Pub Date : 2023-06-22DOI: 10.3389/fenvc.2023.1216245
Amadou Oumarou Amadou, Martina Cera, Stefano Trudu, M. Piredda, S. Cara, G. P. De Gaudenzi, A. Matharu, L. Marchiò, M. Tegoni, A. Muntoni, G. De Gioannis, A. Serpe
Peculiar chemical, mechanical, and magnetic properties make cobalt a key metal for a variety of “hot” applications like the cathode production of Li-ion batteries. Cobalt is also the preferred metallic binder for tungsten carbide tool manufacturing. The recent increasing criticality of cobalt and tungsten is driving the interest of manufacturers and researchers toward high-rate recycling of hard-metal (HM) waste for limiting the demand for raw materials. A simple and environmentally friendly hydrometallurgical route for Co-selective dissolution from HM wastes was developed by using weak, bio-derived, and biodegradable organic acids (OAs). In this study, OAs, namely, acetic (HAc), citric (H3Cit), maleic (H2Mal), lactic (HLac), succinic (H2Suc), lactobionic (HLB), and itaconic (H2It) acids, were selected for their pKa1 values spanning from 1.8 to 4.7 and systematically tested as selective cobalt leaching agents from WC-Co-based wastes in water, isolating the formed complexes in the solid state. Thereby, all of them seemed to be efficient in selective Co leaching, achieving almost quantitative Co dissolution from HM by-products still at low concentration levels and room conditions in a short time, leaving the residual WC unreacted and ready to be re-employed for industrial purposes. Nevertheless, two main categories of organic acids were distinguished depending on their oxidizing/complexing behavior: class 1 OAs, where the metal oxidation is carried out by H+, and class 2 OAs, where oxidation is carried out by an external oxidant like O2. A combined experimental/theoretical investigation is described here to show the reasons behind this peculiar behavior and lay the foundation for a wider discussion on the leaching capabilities of OAs toward elemental metals. Due to the demonstrated effectiveness, low cost, eco-friendliness, and large availability through biotechnological fermentative processes, particular attention is devoted here to the use of HLac in hydrometallurgy as an example of class 2 OA. WC-Co materials recovered by HLac mild hydrometallurgy demonstrated a metallurgical quality suitable for re-employment in the HM manufacturing process.
{"title":"A comparison among bio-derived acids as selective eco-friendly leaching agents for cobalt: the case study of hard-metal waste enhancement","authors":"Amadou Oumarou Amadou, Martina Cera, Stefano Trudu, M. Piredda, S. Cara, G. P. De Gaudenzi, A. Matharu, L. Marchiò, M. Tegoni, A. Muntoni, G. De Gioannis, A. Serpe","doi":"10.3389/fenvc.2023.1216245","DOIUrl":"https://doi.org/10.3389/fenvc.2023.1216245","url":null,"abstract":"Peculiar chemical, mechanical, and magnetic properties make cobalt a key metal for a variety of “hot” applications like the cathode production of Li-ion batteries. Cobalt is also the preferred metallic binder for tungsten carbide tool manufacturing. The recent increasing criticality of cobalt and tungsten is driving the interest of manufacturers and researchers toward high-rate recycling of hard-metal (HM) waste for limiting the demand for raw materials. A simple and environmentally friendly hydrometallurgical route for Co-selective dissolution from HM wastes was developed by using weak, bio-derived, and biodegradable organic acids (OAs). In this study, OAs, namely, acetic (HAc), citric (H3Cit), maleic (H2Mal), lactic (HLac), succinic (H2Suc), lactobionic (HLB), and itaconic (H2It) acids, were selected for their pKa1 values spanning from 1.8 to 4.7 and systematically tested as selective cobalt leaching agents from WC-Co-based wastes in water, isolating the formed complexes in the solid state. Thereby, all of them seemed to be efficient in selective Co leaching, achieving almost quantitative Co dissolution from HM by-products still at low concentration levels and room conditions in a short time, leaving the residual WC unreacted and ready to be re-employed for industrial purposes. Nevertheless, two main categories of organic acids were distinguished depending on their oxidizing/complexing behavior: class 1 OAs, where the metal oxidation is carried out by H+, and class 2 OAs, where oxidation is carried out by an external oxidant like O2. A combined experimental/theoretical investigation is described here to show the reasons behind this peculiar behavior and lay the foundation for a wider discussion on the leaching capabilities of OAs toward elemental metals. Due to the demonstrated effectiveness, low cost, eco-friendliness, and large availability through biotechnological fermentative processes, particular attention is devoted here to the use of HLac in hydrometallurgy as an example of class 2 OA. WC-Co materials recovered by HLac mild hydrometallurgy demonstrated a metallurgical quality suitable for re-employment in the HM manufacturing process.","PeriodicalId":73082,"journal":{"name":"Frontiers in environmental chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49310167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-13DOI: 10.3389/fenvc.2023.1202957
M. Gustin, Sarrah M. Dunham-Cheatham, N. Choma, K. Shoemaker, Natalie Allen
There is much uncertainty regarding the sources of reactive mercury (RM) compounds and atmospheric chemistry driving their formation. This work focused on assessing the chemistry and potential sources of reactive mercury measured in Reno, Nevada, United States, using 1 year of data collected using Reactive Mercury Active System. In addition, ancillary meteorology and criteria air pollutant data, Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) analyses, and a generalized linear model were applied to better understand reactive mercury observations. During the year of sampling, a fire event impacted the sampling site, and gaseous elemental Hg and particulate-bound mercury concentrations increased, as did HgII-S compounds. Data collected on a peak above Reno showed that reactive mercury concentrations were higher at higher elevation, and compounds found in Reno were the same as those measured on the peak. HYSPLIT results demonstrated RM compounds were generated inside and outside of the basin housing Reno. Compounds were sourced from San Francisco, Sacramento, and Reno in the fall and winter, and from long-range transport and the marine boundary layer during the spring and summer. The generalized linear model produced correlations that could be explained; however, when applying the model to similar data collected at two other locations, the Reno model did not predict the observations, suggesting that sampling location chemistry and concentration cannot be generalized. Graphical Abstract
{"title":"Determining sources of reactive mercury compounds in Reno, Nevada, United States","authors":"M. Gustin, Sarrah M. Dunham-Cheatham, N. Choma, K. Shoemaker, Natalie Allen","doi":"10.3389/fenvc.2023.1202957","DOIUrl":"https://doi.org/10.3389/fenvc.2023.1202957","url":null,"abstract":"There is much uncertainty regarding the sources of reactive mercury (RM) compounds and atmospheric chemistry driving their formation. This work focused on assessing the chemistry and potential sources of reactive mercury measured in Reno, Nevada, United States, using 1 year of data collected using Reactive Mercury Active System. In addition, ancillary meteorology and criteria air pollutant data, Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) analyses, and a generalized linear model were applied to better understand reactive mercury observations. During the year of sampling, a fire event impacted the sampling site, and gaseous elemental Hg and particulate-bound mercury concentrations increased, as did HgII-S compounds. Data collected on a peak above Reno showed that reactive mercury concentrations were higher at higher elevation, and compounds found in Reno were the same as those measured on the peak. HYSPLIT results demonstrated RM compounds were generated inside and outside of the basin housing Reno. Compounds were sourced from San Francisco, Sacramento, and Reno in the fall and winter, and from long-range transport and the marine boundary layer during the spring and summer. The generalized linear model produced correlations that could be explained; however, when applying the model to similar data collected at two other locations, the Reno model did not predict the observations, suggesting that sampling location chemistry and concentration cannot be generalized. Graphical Abstract","PeriodicalId":73082,"journal":{"name":"Frontiers in environmental chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49489452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-26DOI: 10.3389/fenvc.2023.1194664
F. Kryuchkov, A. Foldvik, R. Sandodden, S. Uhlig
The chemical 6PPD-quinone is highly toxic to some fish species of the Oncorhynchus and Salvelinus genera and is the oxidation product of the common car tire additive 6PPD. We present a new sample preparation method that involves liquid-liquid extraction of water samples followed by silica-based solid phase extraction prior to LC–MS/MS analysis. The new sample preparation method showed good analyte recovery from spiked water samples (78%–91%) and a low ion suppression effect, surpassing previously published methods. This new method was successfully validated, achieving a limit of quantification of 5 ng/L and estimated expanded measurement uncertainty of 18.6%. In a proof-of-concept study, the method was applied to several water samples from various sources in Southern Norway. These were runoff samples from tunnel washing, from a tunnel runoff treatment plant and downstream of the plant drain. In addition, two water samples from puddles were included: one was run-off from an artificial soccer turf field and one from a puddle on a country road. The results of the analyses revealed that the concentration of 6PPD-quinone was above the LC50 reported for coho salmon (Oncorhynchus kisutch) in all samples except the samples from and downstream of the treatment plant. The highest measured concentration was 258 ng/L, which is the 2.7-fold of the reported LC50 in coho salmon (95 ng/L). Our initial data emphasize the need for more comprehensive environmental monitoring of 6PPD-quinone as well as toxicological studies in aquatic organisms.
{"title":"Presence of 6PPD-quinone in runoff water samples from Norway using a new LC–MS/MS method","authors":"F. Kryuchkov, A. Foldvik, R. Sandodden, S. Uhlig","doi":"10.3389/fenvc.2023.1194664","DOIUrl":"https://doi.org/10.3389/fenvc.2023.1194664","url":null,"abstract":"The chemical 6PPD-quinone is highly toxic to some fish species of the Oncorhynchus and Salvelinus genera and is the oxidation product of the common car tire additive 6PPD. We present a new sample preparation method that involves liquid-liquid extraction of water samples followed by silica-based solid phase extraction prior to LC–MS/MS analysis. The new sample preparation method showed good analyte recovery from spiked water samples (78%–91%) and a low ion suppression effect, surpassing previously published methods. This new method was successfully validated, achieving a limit of quantification of 5 ng/L and estimated expanded measurement uncertainty of 18.6%. In a proof-of-concept study, the method was applied to several water samples from various sources in Southern Norway. These were runoff samples from tunnel washing, from a tunnel runoff treatment plant and downstream of the plant drain. In addition, two water samples from puddles were included: one was run-off from an artificial soccer turf field and one from a puddle on a country road. The results of the analyses revealed that the concentration of 6PPD-quinone was above the LC50 reported for coho salmon (Oncorhynchus kisutch) in all samples except the samples from and downstream of the treatment plant. The highest measured concentration was 258 ng/L, which is the 2.7-fold of the reported LC50 in coho salmon (95 ng/L). Our initial data emphasize the need for more comprehensive environmental monitoring of 6PPD-quinone as well as toxicological studies in aquatic organisms.","PeriodicalId":73082,"journal":{"name":"Frontiers in environmental chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44864298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-25DOI: 10.3389/fenvc.2023.1109537
Marissa C. Despins, R. Mason, A. Aguilar‐Islas, C. Lamborg, C. R. Hammerschmidt, Silvia E. Newell
Methylmercury (MeHg) is a neurotoxin that bioaccumulates to potentially harmful concentrations in Arctic and Subarctic marine predators and those that consume them. Monitoring and modeling MeHg bioaccumulation and biogeochemical cycling in the ocean requires an understanding of the mechanisms behind net mercury (Hg) methylation. The key functional gene pair for Hg methylation, hgcAB, is widely distributed throughout ocean basins and spans multiple microbial phyla. While multiple microbially mediated anaerobic pathways for Hg methylation in the ocean are known, the majority of hgcA homologs have been found in oxic subsurface waters, in contrast to other ecosystems. In particular, microaerophilic Nitrospina, a genera of nitrite-oxidizing bacteria containing a hgcA-like sequence, have been proposed as a potentially important Hg methylator in the upper ocean. The objective of this work was therefore to examine the potential of nitrifiers as Hg methylators and quantify total Hg and MeHg across three Arctic and Subarctic seas (the Gulf of Alaska, the Bering Sea and the Chukchi Sea) in regions where Nitrospina are likely present. In Spring 2021, samples for Hg analysis were obtained with a trace metal clean rosette across these seas. Mercury methylation rates were quantified in concert with nitrification rates using onboard incubation experiments with additions of stable isotope-labeled Hg and NH4 +. A significant correlation between Hg methylation and nitrification was observed across all sites (R 2 = 0.34, p < 0.05), with the strongest correlation in the Chukchi Sea (R 2 = 0.99, p < 0.001). Nitrospina-specific hgcA-like genes were detected at all sites. This study, linking Hg methylation and nitrification in oxic seawater, furthers understanding of MeHg cycling in these high latitude waters, and the ocean in general. Furthermore, these studies inform predictions of how climate and human interactions could influence MeHg concentrations across the Arctic in the future.
甲基汞(MeHg)是一种神经毒素，在北极和亚北极海洋捕食者和食用它们的动物体内生物积累到可能有害的浓度。监测和模拟海洋中甲基汞的生物积累和生物地球化学循环需要了解净汞甲基化背后的机制。Hg甲基化的关键功能基因对hgcAB广泛分布在海洋盆地中，跨越多个微生物门。虽然已知海洋中汞甲基化的多种微生物介导的厌氧途径，但与其他生态系统相比，大多数hgcA同源物已在含氧地下水中被发现。特别是，微嗜气硝化菌(Nitrospina)是一种亚硝酸盐氧化细菌，含有类似hgca的序列，被认为是上层海洋中潜在的重要汞甲基化物。因此，这项工作的目的是研究硝化菌作为汞甲基化剂的潜力，并量化三个北极和亚北极海域(阿拉斯加湾、白令海和楚科奇海)中可能存在亚硝基刺虫的地区的汞和甲基汞总量。2021年春季，在这些海洋中获得了痕量金属清洁花环的汞分析样本。通过添加稳定同位素标记的Hg和NH4 +的机载孵育实验，量化了汞甲基化率和硝化率。汞甲基化与硝化之间存在显著相关性(r2 = 0.34, p < 0.05)，其中楚科奇海的相关性最强(r2 = 0.99, p < 0.001)。所有位点均检测到硝基spina特异性hgca样基因。本研究将含氧海水中的汞甲基化和硝化作用联系起来，进一步了解这些高纬度水域和海洋中的甲基汞循环。此外，这些研究为预测未来气候和人类相互作用如何影响整个北极地区的甲基汞浓度提供了信息。
{"title":"Linked mercury methylation and nitrification across oxic subpolar regions","authors":"Marissa C. Despins, R. Mason, A. Aguilar‐Islas, C. Lamborg, C. R. Hammerschmidt, Silvia E. Newell","doi":"10.3389/fenvc.2023.1109537","DOIUrl":"https://doi.org/10.3389/fenvc.2023.1109537","url":null,"abstract":"Methylmercury (MeHg) is a neurotoxin that bioaccumulates to potentially harmful concentrations in Arctic and Subarctic marine predators and those that consume them. Monitoring and modeling MeHg bioaccumulation and biogeochemical cycling in the ocean requires an understanding of the mechanisms behind net mercury (Hg) methylation. The key functional gene pair for Hg methylation, hgcAB, is widely distributed throughout ocean basins and spans multiple microbial phyla. While multiple microbially mediated anaerobic pathways for Hg methylation in the ocean are known, the majority of hgcA homologs have been found in oxic subsurface waters, in contrast to other ecosystems. In particular, microaerophilic Nitrospina, a genera of nitrite-oxidizing bacteria containing a hgcA-like sequence, have been proposed as a potentially important Hg methylator in the upper ocean. The objective of this work was therefore to examine the potential of nitrifiers as Hg methylators and quantify total Hg and MeHg across three Arctic and Subarctic seas (the Gulf of Alaska, the Bering Sea and the Chukchi Sea) in regions where Nitrospina are likely present. In Spring 2021, samples for Hg analysis were obtained with a trace metal clean rosette across these seas. Mercury methylation rates were quantified in concert with nitrification rates using onboard incubation experiments with additions of stable isotope-labeled Hg and NH4 +. A significant correlation between Hg methylation and nitrification was observed across all sites (R 2 = 0.34, p < 0.05), with the strongest correlation in the Chukchi Sea (R 2 = 0.99, p < 0.001). Nitrospina-specific hgcA-like genes were detected at all sites. This study, linking Hg methylation and nitrification in oxic seawater, furthers understanding of MeHg cycling in these high latitude waters, and the ocean in general. Furthermore, these studies inform predictions of how climate and human interactions could influence MeHg concentrations across the Arctic in the future.","PeriodicalId":73082,"journal":{"name":"Frontiers in environmental chemistry","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44320647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-09DOI: 10.3389/fenvc.2023.1052697
Nnanake-Abasi O. Offiong, J. Edet, S. Shaibu, Nyaknno E. Akan, E. Atakpa, E. Sanganyado, I. Okop, N. Benson, A. Okoh
Metagenomics is the study of genetic information, including the sequences and genomes of microorganisms present in an environment. Since 1998, the full-scale application of this technique to environmental chemistry has brought significant advances in the characterization of the nature and chemical composition/distribution of contaminants present in environmental matrices of contaminated and/or remediated sites. This has been critical in the selection of microorganisms and has contributed significantly to the success of this biological treatment over the years. Metagenomics has gone through different phases of development, which ranges from initial sequencing strategies to next-generation sequencing (NGS), which is a recently developed technology to obtain more robust deoxyribonucleic acid (DNA) profile of microorganisms devoid of chimeric sequences which reduces the quality of metagenomic data. Therefore, the objective of this review is to evaluate the applications of metagenomics in the understanding of environmental dynamics of chemical contaminants during remediation studies. Also, this review presents the relationship between biological characteristics of microorganisms and chemical properties of chemical compounds, which forms the basis of bioremediation and could be useful in developing predictive models that could enhance remediation efficiency. In conclusion, metagenomic techniques have improved the characterisation of chemical contaminants in the environment and provides a correlation for useful prediction of the type of contaminant expected in various environmental matrices.
{"title":"Metagenomics: an emerging tool for the chemistry of environmental remediation","authors":"Nnanake-Abasi O. Offiong, J. Edet, S. Shaibu, Nyaknno E. Akan, E. Atakpa, E. Sanganyado, I. Okop, N. Benson, A. Okoh","doi":"10.3389/fenvc.2023.1052697","DOIUrl":"https://doi.org/10.3389/fenvc.2023.1052697","url":null,"abstract":"Metagenomics is the study of genetic information, including the sequences and genomes of microorganisms present in an environment. Since 1998, the full-scale application of this technique to environmental chemistry has brought significant advances in the characterization of the nature and chemical composition/distribution of contaminants present in environmental matrices of contaminated and/or remediated sites. This has been critical in the selection of microorganisms and has contributed significantly to the success of this biological treatment over the years. Metagenomics has gone through different phases of development, which ranges from initial sequencing strategies to next-generation sequencing (NGS), which is a recently developed technology to obtain more robust deoxyribonucleic acid (DNA) profile of microorganisms devoid of chimeric sequences which reduces the quality of metagenomic data. Therefore, the objective of this review is to evaluate the applications of metagenomics in the understanding of environmental dynamics of chemical contaminants during remediation studies. Also, this review presents the relationship between biological characteristics of microorganisms and chemical properties of chemical compounds, which forms the basis of bioremediation and could be useful in developing predictive models that could enhance remediation efficiency. In conclusion, metagenomic techniques have improved the characterisation of chemical contaminants in the environment and provides a correlation for useful prediction of the type of contaminant expected in various environmental matrices.","PeriodicalId":73082,"journal":{"name":"Frontiers in environmental chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45514175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-29DOI: 10.3389/fenvc.2023.1191236
J. Jiménez-Lamana, Andreas Gondikas, K. Mattsson, J. Gigault
The evaluation of the environmental impact of nanoand microplastics is one of the biggest environmental challenges nowadays. Indeed, the massive consumption of plastics is leading to the occurrence of micronic and submicronic plastic particles in almost all environmental compartments (water, air, soils, food, interfaces. . .). From an environmental risk assessment point of view, the development of new analytical strategies able to detect, identify and quantify nanoand microplastics at low concentration in a wide range of environmental matrices is required. However, the analysis and monitoring of nano/microplastics pollution is specially challenging due to several reasons. First of all, dedicated and complex sample preparation procedures must be developed, since the use of analytical techniques commonly used for the analysis of inorganic nanoparticles is not straightforward. Secondly, there exist large Research Topic between plastic particles on the physical-chemical properties that regulate the particles fate, e.g., density, porosity, composition. Attachment of microorganisms and biofilm growth on plastic surfaces further complicate the environmental fate and reactivity of plastic particles, necessitating complex sample treatment prior to analysis. Therefore, upgrading existing or developing new methods and analytical strategies for quantifying the numbers and physical-chemical properties of nanoand microplastics in the environment is essential. In this context, the current Research Topic “Analytical methodologies for the nalysis and monitoring of nano/microplastic pollution”was focused on providing a global overview of the most recent analytical strategies developed to fill the gap of the analysis of nano/ microplastics in different environmental compartments. The Research Topic includes 3 Original Research and one Methods article, which are summarized below: In the first Original Research article, Goedecke et al. investigated the occurrence and the mass fractions of microplastics in a municipal wastewater treatment plant (WWTP) effluent for several days in winter and summer. For this purpose, authors applied a fractionated filtration of the effluent by using three different mesh sizes (500, 100, and 50 μm). This OPEN ACCESS
{"title":"Editorial: Analytical methodologies for the analysis and monitoring of nano/microplastics pollution","authors":"J. Jiménez-Lamana, Andreas Gondikas, K. Mattsson, J. Gigault","doi":"10.3389/fenvc.2023.1191236","DOIUrl":"https://doi.org/10.3389/fenvc.2023.1191236","url":null,"abstract":"The evaluation of the environmental impact of nanoand microplastics is one of the biggest environmental challenges nowadays. Indeed, the massive consumption of plastics is leading to the occurrence of micronic and submicronic plastic particles in almost all environmental compartments (water, air, soils, food, interfaces. . .). From an environmental risk assessment point of view, the development of new analytical strategies able to detect, identify and quantify nanoand microplastics at low concentration in a wide range of environmental matrices is required. However, the analysis and monitoring of nano/microplastics pollution is specially challenging due to several reasons. First of all, dedicated and complex sample preparation procedures must be developed, since the use of analytical techniques commonly used for the analysis of inorganic nanoparticles is not straightforward. Secondly, there exist large Research Topic between plastic particles on the physical-chemical properties that regulate the particles fate, e.g., density, porosity, composition. Attachment of microorganisms and biofilm growth on plastic surfaces further complicate the environmental fate and reactivity of plastic particles, necessitating complex sample treatment prior to analysis. Therefore, upgrading existing or developing new methods and analytical strategies for quantifying the numbers and physical-chemical properties of nanoand microplastics in the environment is essential. In this context, the current Research Topic “Analytical methodologies for the nalysis and monitoring of nano/microplastic pollution”was focused on providing a global overview of the most recent analytical strategies developed to fill the gap of the analysis of nano/ microplastics in different environmental compartments. The Research Topic includes 3 Original Research and one Methods article, which are summarized below: In the first Original Research article, Goedecke et al. investigated the occurrence and the mass fractions of microplastics in a municipal wastewater treatment plant (WWTP) effluent for several days in winter and summer. For this purpose, authors applied a fractionated filtration of the effluent by using three different mesh sizes (500, 100, and 50 μm). This OPEN ACCESS","PeriodicalId":73082,"journal":{"name":"Frontiers in environmental chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48422925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-23DOI: 10.3389/fenvc.2023.1164372
Isaac Luttah, Daniel O. Onunga, Victor O. Shikuku, Benton Onyango Otieno, C. Kowenje
Alkali-activated municipal waste incineration fly ash (MWFA)-based geopolymers (GPA, GPB, and GPC) were synthesized under different sodium silicate to sodium hydroxide (SS/SH) ratios. The geopolymers were applied in the removal of endosulfan, a persistent and toxic chemical, from water. The adsorbents were characterized by XRD, SEM-EDX, and FTIR. Variation of SS/SH ratios resulted in morphologically distinguishable geopolymers with different compositions. The adsorption equilibrium data were best described by the Langmuir isotherm. The maximum adsorption capacities increased with an increase in SS/SH ratios in the order 1.87, 15.89, 16.97, and 20.01 mg/g for MWFA, GPA, GPB, and GPC, respectively. The kinetic data were best described by the pseudo-first-order model wherein the adsorption rate ( k 1 ) was independent of the SS/SH ratios and the geopolymer composition. The thermodynamic parameters, that is, enthalpy (∆H > 0), Gibbs free energy (∆G < 0), entropy (∆S > 0), and activation energy (Ea > 0), show that the processes were endothermic, spontaneous, physical (Ea and ∆H < 40 kJ/mol), and entropy-driven. Alkalination was beneficial since the geopolymers had a higher adsorption capacity (∼8–10 times) and affinity for endosulfan (∼30 times) than the precursor material (MWFA). The adsorption mechanism entailed electrostatic interactions and hydrogen bonding. The MWFA-based geopolymers are, therefore, potential alternative low-cost adsorbents for the removal of endosulfan from water and a strategy for the valorization of MWFA. Graphical Abstract
{"title":"Removal of endosulfan from water by municipal waste incineration fly ash-based geopolymers: Adsorption kinetics, isotherms, and thermodynamics","authors":"Isaac Luttah, Daniel O. Onunga, Victor O. Shikuku, Benton Onyango Otieno, C. Kowenje","doi":"10.3389/fenvc.2023.1164372","DOIUrl":"https://doi.org/10.3389/fenvc.2023.1164372","url":null,"abstract":"Alkali-activated municipal waste incineration fly ash (MWFA)-based geopolymers (GPA, GPB, and GPC) were synthesized under different sodium silicate to sodium hydroxide (SS/SH) ratios. The geopolymers were applied in the removal of endosulfan, a persistent and toxic chemical, from water. The adsorbents were characterized by XRD, SEM-EDX, and FTIR. Variation of SS/SH ratios resulted in morphologically distinguishable geopolymers with different compositions. The adsorption equilibrium data were best described by the Langmuir isotherm. The maximum adsorption capacities increased with an increase in SS/SH ratios in the order 1.87, 15.89, 16.97, and 20.01 mg/g for MWFA, GPA, GPB, and GPC, respectively. The kinetic data were best described by the pseudo-first-order model wherein the adsorption rate ( k 1 ) was independent of the SS/SH ratios and the geopolymer composition. The thermodynamic parameters, that is, enthalpy (∆H > 0), Gibbs free energy (∆G < 0), entropy (∆S > 0), and activation energy (Ea > 0), show that the processes were endothermic, spontaneous, physical (Ea and ∆H < 40 kJ/mol), and entropy-driven. Alkalination was beneficial since the geopolymers had a higher adsorption capacity (∼8–10 times) and affinity for endosulfan (∼30 times) than the precursor material (MWFA). The adsorption mechanism entailed electrostatic interactions and hydrogen bonding. The MWFA-based geopolymers are, therefore, potential alternative low-cost adsorbents for the removal of endosulfan from water and a strategy for the valorization of MWFA. Graphical Abstract","PeriodicalId":73082,"journal":{"name":"Frontiers in environmental chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47015803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-02DOI: 10.3389/fenvc.2023.1114807
B. Crowley, Emily Michelle Bruff Simpson, Sarah Jayne Hammer, Joshua M. Smith, T. Johnson
Most researchers assume minimal impact of pretreatment on strontium isotope ratios (87Sr/86Sr) for bones and teeth, and methods vary tremendously. We compared 14 pretreatment methods, including no prep other than powdering enamel, ashing, soaking in water, an oxidizing agent (bleach or hydrogen peroxide) or acetic acid (0.1 M, 1.0 M, and 1.0 M buffered with calcium acetate), and a combination of these steps. We prepared and analyzed aliquots of powdered molar enamel from three proboscideans (one modern captive Indian elephant, Elephas maximus indicus; one Pleistocene mastodon, Mammut americanum; and one Miocene gomphothere, Afrochoerodon kisumuensis). Each pretreatment was performed in triplicate and we measured 87Sr/86Sr, Sr concentration, and uranium (U) concentration, using the same lab space and instrumentation for all samples. Variability in 87Sr/86Sr and Sr and U concentrations was considerable across pretreatments. Mean 87Sr/86Sr across methods ranged from 0.70999 to 0.71029 for the modern tooth, 0.71458 to 0.71502 for the Pleistocene tooth, and 0.70804 to 0.70817 for the Miocene tooth. The modern tooth contained the least Sr and negligible U. The Pleistocene tooth contained slightly more Sr and measurable amounts of U, and the Miocene tooth had approximately 5x more Sr and U than the Pleistocene tooth. For all three teeth, variance in 87Sr/86Sr, Sr concentrations, and U concentrations among replicates was statistically indistinguishable across pretreatments, but there were apparent differences among pretreatments for the modern and Pleistocene teeth. Both contained relatively little Sr, and it is possible that small amounts of exogenous Sr from reagents, building materials or dust affected some replicates for some pretreatments. For the modern tooth, median 87Sr/86Sr varied considerably (but statistically insignificantly) across pretreatments. For the Pleistocene tooth, variability in median 87Sr/86Sr was also considerable; some pretreatments were statistically distinct but there were no obvious patterns among methods. For the Miocene tooth, variability in median 87Sr/86Sr was much smaller, but there were significant differences among pretreatments. Most pretreatments yielded 87Sr/86Sr and Sr concentrations comparable to, or lower than, untreated powder, suggesting selective removal of exogenous material with high 87Sr/86Sr. Further evaluation of the mechanisms driving isotopic variability both within and among pretreatment methods is warranted. Researchers should clearly report their methods and avoid combining data obtained using different methods. Small differences in 87Sr/86Sr could impact data interpretations, especially in areas where isotopic variability is low.
{"title":"Comparison of powdered enamel sample pretreatment methods for strontium isotope analysis","authors":"B. Crowley, Emily Michelle Bruff Simpson, Sarah Jayne Hammer, Joshua M. Smith, T. Johnson","doi":"10.3389/fenvc.2023.1114807","DOIUrl":"https://doi.org/10.3389/fenvc.2023.1114807","url":null,"abstract":"Most researchers assume minimal impact of pretreatment on strontium isotope ratios (87Sr/86Sr) for bones and teeth, and methods vary tremendously. We compared 14 pretreatment methods, including no prep other than powdering enamel, ashing, soaking in water, an oxidizing agent (bleach or hydrogen peroxide) or acetic acid (0.1 M, 1.0 M, and 1.0 M buffered with calcium acetate), and a combination of these steps. We prepared and analyzed aliquots of powdered molar enamel from three proboscideans (one modern captive Indian elephant, Elephas maximus indicus; one Pleistocene mastodon, Mammut americanum; and one Miocene gomphothere, Afrochoerodon kisumuensis). Each pretreatment was performed in triplicate and we measured 87Sr/86Sr, Sr concentration, and uranium (U) concentration, using the same lab space and instrumentation for all samples. Variability in 87Sr/86Sr and Sr and U concentrations was considerable across pretreatments. Mean 87Sr/86Sr across methods ranged from 0.70999 to 0.71029 for the modern tooth, 0.71458 to 0.71502 for the Pleistocene tooth, and 0.70804 to 0.70817 for the Miocene tooth. The modern tooth contained the least Sr and negligible U. The Pleistocene tooth contained slightly more Sr and measurable amounts of U, and the Miocene tooth had approximately 5x more Sr and U than the Pleistocene tooth. For all three teeth, variance in 87Sr/86Sr, Sr concentrations, and U concentrations among replicates was statistically indistinguishable across pretreatments, but there were apparent differences among pretreatments for the modern and Pleistocene teeth. Both contained relatively little Sr, and it is possible that small amounts of exogenous Sr from reagents, building materials or dust affected some replicates for some pretreatments. For the modern tooth, median 87Sr/86Sr varied considerably (but statistically insignificantly) across pretreatments. For the Pleistocene tooth, variability in median 87Sr/86Sr was also considerable; some pretreatments were statistically distinct but there were no obvious patterns among methods. For the Miocene tooth, variability in median 87Sr/86Sr was much smaller, but there were significant differences among pretreatments. Most pretreatments yielded 87Sr/86Sr and Sr concentrations comparable to, or lower than, untreated powder, suggesting selective removal of exogenous material with high 87Sr/86Sr. Further evaluation of the mechanisms driving isotopic variability both within and among pretreatment methods is warranted. Researchers should clearly report their methods and avoid combining data obtained using different methods. Small differences in 87Sr/86Sr could impact data interpretations, especially in areas where isotopic variability is low.","PeriodicalId":73082,"journal":{"name":"Frontiers in environmental chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44660234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-07DOI: 10.3389/fenvc.2023.1151859
A. Zanoletti, E. Bontempi
Floods are one of the most common natural disasters worldwide. Their increasing incidence in the past years is mainly due to the consequences of climate change coupled with a general trend of the increase of surface impermeabilization in the cities. In particular, the past years’ rapid urbanization and human land use originated environment modification, with consequent surface modification: in the urban area, most of the surface is covered by buildings and impermeable pavements, which strongly limits snowmelt and rainwater infiltration into the subsurface. However, floods are sometimes predictable events (Enríquez et al., 2022). To account for the vulnerability of a territory, due to extreme events, patterns of development coupled with demographic studies are considered. As a result, the score of flood risk is available as a risk index, evaluated by a dedicated committee of the European (European Commission, 2022). The 2022 flood risk is shown in Figure 1. It appears that only a few countries have a relatively low risk (less than 5), and Vietnam and Bangladesh are the countries with the higher flood risk (the index score is 10). Urban runoff is water deriving from rain and outdoor water usage, comprising stormwater and snowmelt, which drains from roofs, roads, car parks sidewalks, driveways, and other surfaces, and does not soak into the ground. It is widely recognised as a major carrier for the pollutants transport and release in the urban environment. Therefore, it also represents a significant contributor to the degradation of surface water bodies (EPA, 2003). As a consequence, urban runoff is one of the key pathways in the transfer of pollutants to the aquatic and marine environment. The contaminants associated with urban runoff can be divided into different categories such as heavy metals, solids, toxic chemicals, biodegradable organic matter (chemical or biochemical oxygen demand COD/BOD), organic micropollutants (among them polycyclic aromatic hydrocarbons PAHs, polychlorinated biphenyls PCBs), pathogenic microorganisms (such as Escherichia Coli), nutrients (nitrogen and phosphorus) and microplastics (Wei et al., 2013; Piñon-Colin et al., 2020). For example, Wang et al. (2022) reveal that the concentrations of microplastics in urban stormwater are much higher than those found in wastewater effluents. The source of pollutants can be natural (soil, leaves and organic debris) or anthropogenic (construction materials, exhausted particles, roadway debris, fertilizers, and so on) (TrujilloGonzález et al., 2019). Generally, the road deposited sediment represents one of the primary contaminants contributors to urban runoff (Piñon-Colin et al., 2020). In the worst cases, when the stormwater collection is in connection with the sanitary sewage system, an accidental release of raw sewage may also happen because of important precipitation events, with the result of dramatic environmental and economic impacts. OPEN ACCESS
{"title":"Editorial: Urban runoff of pollutants and their treatment","authors":"A. Zanoletti, E. Bontempi","doi":"10.3389/fenvc.2023.1151859","DOIUrl":"https://doi.org/10.3389/fenvc.2023.1151859","url":null,"abstract":"Floods are one of the most common natural disasters worldwide. Their increasing incidence in the past years is mainly due to the consequences of climate change coupled with a general trend of the increase of surface impermeabilization in the cities. In particular, the past years’ rapid urbanization and human land use originated environment modification, with consequent surface modification: in the urban area, most of the surface is covered by buildings and impermeable pavements, which strongly limits snowmelt and rainwater infiltration into the subsurface. However, floods are sometimes predictable events (Enríquez et al., 2022). To account for the vulnerability of a territory, due to extreme events, patterns of development coupled with demographic studies are considered. As a result, the score of flood risk is available as a risk index, evaluated by a dedicated committee of the European (European Commission, 2022). The 2022 flood risk is shown in Figure 1. It appears that only a few countries have a relatively low risk (less than 5), and Vietnam and Bangladesh are the countries with the higher flood risk (the index score is 10). Urban runoff is water deriving from rain and outdoor water usage, comprising stormwater and snowmelt, which drains from roofs, roads, car parks sidewalks, driveways, and other surfaces, and does not soak into the ground. It is widely recognised as a major carrier for the pollutants transport and release in the urban environment. Therefore, it also represents a significant contributor to the degradation of surface water bodies (EPA, 2003). As a consequence, urban runoff is one of the key pathways in the transfer of pollutants to the aquatic and marine environment. The contaminants associated with urban runoff can be divided into different categories such as heavy metals, solids, toxic chemicals, biodegradable organic matter (chemical or biochemical oxygen demand COD/BOD), organic micropollutants (among them polycyclic aromatic hydrocarbons PAHs, polychlorinated biphenyls PCBs), pathogenic microorganisms (such as Escherichia Coli), nutrients (nitrogen and phosphorus) and microplastics (Wei et al., 2013; Piñon-Colin et al., 2020). For example, Wang et al. (2022) reveal that the concentrations of microplastics in urban stormwater are much higher than those found in wastewater effluents. The source of pollutants can be natural (soil, leaves and organic debris) or anthropogenic (construction materials, exhausted particles, roadway debris, fertilizers, and so on) (TrujilloGonzález et al., 2019). Generally, the road deposited sediment represents one of the primary contaminants contributors to urban runoff (Piñon-Colin et al., 2020). In the worst cases, when the stormwater collection is in connection with the sanitary sewage system, an accidental release of raw sewage may also happen because of important precipitation events, with the result of dramatic environmental and economic impacts. OPEN ACCESS","PeriodicalId":73082,"journal":{"name":"Frontiers in environmental chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48581535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-26DOI: 10.3389/fenvc.2023.1090704
Andreas Gondikas, K. Mattsson, M. Hassellöv
Microplastics in the marine environment have been the focus of intense research recently, however little attention has been given to boat paint sources, despite its direct influence on the marine ecosystem. This is largely due to the lack of established analytical methods. Microplastics from boating sources may originate from antifouling paints on the underwater body, surface coatings on the top sides, deck, and superstructure, as well as plastic parts of the boat construction. Their release can occur during construction, operation (leisure boats and commercial ships), service, and maintenance, from the materials themselves or used chemicals (e.g., abrasive detergents). Most importantly, boat paint microplastics containing biocides, such as the metals copper and zinc, and particles containing tin (residues from old or current use of tributyl-tin ship hull paints) should raise higher concern on potential environmental impacts. This study aims to provide practical insight on methods for the quantification of boat paint microplastics in marine waters and provide a baseline survey on their occurrence. Sampling and analysis methods are applied on case studies, i.e., marinas on the Swedish coast. A multi-method approach for identifying and characterizing boat paint microplastics based on visual and chemical characteristics is presented. In general, the measured content of biocide-containing microplastics was remarkably high in all marinas, with concentration levels of copper-rich particles >10 μm between 400 and 1400 particles per L. Given that biocide paint particles are manufactured to be toxic, it is particularly important to take into account field measurements in future environmental status assessments. This work underlines the importance of monitoring data in the action work between relevant authorities and stakeholders.
{"title":"Methods for the detection and characterization of boat paint microplastics in the marine environment","authors":"Andreas Gondikas, K. Mattsson, M. Hassellöv","doi":"10.3389/fenvc.2023.1090704","DOIUrl":"https://doi.org/10.3389/fenvc.2023.1090704","url":null,"abstract":"Microplastics in the marine environment have been the focus of intense research recently, however little attention has been given to boat paint sources, despite its direct influence on the marine ecosystem. This is largely due to the lack of established analytical methods. Microplastics from boating sources may originate from antifouling paints on the underwater body, surface coatings on the top sides, deck, and superstructure, as well as plastic parts of the boat construction. Their release can occur during construction, operation (leisure boats and commercial ships), service, and maintenance, from the materials themselves or used chemicals (e.g., abrasive detergents). Most importantly, boat paint microplastics containing biocides, such as the metals copper and zinc, and particles containing tin (residues from old or current use of tributyl-tin ship hull paints) should raise higher concern on potential environmental impacts. This study aims to provide practical insight on methods for the quantification of boat paint microplastics in marine waters and provide a baseline survey on their occurrence. Sampling and analysis methods are applied on case studies, i.e., marinas on the Swedish coast. A multi-method approach for identifying and characterizing boat paint microplastics based on visual and chemical characteristics is presented. In general, the measured content of biocide-containing microplastics was remarkably high in all marinas, with concentration levels of copper-rich particles >10 μm between 400 and 1400 particles per L. Given that biocide paint particles are manufactured to be toxic, it is particularly important to take into account field measurements in future environmental status assessments. This work underlines the importance of monitoring data in the action work between relevant authorities and stakeholders.","PeriodicalId":73082,"journal":{"name":"Frontiers in environmental chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44332846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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