16 results on '"Ricklund N"'
Search Results
2. Mass balance of decabromodiphenyl ethane and decabromodiphenyl ether in a WWTP
- Author
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Ricklund, N., Kierkegaard, A., McLachlan, M., Wahlberg, C., Ricklund, N., Kierkegaard, A., McLachlan, M., and Wahlberg, C.
- Published
- 2008
- Full Text
- View/download PDF
3. Decabromodiphenyl ethane in sewage sludge – A global survey
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Ricklund, N, Kierkegaard, A, McLachlan, M, Ricklund, N, Kierkegaard, A, and McLachlan, M
- Published
- 2008
4. Bioaccumulation of decabromodiphenyl ethane (dbdpe) in the Western Scheldt estuary
- Author
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Ricklund, N., Kierkegaard, A., McLachlan, M. S., Leonards, P. E. G., Ricklund, N., Kierkegaard, A., McLachlan, M. S., and Leonards, P. E. G.
- Abstract
Decabromodiphenyl ethane (dbdpe) is a brominated flame retardant (BFR) with both a similar chemical structure and similar technical applications to a chemical of recognized environmental concern, decabromodiphenyl ether (decaBDE). Bioaccumulation has been one of the most controversial issues in the risk assessment of decaBDE, but it has not been measured for dbdpe. During the last several years, dbdpe has been detected in a variety of biota, which suggests that it is bioavailable. In this work, dbdpe was analyzed together with decaBDE in a benthic and pelagic food web in the Western Scheldt estuary, an environment known to be contaminated with the two BFRs. The biota-sediment accumulation factors for benthic invertebrates were low (0.0008-0.005) for both chemicals. This weak bioaccumulation into the lowest trophic levels of the food web may have been due to a poor bioavailability of the BFRs into the estuary. Both chemicals were transferred up through the food web, but biodilution was observed, not biomagnification (BMFs 0.2-0.8). The bioaccumulation behavior of dbdpe was similar to that of decaBDE.
5. Children's exposure to halogenated flame retardants and organophosphate esters through dermal absorption and hand-to-mouth ingestion in Swedish preschools.
- Author
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Sjöström Y, Tao F, Ricklund N, de Wit CA, Hagström K, and Hagberg J
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- Humans, Sweden, Child, Preschool, Endocrine Disruptors analysis, Esters analysis, Male, Female, Environmental Pollutants analysis, Environmental Monitoring, Flame Retardants analysis, Organophosphates analysis, Skin Absorption, Environmental Exposure statistics & numerical data
- Abstract
Children are exposed to endocrine disrupting chemicals (EDCs) through inhalation and ingestion, as well as through dermal contact in their everyday indoor environments. The dermal loadings of EDCs may contribute significantly to children's total EDC exposure due to dermal absorption as well as hand-to-mouth behaviors. The aim of this study was to measure potential EDCs, specifically halogenated flame retardants (HFRs) and organophosphate esters (OPEs), on children's hands during preschool attendance and to assess possible determinants of exposure in preschool indoor environments in Sweden. For this, 115 handwipe samples were collected in winter and spring from 60 participating children (arithmetic mean age 4.5 years, standard deviation 1.0) and analyzed for 50 compounds. Out of these, 31 compounds were identified in the majority of samples. Levels were generally several orders of magnitude higher for OPEs than HFRs, and 2-ethylhexyl diphenyl phosphate (EHDPP) and tris(2-butoxyethyl) phosphate (TBOEP) were detected in the highest median masses, 61 and 56 ng/wipe, respectively. Of the HFRs, bis(2-ethyl-1-hexyl)-2,3,4,5-tetrabromobenzoate (BEH-TEBP) and 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE-209) were detected in the highest median masses, 2.8 and 1.8 ng/wipe, respectively. HFR and/or OPE levels were found to be affected by the number of plastic toys, and electrical and electronic devices, season, municipality, as well as building and/or renovation before/after 2004. Yet, the calculated health risks for single compounds were below available reference dose values for exposure through dermal uptake as well as for ingestion using mean hand-to-mouth contact rate. However, assuming a high hand-to-mouth contact rate, at the 95th percentile, the calculated hazard quotient was above 1 for the maximum handwipe mass of TBOEP found in this study, suggesting a risk of negative health effects. Furthermore, considering additive effects from similar compounds, the results of this study indicate potential concern if additional exposure from other routes is as high., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)
- Published
- 2024
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6. Circulating lung-cancer-related non-coding RNAs are associated with occupational exposure to hexavalent chromium - A cross-sectional study within the SafeChrom project.
- Author
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Jiang Z, Person R, Lundh T, Pineda D, Engfeldt M, Krais AM, Hagberg J, Ricklund N, Vogel U, Saber AT, Tondel M, Albin M, and Broberg K
- Subjects
- Humans, Cross-Sectional Studies, Male, Middle Aged, Adult, Female, RNA, Long Noncoding genetics, RNA, Long Noncoding blood, MicroRNAs blood, MicroRNAs genetics, RNA, Untranslated blood, RNA, Untranslated genetics, Chromium blood, Occupational Exposure, Lung Neoplasms genetics, Lung Neoplasms chemically induced
- Abstract
Background: Hexavalent chromium (Cr(Ⅵ)) is classified as a group 1 human carcinogen and increases the risk of lung cancer. Non-coding RNAs (ncRNAs) have key regulatory roles in lung cancer, but less is known about their relation to Cr(Ⅵ) exposure., Objectives: We aimed to 1) measure the expression of lung cancer-related circulating ncRNAs in exposed workers and controls; 2) assess associations between ncRNAs expression and Cr concentrations in red blood cells (RBC) and urine; and 3) evaluate correlations between the ncRNAs., Methods: The study included 111 Cr(VI) exposed workers and 72 controls recruited from the SafeChrom project. Cr concentrations were measured in RBC (biomarker of long-term exposure) and urine (biomarker of short-term exposure) samples. Long ncRNA (lncRNA) and microRNA (miRNA) were extracted from plasma followed by deoxyribonuclease treatment, complementary DNA synthesis, and quantitative real-time polymerase chain reaction using target-specific assays for three lncRNAs (H19, MALAT1, NORAD), and four miRNAs (miR-142-3p, miR-15b-5p, miR-3940-5p, miR-451a)., Results: Expression levels of lncRNAs MALAT1 and NORAD, and all four miRNAs, were significantly lower in Cr(VI) exposed workers compared with controls, and correlated significantly with RBC-Cr concentrations (r
S = -0.16 to -0.38). H19 was non-significantly increased in exposed workers but significantly correlated with miR-142-3p (rS = -0.33) and miR-15b-5p (rS = -0.30), and NORAD was significantly positively correlated with all four miRNAs (rS = 0.17 to 0.46). In multivariate regression models adjusting for confounders, expressions of lncRNAs MALAT1 and NORAD and all miRNAs were still significantly lower in the exposed group compared with controls, and the expression decreased with increasing RBC-Cr concentrations., Conclusions: Cr(VI) exposure was inversely and in a dose-response manner associated with the expression of circulating non-coding RNA, which suggests ncRNAs as potential biomarkers for Cr(VI)-induced toxicity. Correlations between miRNAs and lncRNAs suggest that they participate in the same lncRNA-miRNA-messenger RNA regulatory axes, which may play important roles in Cr(VI) carcinogenesis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)- Published
- 2024
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7. Hexavalent chromium still a concern in Sweden - Evidence from a cross-sectional study within the SafeChrom project.
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Jiang Z, Schenk L, Assarsson E, Albin M, Bertilsson H, Dock E, Hagberg J, Karlsson LE, Kines P, Krais AM, Ljunggren S, Lundh T, Modig L, Möller R, Pineda D, Ricklund N, Saber AT, Storsjö T, Amir ET, Tinnerberg H, Tondel M, Vogel U, Wiebert P, Broberg K, and Engfeldt M
- Subjects
- Male, Humans, Female, Sweden, Cross-Sectional Studies, Bayes Theorem, Environmental Monitoring, Chromium urine, Stainless Steel analysis, Carcinogens, Air Pollutants, Occupational analysis, Occupational Exposure analysis
- Abstract
Objectives: Hexavalent chromium (Cr(VI)) is classified as a human carcinogen. Occupational Cr(VI) exposure can occur during different work processes, but the current exposure to Cr(VI) at Swedish workplaces is unknown., Methods: This cross-sectional study (SafeChrom) recruited non-smoking men and women from 14 companies with potential Cr(VI) exposure (n = 113) and controls from 6 companies without Cr(VI) exposure (n = 72). Inhalable Cr(VI) was measured by personal air sampling (outside of respiratory protection) in exposed workers. Total Cr was measured in urine (pre- and post-shift, density-adjusted) and red blood cells (RBC) (reflecting Cr(VI)) in exposed workers and controls. The Bayesian tool Expostats was used to assess risk and evaluate occupational exposure limit (OEL) compliance., Results: The exposed workers performed processing of metal products, steel production, welding, plating, and various chemical processes. The geometric mean concentration of inhalable Cr(VI) in exposed workers was 0.15 μg/m
3 (95% confidence interval: 0.11-0.21). Eight of the 113 exposed workers (7%) exceeded the Swedish OEL of 5 μg/m3 , and the Bayesian analysis estimated the share of OEL exceedances up to 19.6% for stainless steel welders. Median post-shift urinary (0.60 μg/L, 5th-95th percentile 0.10-3.20) and RBC concentrations (0.73 μg/L, 0.51-2.33) of Cr were significantly higher in the exposed group compared with the controls (urinary 0.10 μg/L, 0.06-0.56 and RBC 0.53 μg/L, 0.42-0.72). Inhalable Cr(VI) correlated with urinary Cr (rS = 0.64) and RBC-Cr (rS = 0.53). Workers within steel production showed the highest concentrations of inhalable, urinary and RBC Cr. Workers with inferred non-acceptable local exhaustion ventilation showed significantly higher inhalable Cr(VI), urinary and RBC Cr concentrations compared with those with inferred acceptable ventilation. Furthermore, workers with inferred correct use of respiratory protection were exposed to significantly higher concentrations of Cr(VI) in air and had higher levels of Cr in urine and RBC than those assessed with incorrect or no use. Based on the Swedish job-exposure-matrix, approximately 17 900 workers were estimated to be occupationally exposed to Cr(VI) today., Conclusions: Our study demonstrates that some workers in Sweden are exposed to high levels of the non-threshold carcinogen Cr(VI). Employers and workers seem aware of Cr(VI) exposure, but more efficient exposure control strategies are required. National strategies aligned with the European strategies are needed in order to eliminate this cause of occupational cancer., Competing Interests: Declaration of Competing interest The authors declare no conflicts of interest., (Copyright © 2023 The Authors. Published by Elsevier GmbH.. All rights reserved.)- Published
- 2024
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8. Dynamics of pre-shift and post-shift lung function parameters among wood workers in Ghana.
- Author
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Ekman J, Quartey P, Ussif AM, Ricklund N, Egbenya DL, Wiafe GA, Tsegah KM, Karikari A, Löfstedt H, and Djankpa FT
- Abstract
Background: Diseases affecting the lungs and airways contribute significantly to the global burden of disease. The problem in low- and middle-income countries appears to be exacerbated by a shift in global manufacturing base to these countries and inadequate enforcement of environmental and safety standards. In Ghana, the potential adverse effects on respiratory function associated with occupational wood dust exposure have not been thoroughly investigated., Methods: Sixty-four male sawmill workers and 64 non-woodworkers participated in this study. The concentration of wood dust exposure, prevalence and likelihood of association of respiratory symptoms with wood dust exposure and changes in pulmonary function test (PFT) parameters in association with wood dust exposure were determined from dust concentration measurements, symptoms questionnaire and lung function test parameters., Results: Sawmill workers were exposed to inhalable dust concentration of 3.09 ± 0.04 mg/m
3 but did not use respirators and engaged in personal grooming habits that are known to increase dust inhalation. The sawmill operators also showed higher prevalence and likelihoods of association with respiratory symptoms, a significant cross-shift decline in some PFT parameters and a shift towards a restrictive pattern of lung dysfunction by end of daily shift. The before-shift PFT parameters of woodworkers were comparable to those of non-woodworkers, indicating a lack of chronic effects of wood dust exposure., Conclusions: Wood dust exposure at the study site was associated with acute respiratory symptoms and acute changes in some PFT parameters. This calls for institution and enforcement of workplace and environmental safety policies to minimise exposure at sawmill operating sites, and ultimately, decrease the burden of respiratory diseases., Competing Interests: Competing interests: The authors declare that they have no competing interests., (Copyright © 2023 Korean Society of Occupational & Environmental Medicine.)- Published
- 2023
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9. Self-reported symptoms in Swedish hairdressers and association with exposure to volatile organic compounds (VOCs), including aldehydes.
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Ricklund N, Bryngelsson IL, and Hagberg J
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- Humans, Self Report, Aldehydes, Cough epidemiology, Cross-Sectional Studies, Sweden epidemiology, Headache, Volatile Organic Compounds adverse effects, Drug-Related Side Effects and Adverse Reactions
- Abstract
Background: Working as a hairdresser involves combined exposure to multiple chemicals in hair treatment products that may induce symptoms in airways and skin., Methods: In this cross-sectional study, perceived symptoms among Swedish hairdressers at 10 hair salons were surveyed through a questionnaire. Associations with personal exposure to volatile organic compounds (VOCs), including aldehydes, and their corresponding hazard index (HI), based on the estimated risk for non-cancer health effects, were examined. The prevalence of four out of 11 symptoms was compared to available reference datasets from two other studies of office workers and school staff., Results: All 11 surveyed symptoms were reported among the hairdressers (n = 38). For the whole study group, the most prevalent symptoms were dripping nose (n = 7) and headache (n = 7), followed by eczema (n = 6), stuffed nose (n = 5), cough (n = 5) and discomfort with strong odors (n = 5). Significant relationships between exposure and symptoms were scarce. The exception was total VOC (TVOC) exposure adjusted to worked years in the profession; a difference was observed for any symptom between hairdressers in the group with 20 + years compared to 0-5 years in the profession (logistic regression, OR 0.03, 95% CI 0.001-0.70). Out of the four symptoms available for comparison, the prevalence of headache and cough was significantly higher in hairdressers than in controls (OR 5.18, 95% CI 1.86-13.43 and OR 4.68, 95% CI 1.17-16.07, respectively)., Conclusions: Adverse health effects related to occupation was common among the hairdressers, implying a need for exposure control measures in hair salons. Symptoms of headache and cough were more frequently reported by hairdressers than staff in offices and schools. A healthy worker effect among the hairdressers was indicated in the group with 20 + years compared to 0-5 years in the profession. Significant relationships between measured exposure and symptoms were scarce but gave information about advantages and disadvantages of the different exposure measures. The study design could be improved by increasing the size of the study population, using a better match of reference data and increasing the applicability and representability over time of the measured exposure., (© 2023. BioMed Central Ltd., part of Springer Nature.)
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- 2023
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10. Occupational Exposure to Volatile Organic Compounds (VOCs), Including Aldehydes for Swedish Hairdressers.
- Author
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Ricklund N, Bryngelsson IL, and Hagberg J
- Subjects
- Humans, Aldehydes, Sweden, Formaldehyde, Occupational Exposure, Volatile Organic Compounds
- Abstract
Working as a professional hairdresser involves the daily usage of many different hair treatment products containing chemicals in complex mixtures. Exposure may induce symptoms in the airways and on the skin. In this study, exposure of hairdressers to volatile organic compounds (VOCs), including aldehydes, was measured in the personal breathing zone in the spring of 2017. The study included 30 hairdressers evenly distributed over ten hair salons in the town of Örebro, Sweden. Work tasks and indoor climate were also surveilled. A hazard index (HI) based on chronic reference values for health was calculated to indicate combined exposure risk. In total, 90 VOCs, including nine aldehydes, were identified. Individual exposure expressed as a total concentration of VOCs (TVOCs) were in the range of 50-3600 µg/m3 toluene equivalent (median 460 µg/m3) and the HI was in the range 0.0046-13 (median 0.9). Exposure was more strongly influenced by variability among hairdressers than among salons. The HI indicated an increased risk of non-carcinogenic effects (HI ≥ 1) at four of the 10 hair salons. Individual working procedures, ventilation, volumetric usage of hair treatment products, certain chemicals in products (formaldehyde, isopropanol, and 2,4- and 2,6-toluene diisocyanate), and availability of reference values may have affected estimates of exposure risks. Nevertheless, the HI may be suitable as a screening tool to assess potential exposure risk posed to hairdressers since it considers the complexity of chemical mixtures and the chronic component of VOC exposure occurring in all indoor environments., (© The Author(s) 2022. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.)
- Published
- 2023
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11. Changes in Reported Symptoms Attributed to Office Environments in Sweden between 1995 and 2020.
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Egfors D, Gunnarsson AG, and Ricklund N
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- Cross-Sectional Studies, Headache complications, Humans, Surveys and Questionnaires, Sweden epidemiology, Air Pollution, Indoor, Sick Building Syndrome etiology
- Abstract
Non-specific building-related symptoms (NBRSs) describe various symptoms in those affected. Questionnaires are the first step in investigating suspected NBRSs in office environments and have been used for over two decades. However, changes in reporting of symptoms among office workers over time are currently unknown. The overall aim was thus to investigate if reported symptoms and perceived causality to the office environment have changed during 25 years of using the MM 040 NA Office questionnaire. A cross-sectional study of 26,477 questionnaires from 1995-2020 was conducted, where 12 symptoms and perceived causality to office environment were examined using logistic regression analyses of 5-year groups adjusted for sex and atopy. Reporting trends in the year groups varied slightly among symptoms, but eight symptoms were statistically significant in the 2015-2020 group compared to the 1995-1999 group. Seven symptoms had increased: fatigue, heavy-feeling head, headache, difficulties concentrating, itchy/irritated eyes, congested/runny nose, and dry/red hands. One symptom decreased: hoarseness/dry throat. Perceived causality of symptoms to the office environment decreased to a statistically significant degree in 2015-2020 for 11 symptoms, and there was an overall trend of decreasing perceived causality throughout the year groups for most symptoms. The observed time trends suggest a need for up-to-date reference data, to keep up with changes in symptom reporting in office environments over time.
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- 2022
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12. Occurrence of brominated dioxins in a study using various firefighting methods.
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Bjurlid F, Kärrman A, Ricklund N, and Hagberg J
- Abstract
The use of different firefighting methods influences how fast a fire is extinguished and how fast the temperature drops in the area affected by the fire. These differences may also influence the formation of harmful pollutants during firefighting of an accidental fire. The aim was to study occurrence of brominated dibenzo-p-dioxins and furans (PBDD/Fs) in gas and soot during five fire scenarios resembling a small apartment fire and where different firefighting methods were used. Samples of gas and soot were taken both during the buildup of the fire and during the subsequent extinguishing of the fire while using different firefighting methods (nozzle, compressed air foam system, cutting extinguisher) and an extinguishing additive. New containers equipped with identical sets of combustible material were used for the five tests. The use of different firefighting methods and extinguishing additive induced variations in concentration and congener profiles of detected PBDD/Fs. The concentration range of ∑PBDD/Fs in gas was 4020-18,700pg/m
3 , and in soot 76-4092pg/m2 . PBDFs were the predominant congeners and 1,2,3,4,6,7,8-HpBDF was the most abundant congener. Chlorinated dibenzo-p-dioxins and furans (PCDD/Fs) were also monitored. The PBDD/Fs contributed with in average 97% to the total (PCDD/Fs plus PBDD/Fs) toxic equivalents, in soot and gas. During extinguishing, the shorter time the temperature was around 300°C, the lower occurrence of PBDD/Fs. In the study the firefighting methods showed a difference in how effectively they induced a temperature decrease below 300°C in the fire zone during quenching, where cutting extinguishing using additive and the compressed air foam system showed the fastest drop in temperature., (Copyright © 2017 Elsevier B.V. All rights reserved.)- Published
- 2017
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13. Levels and potential sources of decabromodiphenyl ethane (DBDPE) and decabromodiphenyl ether (DecaBDE) in lake and marine sediments in Sweden.
- Author
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Ricklund N, Kierkegaard A, and McLachlan MS
- Subjects
- Environmental Monitoring, Fresh Water chemistry, Seawater chemistry, Sweden, Bromobenzenes analysis, Flame Retardants analysis, Geologic Sediments chemistry, Halogenated Diphenyl Ethers analysis, Water Pollutants, Chemical analysis
- Abstract
Decabromodiphenyl ethane (DBDPE) is a brominated flame retardant (BFR) used as a replacement for the structurally similar decabromodiphenyl ether (decaBDE), which is a regulated environmental contaminant of concern. DBDPE has been found in indoor dust, sewage sludge, sediment, and biota, but little is known about its occurrence and distribution in the environment In this paper, sediment was analyzed from 11 isolated Swedish lakes and along a transect running from central Stockholm through the Stockholm archipelago to the Baltic Sea. DBDPE was present in all samples. In lake sediment, the levels ranged from 0.23 to 11 ng/g d.wt. and were very similar to the levels of decaBDE (0.48-11 ng/g d.wt.). Since the lakes have no known point sources of BFRs, their presence in the sediments provides evidence for long-range atmospheric transport and deposition. In the marine sediment, the DBDPE and decaBDE levels decreased by a factor of 20-50 over 40 km from the inner harbor to the outer archipelago. There the DBDPE and decaBDE levels were similar to the levels in nearby isolated lakes. The results indicate that contamination of the Swedish environment with DBDPE has already approached that of decaBDE, and that this contamination is primarily occurring via the atmosphere.
- Published
- 2010
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14. Mass balance of decabromodiphenyl ethane and decabromodiphenyl ether in a WWTP.
- Author
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Ricklund N, Kierkegaard A, McLachlan MS, and Wahlberg C
- Subjects
- Cities, Isotope Labeling, Risk Assessment, Sewage analysis, Sewage chemistry, Sweden, Time Factors, Waste Disposal, Fluid instrumentation, Bromobenzenes analysis, Environmental Monitoring, Flame Retardants analysis, Halogenated Diphenyl Ethers analysis, Waste Disposal, Fluid methods, Water Pollutants, Chemical analysis
- Abstract
The additive flame retardant decabromodiphenyl ethane (deBDethane) has been identified in the environment, but little is known about its environmental behaviour. It is structurally similar to decabromodiphenyl ether (decaBDE), making it conceivable that it may also become an environmental contaminant of concern. In this study a mass balance of deBDethane and decaBDE was undertaken in a modern WWTP in Stockholm serving 7.05x10(5) inhabitants. Flow proportional samples of plant influent and effluent as well as daily grab samples of digested sludge were collected during two 7-day periods. All samples were analyzed with GC/HRMS using isotope labelled internal standards. The mean mass flows of deBDethane and decaBDE to the WWTP were 6.0 g per day and 55 g per day, respectively. Of this, less than 1% of both BFRs left the WWTP via the effluent, while the bulk was sequestered into the digested sludge, where the mean concentrations of deBDethane and decaBDE were 81 and 800 ng g(-1)d.wt., respectively. It is concluded that the transfer efficiency of deBDethane from the technosphere to the environment via WWTPs is similar to that of decaBDE.
- Published
- 2009
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15. An international survey of decabromodiphenyl ethane (deBDethane) and decabromodiphenyl ether (decaBDE) in sewage sludge samples.
- Author
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Ricklund N, Kierkegaard A, and McLachlan MS
- Subjects
- Flame Retardants analysis, Quality Control, Bromobenzenes analysis, Data Collection, Halogenated Diphenyl Ethers analysis, Internationality, Sewage chemistry
- Abstract
Decabromodiphenyl ethane (deBDethane) is an additive flame retardant marketed as a replacement for decabromodiphenyl ether (decaBDE). The structures of the two chemicals are similar, and hence deBDethane may also become an environmental contaminant of concern. Environmental data on deBDethane are scarce. Since sewage sludge is an early indicator of leakage of these chemicals into the environment, an international survey of deBDethane and decaBDE levels in sludge was conducted. Samples were collected from 42 WWTPs in 12 different countries and analyzed with GC/LRMS. DeBDethane was present in sludge from all countries and may therefore be a worldwide concern. The levels of deBDethane in sludge samples from the Ruhr area of Germany were the highest so far reported in the literature (216 ng g(-1)d.wt.). The [deBDethane]/[decaBDE] quotient for the whole data set ranged from 0.0018 to 0.83. High ratios were found in and around Germany where deBDethane imports are known to have been high and substitution of decaBDE with deBDethane is likely to have occurred. Low ratios were found in the USA and the UK, countries that have traditionally been large users of decaBDE. An estimate of the flux of deBDEthane from the technosphere via WWTPs to the environment within the European Union gave 1.7+/-0.34 mg annually per person. The corresponding value for decaBDE was 41+/-22 mg annually per person.
- Published
- 2008
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16. Silica gel as a particulate carrier of poorly water-soluble substances in aquatic toxicity testing.
- Author
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Breitholtz M, Ricklund N, Bengtsson BE, and Persson NJ
- Subjects
- Animals, Copepoda chemistry, Halogenated Diphenyl Ethers, Hydrogen-Ion Concentration, Larva drug effects, Larva growth & development, Phenyl Ethers analysis, Phenyl Ethers chemistry, Phenyl Ethers toxicity, Polybrominated Biphenyls analysis, Polybrominated Biphenyls chemistry, Polybrominated Biphenyls toxicity, Seawater, Silica Gel, Silicon Dioxide toxicity, Copepoda drug effects, Environmental Monitoring methods, Models, Chemical, Silicon Dioxide chemistry, Toxicity Tests methods
- Abstract
Aquatic toxicity tests were originally developed for water-soluble substances. However, many substances are hydrophobic and thus poorly water-soluble, resulting in at least two major implications. Firstly, toxicity may not be reached within the range of water solubility of the tested compound(s), which may result in the formation of solids or droplets of the tested substance and consequently an uneven exposure. Secondly, because of multi-phase distribution of the tested substance it may be complicated to keep exposure concentrations constant. To overcome such problems, we have introduced silica gel as a particulate carrier in a toxicity test with the benthic copepod Nitocra spinipes. The main objective of the current study was to evaluate whether a controlled exposure could be achieved with the help of silica gel for testing single poorly water-soluble substances. A secondary objective was to evaluate whether an equilibrium mass balance model could predict internal concentrations that were consistent with the toxicity data and measured internal concentrations of two model hydrophobic substances, i.e., the polybrominated diphenyl ethers BDE-47 and BDE-99. Larval N. spinipes were exposed for 6 days to BDE-47 and BDE-99, respectively, in the silica gel test system and, for comparative reasons, in a similar and more traditional semi-static water test system. Via single initial amounts of the model substances administered on the silica gel, effects on both larval development and mortality resulted in higher and more concentration-related toxicity than in the water test system. We conclude that the silica gel test system enables a more controlled exposure of poorly water-soluble substances than the traditional water test system since the concentration-response relationship becomes distinct and there is no carrier solvent present during testing. Also, the single amount of added substance given in the silica gel test system limits the artefacts (e.g., increased chemical load in test system) that a semi-static renewal may introduce when testing substances that partition to non-water phases. However, measured and modelled internal concentrations did not match toxicity, which may indicate that chemical equilibrium was not reached during the test. Further experiments are thus needed to explain the processes behind the observed positive effects of silica gel and a kinetic model would likely also be more appropriate to describe the concentrations and distributions in the two test systems.
- Published
- 2007
- Full Text
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