Environmental context Water soluble ions (WSIs) in aerosols, especially in marine secondary aerosols, can participate in the formation of cloud condensation nuclei (CCN) in the marine boundary layer, which can affect global climate. In our study, in-situ gas and aerosol compositions were analysed to explore the formation paths and forms of secondary aerosols in the Southern Ocean (SO) in summer. Our study provided novel data on these formation mechanisms of secondary aerosols in the SO, with potential impacts on our understanding of global climate change. Abstract Water-soluble ions (WSIs) in aerosols, especially marine secondary aerosols, may participate in the formation of cloud condensation nuclei (CCN) in the marine boundary layer and affect the global climate. However, there is still a lack of studies on the background concentrations and the formation mechanisms of marine secondary aerosols in polar areas. High time resolution concentrations of WSIs in aerosols were analysed by an in situ gas and aerosol composition monitoring system in the Southern Ocean (SO) to identify the formation of marine secondary aerosols including methanesulfonic acid (MSA), SO42− and NO3−. The average hourly mass concentration of WSIs was 663 ng m−3 and secondary aerosols accounted for 49.8 ± 20.2 % of the WSIs. SO42− and NO3− were mainly formed by homogeneous reaction, whereas homogeneous and heterogeneous reactions together contributed to the formation of MSA− in aerosols in the SO. The melting of sea ice and the increase of chlorophyll-a (Chl-a) concentration contributed to the formation of MSA−. MSA-Na, MSA-NH4+, MSA-SO42−, MSA-Mg, MSA-K and MSA-Cl existed in marine aerosols. Secondary inorganic aerosols existed mainly in the forms of NH4NO3, (NH4)2SO4, Na2SO4 and MgSO4. The results enrich the data of WSI concentrations and formation mechanisms of secondary aerosols in the SO.
气溶胶尤其是海洋次生气溶胶中的水溶性离子(wsi)参与海洋边界层云凝结核(CCN)的形成，进而影响全球气候。本研究分析了南大洋夏季次生气溶胶的形成路径和形态，探讨了南大洋夏季次生气溶胶的成因。我们的研究为这些次生气溶胶在SO中的形成机制提供了新的数据，对我们对全球气候变化的理解有潜在的影响。气溶胶尤其是海洋次生气溶胶中的水溶性离子(wsi)可能参与海洋边界层云凝结核(CCN)的形成并影响全球气候。然而，目前对极地海洋次生气溶胶的背景浓度及其形成机制的研究还很缺乏。利用南大洋气体和气溶胶成分原位监测系统分析了气溶胶中wsi的高时间分辨率浓度，以确定海洋二次气溶胶包括甲烷磺酸(MSA)、SO42−和NO3−的形成。wsi的平均小时质量浓度为663 ng m−3，次生气溶胶占wsi的49.8±20.2%。SO42−和NO3−主要通过均相反应生成，而均相反应和非均相反应共同促进了SO中气溶胶中MSA−的生成。海冰的融化和叶绿素-a (Chl-a)浓度的增加是MSA−形成的主要原因。海洋气溶胶中存在MSA-Na、MSA-NH4+、MSA-SO42−、MSA-Mg、MSA-K和MSA-Cl。二次无机气溶胶主要以NH4NO3、(NH4)2SO4、Na2SO4和MgSO4的形式存在。研究结果丰富了大气中WSI浓度和二次气溶胶形成机制的数据。
{"title":"Formation of marine secondary aerosols in the Southern Ocean, Antarctica","authors":"Shanshan Wang, Jinpei Yan, Qi Lin, Miming Zhang, Suqing Xu, Shuhui Zhao, Meina Ruan","doi":"10.1071/en21068","DOIUrl":"https://doi.org/10.1071/en21068","url":null,"abstract":"Environmental context Water soluble ions (WSIs) in aerosols, especially in marine secondary aerosols, can participate in the formation of cloud condensation nuclei (CCN) in the marine boundary layer, which can affect global climate. In our study, in-situ gas and aerosol compositions were analysed to explore the formation paths and forms of secondary aerosols in the Southern Ocean (SO) in summer. Our study provided novel data on these formation mechanisms of secondary aerosols in the SO, with potential impacts on our understanding of global climate change. Abstract Water-soluble ions (WSIs) in aerosols, especially marine secondary aerosols, may participate in the formation of cloud condensation nuclei (CCN) in the marine boundary layer and affect the global climate. However, there is still a lack of studies on the background concentrations and the formation mechanisms of marine secondary aerosols in polar areas. High time resolution concentrations of WSIs in aerosols were analysed by an in situ gas and aerosol composition monitoring system in the Southern Ocean (SO) to identify the formation of marine secondary aerosols including methanesulfonic acid (MSA), SO42− and NO3−. The average hourly mass concentration of WSIs was 663 ng m−3 and secondary aerosols accounted for 49.8 ± 20.2 % of the WSIs. SO42− and NO3− were mainly formed by homogeneous reaction, whereas homogeneous and heterogeneous reactions together contributed to the formation of MSA− in aerosols in the SO. The melting of sea ice and the increase of chlorophyll-a (Chl-a) concentration contributed to the formation of MSA−. MSA-Na, MSA-NH4+, MSA-SO42−, MSA-Mg, MSA-K and MSA-Cl existed in marine aerosols. Secondary inorganic aerosols existed mainly in the forms of NH4NO3, (NH4)2SO4, Na2SO4 and MgSO4. The results enrich the data of WSI concentrations and formation mechanisms of secondary aerosols in the SO.","PeriodicalId":11714,"journal":{"name":"Environmental Chemistry","volume":"3 1","pages":""},"PeriodicalIF":4.3,"publicationDate":"2021-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75023064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Environmental context Marine-derived non-methane hydrocarbons (NMHCs) are thought to affect atmospheric oxidation balance and aerosol formation, hence playing an important role in regulating climate. In this study, we report the distributions and sea-to-air fluxes of 10 NMHCs in the East China Sea (ECS), and assess the roles of phytoplankton assemblages in the occurrence and emission of NMHCs in the ECS. The results will improve our understanding of the biogeochemical cycling of NMHCs in marine systems. Abstract Non-methane hydrocarbons (NMHCs) are important reactive trace-gases that are emitted from oceanic sources. However, it remains unclear how phytoplankton, either total biomass or specific species, affect the generation and emission of NMHCs. This study conducted field observations of NMHCs in the East China Sea (ECS) in autumn, 2014. The mean concentrations of ethane, propane, i-butane, n-butane, pentane, ethene, propene, 1-butene, 1-pentene and isoprene were 20.1 ± 3.6, 20.3 ± 20.2, 4.5 ± 0.9, 10.5 ± 2.3, 14.8 ± 3.4, 63.7 ± 20.8, 23.6 ± 6.6, 7.4 ± 2.9, 15.9 ± 4.3 and 69.4 ± 24.9 pmol L−1 respectively. Horizontal and vertical profiles of NMHCs showed that different water masses had distinct influences and the coastal areas had generally higher concentrations of NMHCs. There were significant positive correlations between alkanes or alkenes, which suggested that their production and fates in the surface seawater were similar. A significant positive correlation was observed between the isoprene and Chl-a concentrations, while no significant correlation was found between Chl-a and any other NMHCs. These results highlighted that, although NMHCs can be produced by phytoplankton, using Chl-a data or phytoplankton assemblages to estimate the production of other NMHCs in seawater is unreliable. Therefore, future research must determine the factors that control the production of these NMHCs. In addition, the results of estimated sea-to-air fluxes of NMHCs underscored the importance of the ECS as a source of NMHCs and the related atmospheric volatile organic compounds.
{"title":"Occurrence and emission of non-methane hydrocarbons in the East China Sea: roles of phytoplankton assemblages","authors":"Jian‐Long Li, Xing Zhai, Rong‐Liang Chen, Ying-Cui Wu, Hong‐Hai Zhang","doi":"10.1071/en21066","DOIUrl":"https://doi.org/10.1071/en21066","url":null,"abstract":"Environmental context Marine-derived non-methane hydrocarbons (NMHCs) are thought to affect atmospheric oxidation balance and aerosol formation, hence playing an important role in regulating climate. In this study, we report the distributions and sea-to-air fluxes of 10 NMHCs in the East China Sea (ECS), and assess the roles of phytoplankton assemblages in the occurrence and emission of NMHCs in the ECS. The results will improve our understanding of the biogeochemical cycling of NMHCs in marine systems. Abstract Non-methane hydrocarbons (NMHCs) are important reactive trace-gases that are emitted from oceanic sources. However, it remains unclear how phytoplankton, either total biomass or specific species, affect the generation and emission of NMHCs. This study conducted field observations of NMHCs in the East China Sea (ECS) in autumn, 2014. The mean concentrations of ethane, propane, i-butane, n-butane, pentane, ethene, propene, 1-butene, 1-pentene and isoprene were 20.1 ± 3.6, 20.3 ± 20.2, 4.5 ± 0.9, 10.5 ± 2.3, 14.8 ± 3.4, 63.7 ± 20.8, 23.6 ± 6.6, 7.4 ± 2.9, 15.9 ± 4.3 and 69.4 ± 24.9 pmol L−1 respectively. Horizontal and vertical profiles of NMHCs showed that different water masses had distinct influences and the coastal areas had generally higher concentrations of NMHCs. There were significant positive correlations between alkanes or alkenes, which suggested that their production and fates in the surface seawater were similar. A significant positive correlation was observed between the isoprene and Chl-a concentrations, while no significant correlation was found between Chl-a and any other NMHCs. These results highlighted that, although NMHCs can be produced by phytoplankton, using Chl-a data or phytoplankton assemblages to estimate the production of other NMHCs in seawater is unreliable. Therefore, future research must determine the factors that control the production of these NMHCs. In addition, the results of estimated sea-to-air fluxes of NMHCs underscored the importance of the ECS as a source of NMHCs and the related atmospheric volatile organic compounds.","PeriodicalId":11714,"journal":{"name":"Environmental Chemistry","volume":"1 1","pages":""},"PeriodicalIF":4.3,"publicationDate":"2021-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89744060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Chaaban, B. Lartiges, Eliane El Hayek, V. Kazpard, C. Plisson-Chastang, P. Vicendo, C. Caillet
Environmental context The molecular organisation of humic substances is key to understanding various natural and engineered processes, such as metal speciation and bioavailability. Two main models have been proposed: polymeric organisation and supramolecular organisation. A physicochemical approach, based on the interaction of humic acid with increasing amounts of cationic surfactants, leads to a sequence of molecular structures that provides support to the supramolecular view of humic organisation. Abstract The structural organisation of extracted humic matter, polymeric or supramolecular, has been a long-standing controversial issue. In this paper, we show that the interaction between a reference humic material, the Suwannee River Humic Acid (SRHA), and a homologous series of cationic surfactants (n-alkyl trimethyl ammonium chloride) provides key insights to resolve the controversy. By combining measurements of turbidity, electrophoretic mobility, surface tension and cryogenic transmission electron microscopy, we show that: (i) the binding of cationic surfactant to the anionic humic acid is initially triggered by electrostatic interactions; (ii) the contrasting evolution of turbidity–surfactant concentration curves implies that the surfactant alkyl chain interacts with the hydrophobic moieties of humic matter from very low concentrations of surfactant; (iii) a drastic restructuring of humic matter occurs on surfactant binding, which brings out supplementary anionic humic sites; (iv) in the presence of C12 cationic surfactant, SRHA spontaneously forms stable nanoscale unilamellar vesicles, which, in addition to the high surface activity of complexes, could be of interest in the remediation of oil-contaminated environments; (v) the sequence of molecular structures obtained from SRHA with increasing amounts of C12-cationic surfactant – humic-rich vesicles, aggregates, surfactant-rich vesicles – bears striking similarities with the phase behaviour of aqueous mixtures of anionic and cationic surfactants, thus supporting the supramolecular view of humic structure.
{"title":"Complexes of humic acid with cationic surfactants support the supramolecular view of extracted humic matter","authors":"A. Chaaban, B. Lartiges, Eliane El Hayek, V. Kazpard, C. Plisson-Chastang, P. Vicendo, C. Caillet","doi":"10.1071/en21031","DOIUrl":"https://doi.org/10.1071/en21031","url":null,"abstract":"Environmental context The molecular organisation of humic substances is key to understanding various natural and engineered processes, such as metal speciation and bioavailability. Two main models have been proposed: polymeric organisation and supramolecular organisation. A physicochemical approach, based on the interaction of humic acid with increasing amounts of cationic surfactants, leads to a sequence of molecular structures that provides support to the supramolecular view of humic organisation. Abstract The structural organisation of extracted humic matter, polymeric or supramolecular, has been a long-standing controversial issue. In this paper, we show that the interaction between a reference humic material, the Suwannee River Humic Acid (SRHA), and a homologous series of cationic surfactants (n-alkyl trimethyl ammonium chloride) provides key insights to resolve the controversy. By combining measurements of turbidity, electrophoretic mobility, surface tension and cryogenic transmission electron microscopy, we show that: (i) the binding of cationic surfactant to the anionic humic acid is initially triggered by electrostatic interactions; (ii) the contrasting evolution of turbidity–surfactant concentration curves implies that the surfactant alkyl chain interacts with the hydrophobic moieties of humic matter from very low concentrations of surfactant; (iii) a drastic restructuring of humic matter occurs on surfactant binding, which brings out supplementary anionic humic sites; (iv) in the presence of C12 cationic surfactant, SRHA spontaneously forms stable nanoscale unilamellar vesicles, which, in addition to the high surface activity of complexes, could be of interest in the remediation of oil-contaminated environments; (v) the sequence of molecular structures obtained from SRHA with increasing amounts of C12-cationic surfactant – humic-rich vesicles, aggregates, surfactant-rich vesicles – bears striking similarities with the phase behaviour of aqueous mixtures of anionic and cationic surfactants, thus supporting the supramolecular view of humic structure.","PeriodicalId":11714,"journal":{"name":"Environmental Chemistry","volume":"81 1","pages":""},"PeriodicalIF":4.3,"publicationDate":"2021-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90593328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Černá, K. Michalíková, Jaroslav Semerád, T. Cajthaml
Environmental context Endocrine disrupting compounds (EDCs) are among the most recently targeted micropollutants detected in wastewater treatment plant (WWTP) effluents and in aquatic environments. There is a need for the development of robust analytical methods for most relevant estrogenic EDCs. This study provides optimisation of analytical techniques and addresses several relevant aspects that are often overlooked in the literature. The method was finally successfully employed for the analysis of WWTP effluents. Abstract Two analytical approaches – liquid chromatography–tandem mass spectrometry (LC-MS/MS) and gas chromatography–tandem mass spectrometry (GC-MS/MS) methods – were compared for the simultaneous determination of the 19 most important oestrogenic endocrine disrupting chemicals (EDCs), such as 17β-oestradiol, oestrone, 17α-ethinyloestradiol, bisphenol A and triclosan in wastewater treatment plant effluents. To lower the instrument limits of detection (ILODs), a derivatisation step preceded detection in both methods. The stability, sensitivity and ease of use of dansylation (Dns) for LC-MS/MS and trimethylsilylation (TMS) for GC-MS/MS derivatives were evaluated before method validation. TMS derivatisation products were highly unstable over time. Parameters such as susceptibility to matrix effects and the stability of monodansylated and didansylated derivatisation products of phytohormones are discussed. Lower ILODs of highly potent EDCs (0.11 ng mL−1 for 17β-oestradiol, 0.01 ng mL−1 for 17α-ethinyloestradiol and 0.22 ng mL−1 for oestrone) and stability of derivatisation products within 7 days were achieved using LC–MS/MS; therefore, further validation of this method at environmentally relevant concentrations was conducted. The method limits of detection (MLODs) met the requirements of the European Union defined in Directive 2008/105/ES for 17α-ethinyloestradiol (0.035 ng L−1) and 17β-oestradiol (0.4 ng L−1). Twenty samples of wastewater treatment plant effluent from the Czech Republic were screened using LC-MS/MS. Fifteen of the EDCs were detected in at least one sample. The most abundant EDCs were bisphenol A, with a concentration up to 1107 ng L−1, and triclosan, with a concentration up to 76 ng L−1. No seasonal trend between late spring and autumn samples was observed in the frequency or quantity of analytes.
环境背景内分泌干扰化合物(EDCs)是最近在污水处理厂(WWTP)流出物和水生环境中检测到的目标微污染物之一。有必要为大多数相关的雌激素EDCs开发可靠的分析方法。本研究提供了分析技术的优化，并解决了文献中经常被忽视的几个相关方面。最后将该方法成功应用于污水处理厂污水的分析。摘要比较了液相色谱-串联质谱(LC-MS/MS)和气相色谱-串联质谱(GC-MS/MS)两种分析方法同时测定污水处理厂出水中17β-雌二醇、雌酮、17α-炔雌醇、双酚A和三氯生等19种最重要的雌激素内分泌干扰物质。为了降低仪器检测限(ILODs)，两种方法的检测前都有一个衍生化步骤。在方法验证前，对LC-MS/MS的丹基化(Dns)和GC-MS/MS衍生物的三甲基硅基化(TMS)的稳定性、灵敏度和易用性进行了评价。随着时间的推移，TMS衍生产品高度不稳定。讨论了对基质效应的敏感性以及植物激素的单、二丹酰衍生物的稳定性等参数。高效EDCs (17β-雌二醇为0.11 ng mL - 1, 17α-炔雌醇为0.01 ng mL - 1，雌二醇为0.22 ng mL - 1)的ilod较低，衍生产物在7天内稳定;因此，在环境相关浓度下对该方法进行了进一步验证。方法检出限(mlod)符合欧盟指令2008/105/ES对17α-炔雌醇(0.035 ng L−1)和17β-炔雌醇(0.4 ng L−1)的要求。采用LC-MS/MS对来自捷克共和国的20个污水处理厂的废水进行了筛选。在至少一个样本中检测到15种EDCs。EDCs含量最高的是双酚A，浓度高达1107 ng L−1，三氯生浓度高达76 ng L−1。晚春和秋季样品在分析物的频率或数量上没有观察到季节性趋势。
{"title":"Analytical determination of oestrogenic endocrine disruptors: the method of choice for wastewater treatment plant effluents","authors":"T. Černá, K. Michalíková, Jaroslav Semerád, T. Cajthaml","doi":"10.1071/en21028","DOIUrl":"https://doi.org/10.1071/en21028","url":null,"abstract":"Environmental context Endocrine disrupting compounds (EDCs) are among the most recently targeted micropollutants detected in wastewater treatment plant (WWTP) effluents and in aquatic environments. There is a need for the development of robust analytical methods for most relevant estrogenic EDCs. This study provides optimisation of analytical techniques and addresses several relevant aspects that are often overlooked in the literature. The method was finally successfully employed for the analysis of WWTP effluents. Abstract Two analytical approaches – liquid chromatography–tandem mass spectrometry (LC-MS/MS) and gas chromatography–tandem mass spectrometry (GC-MS/MS) methods – were compared for the simultaneous determination of the 19 most important oestrogenic endocrine disrupting chemicals (EDCs), such as 17β-oestradiol, oestrone, 17α-ethinyloestradiol, bisphenol A and triclosan in wastewater treatment plant effluents. To lower the instrument limits of detection (ILODs), a derivatisation step preceded detection in both methods. The stability, sensitivity and ease of use of dansylation (Dns) for LC-MS/MS and trimethylsilylation (TMS) for GC-MS/MS derivatives were evaluated before method validation. TMS derivatisation products were highly unstable over time. Parameters such as susceptibility to matrix effects and the stability of monodansylated and didansylated derivatisation products of phytohormones are discussed. Lower ILODs of highly potent EDCs (0.11 ng mL−1 for 17β-oestradiol, 0.01 ng mL−1 for 17α-ethinyloestradiol and 0.22 ng mL−1 for oestrone) and stability of derivatisation products within 7 days were achieved using LC–MS/MS; therefore, further validation of this method at environmentally relevant concentrations was conducted. The method limits of detection (MLODs) met the requirements of the European Union defined in Directive 2008/105/ES for 17α-ethinyloestradiol (0.035 ng L−1) and 17β-oestradiol (0.4 ng L−1). Twenty samples of wastewater treatment plant effluent from the Czech Republic were screened using LC-MS/MS. Fifteen of the EDCs were detected in at least one sample. The most abundant EDCs were bisphenol A, with a concentration up to 1107 ng L−1, and triclosan, with a concentration up to 76 ng L−1. No seasonal trend between late spring and autumn samples was observed in the frequency or quantity of analytes.","PeriodicalId":11714,"journal":{"name":"Environmental Chemistry","volume":"81 1","pages":""},"PeriodicalIF":4.3,"publicationDate":"2021-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81726363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Environmental context Organobromine compounds are a potential environmental hazard, but there are many uncertainties about their natural sources. This paper investigated the photochemical generation of bromophenols in the presence of dissolved organic matters (DOMs) and proxies, and demonstrated that DOMs enhance the photobromination reaction. The result indicates that the bromination process induced by sunlit DOMs likely contributes to the natural sources of organobromine compounds in the marine environment. Abstract Organobromine compounds are substantial environmental hazards owing to their high toxicity on organisms. Here we study the photochemical formation of bromophenols from phenol in bromide aqueous solutions (0.8–80 mM) in the presence of anthraquinone-2-sulfonate (AQ2S) and benzophenone (BP), which were adopted as the proxies of dissolved organic matter (DOM) having quinones and aromatic ketones structures. The formation of bromophenols increased with the increase of the concentrations of AQ2S and BP, and the promotion effect was in the order AQ2S > BP. Bromide and chloride ions were found to promote the formation of bromophenols. Moreover, natural DOM from Suwannee River was found to enhance this photobromination reaction at a low concentration (1 mg L−1). These results demonstrate the generation of reactive halogen species from sunlit DOM, and such a process could account for the abiotic source of organobromine compounds in a marine environment, as terrestrial DOM distributes universally in estuaries and coastal seawater and could diffuse to the open sea.
{"title":"Enhanced formation of bromophenols by anthraquinone-2-sulfonate and benzophenone: implications for photochemical production of organobromine compounds by dissolved organic matter in a marine environment*","authors":"Hui Liu, X. Qiu, Xiaomei Zhu, Bing Sun, Xiaoxing Zhang","doi":"10.1071/en21036","DOIUrl":"https://doi.org/10.1071/en21036","url":null,"abstract":"Environmental context Organobromine compounds are a potential environmental hazard, but there are many uncertainties about their natural sources. This paper investigated the photochemical generation of bromophenols in the presence of dissolved organic matters (DOMs) and proxies, and demonstrated that DOMs enhance the photobromination reaction. The result indicates that the bromination process induced by sunlit DOMs likely contributes to the natural sources of organobromine compounds in the marine environment. Abstract Organobromine compounds are substantial environmental hazards owing to their high toxicity on organisms. Here we study the photochemical formation of bromophenols from phenol in bromide aqueous solutions (0.8–80 mM) in the presence of anthraquinone-2-sulfonate (AQ2S) and benzophenone (BP), which were adopted as the proxies of dissolved organic matter (DOM) having quinones and aromatic ketones structures. The formation of bromophenols increased with the increase of the concentrations of AQ2S and BP, and the promotion effect was in the order AQ2S > BP. Bromide and chloride ions were found to promote the formation of bromophenols. Moreover, natural DOM from Suwannee River was found to enhance this photobromination reaction at a low concentration (1 mg L−1). These results demonstrate the generation of reactive halogen species from sunlit DOM, and such a process could account for the abiotic source of organobromine compounds in a marine environment, as terrestrial DOM distributes universally in estuaries and coastal seawater and could diffuse to the open sea.","PeriodicalId":11714,"journal":{"name":"Environmental Chemistry","volume":"262 1","pages":""},"PeriodicalIF":4.3,"publicationDate":"2021-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76968423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. K. Boreddy, P. Hegde, A. Aswini, M. Williams, R. Elavarasi, T. V. L. Kumar
Environmental context The export of various man-made pollutants from northern India has a large impact on aerosol formation processes, their transformations and regional environmental chemistry over tropical peninsular India. The quantitative source apportionment of organic aerosols performed in this study provides a better understanding of their sources and implications for climate and air-quality management policies in South Asia. Abstract This study highlights seasonal characteristics, sources, daytime (sea-breeze) and night-time (land-breeze) variations of carbonaceous and water-soluble ionic components in PM10 (<10 µm particulate matter) aerosols from the east coast (Chennai city) of tropical India. Elemental and organic carbon (EC and OC) were found to be higher in winter when air masses were delivered from the northern part of India covered by the Indo-Gangetic-Plains whereas lower concentrations were observed during summer and monsoon associated with marine air masses. Sea salts (Na+ and Cl–), dust (Ca2+ and Mg2+) and nitrates (NO3–) were found to be highest in monsoon, suggesting these species may be co-transported over the sampling site with marine air masses. Using air mass back-trajectory analysis, linear relationships between chemical species and specific mass ratios, we demonstrate that east coast urban aerosols are strongly influenced by aged anthropogenic sources including biomass burning in winter and post monsoon while aged marine emissions mixed with local pollutants (dust and vehicular) are important in monsoon and summer. Further, the mesoscale phenomenon was reflected in measured chemical constituents during the study period. Positive-matrix-factorisation (PMF) analysis confirmed that OC aerosols are largely attributable to chemically aged anthropogenic (53 % in the day and 39 % in the night) and combustion-derived (17 % and 39 %) sources in winter and sea salts mixed with dust and vehicular emissions (61 % and 52 %) during monsoon. These important insights about the sources and formation processes of organic aerosols will help in understanding the formation of atmospheric brown clouds over south Asia.
{"title":"Seasonal variations in characteristics, sources and diurnal patterns of carbonaceous and water-soluble constituents in urban aerosols from the east coast of tropical India","authors":"S. K. Boreddy, P. Hegde, A. Aswini, M. Williams, R. Elavarasi, T. V. L. Kumar","doi":"10.1071/EN21017","DOIUrl":"https://doi.org/10.1071/EN21017","url":null,"abstract":"Environmental context The export of various man-made pollutants from northern India has a large impact on aerosol formation processes, their transformations and regional environmental chemistry over tropical peninsular India. The quantitative source apportionment of organic aerosols performed in this study provides a better understanding of their sources and implications for climate and air-quality management policies in South Asia. Abstract This study highlights seasonal characteristics, sources, daytime (sea-breeze) and night-time (land-breeze) variations of carbonaceous and water-soluble ionic components in PM10 (<10 µm particulate matter) aerosols from the east coast (Chennai city) of tropical India. Elemental and organic carbon (EC and OC) were found to be higher in winter when air masses were delivered from the northern part of India covered by the Indo-Gangetic-Plains whereas lower concentrations were observed during summer and monsoon associated with marine air masses. Sea salts (Na+ and Cl–), dust (Ca2+ and Mg2+) and nitrates (NO3–) were found to be highest in monsoon, suggesting these species may be co-transported over the sampling site with marine air masses. Using air mass back-trajectory analysis, linear relationships between chemical species and specific mass ratios, we demonstrate that east coast urban aerosols are strongly influenced by aged anthropogenic sources including biomass burning in winter and post monsoon while aged marine emissions mixed with local pollutants (dust and vehicular) are important in monsoon and summer. Further, the mesoscale phenomenon was reflected in measured chemical constituents during the study period. Positive-matrix-factorisation (PMF) analysis confirmed that OC aerosols are largely attributable to chemically aged anthropogenic (53 % in the day and 39 % in the night) and combustion-derived (17 % and 39 %) sources in winter and sea salts mixed with dust and vehicular emissions (61 % and 52 %) during monsoon. These important insights about the sources and formation processes of organic aerosols will help in understanding the formation of atmospheric brown clouds over south Asia.","PeriodicalId":11714,"journal":{"name":"Environmental Chemistry","volume":"23 1","pages":"45-60"},"PeriodicalIF":4.3,"publicationDate":"2021-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72845173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Environmental context The effects of the presence of polymer additives and polymeric structure on sorption of xenobiotics to microplastics remain unclear. Our results combined data from experimental sorption batch experiments using three environmentally relevant model sorbates with confocal microscopy. This provides clear evidence that both factors play a major role in sorption strength and the underlying sorption process, affecting sorption onto the particle surface and partitioning into the bulk polymer. Abstract Microplastics are particulate contaminants of global concern. Interactions of microplastics with organic contaminants are frequently studied with commercially available polymer materials as surrogates. The influence of the polymer structure (i.e. internal 3D polymer geometry and monomer chain length) and the presence of additives on their interactions with xenobiotics remains unclear. This work investigates sorption of three sorbates of environmental concern to two polyamide (PA) and two polyvinyl chloride (PVC) sorbents of different molecular composition and additive content, respectively. Sorption was studied using complementary data from sorption isotherms and confocal laser-scanning microscopy. The additives in PVC increased sorption affinity owing to an increased sorbent hydrophobicity and a higher void volume within the polymer. Surface area normalisation indicated surface adsorption for unplasticised PVC and absorption for 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH)-plasticised PVC, which were confirmed using confocal laser-scanning microscopy. The strong sorption to PA was mainly driven by hydrogen-bond interactions. The contribution depended on the molecular features of the sorbent and the sorbate. Confocal laser-scanning microscopy showed that PA6 was taking up more sorbate into its bulk polymer matrix than PA12, the two being different in their chemical composition. This difference could be attributed to the higher swelling capability of PA6. The results emphasise that the molecular structure of the polymer and the presence of additives have to be taken into consideration when sorption of organic substances to plastics is investigated.
{"title":"Additives and polymer composition influence the interaction of microplastics with xenobiotics","authors":"Darius Hummel, A. Fath, T. Hofmann","doi":"10.1071/EN21030","DOIUrl":"https://doi.org/10.1071/EN21030","url":null,"abstract":"Environmental context The effects of the presence of polymer additives and polymeric structure on sorption of xenobiotics to microplastics remain unclear. Our results combined data from experimental sorption batch experiments using three environmentally relevant model sorbates with confocal microscopy. This provides clear evidence that both factors play a major role in sorption strength and the underlying sorption process, affecting sorption onto the particle surface and partitioning into the bulk polymer. Abstract Microplastics are particulate contaminants of global concern. Interactions of microplastics with organic contaminants are frequently studied with commercially available polymer materials as surrogates. The influence of the polymer structure (i.e. internal 3D polymer geometry and monomer chain length) and the presence of additives on their interactions with xenobiotics remains unclear. This work investigates sorption of three sorbates of environmental concern to two polyamide (PA) and two polyvinyl chloride (PVC) sorbents of different molecular composition and additive content, respectively. Sorption was studied using complementary data from sorption isotherms and confocal laser-scanning microscopy. The additives in PVC increased sorption affinity owing to an increased sorbent hydrophobicity and a higher void volume within the polymer. Surface area normalisation indicated surface adsorption for unplasticised PVC and absorption for 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH)-plasticised PVC, which were confirmed using confocal laser-scanning microscopy. The strong sorption to PA was mainly driven by hydrogen-bond interactions. The contribution depended on the molecular features of the sorbent and the sorbate. Confocal laser-scanning microscopy showed that PA6 was taking up more sorbate into its bulk polymer matrix than PA12, the two being different in their chemical composition. This difference could be attributed to the higher swelling capability of PA6. The results emphasise that the molecular structure of the polymer and the presence of additives have to be taken into consideration when sorption of organic substances to plastics is investigated.","PeriodicalId":11714,"journal":{"name":"Environmental Chemistry","volume":"212 1","pages":""},"PeriodicalIF":4.3,"publicationDate":"2021-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76143732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Environmental context Contaminants adsorbed in aerosols are transported and deposited effectively to the respiratory system compared to their vapours. Measuring the extremely low concentration of highly volatile contaminants contained in aerosols is challenging; hence assessing their adverse effects on environmental and human health is less understood. The measured concentrations of these contaminants are similar to less volatile chemicals sampled from diverse environmental aerosols, suggesting that their contribution cannot be neglected. Abstract Volatile organic compounds (VOCs) are not expected to partition onto aerosols because of their high vapour pressure. Studies on gas–aerosol partitioning of VOCs have been limited because of the challenge in discriminating the small mass fraction of the VOCs in the aerosol relative to that in the gas phase. Here, we developed a bench-scale system to investigate the partitioning of a surrogate VOC, 1,2-dichlorobenzene (1,2-DCB), into inorganic and organic aerosols under different relative humidities (RHs) and temperatures. The partitioning coefficient (Kip) of 1,2-DCB into succinic acid (SA) aerosol was ~10× higher than those into ammonium sulfate (Am Sulf) aerosol. These Kip corresponded to 0.23–3.27 pg 1,2-DCB µg−1 of SA aerosol and 0.02–3.82 pg 1,2-DCB µg−1 of Am Sulf aerosol for RH levels of 5–95 %. Sorption of 1,2-DCB onto Am Sulf aerosol followed the classic relationship between Kip and RH, whereas that onto SA did not. For Am Sulf aerosols, RH levels exceeding 50 % have a negligible effect on partitioning, in which the extremely low amount of 1,2-DCB partitioned into the aerosol via dissolution. The octanol–air partition (KOA) model predicted the Kip of 1,2-DCB for SA aerosol better than the saturated vapour pressure partition (Pi0) model, whereas the Pi0 model predicted Kip better than the KOA model only when absorptive partitioning was considered.
{"title":"Partitioning of 1,2-dichlorobenzene onto organic and inorganic aerosols","authors":"Jeonghyeon Ahn, G. Rao, Eric P. Vejerano","doi":"10.1071/EN21016","DOIUrl":"https://doi.org/10.1071/EN21016","url":null,"abstract":"Environmental context Contaminants adsorbed in aerosols are transported and deposited effectively to the respiratory system compared to their vapours. Measuring the extremely low concentration of highly volatile contaminants contained in aerosols is challenging; hence assessing their adverse effects on environmental and human health is less understood. The measured concentrations of these contaminants are similar to less volatile chemicals sampled from diverse environmental aerosols, suggesting that their contribution cannot be neglected. Abstract Volatile organic compounds (VOCs) are not expected to partition onto aerosols because of their high vapour pressure. Studies on gas–aerosol partitioning of VOCs have been limited because of the challenge in discriminating the small mass fraction of the VOCs in the aerosol relative to that in the gas phase. Here, we developed a bench-scale system to investigate the partitioning of a surrogate VOC, 1,2-dichlorobenzene (1,2-DCB), into inorganic and organic aerosols under different relative humidities (RHs) and temperatures. The partitioning coefficient (Kip) of 1,2-DCB into succinic acid (SA) aerosol was ~10× higher than those into ammonium sulfate (Am Sulf) aerosol. These Kip corresponded to 0.23–3.27 pg 1,2-DCB µg−1 of SA aerosol and 0.02–3.82 pg 1,2-DCB µg−1 of Am Sulf aerosol for RH levels of 5–95 %. Sorption of 1,2-DCB onto Am Sulf aerosol followed the classic relationship between Kip and RH, whereas that onto SA did not. For Am Sulf aerosols, RH levels exceeding 50 % have a negligible effect on partitioning, in which the extremely low amount of 1,2-DCB partitioned into the aerosol via dissolution. The octanol–air partition (KOA) model predicted the Kip of 1,2-DCB for SA aerosol better than the saturated vapour pressure partition (Pi0) model, whereas the Pi0 model predicted Kip better than the KOA model only when absorptive partitioning was considered.","PeriodicalId":11714,"journal":{"name":"Environmental Chemistry","volume":"79 1","pages":""},"PeriodicalIF":4.3,"publicationDate":"2021-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77192921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Miming Zhang, C. Marandino, Jinpei Yan, Qi Lin, Keyhong Park, Guojie Xu
Environmental context The ocean-produced dimethyl sulfide (DMS) molecule is thought to affect cloud formation and the solar radiation budget at the Earth’s surface, hence playing an important role in regulating climate. In this study, we calculated the DMS sea-to-air flux across the Southern Ocean, south-east Indian Ocean and north-west Pacific Ocean, and analysed the influence of DMS fluxes on sulfate aerosols. These results improved our understanding of the effects of DMS emissions on sulfate compounds in the atmosphere over the global ocean. Abstract Oceanic dimethyl sulfide (DMS) is the most abundant biogenic sulfur compound emitted into the atmosphere and could indirectly regulate the global climate by impacting end product sulfate aerosols. DMS emissions and their influence on sulfate aerosols, i.e. methanesulfonic acid (MSA) and non-sea-salt sulfate (nss-SO42–), were investigated over the Atlantic Ocean and Indian Ocean sectors of the Southern Ocean (SO), the south-east Indian Ocean, and the north-west Pacific Ocean from February to April 2014 during the 30th Chinese National Antarctic Research Expedition. We found a strong large-scale DMS source in the marginal sea ice zone from 34 °W to 14 °E of the SO (south of 60 °S), in which the mean flux was 49.0 ± 65.6 μmol m−2 d−1 (0.6–308.3 μmol m−2 d−1, n = 424). We also found a second large-scale DMS source in the South Subtropical Front (~40 °S, up to 50.8 μmol m−2 d−1). An inconsistency between concentrations of atmospheric sulfate compounds and DMS emissions along the cruise track was observed. The horizontal advection of air masses was likely the main reason for this discrepancy. Finally, the biological exposure calculation results also indicated that it is very difficult to observe a straightforward relationship between oceanic biomass and atmospheric MSA.
{"title":"DMS sea-to-air fluxes and their influence on sulfate aerosols over the Southern Ocean, south-east Indian Ocean and north-west Pacific Ocean","authors":"Miming Zhang, C. Marandino, Jinpei Yan, Qi Lin, Keyhong Park, Guojie Xu","doi":"10.1071/EN21003","DOIUrl":"https://doi.org/10.1071/EN21003","url":null,"abstract":"Environmental context The ocean-produced dimethyl sulfide (DMS) molecule is thought to affect cloud formation and the solar radiation budget at the Earth’s surface, hence playing an important role in regulating climate. In this study, we calculated the DMS sea-to-air flux across the Southern Ocean, south-east Indian Ocean and north-west Pacific Ocean, and analysed the influence of DMS fluxes on sulfate aerosols. These results improved our understanding of the effects of DMS emissions on sulfate compounds in the atmosphere over the global ocean. Abstract Oceanic dimethyl sulfide (DMS) is the most abundant biogenic sulfur compound emitted into the atmosphere and could indirectly regulate the global climate by impacting end product sulfate aerosols. DMS emissions and their influence on sulfate aerosols, i.e. methanesulfonic acid (MSA) and non-sea-salt sulfate (nss-SO42–), were investigated over the Atlantic Ocean and Indian Ocean sectors of the Southern Ocean (SO), the south-east Indian Ocean, and the north-west Pacific Ocean from February to April 2014 during the 30th Chinese National Antarctic Research Expedition. We found a strong large-scale DMS source in the marginal sea ice zone from 34 °W to 14 °E of the SO (south of 60 °S), in which the mean flux was 49.0 ± 65.6 μmol m−2 d−1 (0.6–308.3 μmol m−2 d−1, n = 424). We also found a second large-scale DMS source in the South Subtropical Front (~40 °S, up to 50.8 μmol m−2 d−1). An inconsistency between concentrations of atmospheric sulfate compounds and DMS emissions along the cruise track was observed. The horizontal advection of air masses was likely the main reason for this discrepancy. Finally, the biological exposure calculation results also indicated that it is very difficult to observe a straightforward relationship between oceanic biomass and atmospheric MSA.","PeriodicalId":11714,"journal":{"name":"Environmental Chemistry","volume":"12 1","pages":""},"PeriodicalIF":4.3,"publicationDate":"2021-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89802537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Environmental context Dimethyl trisulfide (DMTS) is a malodorous compound formed from decomposing algal matter and can severely compromise the quality of drinking water. The reactivity of DMTS toward cyanide was studied in aqueous solutions at environmentally relevant conditions. It was found that the half-lives of DMTS in the presence of free cyanide varied from several months to several thousand years depending on environmental conditions. Abstract Organically bound sulfur in the form of mono-, di- and polysulfide bridges constitutes a significant fraction of this element in recent and ancient sediments. In water columns of lakes, the concentrations of organo-sulfur compounds are much lower, and they are present in the form of malodorous dimethyl polysulfides. Currently, information regarding reactivity of organic polysulfides towards nucleophiles that are stronger than hydroxyl anions is lacking. In this work, the reaction kinetics of dimethyl trisulfide (DMTS) with the strong nucleophile and important environmental pollutant cyanide as a function of concentrations of reactants, pH and temperature were studied. It was found that the reaction rate constant as well as the activation energy of the reaction strongly depend on pH. The experimental data agree well with the existence of two distinct pathways: slow reaction between protonated cyanide and DMTS under acidic and neutral conditions and fast reaction between cyanide anion and DMTS under highly alkaline conditions. However, reactions of DMTS with the iron cyanide complexes hexacyanoferrate(ii) and hexacyanoferrate(iii) have no environmental significance since they are slower than the rate of DMTS decomposition. Under environmentally relevant conditions, rates of reactions of free cyanide with DMTS will be lower than the reaction with inorganic polysulfides or tetrathionate, but faster than the reaction with thiosulfate. Examples of application of kinetic parameters for calculation of rates of cyanide consumption in industrial and non-polluted natural aquatic systems as well as a protocol for quantification of organic polysulfide sulfur based on reaction with cyanide are provided.
{"title":"Kinetics and mechanism of the reaction between dimethyl trisulfide and cyanide","authors":"I. Kurashova, Alexey Kamyshny Jr","doi":"10.1071/EN20104","DOIUrl":"https://doi.org/10.1071/EN20104","url":null,"abstract":"Environmental context Dimethyl trisulfide (DMTS) is a malodorous compound formed from decomposing algal matter and can severely compromise the quality of drinking water. The reactivity of DMTS toward cyanide was studied in aqueous solutions at environmentally relevant conditions. It was found that the half-lives of DMTS in the presence of free cyanide varied from several months to several thousand years depending on environmental conditions. Abstract Organically bound sulfur in the form of mono-, di- and polysulfide bridges constitutes a significant fraction of this element in recent and ancient sediments. In water columns of lakes, the concentrations of organo-sulfur compounds are much lower, and they are present in the form of malodorous dimethyl polysulfides. Currently, information regarding reactivity of organic polysulfides towards nucleophiles that are stronger than hydroxyl anions is lacking. In this work, the reaction kinetics of dimethyl trisulfide (DMTS) with the strong nucleophile and important environmental pollutant cyanide as a function of concentrations of reactants, pH and temperature were studied. It was found that the reaction rate constant as well as the activation energy of the reaction strongly depend on pH. The experimental data agree well with the existence of two distinct pathways: slow reaction between protonated cyanide and DMTS under acidic and neutral conditions and fast reaction between cyanide anion and DMTS under highly alkaline conditions. However, reactions of DMTS with the iron cyanide complexes hexacyanoferrate(ii) and hexacyanoferrate(iii) have no environmental significance since they are slower than the rate of DMTS decomposition. Under environmentally relevant conditions, rates of reactions of free cyanide with DMTS will be lower than the reaction with inorganic polysulfides or tetrathionate, but faster than the reaction with thiosulfate. Examples of application of kinetic parameters for calculation of rates of cyanide consumption in industrial and non-polluted natural aquatic systems as well as a protocol for quantification of organic polysulfide sulfur based on reaction with cyanide are provided.","PeriodicalId":11714,"journal":{"name":"Environmental Chemistry","volume":"99 1","pages":""},"PeriodicalIF":4.3,"publicationDate":"2021-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79696859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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