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1.
J Environ Manage ; 301: 113840, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34607138

RESUMO

This study investigated the long-term leachability of antimony (Sb) in a smelting residue (39519 mg/kg) solidified/stabilized by reactive magnesia (MgO). Different dosages of MgO (0% as control, 2%, 5%, and 10% on a dry basis) were compared, and the long-term performance was evaluated by an accelerated exposure test consist of 20 consecutive leaching steps with simulated strong acid rain (SAR, HNO3: H2SO4 = 1:2, pH = 3.20) as the extractant. Notably, the MgO treatments efficiently reduced the Sb leachability. Compared to the original slag (8.3 mg/L), the leaching concentrations based on a Chinese standard HJ/T299-2007 were reduced by 58%, 79%, 85%, and 86% at MgO dosages of 0%, 2%, 5%, and 10%, respectively. Because the studied slag was rich in oxides like SiO2, CaO, and MgO, the hydration reactions probably happened during the aging processes with oxic water. It was inferred that the formed hydration products have a self-solidification/stabilization function to suppress the Sb leaching from the solid phase. The mineralogical characterization results proved that the hydrated Mg(OH)2 played an essential role in the decrease of Sb leachability. Besides, the MgO addition promoted the hydration of this smelting slag and formed new hydrate gels that immobilize Sb in this slag. Our results confirmed that MgO-amended slags were resistant to continuous SAR corrosion. Compared to the control, the dosage of 5% MgO could effectively reduce the cumulatively released Sb by 57%, with only 0.46% of total Sb could be leached. The decomposition of Mg(OH)2 and hydrate gels determined the re-release of Sb in a long term. Our work has demonstrated that reactive MgO amendment could be potentially selected as an effective strategy for the treatment of Sb-containing smelting residues in field conditions.


Assuntos
Chuva Ácida , Antimônio , Óxido de Magnésio , Dióxido de Silício
2.
Sci Total Environ ; 800: 149626, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34426327

RESUMO

Modeling studies project that in the future surface waters in the northeast US will continue to recover from acidification over decades following reductions in atmospheric sulfur dioxide and nitrogen oxides emissions. However, these studies generally assume stationary climatic conditions over the simulation period and ignore the linkages between soil and surface water recovery from acid deposition and changing climate, despite fundamental impacts to watershed processes and comparable time scales for both phenomena. In this study, the integrated biogeochemical model PnET-BGC was applied to two montane forest watersheds in the Adirondack region of New York, USA to evaluate the recovery of surface waters from historical acidification in response to possible future changes in climate and atmospheric sulfur and nitrogen deposition. Statistically downscaled climate scenarios on average project warmer temperatures and greater precipitation for the Adirondack by the end of the century. Model simulations suggest under constant climate, acid-sensitive Buck Creek would gain 12.8 µeq L-1 of acid neutralizing capacity (ANC) by 2100 from large reductions in deposition, whereas acid insensitive Archer Creek is projected to gain 7.9 µeq L-1 of ANC. However, climate change could limit those improvements in acid-base status. Under climate change, a negative offset relative to the ANC increases with no climate change are projected for both streams by 2100. In acid-insensitive Archer Creek the negative offset (-8.5 µeq L-1) was large enough that ANC is projected to decrease by -0.6 µeq L-1, whereas in acid-sensitive Buck Creek, the negative offset (-0.4 µeq L-1) resulted in a slight decline of the projected future ANC increase to 12.4 µeq L-1. Calculated target loads for 2150 for both sites decreased when future climate change was considered in model simulations, which suggests further reductions in acid deposition may be necessary to restore ecosystem structure and function under a changing climate.


Assuntos
Chuva Ácida , Rios , Chuva Ácida/análise , Mudança Climática , Ecossistema , Monitoramento Ambiental , New York , Nitrogênio , Enxofre/análise
3.
Environ Monit Assess ; 193(9): 597, 2021 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-34427782

RESUMO

In this study, the rainfall, pH, conductivity, and ionic component data for Guilin from 2015 to 2017 were analyzed. Specifically, the relationship between the pH value of the rainfall, the change of each ion in the rainfall, and the primary ion sources was examined. The main results obtained were as follows. During the 3-year study period, the average annual pH value of Guilin was 5.45 and exhibited a downward trend. The seasonal variation of rainfall acidity was pronounced, with high pH values and low frequencies of acid rain in summer, and low pH values and high frequencies of acid rain in winter. From 2015 to 2017, the relative order of the average concentrations of the ionic components in the rainfall was SO42- > NO3- > Ca2+ > Cl- > NH4+ > Na+ > K+ > Mg2+ > F-, the annual average concentration of each ionic component displayed a downward trend, and seasonal changes were obvious. Only NH4+ showed an upward trend in rainfall. The (SO42-)/(NO3-) ratio was basically < 3 and manifested a downward trend; (Ca2+)/(NH4+) rose sharply in August and September each year. Using correlation analysis and enrichment factor analysis, it was concluded that the rainfall in Guilin is mainly affected by SO2, NOx, and NH3, with the geological conditions in the karst area also contributing a certain amount to the rainfall acidity. Calculating the enrichment factor revealed that most of the Ca2+ came from a crustal source; half the Mg2+ came from the ocean and half came from the crust; and most of K+ and Cl- originated from the ocean. Human activities contributed most of the SO42- and NO3- in the rainfall.


Assuntos
Chuva Ácida , Monitoramento Ambiental , Chuva Ácida/análise , China , Cidades , Humanos , Estações do Ano
4.
J Environ Manage ; 297: 113213, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34329914

RESUMO

Anthropogenic driven acid gases emission has caused acid rain in many regions globally. Although efforts have been made to assess the effects of acid rain on terrestrial ecosystems, a systematic assessment of growth-related traits across plant aboveground and belowground is lacking. Hence, we performed a phylogenetically controlled meta-analysis of 755 observations from 69 independent studies to quantify the effects of acid rain on six growth-related traits of plant. We estimated the inhibitory effects of acid rain on plant growth in general and found that aboveground and belowground plant parts responded differently. The acidity of acid rain and acid rain interval had direct modulation effects on plant growth. We also found that there were interactions between acid rain pH and other acid rain characteristics (i.e., acid rain interval, mole ratio of S:N, and acid rain rate) and experimental characteristics (i.e., initial soil pH and plant exposure part), indicating that there were pH-dependent interaction patterns. Thus, an effective approach to evaluate and predict the effects of acid rain on plant growth is to fully consider the direct effects of acid rain pH and the interactions between acid rain pH and other factors.


Assuntos
Chuva Ácida , Ecossistema , Desenvolvimento Vegetal , Plantas , Solo
5.
Planta ; 254(2): 41, 2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34327596

RESUMO

MAIN CONCLUSION: Exogenous calcium enhances rice tolerance to acid rain stress by regulating isozymes composition and transcriptional expression of ascorbate peroxidase and glutathione reductase. Calcium (Ca) participates in signal transduction in plants under abiotic stress, and addition of Ca2+ is beneficial to alleviate damage of plants caused by acid rain. To clarify the effect of exogenous Ca2+ on tolerance of plants to acid rain stress, we investigated regulation of Ca2+ (5 mM) on activities, isozymes composition and transcriptional expression of ascorbate peroxidase (APX) and glutathione reductase (GR), redox state, and H2O2 concentration and growth in rice leaves and roots under simulated acid rain (SAR) stress. SAR (pH 3.5/2.5) decreased the total activities of APX and GR in rice by decreasing the concentration of APX isoforms (APXII in leaves and APXIII in roots) as well as activation degree of GR isozymes and transcription level of GR1, indicating that SAR (pH 3.5/2.5) destroyed the redox state in rice cells and induced H2O2 excessive accumulation, and inhibited growth of rice. Exogenous Ca2+ alleviated SAR-induced inhibition on activities of APX and GR by regulating the concentration, activation, and transcription of their isozymes, and then maintained the redox level of cells and protected cells from oxidative damage, being beneficial to the growth of rice. Therefore, the promotion of exogenous Ca2+ on activities of APX and GR can be important to enhance rice tolerance to acid rain by maintaining redox state and avoiding oxidative damage.


Assuntos
Chuva Ácida , Oryza , Chuva Ácida/efeitos adversos , Antioxidantes , Ascorbato Peroxidases/metabolismo , Cálcio , Glutationa/metabolismo , Glutationa Redutase/metabolismo , Peróxido de Hidrogênio , Oryza/genética , Oryza/metabolismo , Estresse Oxidativo , Plântula/metabolismo
6.
J Hazard Mater ; 420: 126612, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34265655

RESUMO

Arsenopyrite is widely distributed and weathers readily in the nature, releases As and pollutes the surrounding environment. Acid rain is acidic in nature as contains sulfur oxides (SOx) and nitrogen oxides (NOx), and is a typical hazardous material to human. When arsenopyrite encounters acid rain, their interaction effect may aggregate environmental degradation. In this work, the weathering behavior of arsenopyrite in simulated acid rain was studied using the electrochemical techniques and surface analysis. Cyclic voltammetry and Raman and XPS confirmed that FeAsS was oxidized to Fe2+, AsO33- and S0 at the initial phase, then, Fe2+ was converted to Fe3+, S0 transformed to SO32- and ultimately to SO42-, and AsO33- to AsO43- with the accumulation of H+. Polarization curve revealed higher temperature or higher acidity of acid rain increased the weathering trend and rate of arsenopyrite, and electrochemical impedance spectroscopic measurements showed the causes behind this to be smaller resistance and greater capacitance at the double layer and passivation film. Arsenopyrite weathering rate and temperature has a relationship: lnk = -3824.8/T + 10.305, via a transition state with activation enthalpy 29.37 kJ mol-1 and activation entropy - 167.40 J mol-1 K-1. This study provides a rapid and quantitative in-situ electrochemical method for arsenopyrite weathering and an improved understanding of arsenopyrite weathering in acid rain condition. The results have powerful implications for the remediation and management of As-bearing sites affected by mining activities in acid rain area.


Assuntos
Chuva Ácida , Arsênio , Arsenicais , Compostos de Ferro , Proteínas Adaptadoras de Transdução de Sinal , Arsenicais/metabolismo , Humanos , Compostos de Ferro/metabolismo , Minerais/metabolismo , Sulfetos/metabolismo
7.
Chemosphere ; 281: 130916, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34029961

RESUMO

Cement-soda residue (CSR) has been proven to be an effective binder for treating heavy metal-contaminated soils, and the durability is its most important characteristic. In this study, the effects of acid rain (AR) on the leaching behavior of CSR-solidified/stabilized, zinc-contaminated soils were investigated using flexible-wall soil column leaching tests. After leaching, some parameters were determined such as the unconfined compressive strength (UCS) and permeability coefficient of the samples, the concentrations of Zn2+ and Ca2+ in the filtrate. The test results showed that after AR leaching, the UCS of the solidified soil samples decreased and the permeability coefficient increased, while the zinc concentration in the filtrate always met the third grade of the applicable standard, the Chinese National Environmental Quality Standards (<1 mg⋅L-1). To reveal the binding mechanism, scanning electron microscopy (SEM) and mercury intrusion testing (MIP) were used to observe the microscopic characteristics of the soil samples. At the micro scale, the MIP and SEM results confirmed that the hydration products in the soil samples-hydrated calcium silicate, calcium hydroxide, and calcium zincate hydrate-partially dissolved during AR leaching, resulting in the loss of their internal structure. Consequently, the high alkalinity of the soda residue contributed to H+ neutralization in the AR leaching agent, indicating that soda residue can not only solidify heavy metal zinc ions effectively but can also buffer the erosive effect of AR on soil.


Assuntos
Chuva Ácida , Metais Pesados , Poluentes do Solo , Materiais de Construção , Metais Pesados/análise , Solo , Poluentes do Solo/análise , Zinco
8.
Bull Environ Contam Toxicol ; 106(6): 965-969, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34043030

RESUMO

The soil contaminated with heavy metals requires special attention due to its adverse effects on health of human and animals. The effects of simulated acid rain with different pH values on transport of heavy metal in contaminated soil of Phyllostachys pubescens forest were studied by indoor leaching column test. The results revealed that particle size of soil was mainly concentrated in range of more than 50 µm. The content of heavy metals in particles less than 50 µm was relatively high. The Pb and Zn were mainly adsorbed on colloidal particles and were transported during simulated acid rain. The release of Fe and Al increased the release of particulate matter in soil leaching solution. The mobility of Zn was increased at low pH.


Assuntos
Chuva Ácida , Metais Pesados , Poluentes do Solo , Poluição Ambiental , Humanos , Metais Pesados/análise , Solo , Poluentes do Solo/análise
9.
Environ Sci Pollut Res Int ; 28(31): 42776-42786, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33822300

RESUMO

Acid rain is considered one of the most serious plant abiotic stresses. Photosynthesis is the basis of crop growth and development. The effect of acid rain on barley photosynthesis remains unclear. A glasshouse experiment was conducted, and the photosynthetic rate, chlorophyll (Chl) fluorescence, and pigment content of barley were measured in simulated acid rain (SAR) under pH 6.5, 5.5, 4.5, and 3.5. The results showed that net photosynthetic rate, maximal photosynthetic rate, and light saturation point decreased and the light compensation point, and dark respiration rate increased with increasing acidity. The results suggested that photosynthesis in barley plants was inhibited by SAR stress. The Chl content and stomatal conductance declined in parallel with the reduced net photosynthetic rate when barley plants were under SAR stress conditions. This indicated that non-stomatal factors may contribute to reduced photosynthesis under acid rain stress. Acid rain had greater effects on the photosynthesis of the acid rain-sensitive plant Zhepi 33 than on non-sensitive Kunlun 12. A significant difference in parameters such as the maximal fluorescence, variable fluorescence, and active PSII reaction centers was found among the SAR treatments and may be used to evaluate the sensitivity of plants to acid rain stress. The visualization model showed that the photosynthetic reaction centers were inactivated in acid rain stressed barley plants. These findings are valuable for the evaluation of the plant sensitivity to acid rain stress and may be used for the detection and monitoring of acid rain effects on plants in the future.


Assuntos
Chuva Ácida , Hordeum , Clorofila/análise , Fluorescência , Fotossíntese , Folhas de Planta/química
10.
Ying Yong Sheng Tai Xue Bao ; 32(4): 1213-1220, 2021 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-33899389

RESUMO

Based on a long-term simulated acid rain experiment, soil N2O emission fluxes were measured using static chambers and the gas chromatography method in a coniferous and broadleaved mixed forest and a monsoon evergreen broadleaved forest in southern China. During the five-year observation periods (2014-2018), soil N2O emission fluxes in the two forests showed obvious seasonal variation. The soil N2O emission fluxes in wet season were significantly higher than that in dry season, with a large annual variation. Due to the decreases of precipitation, soil N2O emission fluxes of the two forests in 2017 and 2018 were generally low. Soil N2O emission flux was positively correlated with soil temperature and soil moisture. In the monsoon evergreen broadleaved forest, soil N2O emission flux in the control plot was 12.6 µg N2O·m-2·h-1. Soil N2O emission fluxes under the pH 3.5 and pH 3.0 treatments increased by 42.9% and 61.1%, respectively. Soil N2O emission was significantly increased under simulated acid rain in the monsoon evergreen broadleaved forest. Acid rain promoted soil N2O emission in the coniferous and broadleaved mixed forest, but without significant difference among the treatments. Under the scenario of increasing acid rain, soil N2O emission fluxes in typical subtropical southern China forests would increase, and the magnitude of such increase was different among forest types.


Assuntos
Chuva Ácida , Solo , China , Florestas , Óxido Nitroso/análise
11.
Environ Pollut ; 282: 116997, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-33819777

RESUMO

This study evaluated the chronic toxicity (30 days) of different sizes of polyethylene terephthalate (PET) microplastics (60-3000 µm) provided alone or in combination with acid rain, on garden cress (Lepidium sativum). Both biometrical and physiological traits have been evaluated: i) percentage inhibition of seed germination, plant height, leaf number and fresh biomass production; ii) oxidative stress responses (hydrogen peroxide; ascorbic acid and glutathione production); iii) impairment in photosynthetic machinery in term of pigments production; iv) aminolevulinic acid and proline production. Results highlighted that different sizes of PET, alone or in combination with acid rain, are able to negatively affect both biometrical and physiological plant traits. In particular, the lower size of microplastics is able to negatively affect growth and development, as well as to trigger the oxidative burst. Regarding the pigments production, PET coupled with acid rain, induced a higher production of Chl-b, and an inhibition of aminolevulinic acid.


Assuntos
Chuva Ácida , Microplásticos , Lepidium sativum , Plásticos , Polietilenotereftalatos
12.
J Environ Manage ; 289: 112431, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33819655

RESUMO

The aim of this work is to evaluate the atmospheric rainwater chemistry and neutralization potential in oil producing areas of southern region of Nigeria. Rainwater samples were analysed for pH, EC, Cl-, SO42+, NO3-, Ca2+, and NH4+. Correlation, principal component analysis (PCA) and neutralization indicators as source apportionment methods were used to determine atmospheric acid precursors . Results show that the collected samples were severely acidified with pH value of 5.5 in oil producing communities and weak acid: pH 6.5 in non oil producing areas and varied with seasons. Fractional acidity (FA) constituted 98-99% of neutralizing ability, neutralization factor (NF) recorded Cl-, Ca2+ and NH4+ in values of 0.41, 0.43 and 0.003 with Ca2+ from sea salt, being the most neutralizing substance than NH4+from agricultural practice. The neutralizing and acidifying potentials (NP/AP) recorded a mean of 0.4, showing weak alkaline effect on atmospheric acid rain in oil producing communities. The positive correlation among ionic species implicates pH, SO42+and NO3 as causes of severe atmospheric acidity. Conclusions were made that enforcement of the existing environmental laws to checkmate the emission of acid precursors is crucial for the survival of man and entire ecosystem.


Assuntos
Chuva Ácida , Poluentes Atmosféricos , Chuva Ácida/análise , Poluentes Atmosféricos/análise , Ecossistema , Monitoramento Ambiental , Humanos , Nigéria , Estações do Ano
13.
J Environ Manage ; 289: 112501, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33823413

RESUMO

A large amount of mine wastes is generated every year through mining and mineral processing operation. The management of mine tailings is an attractive topic for researchers from both environmental and economic aspects. Mine tailings have shown a capacity as a raw material for the construction industry or a substitution for previous materials to produce the cement. It is applied in some specific environments such as offshores or massive projects like large bridges and tunnels. However, the cement industry has caused a variety of environmental issues. The production of Portland cement on an industrial scale increases the greenhouse effects and generates acidic rains. It releases greenhouse gases by the generation of carbon dioxide. In recent years, strict environmental regulations led to more efforts from mining industries to manage their tailings. A new approach to decrease the environmental issues, improve cement technology and obtain economic benefits is the use of mine tailings for cement production. Mine tailings in the cement mixtures decrease the initial hydration, retard the setting time, and lower the product mechanical strength. These problems can be fixed by the use of additives. Additives as chemical compounds are added to a cemented paste to change its properties and improve its performance. Therefore, the additives in cemented paste tailings can increase the pump-ability, reduce the water-to-cement ratio, increase density, or even adjust setting time and hydration according to the desired purposes. However, the amount of additives in the cemented paste tailings changes based on the type of additive. It should be optimized to cause a positive effect on the cement properties. Furthermore, the additives and their adaptation to the physical and chemical characteristics in cement and tailings is an important issue that should be investigated. In this paper, the usage of several chemical additives was studied, which can strengthen the properties of cemented paste tailings during backfilling operation. It can cause a better condition to decrease the environmental problems for the cement industry and mine tailings. A review of previous works is presented with an explanation of the gaps in previous studies.


Assuntos
Chuva Ácida , Materiais de Construção , Minerais , Mineração
14.
Environ Pollut ; 281: 117110, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33872891

RESUMO

Acidic deposition contributes to a range of environmental impacts across forested landscapes, including acidification of soil and drainage water, toxic aluminum mobilization, depletion of available soil nutrient cations, and impacts to forest and aquatic species health and biodiversity. In response to decreasing levels of acidic deposition, soils and drainage waters in some regions of North America have become gradually less acidic. Thresholds of atmospheric deposition at which adverse ecological effects are manifested are called critical loads (CLs) and/or target loads (TLs). Target loads are developed based on approaches that account for spatial and temporal aspects of acidification and recovery. Exceedance represents the extent to which current or projected future levels of acidic deposition exceed the level expected to cause ecological harm. We report TLs of sulfur (S) and nitrogen (N) deposition and the potential for ecosystem recovery of watershed soils and streams in the Adirondack region of New York State, resources that have been less thoroughly investigated than lakes. Regional TLs were calculated by statistical extrapolation of hindcast and forecast simulations of 25 watersheds using the process-based model PnET-BGC coupled with empirical observations of stream hydrology and established sensitivity of sugar maple (Acer saccharum) to soil base saturation and brook trout (Salvelinus fontinalis) to stream acid neutralizing capacity (ANC). Historical impacts and the expected recovery timeline of regional soil and stream chemistry and fish community condition within the Adirondack Park were evaluated. Analysis suggests that many low-order Adirondack streams and associated watershed soils have low TLs (<40 meq/m2/yr of N + S deposition) to achieve specified benchmarks for recovery of soil base saturation or stream ANC. Acid-sensitive headwater and low-order streams and watershed soils in the region are expected to experience continued adverse effects from N and S deposition well into the future even under aggressive emissions reductions. Watershed soils and streams in the western Adirondack Park are particularly vulnerable to acidic deposition and currently in exceedance of TLs. The methods used for linking statistical and process-based models to consider chemical and biological response under varying flow conditions at the regional scale in this study can be applied to other areas of concern.


Assuntos
Chuva Ácida , Solo , Animais , Ecossistema , Monitoramento Ambiental , New York , Nitrogênio , América do Norte , Enxofre/análise
15.
Plant Sci ; 306: 110876, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33775371

RESUMO

Acid rain, as a typical abiotic stress, damages plant growth and production. Calcium (Ca) mediates plant growth and links the signal transduction in plants for adapting to abiotic stresses. To understand the effect of Ca2+ on plant adaptable response to acid rain, we investigated changes in activities and gene expression of antioxidative enzymes and fatty acid composition of membrane lipid in rice seedlings treated with exogenous Ca2+ (5 mM) or/and simulated acid rain (SAR, pH 3.5 / 2.5). Exogenous Ca2+ enhanced activities of superoxide dismutase, catalase and peroxidase isozymes in rice leaves under SAR stress by promoting activation of existing isoforms and up-regulation of Cu/Zn-SOD1, Cu/Zn-SOD2, Cu/Zn-SOD3, CAT1, CAT2 and POD1. Compared to SAR treatment alone, exogenous Ca2+ alleviated SAR-induced oxidative damage to cell membrane by enhancing antioxidative capacity, as shown by the decrease in concentrations of H2O2, O2- and malondialdehyde in rice leaves. Meanwhile, Ca2+ alleviated SAR-induced decrease in unsaturation of membrane lipid for maintaining membrane fluidity. Finally, exogenous Ca2+ alleviated SAR-induced inhibition on relative growth rate of rice. Therefore, Ca2+ could play a role in regulating activities of antioxidative enzymes as well as maintaining unsaturation of membrane lipid for enhancing tolerance in rice seedlings to acid rain stress.


Assuntos
Chuva Ácida/efeitos adversos , Adaptação Fisiológica , Antioxidantes/metabolismo , Cálcio/metabolismo , Isoenzimas/metabolismo , Oryza/enzimologia , Oryza/crescimento & desenvolvimento , Estresse Fisiológico/fisiologia , Produtos Agrícolas/enzimologia , Produtos Agrícolas/crescimento & desenvolvimento
16.
Ecotoxicol Environ Saf ; 215: 112152, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33780781

RESUMO

The relationship between soil respiration (SR) and microbial community structure (MCS) is relevant to changes in forest soil ecosystem stability and chemical cycling under acid rain. Simulated acid rain treatments of pH 4.5 (control), 4.0, 3.25 and 2.5 were applied to two forest stands in the Three Gorges Reservoir Area of Jinyun Mountain, Chongqing. We used phospholipid fatty acid (PLFA) analysis to observe the MCS in the 0-10 cm soil layer and measured SR in situ from January 2016 to December 2017. Additionally, we determined the effects of soil properties on the MCS and SR. Acid rain simulation significantly increased the fungal PLFA abundance and decreased the bacterial PLFA abundance in the mixed coniferous and broad-leaved forest (CF). However, in the evergreen broad-leaved forest (BF), the abundance of bacterial and fungal PLFAs did not differ significantly among treatments. Redundancy analysis (RDA) showed that significant changes in the MSC were mainly due to the C/N ratio, hydrolysable N content, content, fine root biomass and sucrase activity. Acid rain simulation in the CF and BF significantly inhibited SR, but the SR sensitivity to simulated acid rain differed among forests. In 2017, the annual mean SR in the CF under the pH 4.0, 3.25 and 2.5 treatments decreased significantly by 6.1%, 19.2% and 28.9%, but in the BF, SR decreased significantly by 25.6% only under pH 2.5. The structural equation model showed that the relationship between the MCS and the variation in SR was closer and more direct than that with soil nutrients. The microbial community structure was an important factor driving the response of soil respiration to acid rain.


Assuntos
Chuva Ácida , Florestas , Microbiologia do Solo , Bactérias , Biomassa , China , Fungos , Microbiota , Respiração , Solo/química
17.
Mol Biol Rep ; 48(3): 2243-2251, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33689094

RESUMO

Although nitric oxide (NO) is a key regulatory molecule in plants, its function in plants under conditions of simulated acid rain (SAR) has not been fully established yet. In this study, exogenous sodium nitroprusside (SNP) at three different concentrations were applied to mung bean seedlings. Malondialdehyde (MDA), NO, hydrogen peroxide (H2O2), antioxidant enzyme activities, and nitrate reductases (NR) were measured. Real time PCR was used to measure the NR expression. Compared to the control, the NR activity and NO content under the pH 2 SAR decreased by 79% and 85.6% respectively. Meanwhile, the SAR treatment reduced the activities of superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), while increased MDA content. Application of SNP could potentially reverse the adverse impact of SAR, depending on its concentration. For plants under the pH 2 SAR and 0.25 mM SNP condition, the activities of SOD, POD, APX increased by 123%, 291%, and 135.7% respectively, meanwhile, MDA concentration decreased by 43%, NR activities increased by 269%, and NO concentration increased by 123.6% compared with plants undergoing only pH 2 SAR. The relative expression of the NR1 gene was 2.69 times higher than that of pH 2 SAR alone. Overall, the application of 0.25 mM SNP eliminated reactive oxygen species (ROS) by stimulating antioxidant enzyme activities, reducing oxidative stress and mitigating the toxic effects of SAR on mung bean seedlings. This research provides a foundation for further research on the mechanism of NO on plants under SAR conditions.


Assuntos
Chuva Ácida , Óxido Nítrico/farmacologia , Plântula/fisiologia , Estresse Fisiológico/efeitos dos fármacos , Vigna/fisiologia , Antioxidantes/metabolismo , Catalase/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Nitrato Redutase/genética , Nitrato Redutase/metabolismo , Nitroprussiato/farmacologia , Folhas de Planta/efeitos dos fármacos , Plântula/efeitos dos fármacos , Estresse Fisiológico/genética , Vigna/efeitos dos fármacos , Vigna/genética
18.
Environ Sci Pollut Res Int ; 28(27): 36753-36764, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33710488

RESUMO

Understanding the effect of acid rain to landslides is crucial for a better landslide risk assessment. This work aims to reveal the unsuspected but key role of acid rain in Panzhihua airport landslide, China. Firstly, we propose a hypothesis that acid rain may aggravate the slaking behavior of mudstone at weak interlayer and make it more fragmented, eventually further reducing its shear strength and predisposing the Panzhihua airport landslide. Subsequently, mudstone samples are subjected to slaking durability test, respectively, using water with a pH of 7 and two dilute hydrochloric acid solution with pH of 5 and 3. Slaking durability index (Idn) is adopted aiming to quantitatively evaluate the impact of acid rain on the slaking. Moreover, the mechanisms of acid rain affecting the slaking behavior of mudstone are revealed by (1) analyzing cation compositions changes in different pH slaking fluid and (2) observing micro-structure change of mudstone-chip before and after acid rain treatment. Finally, three works are conducted as evidences to prove that acid rain indeed plays a key role in the occurrence of Panzhihua airport landslide, including (1) analysis of the link between the slaking behavior of mudstone and its shear strength, (2) comparison of cations between spring water at the edge of the toe of landslide and acid rain, and (3) comparison of mineral contents of mudstone samples collected from different locations. These findings have implications for comprehensively analyzing the formation mechanism of landslide in acid rain area (such as Europe, North America, and China).


Assuntos
Chuva Ácida , Deslizamentos de Terra , Aeroportos , China , Europa (Continente) , América do Norte
19.
Molecules ; 26(4)2021 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-33562098

RESUMO

Air pollution has been a long-term problem, especially in urban areas, that eventually accelerates the formation of acid rain (AR), but recently it has emerged as a serious environmental issue worldwide owing to industrial and economic growth, and it is also considered a major abiotic stress to agriculture. Evidence showed that AR exerts harmful effects in plants, especially on growth, photosynthetic activities, antioxidant activities and molecular changes. Effectiveness of several bio-regulators has been tested so far to arbitrate various physiological, biochemical and molecular processes in plants under different diverse sorts of environmental stresses. In the current review, we showed that silicon (tetravalent metalloid and semi-conductor), glutathione (free thiol tripeptide) and melatonin (an indoleamine low molecular weight molecule) act as influential growth regulators, bio-stimulators and antioxidants, which improve plant growth potential, photosynthesis spontaneity, redox-balance and the antioxidant defense system through quenching of reactive oxygen species (ROS) directly and/or indirectly under AR stress conditions. However, earlier research findings, together with current progresses, would facilitate the future research advancements as well as the adoption of new approaches in attenuating the consequence of AR stress on crops, and might have prospective repercussions in escalating crop farming where AR is a restraining factor.


Assuntos
Chuva Ácida/efeitos adversos , Glutationa/farmacologia , Melatonina/farmacologia , Plantas/efeitos dos fármacos , Silício/farmacologia , Estresse Fisiológico/efeitos dos fármacos
20.
Ecotoxicol Environ Saf ; 208: 111718, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396049

RESUMO

Plastics enter in terrestrial natural system primarily by agricultural purposes, while acid rain is the result of anthropogenic activities. The synergistic effects of microplastics and acid rain on plant growth are not known. In this study, different sizes of polyethylene terephthalate (PET) and acid rain are tested on Lepidium sativum, in two separate experimental sets. In the first one we treated plants only with PET, in the second one we used PET and acid rain together. In both experimentations we analyzed: i) plant biometrical parameters (shoot height, leaf number, percentage inhibition of seed germination, fresh biomass), and ii) oxidative stress responses (hydrogen peroxide; ascorbic acid and glutathione). Results carried out from our experiments highlighted that different sizes of polyethylene terephthalate are able to affect plant growth and physiological responses, with or without acid rain supplied during acute toxicity (6 days). SHORT DESCRIPTION: This study showed that different sizes of PET microplastics affect physiological and biometrical responses of Lepidum sativum seedlings, with or without acid rain; roots and leaves responded differently.


Assuntos
Chuva Ácida/toxicidade , Lepidium sativum/efeitos dos fármacos , Microplásticos/toxicidade , Polietilenotereftalatos/toxicidade , Poluentes Químicos da Água/toxicidade , Lepidium sativum/crescimento & desenvolvimento , Lepidium sativum/metabolismo , Lepidium sativum/fisiologia , Microplásticos/química , Estresse Oxidativo/efeitos dos fármacos , Tamanho da Partícula , Folhas de Planta/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Polietilenotereftalatos/química , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/fisiologia , Poluentes Químicos da Água/química
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