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1.
Environ Sci Technol ; 55(8): 4227-4242, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33760581

RESUMO

Atmospheric oxidation of sulfur dioxide (SO2) forms sulfate-containing aerosol particles that impact air quality, climate, and human and ecosystem health. It is well-known that in-cloud oxidation of SO2 frequently dominates over gas-phase oxidation on regional and global scales. Multiphase oxidation involving aerosol particles, fog, and cloud droplets has been generally thought to scale with liquid water content (LWC) so multiphase oxidation would be negligible for aerosol particles due to their low aerosol LWC. However, recent field evidence, particularly from East Asia, shows that fast sulfate formation prevails in cloud-free environments that are characterized by high aerosol loadings. By assuming that the kinetics of cloud water chemistry prevails for aerosol particles, most atmospheric models do not capture this phenomenon. Therefore, the field of aerosol SO2 multiphase chemistry has blossomed in the past decade, with many oxidation processes proposed to bridge the difference between modeled and observed sulfate mass loadings. This review summarizes recent advances in the fundamental understanding of the aerosol multiphase oxidation of SO2, with a focus on environmental conditions that affect the oxidation rate, experimental challenges, mechanisms and kinetics results for individual reaction pathways, and future research directions. Compared to dilute cloud water conditions, this paper highlights the differences that arise at the molecular level with the extremely high solute strengths present in aerosol particles.


Assuntos
Poluentes Atmosféricos , Dióxido de Enxofre , Aerossóis/análise , Poluentes Atmosféricos/análise , Ecossistema , Extremo Oriente , Humanos , Sulfatos/análise
2.
Environ Sci Technol ; 55(5): 3081-3090, 2021 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-33566583

RESUMO

Water-soluble inorganic (WSI) ions are major components of ambient air PM2.5 (particulate matter of diameter ≤2.5 µm); however, their potential health effects are understudied. On C57BL/6 mice, we quantified the effect of three major PM2.5 WSIs (NO3-, SO42-, and NH4+) on respiratory systems. Exposure scenarios include different WSI types, concentrations, animal development stages (young vs adult), and sex. The exposure effects were comprehensively assessed, with special focus on the respiratory function and tissue/cell level changes. Chronic PM2.5 NO3- exposure produced significant respiratory function decline, mainly presented as airflow obstruction. The decline was more profound in young mice than in adult mice. In young mice, exposure to 22 µg/m3 PM2.5 NO3- reduced FEV0.05 (forced expiratory volume in 0.05 s) by 11.3% (p = 9.6 × 10-3) and increased pulmonary neutrophil infiltration by 7.9% (p = 7.1 × 10-3). Causality tests identified that neutrophil infiltration was involved in the biological mechanism underlying PM2.5 NO3- toxicity. In contrast, the effects of PM2.5 SO42- were considerably weaker than NO3-. PM2.5 NO3- exposure was 3.4 times more potent than PM2.5 SO42- in causing reduction of the peak expiratory flow. PM2.5 NH4+ exposure had no statistically significant effects on the respiratory function. In summary, this study provided strong evidence on the adverse impacts of PM2.5 WSIs, where the impacts were most profound in young mice exposed to PM2.5 NO3-. If confirmed in humans, toxicity of PM2.5 WSI will have broad implications in environment health and policy making.


Assuntos
Poluentes Atmosféricos , Compostos de Amônio , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/toxicidade , Animais , Monitoramento Ambiental , Camundongos , Camundongos Endogâmicos C57BL , Nitratos/toxicidade , Tamanho da Partícula , Material Particulado/análise , Material Particulado/toxicidade , Sistema Respiratório , Estações do Ano , Sulfatos/análise
3.
Ecotoxicol Environ Saf ; 213: 112036, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33588187

RESUMO

A hydroponic method was performed to explore the effects of sulfate supply on the growth, manganese (Mn) accumulation efficiency and Mn stress alleviation mechanisms of Polygonum lapathifolium Linn. Three Mn concentrations (1, 8 and 16 mmol L-1, representing low (Mn1), medium (Mn8) and high (Mn16) concentrations, respectively) were used. Three sulfate (S) levels (0, 200, and 400 µmol L-1, abbreviated as S0, S200 and S400, respectively) were applied for each Mn concentration. (1) The average biomass (g plant-1) of P. lapathifolium was ordered as Mn8 (6.36) > Mn1 (5.25) > Mn16 (4.16). Under Mn16 treatment, S addition increased (P < 0.05) biomass by 29.96% (S200) and 53.07% (S400) compared to that S0. The changes in the net photosynthetic rate and mean daily increase in biomass were generally consistent with the changes in biomass. (2) Mn accumulation efficiency (g plant-1) was ordered as Mn8 (99.66) > Mn16 (58.33) > Mn1 (27.38); and S addition increased (p < 0.05) plant Mn accumulation and Mn transport, especially under Mn16 treatment. (3) In general, antioxidant enzyme activities (AEAs) and malondialdehyde (MDA) in plant leaves were ordered in Mn16 > Mn8 > Mn1. Sulfate addition decreased (P < 0.05) AEAs and MDA under Mn16 treatment, while the changes were minor under Mn1 and Mn8 treatments. (4) Amino acid concentrations generally increased with increasing Mn concentration and S level. In summary, the medium Mn treatment promoted plant growth and Mn bioaccumulation; sulfate, especially at 400 µmol L-1 S, can effectively promote plant growth and Mn accumulation efficiency. The most suitable bioremediation strategy was Mn16 with 400 µmol L-1 S.


Assuntos
Biodegradação Ambiental , Manganês/toxicidade , Polygonum/fisiologia , Sulfatos/metabolismo , Antioxidantes/metabolismo , Biomassa , Hidroponia , Malondialdeído/metabolismo , Manganês/metabolismo , Desenvolvimento Vegetal , Folhas de Planta/metabolismo , Plantas/metabolismo , Polygonum/crescimento & desenvolvimento , Poluentes do Solo/análise , Sulfatos/análise
4.
Arch Environ Contam Toxicol ; 80(1): 92-106, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33388838

RESUMO

Groundwater is the main sources of water supply for drinking purposes in the Ordos Basin in the northwestern part of China. In order to sustain and protect the quality of groundwater resources, shallow groundwater samples were collected and analyzed to identify the hydrogeochemical characteristics, and to evaluate health risk to human. Cluster analysis showed that the 134 groundwater samples were divided into three classes (i.e., class 1, class 2, class 3). The groundwater types are mostly characterized by SO4-Cl type and SO4 type, mixed HCO3 type. The primary natural mechanisms controlling the chemical compositions are water-rock interaction and evaporation-precipitation. The extremely high concentrations of sulfate could be caused by contamination from pyrite or from infiltration of sulfate from inorganic fertilizers or from wastewater discharges. Results of the assessment of the health risks for ingestion of Cl-, NO3-, F-, Cr, and As in drinking water indicated that the total health risks are beyond the US EPA acceptable level of 10-6 per year for consumption of groundwater sourced from all three cluster classes. The highest risks were for ingestion of arsenic and chromium in groundwater. The highest total risks to adults and children were 1.51 × 10-5 and 2.45 × 10-2 (class 1), 4.12 × 10-4 and 8.98 × 10-3 (class 2), 3.06 × 10-3 and 5.49 × 10-2 (class 3), respectively. The study showed that there is a high risk of health problems among the residents of the Ordos Basin in China that are ingesting contaminated drinking water, with the health risks to children higher than the risks to adults.


Assuntos
Monitoramento Ambiental/métodos , Água Subterrânea , Poluentes Químicos da Água/agonistas , Abastecimento de Água/métodos , Adulto , Arsênico/análise , Criança , China , Fertilizantes , Água Subterrânea/química , Água Subterrânea/normas , Humanos , Medição de Risco , Sulfatos/análise , Poluentes Químicos da Água/análise , Abastecimento de Água/normas
5.
Arch Environ Contam Toxicol ; 80(1): 31-40, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33388839

RESUMO

In this study, the quality of groundwater was assessed in a semi-arid region of India by using an entropy weighted water quality index (EWQI) and a pollution index of groundwater (PIG). The EWQI and PIG methods were used to evaluate data on physicochemical parameters in relation to drinking water quality standards. Groundwater samples were collected from the Dubbak region, Telangana state, India, and were analyzed for pH, total hardness, electrical conductivity, total dissolved solids, bicarbonate (HCO3-), chloride (Cl-), sulfate (SO42-), nitrate (NO3-), fluoride (F-), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), and potassium (K+). The groundwater of the study region is alkaline in nature. The abundance of cations and anions based on their mean values is in the following order: Na+ > Ca2+ > Mg2+ > K+ and Cl- > HCO3- > NO3- > SO42- > F-, respectively. The calculated EWQI values ranged from 49.0 to 174.6, with an average of 93.3. Overall, EWQI data showed that only 60% of groundwater samples were of suitable quality for drinking, although only marginally, whereas the remaining 40% of samples were unsuitable for drinking purposes and would therefore require treatment. The values of PIG varied from 0.5 to 1.8, with an average of 1.0, which showed that only 63% of groundwater samples from the study area were suitable for drinking purposes.


Assuntos
Água Potável/normas , Entropia , Monitoramento Ambiental/métodos , Água Subterrânea/química , Poluentes Químicos da Água/análise , Qualidade da Água/normas , Cloretos/análise , Fluoretos/análise , Índia , Magnésio/análise , Minerais/análise , Nitratos/análise , Saúde da População Rural , Sulfatos/análise
6.
ACS Appl Mater Interfaces ; 13(4): 5551-5563, 2021 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33471995

RESUMO

Heparin is a complex glycosaminoglycan, derived mainly from pig mucosa, used therapeutically for its anticoagulant activity. Yet, owing largely to the chain complexity, the progressive effects of environmental conditions on heparin structure have not been fully described. A systematic study of the influence of acidic hydrolysis on heparin chain length and substitution has therefore been conducted. Changes in the sulfation pattern, monitored via 2D NMR, revealed initial de-N-sulfation of the molecule (pH 1/ 40 °C) and unexpectedly identified the secondary sulfate of iduronate as more labile than the 6-O-sulfate of glucosamine residues under these conditions (pH 1/ 60 °C). Additionally, the loss of sulfate groups, rather than depolymerization, accounted for most of the reduction in molecular weight. This provides an alternative route to producing partially 2-O-de-sulfated heparin derivatives that avoids using conventional basic conditions and may be of value in the optimization of processes associated with the production of heparin pharmaceuticals.


Assuntos
Anticoagulantes/química , Heparina/química , Sulfatos/análise , Animais , Concentração de Íons de Hidrogênio , Hidrólise , Espectroscopia de Ressonância Magnética , Suínos
7.
Chemosphere ; 262: 128000, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182106

RESUMO

Peroxydisulfate-based advanced oxidation process has drawn increasing interest recently. Quenching the residual peroxydisulfate is essential for the accurate measurement of the concentration of target pollutants. However, it was rarely discussed which reductant is best for peroxydisulfate quenching. In this study, how the quenching of peroxydisulfate by four commonly used quenchers (methanol, ascorbic acid, sodium thiosulfate and sodium sulfite) affected the concentration of carbamazepine was investigated. Sodium sulfite reacted with carbamazepine directly, with the highest removal rate up to 39%. Higher carbamazepine removal rate was achieved by peroxydisulfate/sodium sulfite than by sodium sulfite alone. SO3•- and SO5•- rather than SO4•- played the major role in carbamazepine removal by sodium sulfite or peroxydisulfate/sodium sulfite. Methanol was found unable to reduce peroxydisulfate. Ascorbic acid, when used with a concentration more than three times higher than that of peroxydisulfate, was the best quencher with the lowest carbamazepine removal rate observed at a pH range of 3.5-10.0. Sodium thiosulfate was unfit for peroxydisulfate quenching at pH 3.5 as it was decomposed and formed bisulfite under strong acidic condition. The results of this study provided valuable guidance to the selection of proper quenchers for peroxydisulfate-related advanced oxidation processes.


Assuntos
Substâncias Redutoras/análise , Compostos de Sódio/análise , Sulfatos/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Oxirredução , Sulfitos/química , Tiossulfatos/química
8.
Chemosphere ; 262: 127745, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32805654

RESUMO

Nitrate (NO3-), sulfate (SO42-) and ammonium (NH4+) in airborne fine particles (PM2.5) play a vital role in the formation of heavy air pollution in northern China. In particular, the increasing contribution of NO3- to PM2.5 has attracted worldwide attention. In this study, a highly time-resolved analyzer was used to measure water-soluble inorganic ions in PM2.5 in one of the fastest-developing megacities, Tianjin, China, from November 15 to March 15 (wintertime heating period) in 2014-2019. Severe PM2.5 pollution episodes markedly decreased during the heating period from 2014 to 2019. The highest concentrations of NO3- and SO42- were recorded in the heating period of 2015/2016. Afterwards, NO3- decreased from 2015/2016 (20.2 ± 23.8 µg/m3) to 2017/2018 (11.6 ± 14.8 µg/m3) but increased with increasing NOx concentrations during the heating period of 2018/2019. A continuous decrease in the SO2 concentration led to a decrease in SO42- from 2015/2016 (16.8 ± 21.8 µg/m3) to 2018/2019 (6.5 ± 8.9 µg/m3). The NO3- and SO42- concentrations increased as the air quality deteriorated. However, the proportion of NO3- and SO42- in PM2.5 slightly increased when the air quality deteriorated from moderate pollution (MP) to severe pollution (SP) levels. The average molar ratios of NH4+ to [NO3-+2 × (SO42-)] were 1.7, 0.9, 1.2, 1.2 and 1.5 for the heating periods of 2014/2015, 2015/2016, 2016/2017, 2017/2018 and 2018/2019, respectively, most of which were higher than 1.0, thus revealing an overall excess of NH4+ during the heating periods. However, the molar equivalent ratios of [NH4+] to [NO3-+2 × (SO42-)] were less than 1 under increasing PM2.5 pollution. The molar equivalent ratios of [NO3-]/[SO42-] were positively correlated with those of [NH4+]/[SO42-]. When the molar equivalent ratios of [NH4+]/[SO42-] were more than 1.5, those of [NO3-]/[SO42-] increased from close to 1 to higher values, indicating that the dominance of NO3- formation played an important role. The results of nonparametric wind regression exhibited distinct hot spots of NO3-, SO42- and NH4+ (higher concentrations) in the wind sectors between NE and SE at wind speeds of approximately 6-21 km/h. The southern areas in the North China Plain and parts of the western areas of China contributed more NO3-, SO42- and NH4+ than other areas to the study site. The abovementioned areas were also characterized by a higher contribution of NO3- than of SO42- to the study site and by NH4+-rich conditions. In summary, more efforts should be made to reduce NOx in the Beijing-Tianjin-Hebei region. This study provides observational evidence of the increasingly important role of nitrate as well as scientific support for formulating effective control strategies for regional haze in China.


Assuntos
Poluentes Atmosféricos/análise , Compostos de Amônio/análise , Nitratos/análise , Sulfatos/análise , Poluentes Atmosféricos/química , Poluição do Ar/análise , China , Monitoramento Ambiental , Material Particulado/análise , Estações do Ano , Transportes , Emissões de Veículos/análise , Água/química , Vento
9.
Chemosphere ; 263: 127991, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32854012

RESUMO

Comprehensive observations have been carried out in Beijing to investigate the impact of the Clean Air Action implemented in 2013 on changes in aerosol chemistry characteristics in heating seasons of 2016-2017 and 2017-2018. Results showed that PM2.5, SO2, NO2, NH3, O3 and CO concentrations decreased by 40.9%, 46.0%, 29.0%, 40.6%, 11.0% and 44.4%, respectively. Significant decreases were also observed for NO3- (32.5%), SO42- (52.9%), NH4+ (56.0%), Cl- (64.6%) and K+ (68.2%), on average. Enhanced PM2.5 pollution has changed from sulfate-driven to nitrate-driven. The decrease in SO2 was more significant than NO2 as a response to one reason of the larger decrease in SO42- concentration. The formation of sulfate was dominated by heterogeneous reactions in two heating seasons. Low pH could facilitate more efficient conversion of SO2 to sulfate. Photochemical reactions played a much more important role in the formation of nitrate in the second heating season, especially in the daytime. The major source regions for sulfate and nitrate were identified by back trajectories and the potential source function (PSCF). More nitrate was brought into Beijing when air masses coming from polluted regions in the southwest prevailed in 2017-2018 heating season. Thus, regional joint prevention and control are of great importance in the achievement of an effective reduction in PM2.5 pollution in the future.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental , Material Particulado/análise , Aerossóis/análise , Ar , Poluição do Ar/análise , Pequim , China , Poluição Ambiental , Calefação , Nitratos/análise , Estações do Ano , Sulfatos/análise
10.
Chemosphere ; 262: 127904, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32799153

RESUMO

Manganese accumulated in corrosion scales on drinking water distribution systems (DWDSs) can be released into bulk water, causing discolouration and thereby leading to customer concerns about drinking water quality. A static release experiment was conducted on iron pipe scales under three different temperatures, pH values, alkalinity values, sulfate (SO42-) concentrations, and disinfectants to study the separate effect of these factors on Mn release from pipe scales under stagnant conditions. Results showed that more Mn was released from corrosion scales under the conditions of lower pH, lower alkalinity, higher temperature, and higher SO42- concentrations. Three commonly used disinfectants, sodium hypochlorite (NaClO), chlorine dioxide (ClO2), and monochloramine (NH2Cl) were found to inhibit the release of Mn from iron corrosion scales, with the ranked order of inhibitory effect of ClO2≈NaClO > NH2Cl under the same CT (product of disinfectant concentration and contact time) value. The orthogonal experimental results indicated that SO42- and alkalinity had extremely significant effects on the release of Mn from pipe scales, while pH and disinfectant type had a significant impact on the release of Mn from pipe scales. Thus, the SO42- concentration and alkalinity of the bulk water should be determined to avoid excessive release of Mn into drinking water. However, further investigation of the effect of disinfectants on Mn release in DWDSs is necessary. This research helps establish a systematic understanding of the influential factors in Mn release from pipe scales into bulk water, as well as their significant relationships.


Assuntos
Água Potável/química , Manganês/análise , Poluentes Químicos da Água/análise , Compostos Clorados , Corrosão , Desinfetantes/análise , Concentração de Íons de Hidrogênio , Ferro , Óxidos , Sulfatos/análise , Temperatura , Qualidade da Água , Abastecimento de Água
11.
Int J Mol Sci ; 21(24)2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33333739

RESUMO

Butylated hydroxytoluene (BHT) and its analogs, butylated hydroxyanisole (BHA) and tert-butyl-hydroquinone (TBHQ), are widely used synthetic preservatives to inhibit lipid oxidation in the food, cosmetic and pharmaceutical industries. Despite their widespread use, little is known about their human exposure and related biotransformation products. The metabolism of these compounds was investigated using in vitro incubations with human and rat liver fractions. Liquid chromatography coupled to high-resolution tandem mass spectrometry was employed to detect and characterize stable and reactive species formed via oxidative metabolism, as well as phase II conjugates. Several oxidative metabolites have been detected, as well as glutathione, glucuronide, and sulfate conjugates, many of which were not previously reported. A combination of accurate mass measurements, MS/MS fragmentation behavior, and isotope-labeling studies were used to elucidate metabolite structures.


Assuntos
Antioxidantes/análise , Hidroxianisol Butilado/metabolismo , Hidroxitolueno Butilado/metabolismo , Animais , Antioxidantes/química , Hidroxianisol Butilado/análogos & derivados , Hidroxianisol Butilado/química , Hidroxitolueno Butilado/análogos & derivados , Hidroxitolueno Butilado/química , Cromatografia Líquida , Glucuronídeos/análise , Glutationa/análise , Humanos , Técnicas In Vitro , Microssomos/metabolismo , Fenóis/análise , Fenóis/metabolismo , Ratos , Sulfatos/análise , Espectrometria de Massas em Tandem
12.
Chemosphere ; 254: 126851, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957275

RESUMO

In this study, daily PM2.5 mass and chemical composition were measure in Lin'an Reginal Background Station, Yangzte River Delta, from March 1, 2018, to February 28, 2019. Organic matter (OM) was found to be the most dominant component in four seasons. The proportions of nitrate in PM2.5 presented dramatically lowest in warm seasons but highest in winter, indicating that NO3- was maily driven by thermodynamics. Regional transportation in winter plays a strong impact on PM2.5 concentration, which showed the highest average mass of 60.1 µg m-3. Sulfate occupied a significant portion of PM2.5 in summer (19%), followed by spring (17%), fall (15%), and winter (12%), respectively, suggesting photochemical processes may play a dominant role in the sulfate formation. Secondary inorganic aerosol (SIA) was the dominant component (70%) in the highest polluted periods (PM2.5 > 75 µg m-3), whereas OM decreased into the lowest fraction (22%) of PM2.5. Nitrate was the most important component in SIA in the highest polluted periods with regarding winter. Source apportionment results shown that winter haze was likely strongly dominated by SIA, which was mainly affected by air masses from the North China Plain and Shang-Hangzhou direction. PM2.5 is known to play an important role in sunlight absorption and reversing to human health, continuous observation on PM2.5 species in a background site can help us to evaluate the control policy, and promote our insights to lifetime, formation pathways, health effects of PM2.5.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Material Particulado/análise , Rios/química , Aerossóis/análise , China , Humanos , Óxidos de Nitrogênio/análise , Estações do Ano , Sulfatos/análise
13.
Chemosphere ; 261: 127769, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32738716

RESUMO

The characteristics of secondary inorganic aerosol including sulfate, nitrate and ammonium (SNA) were investigated during a six-month long heating season in the Harbin-Changchun metropolitan area, i.e., China's only national-level city cluster located in the severe cold climate region. The contribution of SNA to fine particulate matter (PM2.5) tended to decrease with increasing PM2.5 concentration, opposite to the trend repeatedly observed during winter in Beijing. Heterogeneous sulfate formation was still evident when the daily average temperature was as low as below -10 °C, with the preconditions of high relative humidity (RH; above ∼80%) and high nitrogen dioxide (above ∼60 µg/m3). Both the sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR) were enhanced at high RH, reaching ∼0.3. However, the high RH conditions were not commonly seen during the heating season, which should be responsible for the overall lack of linkage between the SNA contribution and PM2.5 temporal variation.


Assuntos
Poluentes Atmosféricos/análise , Clima Frio , Monitoramento Ambiental , Aerossóis/análise , Pequim , China , Cidades , Calefação , Umidade , Nitratos/análise , Dióxido de Nitrogênio , Óxidos de Nitrogênio/análise , Material Particulado/análise , Estações do Ano , Sulfatos/análise
14.
Chemosphere ; 255: 126951, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32417512

RESUMO

The processing of sediment to accurately characterize the spatially-resolved depth profiles of geophysical and geochemical properties along with signatures of microbial density and activity remains a challenge especially in complex contaminated areas. This study processed cores from two sediment boreholes from background and contaminated core sediments and surrounding groundwater. Fresh core sediments were compared by depth to capture the changes in sediment structure, sediment minerals, biomass, and pore water geochemistry in terms of major and trace elements including pollutants, cations, anions, and organic acids. Soil porewater samples were matched to groundwater level, flow rate, and preferential flows and compared to homogenized groundwater-only samples from neighboring monitoring wells. Groundwater analysis of nearby wells only revealed high sulfate and nitrate concentrations while the same analysis using sediment pore water samples with depth was able to suggest areas high in sulfate- and nitrate-reducing bacteria based on their decreased concentration and production of reduced by-products that could not be seen in the groundwater samples. Positive correlations among porewater content, total organic carbon, trace metals and clay minerals revealed a more complicated relationship among contaminant, sediment texture, groundwater table, and biomass. The fluctuating capillary interface had high concentrations of Fe and Mn-oxides combined with trace elements including U, Th, Sr, Ba, Cu, and Co. This suggests the mobility of potentially hazardous elements, sediment structure, and biogeochemical factors are all linked together to impact microbial communities, emphasizing that solid interfaces play an important role in determining the abundance of bacteria in the sediments.


Assuntos
Sedimentos Geológicos/química , Urânio/química , Poluentes Radioativos da Água/química , Bactérias , Água Subterrânea/química , Nitratos/análise , Compostos Orgânicos , Sulfatos/análise , Urânio/análise , Poluentes Radioativos da Água/análise
15.
Environ Pollut ; 264: 114769, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32428816

RESUMO

Soluble iron (FeS) in aerosols contributes to free oxygen radical generation with implications for human health, and potentially catalyzes sulfur dioxide oxidation. It is also an important external source of micronutrients for ocean ecosystems. However, factors controlling FeS concentration and its contribution to total iron (FeT) in aerosols remain poorly understand. Here, FeS and FeT in PM2.5 was studied at four urban sites in eastern China from 21 to 31 December, 2017. Average FeT (869-1490 ng m-3) and FeS (24-68 ng m-3) concentrations were higher in northern than southern China cities, but Fe solubility (%FeS, 2.7-5.0%) showed no spatial pattern. Correlation analyses suggested %FeS was strongly correlated with FeS and PM2.5 instead of FeT concentrations. Individual particle observations confirmed that more than 65% of nano-sized Fe-containing particles were internally mixed with sulfates and nitrates. Furthermore, there was a high correlation between sulfates or nitrates/FeT molar ratio and %FeS. We also found that the sulfates/nitrates had weaker effects on %FeS at RH < 50% than at RH > 50%, suggesting RH as indirect factor can influence %FeS in PM2.5. These results suggest an important role of chemical processing in enhancing %FeS in the polluted atmosphere.


Assuntos
Poluentes Atmosféricos/análise , Aerossóis/análise , China , Cidades , Ecossistema , Monitoramento Ambiental , Humanos , Ferro/análise , Nitratos/análise , Material Particulado/análise , Solubilidade , Sulfatos/análise
16.
Chemosphere ; 251: 126598, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32443236

RESUMO

Here we present a long-term, hourly resolution dataset (from January 2014 to April 2015) of secondary inorganic aerosol (SIA) matter, organic matter (OM) and black carbon (BC) as PM2.5 chemical components in China. Seasonally differentiated weekly diurnal profiles of major particulate species were investigated in conjunction with potential source contribution function (PSCF) analysis. The average concentration of PM2.5 was 48.3 ± 35.1 µg m-3, in which OM was the major constituent (29.7 ± 13.9%), followed by sulfate (25.1 ± 8.1%), nitrate (18.5 ± 8.3%), ammonium (13.3 ± 3.8%), and other trace species (6.8 ± 4.0%). Interestingly, unlike other PM species, OM concentrations kept very similar level among different seasons, indicating on-road traffic is a stable source of PM2.5. Besides, a persistently strong particulate OM pollution belt was found along the lower reaches of Yangtze River. Significant enhancement of SIA (mainly nitrate) was coincided with high PM2.5 mass loading. Source apportionment were conducted and found the overwhelming dominance of long-range transport of the pollutants from north China. Using a case study, we further integrate Weather Research and Forecasting (WRF) meteorological modeling and lidar observation to better understand the evolution process of a typical pollution episode. Our assessment of the extremely large datasets derived from Shanghai supersite demonstrated the online instrumentation as a robust and credible alternative to filter-based sampling techniques for long-term PM2.5 monitoring and characterization in heavily polluted areas.


Assuntos
Poluentes Atmosféricos/análise , Poluentes Atmosféricos/química , Monitoramento Ambiental/métodos , Material Particulado/análise , Material Particulado/química , Aerossóis , China , Cidades , Carvão Mineral/análise , Nitratos/análise , Óxidos de Nitrogênio/análise , Rios/química , Estações do Ano , Sulfatos/análise , Tempo (Meteorologia)
17.
PLoS One ; 15(5): e0232742, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32374788

RESUMO

Caves formed by sulfuric acid dissolution have been identified worldwide. These caves can host diverse microbial communities that are responsible for speleogenesis and speleothem formation. It is not well understood how microbial communities change in response to surface water entering caves. Illumina 16S rRNA sequencing and bioinformatic tools were used to determine the impact of surface water on the microbial community diversity and function within a spring pool found deep in the Monte Conca Cave system in Sicily, Italy. Sulfur oxidizers comprised more than 90% of the microbial community during the dry season and were replaced by potential anthropogenic contaminants such as Escherichia and Lysinibacillus species after heavy rains. One sampling date appeared to show a transition between the wet and dry seasons when potential anthropogenic contaminants (67.3%), sulfur-oxidizing bacteria (13.6%), and nitrogen-fixing bacteria (6.5%) were all present within the spring pool.


Assuntos
Cavernas/microbiologia , Microbiota/genética , Microbiologia da Água , Molhabilidade , Bacillaceae/genética , Sequência de Bases , DNA Bacteriano/genética , Secas , Escherichia/genética , Sulfeto de Hidrogênio/análise , RNA Ribossômico 16S/genética , Chuva , Estações do Ano , Sicília , Microbiologia do Solo , Sulfatos/análise
18.
Environ Sci Technol ; 54(11): 6562-6574, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32339453

RESUMO

In this work, we deployed a single particle aerosol mass spectrometer (SPAMS) at a suburban coastal site in Hong Kong from February 04 to April 17, 2013 to study individual oxalate particles and a monitor for aerosols and gases in ambient air (MARGA) to track the bulk oxalate concentrations in particle matter smaller than 2.5 µm in diameter (PM2.5). A shallow dip in the bulk oxalate concentration was consistently observed before 10:00 am in the morning throughout the observation campaign, corresponding to a 20% decrease in the oxalate concentration on average during the decay process. Such a decrease in PM oxalate was found to be coincident with a decrease in Fe-containing oxalate particles, providing persuasive evidence of Fe-mediated photochemical degradation of oxalate. Oxalate mixed with Fe and Fe_NaK particles, from industry sources, were identified as the dominant factors for oxalate decay in the early morning. We further found an increase of sulfate intensity by a factor of 1.6 on these individual Fe-containing particles during the oxalate decomposition process, suggesting a facilitation of sulfur oxidation. This is the first report on the oxalate-Fe decomposition process with individual particle level information and provides unique evidence to advance our current understanding of oxalate and Fe cycling. The present work also indicates the importance of anthropogenic sourced iron in oxalate-Fe photochemical processing. In addition, V-containing oxalate particles, from ship emissions, also showed evidence of morning photodegradation and need further attention since current models rarely consider photochemical processing of oxalate_V particles.


Assuntos
Poluentes Atmosféricos , Material Particulado , Aerossóis/análise , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Hong Kong , Espectrometria de Massas , Oxalatos , Tamanho da Partícula , Material Particulado/análise , Sulfatos/análise
19.
Ecotoxicol Environ Saf ; 196: 110535, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32224368

RESUMO

Acid rain containing SO42- and NO3- in China has been a public concern for decades. However, a decrease of SO2 has been recorded since the government enacted a series of policies to control its emission. To comprehensively evaluate the consequence of realistic and future acid deposition scenarios, this study explored the effects of mixed acid rain with different molar ratios of SO42- and NO3- (0:1, 1:0, 2:1, 1:1, and 1:2) on stream leaf breakdown through a microcosm experiment. A significant inhibition of leaf breakdown rate was observed when the ratio was 1:2 with reduced microcosm pH, fungal biomass, enzyme activities as well as the frequencies of hub general in the fungal community. In conclusion, the ratio of SO42- and NO3- in acid rain was an important factor that could have a profound impact on leaf breakdown, even on ecosystem structure and functioning of streams.


Assuntos
Chuva Ácida/efeitos adversos , Água Doce/química , Nitratos/toxicidade , Folhas de Planta/metabolismo , Sulfatos/toxicidade , Chuva Ácida/análise , Biodegradação Ambiental/efeitos dos fármacos , Biomassa , China , Ecossistema , Água Doce/microbiologia , Micobioma/efeitos dos fármacos , Nitratos/análise , Sulfatos/análise
20.
Bull Environ Contam Toxicol ; 104(5): 634-641, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32236702

RESUMO

The aim of this study was to characterize the leachate derived from biochar produced from malt spent rootlets (MSR) and to evaluate the required washing level in order to provide water free from inorganic substances. MSR biochar was placed in a column and subjected to six serial washes with distilled water, and the leachate was analysed for main anions and heavy metals. The 1st wash aliquot contained increased levels of mainly phosphates (980 mg/L) and chlorides (760 mg/L), and lower levels of nitrates, sulfates, fluoride and bromide, which were decreased over washes. Zero concentrations were observed after three washes for most anions. The increased levels of Zn, Be, Cs, Mn, V and Se determined in the 1st wash aliquot were eliminated in the successive washes. The toxic potency of each wash aliquot, determined by the use of the fairy shrimp Thamnocephalus platyurus showed that the 1st and 2nd MSR biochar leachates were toxic with 4.52 and 1.46 toxic units (TU), respectively, followed by a significant elimination of toxicity after further washes.


Assuntos
Carvão Vegetal/química , Metais Pesados/toxicidade , Resíduos Sólidos/análise , Poluentes Químicos da Água/toxicidade , Animais , Anostraca/efeitos dos fármacos , Bioensaio , Relação Dose-Resposta a Droga , Dose Letal Mediana , Metais Pesados/análise , Nitratos/análise , Nitratos/toxicidade , Sulfatos/análise , Sulfatos/toxicidade , Testes de Toxicidade , Poluentes Químicos da Água/análise
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