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Polycyclic aromatic hydrocarbons (PAHs), released from petrogenic, pyrogenic or diagenetic sources (degradation of wood materials), are of global concern due to their adverse effects, and potential for long-range transport. While dissolved PAHs have been frequently reported in the literature, there has been no consistent approach of sampling across water bodies. Passive samplers from the AQUA/GAPS-MONET initiative were deployed at 46 sites (28 marine and 18 freshwater), and analyzed for 28 PAHs and six polycyclic musks (PCMs) centrally. Freely dissolved PAH concentrations were dominated by phenanthrene (mean concentration 1500 pg L-1; median 530 pg L-1) and other low molecular weight compounds. Greatest concentrations of phenanthrene, fluoranthene, and pyrene were typically from the same sites, mostly in Europe and North America. Of the PCMs, only galaxolide (72% of samples) and tonalide (61%) were regularly detected, and were significantly cross-correlated. Benchmarking of PAHs relative to penta- and hexachlorobenzene confirmed that the most remote sites (Arctic, Antarctic, and mountain lakes) displayed below average PAH concentrations. Concentrations of 11 of 28 PAHs, galaxolide and tonalide were positively correlated (P < 0.05) with population density within a radius of 5 km of the sampling site. Characteristic PAH ratios gave conflicting results, likely reflecting multiple PAH sources and postemission changes.
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Persistent organic pollutants (POPs) are recognized as pollutants of global concern, but so far, information on the trends of legacy POPs in the waters of the world has been missing due to logistical, analytical, and financial reasons. Passive samplers have emerged as an attractive alternative to active water sampling methods as they accumulate POPs, represent time-weighted average concentrations, and can easily be shipped and deployed. As part of the AQUA-GAPS/MONET, passive samplers were deployed at 40 globally distributed sites between 2016 and 2020, for a total of 21 freshwater and 40 marine deployments. Results from silicone passive samplers showed α-hexachlorocyclohexane (HCH) and γ-HCH displaying the greatest concentrations in the northern latitudes/Arctic Ocean, in stark contrast to the more persistent penta (PeCB)- and hexachlorobenzene (HCB), which approached equilibrium across sampling sites. Geospatial patterns of polychlorinated biphenyl (PCB) aqueous concentrations closely matched original estimates of production and use, implying limited global transport. Positive correlations between log-transformed concentrations of Σ7PCB, ΣDDTs, Σendosulfan, and Σchlordane, but not ΣHCH, and the log of population density (p < 0.05) within 5 and 10 km of the sampling sites also supported limited transport from used sites. These results help to understand the extent of global distribution, and eventually time-trends, of organic pollutants in aquatic systems, such as across freshwaters and oceans. Future deployments will aim to establish time-trends at selected sites while adding to the geographical coverage.
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Poluentes Atmosféricos , Poluentes Ambientais , Hidrocarbonetos Clorados , Praguicidas , Bifenilos Policlorados , Bifenilos Policlorados/análise , Monitoramento Ambiental/métodos , Hexaclorobenzeno/análise , Água Doce , Poluentes Atmosféricos/análise , Praguicidas/análise , Hidrocarbonetos Clorados/análiseRESUMO
Soil attributes and their environmental drivers exhibit different patterns in different geographical directions, along with distinct regional characteristics, which may have important effects on substance migration and transformation such as organic matter and soil elements or the environmental impacts of pollutants. Therefore, regional soil characteristics should be considered in the process of regionalization for environmental management. However, no comprehensive evaluation or systematic classification of the natural soil environment has been established for China. Here, we established an index system for natural soil environmental regionalization (NSER) by combining literature data obtained based on bibliometrics with the analytic hierarchy process (AHP). Based on the index system, we collected spatial distribution data for 14 indexes at the national scale. In addition, three clustering algorithms-self-organizing feature mapping (SOFM), fuzzy c-means (FCM) and k-means (KM)-were used to classify and define the natural soil environment. We imported four cluster validity indexes (CVI) to evaluate different models: Davies-Bouldin index (DB), Silhouette index (Sil) and Calinski-Harabasz index (CH) for FCM and KM, clustering quality index (CQI) for SOFM. Analysis and comparison of the results showed that when the number of clusters was 13, the FCM clustering algorithm achieved the optimal clustering results (DB = 1.16, Sil = 0.78, CH = 6.77 × 106), allowing the natural soil environment of China to be divided into 12 regions with distinct characteristics. Our study provides a set of comprehensive scientific research methods for regionalization research based on spatial data, it has important reference value for improving soil environmental management based on local conditions in China.
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Algoritmos , Solo , Análise por Conglomerados , Geografia , China , Lógica FuzzyRESUMO
Polymers reinforced with virgin carbon fibers (VCF) are being used to make spar caps of wind turbine (WT) blades and polymers with glass fibers (GF) to make skins of the blade components. Here, we assess the life cycle environmental performance of the hybrid blades with spar caps based on VCF and the shells and shear webs based on RCF (recycled CF) composites (RCF-hybrid). The production of the WT blades and associated reinforced polymers is assumed to occur in Sweden, with their uses and end-of-life management in the European region. The functional unit is equivalent to three blades in an offshore WT with the market incumbent blades solely based on the GF composite or the hybrid option. The RCF-hybrid blades offer 12-89% better environmental performance in nine out of 10 impact categories and 6-26% better in six out of 10 impact categories. The RCF-hybrid blades exhibit optimum environmental performance when the VCF manufacturing facilities are equipped with pollution abatement systems including regenerative thermal oxidizers to reduce ammonia and hydrogen cyanide emissions; spar caps are made using VCF epoxy composites through pultrusion and resin infusion molding, and the blade scrap is mechanically recycled at the end of life. The energy and carbon payback times for the RCF-hybrid blades were found to be 5-13% lower than those of the market incumbents.
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Carbono , Reciclagem , Fibra de Carbono , SuéciaRESUMO
Understanding the mechanisms of pollutant removal in Wastewater Treatment Plants (WWTPs) is crucial for controlling effluent quality efficiently. However, the numerous treatment units, operational factors, and the underlying interactions between these units and factors usually obfuscate the comprehensive and precise understanding of the processes. We have previously proposed a machine learning (ML) framework to uncover complex cause-and-effect relationships in WWTPs. However, only one interpretable ML model, Random forest (RF), was studied and the interpretation method was not granular enough to reveal very detailed relationships between operational factors and effluent parameters. Thus, in this paper, we present an upgraded framework involving three interpretable tree-based models (RF, XGboost and LightGBM), three metrics (R2, Root mean squared error (RMSE), and Mean absolute error (MAE)) and a more advanced interpretation system SHapley Additive exPlanations (SHAP). Details of the framework are provided along with a demonstration of its practical applicability based on a case study of the Umeå WWTP in Sweden. Results show that, for both labels TSSe (Total suspended solids in effluent) and PO4e (Phosphate in effluent), the XGBoost models are optimal whereas the RF models are the least optimal, due to overfitting and polarized fitting. This study has yielded multiple new and significant findings with respect to the control of TSSe and PO4e in the Umeå WWTP and other similarly configured WWTPs. Additionally, this study has produced two important generic findings relating to ML applications for WWTPs (or even other process industries) in terms of cause-and-effect investigations. First, the model comparison should be carried out from multiple perspectives to ensure that underlying details are fully revealed and examined. Second, using a precise, robust, and granular (feature attribution available for individual instances) explanation method can bring extra insight into both model comparison and model interpretation. SHAP is recommended as we found it to be of great value in this study.
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Aprendizado de Máquina , Purificação da Água , SuéciaRESUMO
River delta-front estuaries (DEs) are vital interfaces for fluxes between terrestrial and marine environments. However, deep uncertainty exists in estimating the sedimentary pollutant flux from terrestrial environments in DEs due, in part, to a lack of direct measurements in these dynamic and complicated regions and uncertainty in the calculation method. Due to its high sediment content, the Yellow River (YR) has a strong ability to adsorb phosphorus; therefore, it reliably reflects estuarine sedimentary processes. Here, through the comprehensive analysis of field samples, monitoring data and remote sensing images, we conclude that riverine fine particles control the deltaic estuary pollution status and that particle size is the key factor. Based on the stable relationships between phosphorus and heavy metals, with r2 values of 0.990, 0.992, and 0.639 for As, Cd, and Cr, respectively, we estimated that the P flux reached 22.68 g/m2 yr in 2017. Analysis of the YR high-silt sediment load, which has a strong phosphorus adsorption ability and constitutes a substantial fraction of global fluvial sediment transport, revealed a negative correlation between the riverine sediment load and the estuarine phosphorus flux.
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Rios , Poluentes Químicos da Água , China , Monitoramento Ambiental , Estuários , Sedimentos Geológicos , Fósforo/análise , Poluentes Químicos da Água/análiseRESUMO
Thousands of halogenated natural products (HNPs) pervade the terrestrial and marine environment. HNPs are generated by biotic and abiotic processes and range in complexity from low molecular mass natural halocarbons (nHCs, mostly halomethanes and haloethanes) to compounds of higher molecular mass which often contain oxygen and/or nitrogen atoms in addition to halogens (hHNPs). nHCs have a key role in regulating tropospheric and stratospheric ozone, while some hHNPs bioaccumulate and have toxic properties similar those of anthropogenic-persistent organic pollutants (POPs). Both chemical classes have common sources: biosynthesis by marine bacteria, phytoplankton, macroalgae, and some invertebrate animals, and both may be similarly impacted by alteration of production and transport pathways in a changing climate. The nHCs scientific community is advanced in investigating sources, atmospheric and oceanic transport, and forecasting climate change impacts through modeling. By contrast, these activities are nascent or nonexistent for hHNPs. The goals of this paper are to (1) review production, sources, distribution, and transport pathways of nHCs and hHNPs through water and air, pointing out areas of commonality, (2) by analogy to nHCs, argue that climate change may alter these factors for hHNPs, and (3) suggest steps to improve linkage between nHCs and hHNPs science to better understand and predict climate change impacts.
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Produtos Biológicos , Mudança Climática , AnimaisRESUMO
Eight recently isolated microalgal species from Northern Sweden and the culture collection strain Scenedesmus obliquus RISE (UTEX 417) were tested for their ability to remove 19 pharmaceuticals from growth medium upon cultivation in short light path, flat panel photobioreactors. While the growth of one algal species, Chlorella sorokiniana B1-1, was completely inhibited by the addition of pharmaceuticals, and the one of Scenedesmus sp. B2-2 was strongly inhibited, the other algal strains grew well and produced biomass. In general, lipophilic compounds were removed highly efficient from the culture medium by the microalgae (>70% in average within 2 days). The most lipophilic compounds Biperiden, Trihexyphenidyl, Clomipramine and Amitriptyline significantly accumulated in the biomass of most algal species, with a positive correlation between accumulation and their total biomass content. More persistent in the growth medium were hydrophilic compounds like Caffeine, Fluconazole, Trimetoprim, Codeine, Carbamazepin, Oxazepam and Tramadol, which were detected in amounts of above 60% in average after algal treatment. While Coelastrella sp. 3-4 and Coelastrum astroideum RW10 were most efficient to accumulate certain compounds in their biomass, two algae species, Chlorella vulgaris 13-1 and Chlorella saccharophila RNY, were not only highly efficient in removing all 19 pharmaceuticals from the growth medium within 12 days, at the same time only small amounts of these compounds accumulated in their biomass allowing its further use. Chlorella vulgaris 13-1 was able to remove most compounds within 6 days of growth, while Chlorella saccharophila RNY needed 8-10â¯days."Wild" Nordic microalgae therefore are able to remove active pharmaceutical ingredients, equally or more efficient than the investigated culture collection strain, thereby demonstrating their possible use in sustainable wastewater reclamation in Nordic conditions.
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Chlorella vulgaris/crescimento & desenvolvimento , Microalgas/crescimento & desenvolvimento , Preparações Farmacêuticas/análise , Scenedesmus/crescimento & desenvolvimento , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Biomassa , Chlorella vulgaris/efeitos dos fármacos , Chlorella vulgaris/metabolismo , Microalgas/efeitos dos fármacos , Microalgas/metabolismo , Preparações Farmacêuticas/metabolismo , Fotobiorreatores , Scenedesmus/efeitos dos fármacos , Scenedesmus/metabolismo , Especificidade da Espécie , Suécia , Águas Residuárias/química , Poluentes Químicos da Água/metabolismoRESUMO
Bromoanisoles (BAs) arise from O-methylation of bromophenols, produced by marine algae and invertebrates. BAs undergo sea-air exchange and are transported over the oceans. Here we report 2,4-DiBA and 2,4,6-TriBA in air and deposition on the Swedish west coast (Råö) and the interior of arctic Finland (Pallas). Results are discussed in perspective with previous measurements in the northern Baltic region in 2011-2013. BAs in air decreased from south to north in the order Råö > northern Baltic > Pallas. Geometric mean concentrations at Pallas increased significantly (p < 0.05) between 2002 and 2015 for 2,4-DiBA but not for 2,4,6-TriBA. The logarithm of BA partial pressures correlated significantly to reciprocal air temperature at the coastal station Råö and over the Baltic, but only weakly (2,4-DiBA) or not significantly (2,4,6-TriBA) at inland Pallas. Deposition fluxes of BAs were similar at both sites despite lower air concentrations at Pallas, due to greater precipitation scavenging at lower temperatures. Proportions of the two BAs in air and deposition were related to Henry's law partitioning and source regions. Precipitation concentrations were 10-40% of those in surface water of Bothnian Bay, northern Baltic Sea. BAs deposited in the bay catchment likely enter rivers and provide an unexpected source to northern estuaries. BAs may be precursors to higher molecular weight compounds identified by others in Swedish inland lakes.
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Anisóis/análise , Monitoramento Ambiental/métodos , Rios/química , Anisóis/química , Regiões Árticas , Países Bálticos , Finlândia , Oceanos e Mares , SuéciaRESUMO
Here we evaluate the excess lifetime cancer risk (ELCR) posed by 10 PAH-contaminated soils using (i) the currently advocated, targeted chemical-specific approach that assumes dose additivity for carcinogenic PAHs and (ii) a bioassay-based approach that employs the in vitro mutagenic activity of the soil fractions to determine levels of benzo[a]pyrene equivalents and, by extension, ELCR. Mutagenic activity results are presented in our companion paper.1 The results show that ELCR values for the PAH-containing fractions, determined using the chemical-specific approach, are generally (i.e., 8 out of 10) greater than those calculated using the bioassay-based approach; most are less than 5-fold greater. Only two chemical-specific ELCR estimates are less than their corresponding bioassay-derived values; differences are less than 10%. The bioassay-based approach, which permits estimation of ELCR without a priori knowledge of mixture composition, proved to be a useful tool to evaluate the chemical-specific approach. The results suggest that ELCR estimates for complex PAH mixtures determined using a targeted, chemical-specific approach are reasonable, albeit conservative. Calculated risk estimates still depend on contentious PEFs and cancer slope factors. Follow-up in vivo mutagenicity assessments will be required to validate the results and their relevance for human health risk assessment of PAH-contaminated soils.
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Carcinógenos/toxicidade , Neoplasias/induzido quimicamente , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Poluentes do Solo/toxicidade , Animais , Bioensaio , Carcinógenos/análise , Linhagem Celular , Humanos , Camundongos , Hidrocarbonetos Policíclicos Aromáticos/análise , Medição de Risco , Poluentes do Solo/análiseRESUMO
This study employed an in vitro version of the lacZ transgenic rodent mutation assay to assess the mutagenicity of nonpolar neutral and semipolar aromatic soil fractions from 10 PAH-contaminated sites, and evaluated the assumption of dose additivity that is routinely employed to calculate the risk posed by PAH mixtures. Significant mutagenic activity was detected in all nonpolar neutral fractions, and 8 of 10 semipolar aromatic fractions (nonpolar > semipolar). Mutagenic activity of synthetic PAH mixtures that mimic the PAH content of the soils (i.e., 5-PAH or 16-PAH mix) were greater than that of the PAH-containing soil fractions, with 5-PAH mix >16-PAH-mix. Predictions of mutagenic activity, calculated as the sum of the contributions from the mutagenic mixture components, were all within 2-fold of the observed activity of the nonpolar neutral fractions, with one exception. Observed differences in mutagenic activity are likely the result of dynamic metabolic processes, involving a complex interplay of AhR agonsim and saturation of metabolic machinery by competitive inhibition of mixture components. The presence of hitherto unidentified polar compounds present in PAH-contaminated soils may also contribute to overall hazard; however, these compounds are generally not included in current contaminated site risk assessment protocols.
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Mutagênicos/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Poluentes do Solo/toxicidade , Animais , Linhagem Celular , Óperon Lac , Camundongos , Testes de Mutagenicidade , Mutação , TransgenesRESUMO
This paper presents 10 recommendations for improving the European Medicines Agency's guidance for environmental risk assessment of human pharmaceutical products. The recommendations are based on up-to-date, available science in combination with experiences from other chemical frameworks such as the REACH-legislation for industrial chemicals. The recommendations concern: expanding the scope of the current guideline; requirements to assess the risk for development of antibiotic resistance; jointly performed assessments; refinement of the test proposal; mixture toxicity assessments on active pharmaceutical ingredients with similar modes of action; use of all available ecotoxicity studies; mandatory reviews; increased transparency; inclusion of emission data from production; and a risk management option. We believe that implementation of our recommendations would strengthen the protection of the environment and be beneficial to society. Legislation and guidance documents need to be updated at regular intervals in order to incorporate new knowledge from the scientific community. This is particularly important for regulatory documents concerning pharmaceuticals in the environment since this is a research field that has been growing substantially in the last decades.
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Meio Ambiente , Poluentes Ambientais/análise , Preparações Farmacêuticas/análise , Medição de Risco , Poluentes Ambientais/toxicidade , Humanos , IndústriasRESUMO
Bromophenols produced by marine algae undergo O-methylation to form bromoanisoles (BAs), which are exchanged between water and air. BAs were determined in surface water of the northern Baltic Sea (Gulf of Bothnia, consisting of Bothnian Bay and Bothnian Sea) during 2011-2013 and on a transect of the entire Baltic in September 2013. The abundance decreased in the following order: 2,4,6-tribromoanisole (2,4,6-TBA)>2,4-dibromoanisole (2,4-DBA)â«2,6-dibromoanisole (2,6-DBA). Concentrations of 2,4-DBA and 2,4,6-TBA in September were higher in the southern than in the northern Baltic and correlated well with the higher salinity in the south. This suggests south-to-north advection and dilution with fresh riverine water enroute, and/or lower production in the north. The abundance in air over the northern Baltic also decreased in the following order: 2,4,6-TBA>2,4-DBA. However, 2,6-DBA was estimated as a lower limit due to breakthrough from polyurethane foam traps used for sampling. Water/air fugacity ratios ranged from 3.4 to 7.6 for 2,4-DBA and from 18 to 94 for 2,4,6-TBA, indicating net volatilization. Flux estimates using the two-film model suggested that volatilization removes 980-1360 kg of total BAs from Bothnian Bay (38000 km2) between May and September. The release of bromine from outgassing of BAs could be up to 4-6% of bromine fluxes from previously reported volatilization of bromomethanes and bromochloromethanes.
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Poluentes Atmosféricos/química , Anisóis/química , Bromo/química , Água do Mar/química , Poluentes Químicos da Água/química , Movimentos do Ar , Poluentes Atmosféricos/análise , Anisóis/análise , Bromo/análise , Monitoramento Ambiental , Oceanos e Mares , Salinidade , Água do Mar/análise , Suécia , Volatilização , Movimentos da Água , Poluentes Químicos da Água/análiseRESUMO
The pollution trend of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Baltic Sea region was studied based on depth profiles of PCDD/Fs in sediment cores collected from six offshore areas, eight coastal sites impacted by industrial/urban emissions, and one coastal reference site. A general trend was observed for the offshore and coastal reference sites with substantial increase in PCDD/F concentrations in the mid-late 1970s and peak levels during 1985-2002. The overall peak year for PCDD/Fs in Baltic Sea offshore areas was estimated (using spline-fit modeling) to 1994 ± 5 years, and a half-life in sediments was estimated at 29 ± 11 years. For the industrial/urban impacted coastal sites, the temporal trend was more variable with peak years occurring 1-2 decades earlier compared to offshore areas. The substantial reductions from peak levels (38 ± 11% and 81 ± 12% in offshore and coastal areas, respectively) reflect domestic and international actions taken for reduction of the release of PCDD/Fs to the environment. The modeled overall half-life and reductions of PCDD/Fs in offshore Baltic Sea sediment correspond well to both PCDD/F trends in European lakes without any known direct PCDD/F sources (half-lives 30 and 32 years), and previously modeled reduction in atmospheric deposition of PCDD/Fs to the Baltic Sea since 1990. These observations support previous findings of a common diffuse source, such as long-range air transport of atmospheric emissions, as the prime source of PCDD/Fs to the Baltic Sea region. The half-life of PCDD/Fs in Baltic Sea offshore sediments was estimated to be approximately 2 and 4-6 times longer than in semirural and urban European air, respectively. This study highlights the need for further international actions to reduce the levels of PCDD/Fs in Baltic Sea air specifically and in European air in general.
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Benzofuranos/análise , Sedimentos Geológicos/química , Oceanos e Mares , Dibenzodioxinas Policloradas/análogos & derivados , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/história , Poluentes Atmosféricos/análise , Geografia , Meia-Vida , História do Século XX , Plantas/química , Dibenzodioxinas Policloradas/análise , Fatores de TempoRESUMO
Spatial and temporal trends of sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Baltic Sea were evaluated by positive matrix factorization (PMF) and principal component analysis (PCA). Sediment cores were sampled at eight coastal, one coastal reference, and six offshore sites covering the northern to the southern Baltic Sea. The cores, which covered the period 1919-2010, were sliced into 2-3 cm disks among which 8-11 disks per core (in total 141 disks) were analyzed for all tetra- through octa-CDD/Fs. Identification and apportionment of PCDD/F sources was carried out using PMF. Five stable model PCDD/F congener patterns were identified, which could be associated with six historically important source types: (i) atmospheric background deposition (ABD), (ii) use and production of penta-chlorophenol (PCP), (iii) use and production of tetra-chlorophenol (TeCP), (iv) high temperature processes (Thermal), (v) hexa-CDD-related sources (HxCDD), and (vi) chlorine-related sources (Chl), all of which were still represented in the surface layers. Overall, the last four decades of the period 1920-2010 have had a substantial influence on the Baltic Sea PCDD/F pollution, with 88 ± 7% of the total amount accumulated during this time. The 1990s was the peak decade for all source types except TeCP, which peaked in the 1980s in the northern Baltic Sea and has still not peaked in the southern part. The combined impact of atmospheric-related emissions (ABD and Thermal) was dominant in the open sea system throughout the study period (1919-2010) and showed a decreasing south to north trend (always >80% in the south and >50% in the north). Accordingly, to further reduce levels of PCDD/Fs in the open Baltic Sea ecosystem, future actions should focus on reducing atmospheric emissions.
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Benzofuranos/análise , Monitoramento Ambiental/métodos , Sedimentos Geológicos/análise , Dibenzodioxinas Policloradas/análogos & derivados , Poluentes Químicos da Água/análise , Clorofenóis/análise , Dibenzofuranos Policlorados , Dioxinas , Ecossistema , Oceanos e Mares , Dibenzodioxinas Policloradas/análiseRESUMO
Halomethoxybenzenes (HMBs) and related halomethoxyphenols are produced naturally in the marine and terrestrial environment and some also have anthropogenic origins. They are relatively volatile and water soluble and undergo atmospheric exchange with water bodies and soil. Here we report air-surface exchange of HMB compounds brominated anisoles and chlorinated dimethoxybenzenes in a Subarctic lake and catchment in Sweden during September 2022. HMBs were isolated from water on solid-phase extraction cartridges and from ground litter/soil by solvent extraction and determined by capillary gas chromatography - quadrupole mass spectrometry. Identified compounds in lake and stream water in the 10-100 pg L-1 range were 1,2,4,5-tetrachloro-3,6-dimethoxybenzene (DAME) > 2,4-dibromoanisole (DiBA) ≥ 2,4,6-tribromoanisole (TriBA) > 1,2,3,4-tetrachloro-5,6-dimethoxybenzene (tetrachloroveratrole, TeCV). DAME and the related compound 2,3,5,6-tetrachloro-4-methoxyphenol (DA) are reported in Subarctic litter/soil in the range 0.005-1.1 mg kg-1 dry weight (dw), whereas DiBA and TriBA were not detected in any litter/soil sample and TeCV in only one. Exchanges were assessed from concentrations in water and soil, air concentrations from a monitoring station at Pallas, Finland, and the physicochemical properties of the HMBs. Fluxes to and from the lake were estimated using the two-film gas exchange model. Net loadings (deposition minus volatilization) for the month of September were - 23, -15 and - 68 g for DiBA, TriBA and DAME, respectively, which amounted to about 4-7 % of the estimated lake inventory. An exchange assessment for DAME from litter/soil showed significant net volatilization at five sites, net deposition at one site and near-equilibrium at one site. The Torneträsk catchment appeared close to steady state with respect to HMB exchange during September 2022. The situation could be different during the warmer and colder seasons, and extending the study to cover these periods is a suggested next step.
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The widespread use of chlorinated phenols (CPs) as a wood preservative has led to numerous contaminated sawmill sites. However, it remains challenging to assess the extent of in situ degradation of CPs. We evaluated the use of compound-specific chlorine and carbon isotope analysis (Cl- and C-CSIA) to assess CP biotransformation. In a laboratory system, we measured isotopic fractionation during oxidative 2,4,6-trichlorophenol dechlorination by representative soil enzymes (C. fumago chloroperoxidase, horseradish peroxidase, and laccase from T. versicolor). Using a mathematical model, the validity of the Rayleigh approach to evaluate apparent kinetic isotope effects (AKIE) was confirmed. A small but significant Cl-AKIE of 1.0022 ± 0.0006 was observed for all three enzymes, consistent with a reaction pathway via a cationic radical species. For carbon, a slight inverse isotope effect was observed (C-AKIE = 0.9945 ± 0.0019). This fractionation behavior is clearly distinguishable from reported reductive dechlorination mechanisms. Based on these results we then assessed degradation and apportioned different types of technical CP mixtures used at two former sawmill sites. To our knowledge, this is the first study that makes use of two-element CSIA to study sources and transformation of CPs in the environment.
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Clorofenóis/metabolismo , Monitoramento Ambiental/métodos , Poluentes Ambientais/metabolismo , Fungicidas Industriais/metabolismo , Armoracia/enzimologia , Ascomicetos/enzimologia , Basidiomycota/enzimologia , Biodegradação Ambiental , Isótopos de Carbono/isolamento & purificação , Isótopos de Carbono/metabolismo , Fracionamento Químico/métodos , Cloreto Peroxidase/metabolismo , Cloro/isolamento & purificação , Cloro/metabolismo , Halogenação , Peroxidase do Rábano Silvestre/metabolismo , Isótopos/isolamento & purificação , Isótopos/metabolismo , Lacase/metabolismo , Modelos Biológicos , OxirreduçãoRESUMO
Halomethoxybenzenes (HMBs) are a group of compounds with natural and anthropogenic origins. Here we extend a 2002-2015 survey of bromoanisoles (BAs) in the air and precipitation at Råö on the Swedish west coast and Pallas in Subarctic Finland. New BAs data are reported for 2018 and 2019 and chlorinated HMBs are included for these and some previous years: drosophilin A methyl ether (DAME: 1,2,4,5-tetrachloro-3,6-dimethoxybenzene), tetrachloroveratrole (TeCV: 1,2,3,4-tetrachloro-5,6-dimethoxybenzene), and pentachloroanisole (PeCA). The order of abundance of HMBs at Råö was ΣBAs > DAME > TeCV > PeCA, whereas at Pallas the order of abundance was DAME > ΣBAs > TeCA > PeCA. The lower abundance of BAs at Pallas reflects its inland location, away from direct marine influence. Clausius-Clapeyron (CC) plots of log partial pressure (Pair)/Pa versus 1/T suggested distant transport at both sites for PeCA and local exchange for DAME and TeCV. BAs were dominated by distant transport at Pallas and by both local and distant sources at Råö. Relationships between air and precipitation concentrations were examined by scavenging ratios, SR = (ng m-3)precip/(ng m-3)air. SRs were higher at Pallas than Råö due to greater Henry's law partitioning of gaseous compounds into precipitation at colder temperatures. DAME is produced by terrestrial fungi. We screened 19 fungal species from Swedish forests and found seven of them contained 0.01-3.8 mg DAME per kg fresh weight. We suggest that the volatilization of DAME from fungi and forest litter containing fungal mycelia may contribute to atmospheric levels at both sites.
RESUMO
Household dust is an important source of premature exposure to polybrominated diphenyl ethers (PBDEs), especially for children. In this onsite study, 246 dust samples were collected from 224 households in nine Chinese cities during 2018-2019. Questionnaires were administered to explore the association between household-related information and PBDEs in household dust. The median concentration of Σ12PBDEs in household dust from 9 cities was 138 ng/g (94-227 ng/g), with the arithmetic mean of 240 ± 401 ng/g. Among the nine cities, the highest median concentration of Σ12PBDEs in household dust was found in Mianyang (295.57 ng/g), while the lowest was found in Wuxi (23.15 ng/g). BDE-71 was the most dominant congener, ranging from 42.08 % to 98.15 % of the 12 PBDE congeners among 9 cities. Three potential sources for the indoor environment were Penta-BDE, Octa-BDE commercial products, and photolytic bromine from Deca-BDEs based on the largest contribution (81.24 %). Under the moderate exposure scenario, the exposure levels through ingestion and dermal absorption for children were 7.30 × 10-1 ng/kg BW/day and 3.26 × 10-2 ng/kg BW/day, respectively. Temperature, CO2, years of residence, income, family size, household size, use of computers, heating, use of insecticide, and use of humidifiers were influential factors for PBDE concentrations in household dust. Based on the evidence of the correlation between PBDEs and these household parameters, it can be applied to reduce PBDE concentrations in household dust, which is a basis for controlling PBDEs pollution in Chinese households and protecting population health.
Assuntos
Poluição do Ar em Ambientes Fechados , Exposição Ambiental , Criança , Humanos , Exposição Ambiental/análise , Éteres Difenil Halogenados/análise , Poeira/análise , Cidades , Poluição do Ar em Ambientes Fechados/análise , Monitoramento Ambiental , ChinaRESUMO
BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) are typical residential pollutants mainly from biofuel combustion that impose inevitable risk to children. The PAHs in residential dust is universal in most Chinese households with an obvious public health concern. METHODS: In this observational study, a total of 235 residential dust samples from 8 Chinese cities (Panjin, Shijiazhuang, Lanzhou, Luoyang, Xi'an, Wuxi, Mianyang, and Shenzhen) were collected from April 2018 to March 2019, which were extracted and analyzed for 16 priority PAHs by HPLC/FD-UV. Diagnostic ratios, hierarchical clustering analysis and principal component analysis were applied simultaneously for source apportionments. Incremental lifetime cancer risk was employed to estimate children's health risks based on the assumed exposure scenarios. Spearman correlation, Mann-Whitney U test, Kruskal-Wallis H test and Partial Least Squares were used to screen the factors affecting the concentration of PAHs in residential dust. RESULTS: The median concentration of ∑16PAHs in residential dust from 8 cities was 44.11 µg/g (0.04 - 355.79 µg/g). ∑16PAHs were found both higher in dust samples in heating season and from downwind households only in Mianyang (p < 0.05). The leading two sources of PAHs were combustion processes and automobile exhaust emissions based on four principal components that accounted for 74.29 % of the total variance. Indoor air environmental factors, household characteristics, and residents' behavioral lifestyles may be the influencing factors of residential dust PAHs. The carcinogenic risk of children aged 0 - 5 years, under the moderate exposure level of PAHs in residential dust, exceeded the acceptable level (10-5 - 10-4 for dermal contact and 10-6 - 10-5 for ingestion). CONCLUSIONS: There was serious PAHs pollution in residential dust under actual living conditions in eight cities across China. More evidence-based measures were needed to control PAHs pollution to safeguard children's health according to appointed sources and influencing factors in residential dust.