ranging from 4.62 to 47.10 pg g -1 ww and 1.29 to 80.95 pg g -1 ww, respectively. There are no significant correlations between the BFRs levels and fish length (or weight) in these samples. Compared to other areas, the level of BFRs in edible fishes from TGR was low.

Determination of Polybrominated Diphenyl Ethers (PBDEs) in Freshwater Fish Around a Deca-brominated Diphenyl Ether (deca-BDE) Production Facility by Gas Chromatography-Mass Spectrometry (GC-MS)

Polybrominated diphenyl ethers (PBDEs) were determined in 36 fish samples near a deca- brominated diphenyl ether (deca-BDE) production facility in Weifang City, Shandong Province, China. The concentrations of PBDEs in fish muscle and liver samples were from 45.8 to 560 ng g−1 lipid weight (lw) and 327 to 2120 ng g−1, lw, respectively. The highest concentration of PBDEs was found in carp with a mean value of 1370 ng g−1, lw, followed by crucian with a mean of 1030 ng g−1, lw, and grass carp with a mean of 681 ng g−1, lw. Relatively constant congener patterns were observed among the fish species. BDE-47 was the most predominant congener with contributions of 50.1% to 89.7% to the total PBDE concentrations. Different BDE-99/BDE-100 ratios were observed, indicating that the PBDE pattern is species-dependent.

Spectral Distribution and Pollution Characteristics of Polybrominated Diphenyl Ethers in the Air of an Office Building Clustered Area

To evaluate the pollution level, congener distribution, and human exposure of polybrominated diphenyl ethers (PBDEs) in the atmosphere of Beijing's office buildings, outdoor air samples (particles+gas) were collected from a typical scientific area and PBDEs concentrations were quantified using GC-MS. The results showed that the mass concentrations of PBDEs in the gas phase, PM2.5, and PM10 were 2.3-78.6 pg·m-3, 14.4-335.3 pg·m-3, and 11.6-431.7 pg·m-3, respectively, and the annual average mass concentrations were 21.7 pg·m-3, 96.9 pg·m-3, and 149.3 pg·m-3, respectively. BDE-209 was the predominant congener in particulates, accounting for 50% of the total concentration. The mass concentration of PBDEs in the particles decreased in the following order:autumn > winter > summer > spring, with an obvious change in winter and stability in summer. Tri-BDEs mainly existed in the gas phase, and the proportion of PBDEs in the particle phase increased with bromine number. Source analysis indicated that BDE-209 degradation was an important source of other PBDEs in the air. Exposure risk analysis showed that the respiratory intake of children and adults was 18.6 pg·(kg·d)-1 and 7.1 pg·(kg·d)-1, respectively, which is far below the recommended lowest observed adverse effect level of 1 mg·(kg·d)-1. Similarly, the carcinogenic risk values of BDE-209 for children and adults were 2.3×10-9 and 3.7×10-9, respectively, which were much smaller than the carcinogenic risk limit of 10-6, indicating that there was no health hazard from PBDEs in the atmosphere.

Polybrominated diphenyl ethers and novel brominated flame retardants in human milk from the general population in Beijing, China: Occurrence, temporal trends, nursing infants' exposure and risk assessment

The levels of eight polybrominated diphenyl ether (PBDE) congeners, and six novel brominated flame retardants (NBFRs) were determined in human milk collected from Beijing, China in 2014. The tested 111 samples were collected from 37 mothers, and each donor provided one milk sample per month for 3 months after childbirth. Levels of ∑PBDEs (total tri- to deca-BDEs) were in the range of 0.288 to 22.2 ng g−1 lw (lipid weight). BDE-209, with a median level of 2.2 ng g−1 lw, was the predominant congener. Decabromodiphenyl ethane (DBDPE), as an NBFR and a substitute for deca-BDE, was found to be the most abundant BFR in all tested human milk (median:5.96 ng g−1 lw). This result might suggest that the predominantly consumed BFRs in China have changed from PBDEs to PBDE substitutes. Additionally, a comparison to our previous studies conducted in 2005 and 2011 revealed that levels of tri- to hepta-BDEs showed significant reduction from 2005 to 2014, whereas levels of BDE-209 showed no significant variation from 2011 to 2014. Temporal trends of BFR levels over the three months of lactation were also investigated, and no significant changes were found in concentration with time over the three months lactation. For nursing infants up to 6 months old, the median lower bound of daily BFR intakes via human milk ingestion ranged from zero for 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE) and 1,2-bis(2,4,6-tribromophenoxy)-ethane (BTBPE) to 18.7 ng kg−1 bodyweight day−1 for DBDPE. Although the daily dietary BFR intake for nursing infants was found to be much higher than that for adults, the risk assessment evaluated by the margin of exposure (MOE) approach revealed that dietary BFR intake for nursing infants was unlikely to pose significant health risks.

Unexpectedly high concentrations of 2,4-di-tert-butylphenol in human urine

Synthetic phenolic antioxidants (SPAs) have received increasing attention due to the reports of toxicity and environmental contamination. Nevertheless, limited information was available on human burdens of these SPAs, with the exception of 2,6-di-tert-butyl-4-methylphenol (BHT). In our study, BHT as well as six other SPAs were analyzed in human urine samples from United States donors. Three SPA congeners were detected in human urine: BHT, 2,4-di-tert-butylphenol (DBP), and 3-tert-butyl-4-hydroxyanisole (BHA). BHT, which is the congener received most concerns, was detected at low concentrations [geometric mean (GM): 0.06 ng/mL], whereas four of its metabolites were detected at relatively high concentrations (GM: 1.68 ng/mL). Surprisingly, DBP was detected at extremely high concentrations (GM: 18.3 ng/mL). The concentrations of DBP (GM: 25.8 ng/mL), BHT (0.853 ng/mL), and metabolites (GM: 10.5 ng/mL) increased significantly after the urine samples were hydrolyzed by β-glucuronidase (p < 0.01), indicating the prevalence of the conjugated forms of SPAs and their metabolites in human urine. DBP, which has previously received little attention, was the predominant congener, contributing 88.2% and 63.6% to total target concentrations in the urine samples before and after β-glucuronidase hydrolysis, respectively. Thus, previous studies have vastly underestimated the burdens of SPAs to humans. To our knowledge, this is the first study revealing the presence of DBP in human urine.

Study of BDE-47 induced Parkinson's disease-like metabolic changes in C57BL/6 mice by integrated metabolomic, lipidomic and proteomic analysis.

As the predominant congener of polybrominated diphenyl ethers (PBDEs) detected in human serum, 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) has been reported to induce neurotoxicity. However, the possible linkage between BDE-47 and typical neurodegenerative diseases such as Parkinson's disease (PD) is still unclear. Here we carried out omics studies using liquid chromatography-orbitrap mass spectrometry (LC-orbitrap MS) to depict the BDE-47 induced metabolic changes in C57BJ/L mice to explore the possible contribution of BDE-47 exposure to PD pathology. BDE-47 dissolved in corn oil was orally administered to mice for 30 consecutive days. Results of metabolomics and lipidomics studies of PD-related brain regions revealed significant metabolite changes in pathways involved in oxidative stress and neurotransmitter production. Moreover, isobaric tags for relative and absolute quantitation (iTRAQ) proteomics study of the striatum, which is the part of brain that is most intensively studied in PD pathogenesis, revealed that BDE-47 could induce neurotransmitter system disturbance, abnormal phosphorylation, mitochondrial dysfunction and oxidative stress. Overall, this study depicts the possible contribution of BDE-47 exposure to PD pathology and highlights the powerfulness of omics platforms to deepen the mechanistic understanding of environmental pollutant-caused toxicity.

Levels, spatial distribution and isomer profiles of perfluoroalkyl acids in soil, groundwater and tap water around a manufactory in China

In this study, 32 surface soil samples, 24 groundwater samples, and 6 tap water samples were collected around a perfluorosulfonates (PFSAs) manufactory in China to analyze the distributions of perfluoroalkyl acids (PFAAs) including linear and branched isomers. The total concentrations of PFAAs (∑PFAAs) ranged from 1.30 to 913 ng/g on a dry weight basis (dw), 31.4–15656 ng/L, and 11.8–59.7 ng/L in soil, groundwater and tap water samples respectively. Perfluorooctanesulfonate (PFOS) and perfluorobutanoic acid (PFBA) were the predominant PFAAs in the soil whereas PFBA was the predominant congener in groundwater. PFAA concentrations in the soil and groundwater decreased with increasing distance from the manufactory. Shorter-chain PFAAs showed higher proportions in groundwater than in soil samples and that shorter-chain PFAAs exhibited faster decreasing rates in soil samples, which may be due to the differences in the polarity and hydrophobicity of these molecules. For isomer profiles, n-PFHxS, n-PFOS, and n-PFOA were the main isomer in soil samples and groundwater samples. Direct exposure to PFOS and PFOA via the soil and tap water posed relatively low risk to the residents’ health.

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.

Effects of CO2 restriction on growth of Nitzschia closterium: Evidence from stable isotopes and fatty acids

Algae blooms frequently occur in the coastal areas of China, and pose numbers of adverse effects to marine environment. Nitzschia closterium is one of the algal species associated with algae blooms and was selected as the target algae of this work. This study was the first attempt to investigate the effect of carbon source restriction on the growth of N. closterium during marine phytoplankton blooms. Experiments were implemented in the CO2-restricted (include three nutritional conditions) and CO2-unrestricted systems, respectively. The stable isotope ratios (δ13C and δ15N) and fatty acids (FAs) profiles were measured. Here we hypothesized that the deficient carbon source could lead to the changes of stable isotope ratios and FAs profiles in the N. closterium. The results showed that the δ13C of N. closterium enriched under the CO2 restriction during the culture time (the isotopic difference greater than 27.8‰), whereas depleted under CO2-unrestricted system. Furthermore, within the CO2 restriction, δ15N showed the enrichment trend with increasing culture time under the nitrogen deficiency conditions, where leveled off under the nitrogen non-deficiency conditions. A total of 12 FAs in N. closterium were detected. Within CO2 restriction, FA 20:5n-3c was the predominant congener in all the three conditions. In addition, FA 16:1n-7c was highest in nitrogen deficient, while FA 16:3 was highest in phosphorus deficient condition. Consequently, the deficient carbon sources leaded to inhibit the FA (14:0, 16:0, 16:1n-7c, 16:3, 18:0, 18:3n-3c) synthesis. Overall, the present study provided the new approach to investigate the forming mechanisms of marine phytoplankton blooms by using stable carbon and nitrogen isotope compositions as well as FAs profiles.

Monitoring dioxins and furans in plasma of individuals living near a hazardous waste incinerator: Temporal trend after 20 years

The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in 40 plasma samples of individuals living in zones under potential influence of the emissions of a hazardous waste incinerator (HWI) (Tarragona County, Catalonia, Spain). Samples corresponded to subjects of different gender, age and specific areas of residence. The levels of PCDD/Fs were compared to those obtained in a baseline study (1998), as well as in previous surveys (2002, 2007 and 2012). The current mean concentration of PCDD/Fs in plasma was 6.79 pg I-TEQ/g lipid, which was significantly lower than the baseline concentration (27.0 pg I-TEQ/g lipid). A significant decrease was also observed in comparison to the results obtained in 2002 and 2007 (15.7 and 9.4 pg I-TEQ/g, respectively), while the current PCDD/F levels were similar to those obtained in 2012 (6.18 pg I-TEQ/g lipid). This important reduction in plasma PCDD/F levels is in accordance with the decreasing trend in the daily dietary intake of PCDD/Fs, which diminished from 210.1 pg I-TEQ (baseline) to 8.54 pg WHO-TEQ (current). OCDD was the predominant congener in plasma, while 2,3,7,8-TeCDD and 1,2,3,4,7,8,9-HpCDF showed the lowest levels. Based on the above results, as well as other recent data on the levels of PCDD/Fs in human milk, we conclude that the presence of the HWI does not mean additional and significant risks –as regards to PCDD/F exposure-for the population living in the neighborhood of the facility.

High Abundance of Unintentionally Produced Tetrachlorobiphenyls (PCB47/48/75, 51, and 68) in the Atmosphere at a Regional Background Site in East China.

Although polychlorinated biphenyls (PCBs) have been banned for several decades, they are still detected with elevated levels due to their unintentional production from combustion and industrial thermal processes (UP-PCBs). To investigate the composition and current levels of UP-PCBs and understand which sources are controlling PCB burdens in ambient atmosphere, air samples were collected from August 2012 to August 2015 at a background site in east China. An unexpected high abundance of PCB47+48+75 was observed to be the predominant congener with an average concentration of 786 ± 637 pg/m3. It accounted for 48 ± 16% of ΣPCBs, followed by PCB51 (10 ± 4%), PCB11 (8 ± 6%), and PCB68 (7 ± 3%). Seasonal variations with high levels in summer and lowest levels in winter were observed for PCB47+48+75, 51, and 68. These tetrachlorobiphenyl congeners were strongly correlated with temperature ( r2 > 0.7), suggesting the control of temperature-dependent volatilization processes from contaminated surfaces. The decreased occurrence of PCB47+48+75, 51, and 68 in commercial products and their negative correlations (| r| < 0.35) with polycyclic aromatic hydrocarbon (PAHs) and weak correlation with other PCB congeners suggested unique unintentional sources that differ from combustion and industrial thermal processes or pigment, such as the use of polymer sealant, for PCB47+48+75, 51, and 68 in the ambient air.

Contamination and ecological risk of polybrominated diphenyl ethers (PBDEs) in surface sediments of mangrove wetlands: A nationwide study in China

Mangroves act as sinks for terrigenous pollutants to alleviate their influence on offshore marine ecosystem. The nationwide study of PBDEs contamination in mangrove wetlands of China has not been explored, and their risk for human health lack quantitative analysis. In this study, sediment samples were collected in six mangrove wetlands along coastal area of South China to evaluate the levels, congener distributions and ecological risks of eight PBDEs, including BDE-28, -47, −99, −100, −153, −154, −183, and −209. Levels of ∑PBDEs (the sum of seven PBDEs except BDE-209) and BDE-209 were 0.13–2.18 ng g−1 and 1.44–120.28 ng g−1, respectively. In particular, mean level of BDE-209 was highest in Futian, followed by Yunxiao, Fangchenggang, Zhanjiang, Dongzhaigang, and Dongfang. As dominant PBDE congener, BDE-209 accounted for 63.6%–99.1% of the total PBDEs, suggesting the major sources of commercial deca-BDE mixtures. Among seven PBDE congeners except BDE-209, slightly different percentages of PBDE congeners were detected, with BDE-154, -47, and −100 being predominant congeners. Positive relationship was observed for total organic matter (TOM) with BDE-209, with no such relationships found for particle size compositions (clay, silt and sand). As for sediment-dwelling organism, the ecological risks from tri-, tera-, and hexa-BDE congeners could be negligible, and those from penta- and deca-BDE congeners were low or moderate, indicating major ecological risk drivers of penta- and deca-BDE congeners in mangrove wetlands in China. The ecological risk of PBDEs in mangrove sediments for human health was thought to be consumption of fish which would bioaccumulate PBDEs from the contaminated sediment. As for human health, the levels of non-cancer risks of PBDEs were all lower than 1, and the cancer risk was far less than the threshold level (10−6), demonstrating low risk for human health.

Urinary levels, composition profile and cumulative risk of bisphenols in preschool-aged children from Nanjing suburb, China

Due to the extensive use in consumer products, the bisphenols (BPs) pollution in the environments has aggravated and people are frequently exposed to BPs. In this research, four BPs, i.e., bisphenol A (BPA), bisphenol F (BPF), bisphenol S (BPS) and bisphenol AF (BPAF), were determined in urine samples collected from Gaochun District preschool-age children and the concentrations, distribution profiles, potential sources and cumulative risk assessment of the target compounds were studied. Total concentrations of 4 BPs ranged from 2 to 3113.1 ng/L, with the average concentration of 648.6 ng/L. BPA was the predominant congener (accounting for 94%), followed by BPS. Correlation analysis indicated a negative relationship between BPA and BPAF (R = −0.273, p < 0.05). The estimated daily intakes suggested that young females were more sensitive to BPs. Moreover, the cumulative risk for hazard quotient (HQ) of BPA has been evaluated and the results showed that no high risk had occurred. It provided basic information on the occurrence and human exposure to urinary BPs of preschool aged children from Gaochun District.

Human biomonitoring in Australian children: Brominated flame retardants decrease from 2006 to 2015

Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD) were used intensively as flame retardants, worldwide. They have been detected in human serum samples and PBDEs have been found to be elevated in young children. Commercial Penta- and Octa-PBDE mixtures were banned in Australia in 2005, while HBCDD was banned worldwide in 2013. We investigated PBDE and HBCDD concentrations in serum collected from young children. We also investigated temporal trends in PBDE concentration 10 years after their Australian ban.Surplus human blood serum samples were collected through a pathology clinic (n = 800), in 2014/15, stratified by age (0–6, 6–12, 12–18, 18–24, 24–30, 30–36, 36–42, 42–48, 48–54 and 54–60 months) and sex and pooled for analysis of PBDEs (BDEs −28, −47, −99, −100, −153, −154, −183) and HBCDD. In 2014/15, the geometric mean concentration of the sum of all PBDEs measured (ΣPBDEs) was 4.5 ng/g lipid (median: 4.6 ng/g lipid, range: 0.88–26 ng/g lipid). A positive association between BDE-47 concentration and age was observed (R = 0.41, p = 0.008), however there were no trends between other PBDE congeners or HBCDD and age. There were no significant differences between genders for PBDEs (t-test, p = 0.802) or HBCDD (t-test, p = 0.740).The highest concentrations observed were in pools from the females 30–36 month (26 ng/g lipid) and Males 6–12 month (21 ng/g lipid) categories. BDEs −47 and −99 were the predominant congeners with a combined average contribution of 75% of ΣPBDEs.PBDEs showed a significant reduction in children aged 0–4 years over an eight year period. In 2014/15, the mean (range) concentration of BDE-47 is 2.8 (0.23 to 11) ng/g lipid compared to pools in 2006/07 at 19 (3–55) ng/g lipid (p < 0.0001) and for BDE-153 is 0.73 (<0.1 = −2.9) ng/g lipid compared to pools in 2006/07 at 4.7 (2−10) ng/g lipid (p < 0.0001). HBCDD concentrations were lower than PBDEs with a mean concentration of 0.45 ng/g lipid. There were no temporal trends observed for HBCDD when compared to samples collected in 2012. The dominant stereoisomer was α-HBCDD (mean = 0.38 ng/g lipid) with an average contribution of 65% towards ΣHBCDD.Levels of PBDEs in young Australian children have significantly decreased since the bans of commercial Penta- and Octa-BDE in 2005. There has been no observed decrease in HBCDD levels in Australian children since its ban in 2012.

Seasonal variations and inhalation risk assessment of short-chain chlorinated paraffins in PM2.5 of Jinan, China

Short-chain chlorinated paraffins (SCCPs) were added to the Stockholm Convention on Persistent Organic Pollutants (POPs) at the eighth meeting of the conference of the parties in 2017. As a consequence, increasing environmental attention and international regulation on SCCPs is expected in the future. Inhalation uptake of particulate matter (PM) was an important exposure pathway for POPs into the human body. In the present study, a total of eighty PM2.5 samples were collected in the four seasons of the year at an urban site (Shandong University, Jinan) in Shandong province to investigate the seasonal changes of SCCPs and their inhalation exposure risks to human health. The concentrations of SCCPs ranged from 9.80 to 105 ng m−3, with the mean value of 38.7 ng m−3. The highest concentrations of SCCPs were detected in winter, while the lowest concentrations were in summer. SCCPs concentrations were positively correlated with the mass concentrations of PM2.5 (r = 0.629, p < 0.01), and negatively correlated with the ambient temperature (r = −0.447, p < 0.01). The SCCPs congeners with 10 carbon atoms (C10 congeners) and 7 chlorine numbers (Cl7 congeners) were the predominant congeners, which contributed 35% and 37% of the total SCCPs contamination, respectively. The average inhalation exposure was estimated to be 1.75 × 10−4 mg kg−1 day−1 for adults, which is much lower than the “no observed adverse effect level” (NOAEL) of 100 mg kg−1 day−1 given by European risk assessment for SCCPs.

Effect of oil spill on compound-specific stable carbon isotope composition of amino acid in Nitzschia closterium and Heterosigma akashiwo

Marine microalgae, the most important primary producers in marine ecosystems, are susceptible to toxicants and usually selected as the promising organisms for chemical risk testing. The stable carbon isotope ratios (δ13C) of amino acids (AAs) were measured to determine if compound-specific stable isotope analysis could be used to provide insight into the toxic effects of oil spill on the marine microalgae. The water accommodated fractions (WAF) of #180 fuel oil were selected as the toxic targets with different concentrations in acute (96 h) toxic tests. Naphthalene, phenanthrene, anthracene, and fluoranthene were detected as the predominant congeners of polycyclic aromatic hydrocarbons in the WAF, and may be the main toxic components. At the same WAF concentration, the δ13C values of leucine in Nitzschia closterium increased with the culture time, whereas decreased in Heterosigma akashiwo. However, with the increasing WAF concentrations, the δ13C values of glutamic acid exhibited the increasing trend in both of the two kinds of microalgae at the same culture time. The similar phenomenon was also observed for histidine in H. akashiwo, while opposite in N. closterium, but both enriching in δ13C compared to the controlled experiments without the WAF. Under the different culture times and WAF concentrations, the δ13C values of alanine and methionine showed unexpected trend. These findings indicated that the synthesis pathways of AA in microalgae cells were affected by the WAF, thus leading to the carbon isotopic fractionation in AAs. The present study provide a novel approach to explore the toxicity mechanism of primary producers under oil spill stress, and monitor and evaluate the marine ecological risk of oil spill pollution.