Effects of Hydroxylated Polybrominated Diphenyl Ethers in Developing Zebrafish Are Indicative of Disruption of Oxidative Phosphorylation.

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have been detected in humans and wildlife. Using in vitro models, we recently showed that OH-PBDEs disrupt oxidative phosphorylation (OXPHOS), an essential process in energy metabolism. The goal of the current study was to determine the in vivo effects of OH-PBDE reported in marine wildlife. To this end, we exposed zebrafish larvae to 17 OH-PBDEs from fertilisation to 6 days of age, and determined developmental toxicity as well as OXPHOS disruption potential with a newly developed assay of oxygen consumption in living embryos. We show here that all OH-PBDEs tested, both individually and as mixtures, resulted in a concentration-dependant delay in development in zebrafish embryos. The most potent substances were 6-OH-BDE47 and 6'-OH-BDE49 (No-Effect-Concentration: 0.1 and 0.05 µM). The first 24 h of development were the most sensitive, resulting in significant and irreversible developmental delay. All substances increased oxygen consumption, an effect indicative of OXPHOS disruption. Our results suggest that the induced developmental delay may be caused by disruption of OXPHOS. Though further studies are needed, our findings suggest that the environmental concentrations of some OH-PBDEs found in Baltic Sea wildlife in the Baltic Sea may be of toxicological concern.

Disruption of oxidative phosphorylation (OXPHOS) by hydroxylated polybrominated diphenyl ethers (OH-PBDEs) present in the marine environment.

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) are of growing concern, as they have been detected in both humans and wildlife and have been shown to be toxic. Recent studies have indicated that OH-PBDEs can be more toxic than PBDEs, partly due to their ability to disrupt oxidative phosphorylation (OXPHOS), an essential process in energy metabolism. In this study, we determined the OXPHOS disruption potential of 18 OH-PBDE congeners reported in marine wildlife using two in vitro bioassays, namely the classic rat mitochondrial respiration assay, and a mitochondrial membrane potential assay using zebrafish PAC2 cells. Single OH-PBDE congeners as well as mixtures were tested to study potential additive or synergistic effects. An environmental mixture composed of seven OH-PBDE congeners mimicking the concentrations reported in Baltic blue mussels were also studied. We report that all OH-PBDEs tested were able to disrupt OXPHOS via either protonophoric uncoupling and/or inhibition of the electron transport chain. Additionally we show that OH-PBDEs tested in combinations as found in the environment have the potential to disrupt OXPHOS. Importantly, mixtures of OH-PBDEs may show very strong synergistic effects, stressing the importance of further research on the in vivo impacts of these compounds in the environment.

Analysis of polycyclic aromatic hydrocarbons (PAHs) and their derivatives in biochar treated stormwater.

Polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs (oxy-PAHs) and nitrogen heterocyclic polycyclic aromatic compounds (N-PACs) are persistent and semi-volatile organic compounds primarily formed due to incomplete combustion of organic material or, in the case of the derivatives, through transformation reactions of PAHs. Their presence in the environment is ubiquitous and many of them have been proven carcinogenic, teratogenic, and mutagenic. These toxic pollutants can therefore pose a threat to both ecosystem and human health and urges for remediation strategies for PAHs and derivatives from water bodies. Biochar is a carbon-rich material resulting from the pyrolysis of biomass resulting in a very porous matter with high surface area for an enhanced interaction with chemicals. This makes biochar a promising alternative for filtering micropollutants from contaminated aquatic bodies. In this work, a previously developed and validated methodology for the analysis of PAHs, oxy-PAHs and N-PACs in surface water samples was adapted for its utilization in biochar treated stormwater with special emphasis on scaling down the solid-phase extraction as well as including an additional filtering step for the removal of particulate matter in the media.•Optimized extraction method for PAHs, oxy-PAHs and N-PACs from stormwater treated with biochar.•Biochar strongly impacts the stormwater matrix and, therefore, additional steps are required in the extraction methodology.•Solid-phase extraction combined with GC-MS have been used to analyse PAHs, oxy-PAHs and N-PACs in stormwater treated with biochar.

Capping fiberbank sediments to reduce persistent organic pollutants (POPs) fluxes: A large-scale laboratory column experiment.

Deposits of contaminated wood fiber waste (fiberbanks), originating from sawmills and pulp and paper industries, have been found in the aquatic environment in boreal countries. In-situ isolation capping has been proposed as a remediation solution because it has the potential to prevent dispersal of persistent organic pollutants (POPs) from this type of sediment. However, knowledge about the performance of such caps when placed on very soft (unconsolidated), gaseous organic rich sediment is scarce. We investigated the effectiveness of conventional in-situ capping to limit POPs fluxes to the water column from contaminated fibrous sediments that produce gas. A controlled, large-scale laboratory column (40 cm diameter, 2 m height) experiment was performed over 8 months to study changes in sediment-to-water fluxes of POPs and particle resuspension before and after capping the sediment with crushed stones (≥4 mm grain size). Two different cap thicknesses were tested (20 and 45 cm) on two types of fiberbank sediment with different fiber type composition. Results showed that capping fiberbank sediment with a 45 cm gravel cap reduced the sediment-to-water flux by 91-95% for p,p'-DDD, o,p'-DDD, by 39-82% for CB-101, CB-118, CB-138, CB-153, CB-180 and by 12-18% for HCB, whereas for less hydrophobic PCBs, capping was largely ineffective (i.e. CB-28 and CB-52). Although cap application caused particle resuspension, the long-term effect of the cap was reduced particle resuspension. On the other hand, substantial sediment consolidation released large volumes of contaminated pore water into the overlying water body. Importantly, both sediment types produced large amount of gas, observed as gas voids forming inside the sediment and gas ebullition events, which increased pore water advection and affected the structural integrity of the cap. This may limit the practical applicability of this method on fiberbank sediments.

Spatial distribution of legacy pesticides in river sediment from the Republic of Moldova.

Historical use of organochlorine pesticides (OCPs) in the Republic of Moldova could pose a potential risk for the aquatic environment due to the persistence, bioaccumulation and toxic properties of these environmental pollutants. However, knowledge on environmental concentrations of legacy OCPs in Moldova is limited. In this study, surface sediment from the two main rivers; Dniester (8 sites, n = 15) and Prut (6 sites, n = 12), and two tributary rivers; Bîc (11 sites, n = 11) and Raut (6 sites, n = 6), were collected during 2017-2018 and analyzed for hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs) and their transformation products (DDDs and DDEs) using gas chromatography coupled to mass spectrometry (GC-MS/MS). Sediment concentrations of Æ©6DDX (1.9-140 ng g-1 dry weight (dw)) and Æ©4HCHs (n.d-2.5 ng g-1 dw) were found. In the big rivers, the average Æ©6DDX concentration (18 ng g-1 dw) were 35 times higher than Æ©4HCHs (0.51 ng g-1 dw). Whereas, in the small rivers the average Æ©6DDX concentration (32 ng g-1 dw) was approximately 41 times higher than Æ©4HCHs (0.77 ng g-1 dw). Compared to previous studies from Eastern Europe, the sediment levels were generally similar as found in Moldova's neighboring countries (Romania and Ukraine). Overall, the contamination profile indicates long-term ageing of OCPs used in the past in the agricultural sector. Less than half of the sites (45%) had levels that pose a potential risk for benthic organisms. Hence, further work is needed to determine the bioaccumulation of OCPs in the aquatic food web in this region and the associated risks to ecosystems and human health.

Assessing costs and benefits of improved soil quality management in remediation projects: A study of an urban site contaminated with PAH and metals.

Contaminants in the soil may threaten soil functions (SFs) and, in turn, hinder the delivery of ecosystem services (ES). A framework for ecological risk assessments (ERAs) within the APPLICERA - APPLICable site-specific Environmental Risk Assessment research project promotes assessments that consider other soil quality parameters than only contaminant concentrations. The developed framework is: (i) able to differentiate the effects of contamination on SFs from the effects of other soil qualities essential for soil biota; and (ii) provides a robust basis for improved soil quality management in remediation projects. This study evaluates the socio-economic consequences of remediation alternatives stemming from a Tier 1 ERA that focusses on total contaminant concentrations and soil quality standards and a detailed, site-specific Tier 3 Triad approach that is based on the APPLICERA framework. The present study demonstrates how Tier 1 and Tier 3 ERAs differ in terms of the socio-economic consequences of their remediation actions, as well as presents a novel method for the semi-quantitative assessment of on-site ES. Although the presented Tier 3 ERA is more expensive and time-consuming than the more traditional Tier 1 ERA approach, it has the potential to lower the costs of remediation actions, decrease greenhouse gas emissions, reduce other environmental impacts, and minimise socio-economic losses. Furthermore, the remediation actions stemming from the Tier 3 ERA were predicted to exert far less negative ES effects than the actions proposed based on the results of the Tier 1 ERA.

Fluorotelomer alcohols (FTOHs), brominated flame retardants (BFRs), organophosphorus flame retardants (OPFRs) and cyclic volatile methylsiloxanes (cVMSs) in indoor air from occupational and home environments.

Indoor air samples were collected from private homes and various occupational indoor environments using passive air sampler and analysed for fluorotelomer alcohols (FTOHs), brominated flame retardants (BFRs), organophosphorus flame retardants (OPFRs) and cyclic volatile methyl siloxanes (cVMSs). The aim was to investigate their occurrence in indoor air, factors that may affect their presence and human daily exposure dose (DED) via inhalation. In general, levels of cVMSs were 3-4 orders of magnitude greater than the other compound classes. OPFRs concentration was found significantly higher than BFRs in indoor air. The most abundant compounds in each chemical class were 8:2 FTOH, 2,4,6-TBP, TNBP and TCEP and decamethylcyclopentasiloxane (D5). Home samples contained higher level of FTOHs, BFRs and cVMSs than occupational environments, whereas concentration of OPFRs in office samples were higher. BFRs concentrations were significantly correlated with building age and with the number of electronic/electrical devices at the sampling sites. Moreover, significantly lower levels of FTOHs and cVMSs were observed in rooms with forced-ventilation system. Estimated DED via inhalation was significantly higher at home than in office and the total DED was on average 3-5 orders of magnitude lower than the reference value.

Sampling designs for contaminant temporal trend analyses using sedentary species exemplified by the snails Bellamya aeruginosa and Viviparus viviparus.

Environmental monitoring typically assumes samples and sampling activities to be representative of the population being studied. Given a limited budget, an appropriate sampling strategy is essential to support detecting temporal trends of contaminants. In the present study, based on real chemical analysis data on polybrominated diphenyl ethers in snails collected from five subsites in Tianmu Lake, computer simulation is performed to evaluate three sampling strategies by the estimation of required sample size, to reach a detection of an annual change of 5% with a statistical power of 80% and 90% with a significant level of 5%. The results showed that sampling from an arbitrarily selected sampling spot is the worst strategy, requiring much more individual analyses to achieve the above mentioned criteria compared with the other two approaches. A fixed sampling site requires the lowest sample size but may not be representative for the intended study object e.g. a lake and is also sensitive to changes of that particular sampling site. In contrast, sampling at multiple sites along the shore each year, and using pooled samples when the cost to collect and prepare individual specimens are much lower than the cost for chemical analysis, would be the most robust and cost efficient strategy in the long run. Using statistical power as criterion, the results demonstrated quantitatively the consequences of various sampling strategies, and could guide users with respect of required sample sizes depending on sampling design for long term monitoring programs.

Hydroxylated and methoxylated polybrominated diphenyl ethers in long-tailed ducks (Clangula hyemalis) and their main food, Baltic blue mussels (Mytilus trossulus × Mytilus edulis).

Long-tailed ducks (Clangula hyemalis) that breed in northern Europe and western Siberia and commonly winter in the Baltic Sea, are threatened by a significant population decrease. The ducks are, by primarily feeding on Baltic blue mussels (Mytilus trossulus × Mytilus edulis) while wintering in the Baltic Sea, potentially subjected to high levels of toxic hydroxylated polybrominated diphenyl ethers (OH-PBDEs). To assess long-tailed ducks exposure to polybrominated phenols (PBPs), polybrominated anisoles (PBAs), hydroxylated polybrominated diphenyl ethers (OH-PBDEs), their methylated counterparts (MeO-PBDEs) and polybrominated diphenyl ethers (PBDEs), livers of ten long-tailed ducks wintering in the Baltic Sea were analysed. Pattern and levels of analytes in long-tailed ducks (liver) and blue mussels sampled in March and May at nine sites in the Baltic Sea were compared. The geometric mean concentration (ng/g l.w.) in livers of long-tailed ducks and Baltic blue mussels were: Σ(2)PBPs: 0.57 and 48; Σ(2)PBAs: 0.83 and 11; Σ(7)OH-PBDEs: 6.1 and 45; Σ(7)MeO-PBDEs: 3.8 and 69; Σ(7)PBDEs: 8.0 and 7.2, respectively. Based on an estimated daily intake of 450 g fresh blue mussel meat, long-tailed ducks daily dietary intake of brominated substances while foraging in the Baltic Sea in March-May was estimated to; 390 ng Σ(2)PBPs, 90 ng Σ(2)PBAs, 370 ng Σ(7)OH-PBDEs, 590 ng Σ(7)MeO-PBDEs and 59 ng Σ(7)PBDEs. The low levels of PBPs, PBAs, OH-PBDEs and MeO-PBDEs in the long-tailed duck livers compared to blue mussel, despite a continuous daily intake, suggest that these compounds are poorly retained in long-tailed ducks.

Anthropogenic and naturally produced brominated substances in Baltic herring (Clupea harengus membras) from two sites in the Baltic Sea.

In the eutrophicated Baltic Sea, several naturally produced hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have been found in marine biota. OH-PBDEs are toxic to adult and developing zebrafish and shown to be potent disruptors of oxidative phosphorylation (OXPHOS). Disturbed OXPHOS can result in altered energy metabolism and weight loss. In herring, the concentration of OH-PBDEs (i.e. 2'-OH-BDE68 and 6-OH-BDE47) has increased during the period 1980-2010 in the Baltic Proper. Over the same time period, the condition and fat content in Baltic herring have decreased. Given the toxicity and increasing trends of OH-PBDEs in Baltic herring it is important to further assess the exposure to OH-PBDEs in Baltic herring. In this study, the concentrations of OH-PBDEs and related brominated substances i.e. polybrominated phenols (PBPs), polybrominated anisoles (PBAs), methoxylated polybrominated diphenyl ethers (MeO-PBDEs) and polybrominated diphenyl ethers (PBDEs) were measured in herring sampled in the northern Baltic Proper (Askö, n = 12) and the southern Bothnian Sea (Ängskärsklubb, n = 12). The geometric mean (GM) concentrations (ng/g l.w.) at Askö and Ängskärsklubb were; Σ2PBPs: 4.3 and 9.6, Σ(2)PBAs: 34 and 20, Σ(6)OH-PBDEs: 9.4 and 10, Σ(7)MeO-PBDEs: 42 and 150, Σ(6)PBDEs: 54 and 27, respectively. 6-OH-BDE47 dominated the OH-PBDE profile and comprised 87% (Askö) and 91% (Ängskärsklubb) of the ΣOH-PBDEs. At Ängskärsklubb the mean concentration of ΣMeO-PBDEs (150 ng/g l.w.) was 15 times higher than ΣOH-PBDEs. As other fish species are known to metabolically transform MeO-PBDEs to OH-PBDEs, high levels of MeO-PBDEs can be of concern as a precursor for more toxic OH-PBDEs in herring and their roe.

Recovery discrepancies of OH-PBDEs and polybromophenols in human plasma and cat serum versus herring and long-tailed duck plasma.

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have been identified as metabolites of polybrominated diphenyl ethers (PBDEs) and/or as natural products. The OH-PBDEs and polybromophenols have come into focus over the last decade due to their abundance in biota and their potential adverse health effects. The present recovery study aims to validate a commonly used method (published by Hovander et al. 2000) for OH-PBDE analysis in human plasma. Further, the authors intended to determine the method's applicability to serum/plasma matrices from other species than humans. The investigated matrices were human plasma, cat serum, herring- and long-tailed duck plasma. The recovery study included nine OH-PBDEs, four polybromophenols and three methoxylated PBDEs (MeO-PBDEs). Five replicates of each matrix were spiked with these compounds at two dose levels; a low dose (0.5 ng) and a high dose (5 ng) and were cleaned up according to the Hovander method. The recovery of OH-PBDEs and polybromophenols in human plasma and cat serum were high and reproducible at both dose levels whereas the recovery for herring and long-tailed duck plasma were low and insufficient with great variability amongst OH-PBDE congeners at both dose levels. Our data show that the method can be fully applied to matrices like human plasma and cat serum but not for herring and long-tailed duck plasma without further method development. Hence care needs to be taken when applying the method onto other blood matrices without validation since the present study have demonstrated that the recoveries may differ amongst OH-PBDE congeners and specie.