Polybrominated Diphenyl Ethers Concentrations In Sediments Research Articles

Organic matter degradation determines the concentrations of polybrominated diphenyl ethers in sediments. Multivariate learning on environmental and experimental models

Sediment organic matter (SOM) plays an important role in capturing polybrominated diphenyl ethers (PBDEs) due to its affinity to hydrophobic and lipophilic compounds. Previous publications about correlations between PBDE concentrations and SOM content showed discrepancies among the results, reporting either significant positive correlations or no correlations at all. This work aimed to provide a deeper insight into SOM characteristics that might determine the concentrations of PBDEs in sediments. Sediment samples from Mendoza province, Argentina, were analyzed to contrast two models, environmental and experimental, using multivariate learning methods. Mendoza has been going through increasing events of drought and water scarcity, hence the occurrence, transport, and fate of contaminants as PBDEs in aquatic environments is of superlative importance. Principal component analysis (PCA) and partial least squares regression (PLS) were used to evaluate the correlations between physicochemical properties of sediments, semi-quantitative Fourier transform infrared (FTIR) area ratios obtained from SOM spectra, and PBDE concentrations in sediments. Moreover, a linear model was proposed to determine SOM density using FTIR area ratios and it was used as an additional variable in multivariate analyses. The results obtained from PCA and PLS were consistent and revealed that PBDE concentrations in sediments were correlated with a more degraded SOM, characterized by shorter and more branched hydrocarbon chains. PBDE concentrations were also correlated with higher SOM density values, which in turn were correlated with SOM degradation. These findings extend previous understanding and emphasize that not only is the organic matter content a factor in determining PBDE concentrations in sediments, but also and more significantly, its degree of degradation.

Assessment of Polybrominated Diphenyl Ethers (PBDEs) Level and Physico-Chemical Characteristics of Water and Sediment of Gulf of Guinea

The Lagos lagoon is the largest of the four lagoon systems of the Gulf of Guinea coast. This aquatic resource of multiple usages receives diverse organic and inorganic materials from domestic, industrial, emission, and thermal sources. The levels of Polybrominateddiphenyl ethers (PBDEs) were assessed to ascertain the pollution status of surface water and sediment within this lagoon system. Four stations were sampled for PBDEs analysis, and ranged for surface water physicochemical parameters are (27.93 to 28.50 ⁰C), (115.00 to 2152.70 µS/cm), (2.00 to 2.80 mg/L), (6.45 to 7.63), (25.02 to 84.60 NTU), (226.30 to 3999.00 mg/L), for temperature, electrical conductivity, dissolved oxygen, pH, turbidity, and total dissolved solids respectively. While the Total Organic Carbon (TOC) in sampled sediment ranged from 0.5 to 5.71 mg/L., the total concentrations of PBDEs in sediments ranged from 31.6 to 47.5 µg/Kg. Whereas the BDEs concentration in water ranged from 3.7 to 10.5 pg/L, total PBDE concentration of individual congener for water ranged from approximately 0.8 to 12.5 pg/L. The BDE 28 predominates across the locations followed by BDE 99. Impact of PBDEs concentration in the marine environment was evident within the study area.

Field study on bioaccumulation and translocation of polybrominated diphenyl ethers in the sediment-plant system of a national nature reserve, North China

Polybrominated diphenyl ethers (PBDEs) are the ubiquitous contaminants in the coastal wetlands, with high persistence and toxicity. Environmental behaviors of PBDEs in sediment-plant system is a hot research area, where much uncertainties still occurred in field environment. In this study, the sediments and Suaeda heteroptera were synchronously collected to investigate the bioaccumulation and translocation of PBDEs in Liaohe coastal wetland. Mean concentrations of PBDEs in sediments, roots, stems and leaves were 8.37, 6.64, 2.42 and 1.40 ng/g d.w., respectively. Tissue-specific accumulation of PBDEs were detected in Suaeda heteroptera, with predominant accumulation in roots. Congener patterns of PBDEs were similar between sediments and roots, demonstrating root uptake as the key pathway of PBDE bioaccumulation. The proportions of lower brominated congeners increased from roots to leaves, implying the congener-specific translocation. Meanwhile, the lower brominated congeners exhibited higher sediment-tissue bioaccumulation (AFs) and translocation factors (TFs) compared to higher brominated congeners in Suaeda heteroptera, further verifying their preferential translocation. AFs and TFs of PBDEs were both not correlated with their log Kow, which was inconsistent with those of laboratory studies, reflecting the complicated behaviors of PBDEs in field environment. This is the first comprehensive report on bioaccumulation and translocation of PBDEs within Suaeda heteroptera in Liaohe coastal wetland.

Spatial distribution, source analysis, and ecological risk assessment of PBDEs in river sediment around Taihu Lake, China.

The distribution and composition of organic pollutants in sediment are affected by the source and regional environment. To understand the characteristics and risk of polybrominated diphenyl ethers (PBDEs) in the area around Taihu Lake, composite sediment samples (n = 41) were collected in rivers around Taihu Lake to explore the level, spatial distribution, and source of PBDEs. The results showed that the most abundant BDE congener in river sediment was BDE209, followed by BDE99 and BDE47, with median values of 48.7, 2.17, and 1.52ngg-1, respectively. Concentrations of PBDEs in sediments from northern rivers were significantly higher than those from other areas, but the overall risk was at a moderate-lower level compared with research results in other references. Results of principle component analysis (PCA) and source characteristics analysis revealed that most of PBDEs in river sediments around Taihu Lake were mixture of multiple sources, which mainly originated from atmospheric deposition, industrial wastewater, and municipal sewage. TOC showed good correlations with most PBDEs, which implied that PBDE components were influenced by sediment organic matter. Meanwhile, the risk of PBDEs in river sediments in this study area is a moderate-lower level.

Temporal trends of polybrominated diphenyl ethers in the sediment cores from different areas in China

This paper presented the historical data on the temporal trends of polybrominated diphenyl ethers (PBDEs) in the sediment cores collected from the Huaihe River, Yellow River and Chaohu Lake, China. Among the 40 targeted PBDE congeners, only 10, 6, and 9 of them were detected respectively in the samples from the Huaihe River, Yellow River and Chaohu Lake. On average, the total PBDEs concentrations in sediments were highest in Chaohu Lake followed by the Huaihe River and the Yellow River. As compared to other PBDE congeners, BDE-209 had higher concentrations and detection rates. The similar down core variation between PBDEs and total organic carbon (TOC) suggests that TOC is an important factor influencing PBDEs distribution in the sediments. The total PBDEs concentrations showed an increasing trend from bottom to upper sediments before a decreasing trend in the topmost sediments. The rapid urbanization and industrialization of these regions in recent decades may cause the historically increasing concentrations of sedimentary PBDEs, especially BDE-209. The decreasing PBDEs concentrations in topmost sediments was probably related to the strict environmental policies at present.

Distribution, accumulation, and potential risk of polybrominated diphenyl ethers in the marine environment receiving effluents from a sewage treatment plant

We investigated the effect of sewage treatment plant effluent on the distribution and accumulation of polybrominated diphenyl ethers (PBDEs) in the marine environment. PBDEs concentrations in seawater and surface sediments were within the ranges 1.58–6.94 ng/L and 2.18–307 ng/g dw, respectively. PBDE concentrations in sediments gradually decreased with increasing distance from inner bay including the sewage outfall. The contribution of effluent to PBDE distributions was very limited. The concentrations of PBDEs in sediment core decreased exponentially with increasing depth. PBDE concentrations in oysters were 4.7–37 ng/g lw. BDE-209 was the dominant congener in marine environmental samples receiving effluent. Estimated dietary exposures of PBDEs by seafood were 0.01–0.08 ng/kg body weight/day, which were more than six orders of magnitude lower than the reported levels of PBDEs with the no observable adverse effects. Hazard quotients demonstrated that, at present, PBDEs posed no potential risk to benthic organisms in the study area.

Distribution and partitioning of polybrominated diphenyl ethers in sediments from the Pearl River Delta and Guiyu, South China.

Polybrominated diphenyl ethers (PBDEs) were investigated by GC-NCI-MS in sediments collected from the Pearl River Delta (PRD) and Guiyu town, South China. The concentrations of ∑39PBDEs and BDE 209 were in the ranges of 0.31-38.9 ng g-1 and 12.2-488 ng g-1 in the PRD, and 2.57-21,207 ng g-1 and 7.02-66,573 ng g-1 in Guiyu, respectively. The levels of PBDEs in Dongjiang River (DJ), Zhujiang River (ZJ), and Beijiang River (BJ), and Guiyu (GY) followed the order: GY > DJ > ZJ > BJ. The very high PBDE concentration (87,779 ng g-1) was detected at G1 sediment in Guiyu compared with those in sediments from other regions around the world. The PBDE mixtures detected were mainly comprised of penta-, octa-, and deca-BDEs, in which deca-BDE was the dominant constituent. The abundant congeners, excluding BDE-209, were BDE-47, BDE-99, and BDE-183, suggesting the diverse use of commercial products containing these congeners in this region. The concentrations of major congeners were significantly correlated with total organic carbon (TOC) contents (p < .01). A good regression between the logarithmic TOC-normalized BDE average concentrations and their log Kow confirmed that the sorption of PBDEs on sediment organic matter governed their spatial distribution, transport, and fate in the sediments. Furthermore, risk quotients (RQs) derived from concentrations of PBDEs in sediments from our study may pose high ecological risks to exposure of benthic organisms.

Polybrominated diphenyl ethers and its methoxylated analogues in biota and sediment samples from two freshwater lakes in Yangtze River delta

In the present study, sediments and biotas from two freshwater lakes in Yangze delta area were collected and analyzed for polybrominated diphenyl ethers (PBDEs) and methoxylated PBDEs (MeO–PBDEs). The concentrations of PBDEs in sediments and biotas ranged from 0.41 to 5.8 ng/g dry weight and from 4.6 to 100 ng/g lipid weight, respectively, while those of MeO–PBDEs were much lower (sediment: <LOQ-0.014 ng/g dry weight, biota: <LOQ-2.1 ng/g lipid weight). The levels of both brominated substances in sediments and biotas were in the moderate to low range compared with other studies. Different BDE congeners were found between two lakes probably due to the different exogenous sources and metabolic stages. Similar occurrence of higher brominated congeners (e.g., BDE-209) in sediments and biotas indicated sediments as a possible source of PBDEs for biotas. The different contribution of lower and higher brominated congeners between sediments and biotas may be due to the combined effect of biotransformation and bioavailability.

Food Web Bioaccumulation Model for Resident Killer Whales from the Northeastern Pacific Ocean as a Tool for the Derivation of PBDE-Sediment Quality Guidelines.

Resident killer whale populations in the NE Pacific Ocean are at risk due to the accumulation of pollutants, including polybrominated diphenyl ethers (PBDEs). To assess the impact of PBDEs in water and sediments in killer whale critical habitat, we developed a food web bioaccumulation model. The model was designed to estimate PBDE concentrations in killer whales based on PBDE concentrations in sediments and the water column throughout a lifetime of exposure. Calculated and observed PBDE concentrations exceeded the only toxicity reference value available for PBDEs in marine mammals (1500 μg/kg lipid) in southern resident killer whales but not in northern resident killer whales. Temporal trends (1993-2006) for PBDEs observed in southern resident killer whales showed a doubling time of ≈5 years. If current sediment quality guidelines available in Canada for polychlorinated biphenyls are applied to PBDEs, it can be expected that PBDE concentrations in killer whales will exceed available toxicity reference values by a large margin. Model calculations suggest that a PBDE concentration in sediments of approximately 1.0 μg/kg dw produces PBDE concentrations in resident killer whales that are below the current toxicity reference value for 95 % of the population, with this value serving as a precautionary benchmark for a management-based approach to reducing PBDE health risks to killer whales. The food web bioaccumulation model may be a useful risk management tool in support of regulatory protection for killer whales.

Distribution of polybrominated diphenyl ethers in the surface sediments of the Taihu Lake, China

Twenty-eight sediment samples were collected from the Taihu Lake and analyzed to acquire information about the levels, distribution, possible sources, time trend and inventory of polybrominated diphenyl ethers (PBDEs) in the Taihu Lake. Our results showed that the most abundant BDE congeners in surface sediments were BDE-47, 99 and 209, with a median value of 0.124, 0.279, and 22.72ng(gdw)−1, respectively. The levels of BDE-209 in our samples were much higher relative to those of the other BDE congeners and made up more than 80% of the PBDEs levels in almost all samples. Disregarding BDE-209, among the seven PBDEs (BDE-28, 47, 99, 100, 153, 154, 183) more concerned, the most abundant ones were BDE-47 and 99, which contributed 44.65% (ranged from 29.02% to 73.11%), 24.24% (ranged from 2.27% to 39.66%) to ∑7PBDEs, respectively. The correlation between PBDE and TOC was poor, indicating that PBDEs concentrations in sediments of the Taihu Lake were controlled not only by TOC contents, but also by a combined effect of transport, mixing, depositional mechanisms associated with PBDEs, uncontaminated sediments, or fresh input of PBDEs. As expected, the time trend of PBDEs concentration in surface sediment from Taihu Lake were increasing, and the inventory of ∑25PBDEs and BDE-209 were estimated to be 3668kg and 26296kg.

Modeling the Importance of Biota and Black Carbon As Vectors of Polybrominated Diphenyl Ethers (PBDEs) in the Baltic Sea Ecosystem

The POPCYCLING-Baltic model, a nonsteady state spatially resolved mass balance model of chemical transport in the Baltic Sea environment was modified to include black carbon (BC), dissolved organic carbon (DOC) and food-web bioaccumulation. The importance of these modifications to the transport of PBDE congeners BDE-47, -99, -153, and -209 was assessed by comparing time-series simulated with and without black carbon and biota between 1970 and 2005. Inclusion of black carbon improved the model fit to measurements from air, soil, and biota, and had a major effect on the mass balance. Modeled bulk concentrations of PBDEs in sediments and soils increased by a factor of 3 while concentrations in biota decreased by a factor of 2-5. Black carbon also doubled the recovery time of the system due to the limited availability of PBDEs for degradation. In comparison, the inclusion of biota had only a minor effect on the overall mass balance and recovery times. The modified model is constructed as a flexible matrix and can also be applied to persistent organic pollutants in other ecosystems besides the Baltic Sea.