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1.
Rev Environ Contam Toxicol ; 249: 29-70, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30806801

RESUMO

In recent times there has been remarkable development in the field of soil ecotoxicology and risk assessment (RA) models. It is, however, debatable if these RA models are robust representatives for worldwide relevance. In order to investigate this, the current overview aims to address heavy metal threats to soil life in southern Africa by investigating present knowledge and consequences for RA using research in southern Africa as a case. To this end, the focus is on southern African soils, soil life and living conditions. To critically discuss these issues, we report on extensive research conducted in the southern African context and looked how comparable these findings are to RA models employed in the western world. This is done by providing an inventory of selected studies focused on the ecotoxicity of metals towards soil life. It is concluded that there is a dearth of information on southern African soil life, most of which are laboratory-based studies carried out by a handful of researchers. Future research incorporating the available information into a soil ecosystem assessment procedure is paramount. It is recommended that a starting point to tackle this might be the development of holistic sight-specific guidelines for ecological risk assessment at larger spatial scales (km2) which takes into cognizance landscapes, vegetation and faunal characteristics.


Assuntos
Monitoramento Ambiental , Metais Pesados/análise , Poluentes do Solo/análise , África Austral , Medição de Risco , Solo
2.
Zhongguo Zhong Yao Za Zhi ; 44(17): 3627-3632, 2019 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-31602933

RESUMO

In order to understand the pollution of heavy metals in Guizhou soil planting Eucommia ulmoides,the paper has determined the contents of five heavy metals respectively( Cu,Cd,Pb,Hg and As) by atomic absorption spectrophotometry. The soil environmental quality by single factor pollution index was evaluated,nemerow integrated pollution index and potential ecological risk index,the correlation of 5 heavy metals was analyzed and the relationship between heavy medals content and p H value was discussed. The results showed that: ①The soils of LP,SB and ZA-2 had low heavy metals content,LP soil met the first national standard,and other soils met the second national standard; ②The soils of LP,ZA-1 and ZA-2 were all in a clean state,while HX and BZ-1 were in a light pollution state,and the pollution degree was Cu>Pb>As>Cd>Hg; ③The soil of BZ-2 was light warning( medium ecological risk),the soils of HX,BZ-1 and MT were early warning( low ecological risk),the main warning source was Cu and Pb,and the rest were no warning( no ecological risk); ④Cd and As were positively correlated with Pb and Hg,and Cd,Pb and As were positively correlated with p H. The research showed that the soils of LP,SB,ZA-1 and ZA-2 were clean and could be used for E. ulmoides to continue planting,the soils of HX,MT,BZ-1 and BZ-2 were polluted and should be treated in time by effective measures.


Assuntos
Monitoramento Ambiental , Eucommiaceae , Metais Pesados/análise , Poluentes do Solo/análise , China , Medição de Risco , Solo/química
3.
Chemosphere ; 235: 1081-1088, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31561298

RESUMO

A bench-scale apparatus was used for the low-temperature thermal desorption (LTTD) treatment of oil-based drill cuttings (OBDCs). The effects of treatment temperature, treatment duration, sand/OBDCs mixing ratio, and initial oil content on the LTTD treatment performance were investigated. It was found that the petroleum hydrocarbons (PHCs) were barely left in the high-oil-content drill cuttings after LTTD (at 300 °C for 20 min), and thus the overall soil health was improved. The desorption kinetics models of PHCs under various conditions were established, and it was found that the LTTD of OBDCs followed nonlinear least-squares exponential kinetics (adjusted R2 > 0.9). The energy consumption models of LTTD treatment under different temperatures were also developed. The modeling results are of practical guiding significance and useful for designing effective LTTD treatment systems of OBDCs.


Assuntos
Recuperação e Remediação Ambiental/métodos , Hidrocarbonetos/isolamento & purificação , Modelos Teóricos , Petróleo , Adsorção , Temperatura Baixa , Cinética , Poluentes do Solo/análise , Temperatura Ambiente
4.
Chemosphere ; 235: 1172-1179, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31561308

RESUMO

Rice (Oryza sativa L.) was cultivated in a Cd-contaminated soils with rice straw biochar (BC) and water-washed rice straw biochar (W-BC) were applied to investigate the underlying mechanisms and possible reasons for biochar's weakening effects on the immobilization of Cd in soil-rice system. The results indicated that W-BC reduced the Cd concentration in pore water as well as in the roots and shoots of rice by 26.24%, 53.23% and 62.47% respectively. On the contrary, there was an increase in Cd contents by 50.27% in pore water, 2.32% in the roots, and 12.80% in the shoots of rice under BC treatment. Furthermore, Cd content in rice shoot was significantly and positively correlated with Cl- addition to the soil (P < 0.01). This phenomenon could be attributed to several combined effects: (1) the increase of Cl- in the soil decreased the soil pH, enhanced the dissolved organic carbon in soil pore water and increased the complexes of Cd2+ and Cl-, resulting in the release of Cd from solid phase into solution phase, (2) the chloride in the soil increased the uptake of CdCl+ instead of Cd2+ by the roots, thereby causing an increase of Cd in rice tissues. These results demonstrate for the first time that biochar with high chloride content could weaken its immobilization effects on soil Cd and even enhance Cd uptake by rice.


Assuntos
Cádmio/farmacocinética , Carvão Vegetal/farmacologia , Cloro/farmacologia , Oryza/metabolismo , Solo/química , Carvão Vegetal/química , Poluição Ambiental , Poluentes do Solo/análise , Distribuição Tecidual
5.
J Chromatogr A ; 1604: 460473, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31472937

RESUMO

A solvent-assisted vacuum desorption method is developed and combined with gas chromatography-tandem mass spectrometry (GC-MS/MS) for quick determination of soil PAHs. With the assistance of a reduced pressure of 0.0001 kPa and the DMSO/acetone (1:1) mixed solvent, this method allows desorption of PAHs in a moderate temperature of 160 °C. Analytes were trapped in a collection tube and eluted with n-hexan for GC-MS/MS analysis. The entire procedure can be completed within 20 min. In order to validate this method for determining soil PAHs, the solvent-assisted vacuum desorption method, Soxhlet extraction and ASE extraction were applied in different samples of real contaminated soils. Most HMW PAHs showed similar concentrations, yet LMW PAHs with solvent-assisted vacuum desorption presented significantly higher concentrations than those with conventional methods, such as NAP, ANY, ANA and FLU. Further investigation revealed that solvent-assisted vacuum desorption is capable of improving both the extractability and collection efficiency of those four LMW PAHs in real contaminated soil. This method enables desorption of HMW PAHs and provides the additional benefit of improved extractability and collection efficiency for LMW PAHs.


Assuntos
Monitoramento Ambiental/métodos , Cromatografia Gasosa-Espectrometria de Massas , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes do Solo/análise , Solo/química , Solventes/química , Vácuo
6.
Environ Monit Assess ; 191(10): 607, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31485756

RESUMO

The geochemical fractions of heavy metals in sediments are crucial indexes for their mobility and bioavailability evaluations. However, different drying processes of sediment pretreatment could change metal geochemical fractions, especially for Hg, which is potentially volatile. In this study, the influence of pretreatment methods including oven-drying, air-drying, freeze-drying, and fresh sediments on the analysis of Hg fractions in sediments was investigated. Results showed that remarkable differences of Hg concentration were observed between fresh sediments and dried pretreatment sediments (P < 0.05). Briefly, the concentrations of the water-soluble and human stomach acid-soluble fractions in oven-dried and air-dried sediments generally showed significant increasing trends compared with those in the fresh sediments, while the organo-chelated fraction exhibited significant decreasing trends. The cause of this phenomenon was primarily the oxidation of organic matter, aging process, and the diffusion of Hg into micropores. The significant loss was also observed at elemental Hg fraction due to its volatilization effect. The freeze-drying posed minor influence on changes of Hg fraction analysis compared with oven-drying and air-drying. Moreover, the total Hg concentrations in pretreated sediments showed a decline of varying degrees compared with those in fresh sediments ascribing to the volatilization of elemental Hg. Finally, Pearson correlation analysis further confirmed that freeze-drying could minimize the errors of the Hg fraction analysis in sediments.


Assuntos
Dessecação , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Mercúrio/análise , Disponibilidade Biológica , Poluentes do Solo/análise , Volatilização
7.
J Environ Sci (China) ; 85: 107-118, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31471017

RESUMO

Biochar (BC) and rhamnolipid (RL) is used in bioremediation of petroleum hydrocarbons, however, the combined effect of BC and RL in phytoremediation has not been studied until now. In this paper, the phytoremediation of petroleum hydrocarbon-contaminated soil using novel plant Spartina anglica was enhanced by the combination of biochar (BC) and rhamnolipid (RL). Samples of petroleum-contaminated soil (10, 30 and 50 g/kg) were amended by BC, BC+ RL and rhamnolipid modified biochar (RMB), respectively. After 60 day's cultivation, the removal rate of total petroleum hydrocarbons (TPHs) for unplanted soil (UP), planted soil (P), planted soil with BC addition (P-BC), planted soil with BC and RL addition (P-BC + RL) and planted soil with addition of RMB (P-RMB) were 8.6%, 19.1%, 27.7%, 32.4% and 35.1% in soil with TPHs concentration of 30 g/kg, respectively. Compared with UP, the plantation of Spartina anglica significantly decreased the concentration of C8-14 and tricyclic PAHs. Furthermore, the application of BC and RMB alleviated the toxicity of petroleum hydrocarbons to Spartina anglica via improving plant growth with increasing plant height, root vitality and total chlorophyll content. High-throughput sequencing result indicated that rhizosphere microbial community of Spartina anglica was regulated by the application of BC and RMB, with increase of bacteria and plant mycorrhizal symbiotic fungus in biochar and RMB amended soil.


Assuntos
Biodegradação Ambiental , Petróleo/análise , Poaceae/fisiologia , Poluentes do Solo/análise , Carvão Vegetal/química , Glicolipídeos/química , Petróleo/metabolismo , Hidrocarbonetos Policíclicos Aromáticos , Rizosfera , Microbiologia do Solo , Poluentes do Solo/metabolismo
8.
Sci Total Environ ; 692: 1022-1028, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31539934

RESUMO

Contamination of agricultural soil with cadmium (Cd) poses a severe threat to food safety and human health, especially for Cd in rice. It is very important to identify Cd bioaccumulation in rice in order to screen Cd-safe cultivars. In the present study, 183 pairs of rice and soil data collected from Cd-contaminated soil were used to investigate the differences of Cd bioaccumulation in grains among rice cultivars. The results showed that the adverse effect on grain Cd accumulation of japonica was less than that of indica under Cd exposure. The percentage of japonica with grain Cd concentration exceeding 0.2 mg/kg reduced 50.3% compared with indica. Partial correlation analyses suggested that lower pH contributed to Cd accumulation in grains, and a significant increase in grain Cd concentration was observed with increasing soil Cd concentration. The bioaccumulation factors (BCF) of Cd in rice grains could be divided into 5 grades by combining an empirical soil-plant transfer model with species sensitivity distribution (SSD). Grades with lower Cd bioaccumulation (grades 1 and 2) were dominated by japonica, and the intrinsic sensitivity index of Cd-enrichment (k value) and straw to grain transfer factors (TF) increased with ascending grades. Average k value and TF of cultivars in grade 5 were 1.4-7.9 and 1.5-5.7 times higher than those of cultivars in grades 1 to 4, which eventually caused the increase of Cd accumulation in grains. The lower level of Cd absorption and translocation contributed to reducing the bioaccumulation of Cd in rice grains had been proved by the classification of rice on Cd accumulation. Considering the influence of soil properties and intrinsic sensitivity of rice, cultivars with grain Cd bioaccumulation controlled at low levels to safe for human consumption could be identified on Cd-contaminated soils.


Assuntos
Agricultura , Cádmio/análise , Oryza/química , Poluentes do Solo/análise , Monitoramento Ambiental
9.
Environ Monit Assess ; 191(9): 549, 2019 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-31392440

RESUMO

Children are in direct contact with surface soil and may inadvertently ingest and inhale toxic contaminants while playing; hence, special attention should be given to playgrounds regarding toxic contaminants. The concentrations of ten toxic metals were determined in soil samples collected from school playgrounds and children's parks from the southwest region of Saudi Arabia. The soils were moderately alkaline (pH 7.6-8.8), the texture was dominated by sand particles (54-88%), and the organic matter was in the range of 2.06 to 4.82%. Analytical solutions were prepared by microwave-digestion using a HNO3/H2O2 mixture, and the concentrations of toxic elements were measured by inductively coupled plasma mass spectrometry (ICP-MS). Metal concentrations were recorded in the range of 0.014-0.087, 1.14-3.54, 0.85-23.29, 0.77-36.32, 312.6-2065.7, 285.3-822.6, 75.4-240.8, 0.00-53.12, 0.52-6.80, and 1.25-92.12 mg/kg dry soil for Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Zn, respectively. The levels of heavy metals in the studied playgrounds were below the permissible limits, indicating insignificant influence of anthropogenic activities and can be considered as unpolluted soil. Values of the enrichment coefficient (EC) and contamination factor (CF) were found to be less than one, suggesting that the source of these elements is mainly the local soil, with the exception of Ni and Zn in certain playgrounds (CF > 1), which indicates a possible contamination from external sources. The non-carcinogenic hazard index calculated for all of the metals was below one, indicating that the exposure to heavy metal through playground soil is unlikely to produce any adverse health effect in children playing in the playgrounds.


Assuntos
Exposição Ambiental/efeitos adversos , Metais Pesados/análise , Parques Recreativos , Poluentes do Solo/análise , Adolescente , Criança , Monitoramento Ambiental/métodos , Humanos , Peróxido de Hidrogênio/análise , Medição de Risco , Arábia Saudita , Instituições Acadêmicas , Solo/química
10.
Environ Monit Assess ; 191(9): 553, 2019 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-31399836

RESUMO

Pollution has become a problem on a global scale and poses a significant risk in terms of human health and natural ecosystems. Generally, the biggest sources of pollution are municipal and industrial facilities. However, traffic-related air pollution cannot be overlooked as a dangerous source either. There have been various methods of interventions to measure and reduce the risk and effects of traffic-related pollution. In the case of measuring, the use of certain plant species that can accumulate pollutants in their tissues is considered a practical solution. In this study, the aim is to find out the metals that are accumulated in rosemary leaves and stems and the rosemary leaves. In other words, the leaves and the stems are to be used as a biomonitors to reveal the rate of metal pollution along the highway. We try to identify the accumulation ability of traffic-related heavy metals (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) of the Rosmarinus officinalis L. (rosemary) which is used in the refuge and slopes along the highway connecting Adana with Iskenderun (Hatay). Our findings concluded that the rosemary could have a decent capacity to accumulate Al, Cd, Cr, Cu, Fe, Mn, Pb, and Zn in both leaves and stem. We therefore believe that R. officinalis is a great tool in determining the amount of traffic-related pollution in urban areas.


Assuntos
Monitoramento Ambiental/métodos , Metais Pesados/análise , Rosmarinus/química , Poluentes do Solo/análise , Poluição Relacionada com o Tráfego/análise , Cidades , Ecossistema , Humanos , Folhas de Planta/química , Caules de Planta/química , Turquia
11.
Environ Monit Assess ; 191(9): 559, 2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-31402394

RESUMO

Various daily human activities can result in the release of pollutants of different chemical constituents and specific gravities into natural soils. Pollution of natural soils is a recurring occurrence in the environment and it contributes greatly to the alteration of soils properties. The results of an assessment of the effects of selected petroleum-derived and vegetable oils on soil physicochemical and hydraulic properties are presented in this work. Topsoil samples at a depth of 0-20 cm of the same textural class were collected from the order Lixisols and Nitisol within Ogun State, southwest Nigeria. Surface soil samples were collected and treated with petrol, diesel and palm oil at two different volumes (50 and 100 ml). Investigated soil properties include particle size distribution, soil pH, bulk density (BD), total porosity (TP), saturated hydraulic conductivity (Ksat), available water capacity (AWC), total carbon (TC), total nitrogen (TN), organic matter (OM) content, cation exchange capacity (CEC), potassium, sodium, and soil resistivity. Analysis of variance and Pearson's correlation were used to study the variations of the relationship of analyzed soil properties under different soil types and treatments. The regression analysis shows that all the generated models for predicting Ksat values under different soil treatments had R2 values ranging from 0.999 to 1.000. Results showed that treatment with either petroleum-derived or lipids has no effects on soil pH and textural class. Results further revealed that palm oil contamination at 50 ml recorded least values of Ksat in the two soil types. In all cases, BD and Ksat of the contaminated soils of the two sampling locations were reduced compared with their control values. Correlation coefficient showed expected strong negative correlation between TP and BD as well as between any two of organic parameters (TC, TN, and OM) and soil resistivity, TC, and TN at 1% level in both soil types. Two-way ANOVA showed that there were significant differences at 5% level between the two locations with respects to BD, TP, and CEC while significant differences in Ksat, pH, TC, TN, and OM occur between soils from the two locations under various treatments at 5% level.


Assuntos
Monitoramento Ambiental , Petróleo/análise , Poluentes do Solo/análise , Carbono/análise , Humanos , Nigéria , Nitrogênio/análise , Óleos Vegetais/análise , Solo/química , Água/análise
12.
Environ Monit Assess ; 191(9): 545, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31392424

RESUMO

Mercury (Hg) emission from natural soil is one of the most important contributors to global Hg cycles. Research on Hg emission from soil to air has been carried out in China. Currently, most of the research focuses on contaminated sites in China, while research in other regions is rare. To provide more accurate information on Hg emissions from soil to air in China and obtain additional laboratory data to verify the role of solar radiation and temperature in this process, we sampled and measured Hg emission fluxes from various natural soils (range, 48-240 ng/g) across mainland China under different solar radiation (0-900 W·m-2) and temperature (15-45 °C) conditions in a laboratory. We found that in different places in China, Hg emissions from natural soils occurred more easily when the soil Hg concentration, temperature, and solar radiation were high, but the impacts were different among the regions due to different soil types. Hg emissions from natural soils (0.071-24 ng·m2·h-1) were typically lower than those from contaminated sites, suggesting that additional measurements in natural soils are desirable. The results of this study could provide more accurate information on Hg emission from natural soil to air and help establish a nationwide natural soil Hg emission inventory in China.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Mercúrio/análise , Poluentes do Solo/análise , Solo/química , China , Temperatura Ambiente
13.
Environ Monit Assess ; 191(9): 544, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31392486

RESUMO

The development of regional or local maximum permissible concentration (MPC) for a pollutant in the soil requires the field or laboratory simulation of pollution. The experimental design should include the control (uncontaminated soil with the background concentration of the pollutant) and at least three treatments with different pollutant concentrations in the range between 2 and 10 background values. Experiments are performed in at least three replicates. Soil samples are taken 30 days after contamination. In each soil sample, six biological parameters are determined: total bacterial abundance, Azotobacter abundance, catalase activity, dehydrogenase activity, cellulolytic activity, and radish root length. Analyses are made in at least six replicates. From these biological parameters, the integrated biological index (IBI) of soil is calculated. For this purpose, the value of each parameter in the uncontaminated soil is taken as 100%, and its values in the contaminated soils are expressed as percentages. The mean values of six parameters for the contaminated treatments are determined. The obtained IBI values are expressed in percentages of the background. Then, a regression equation describing the decrease in IBI values as a function of pollutant concentration in the soil is derived. The pollutant concentration corresponding to the IBI decrease by 10% of the control, which indicates a disturbance of the holistic biogeocenotic functions of soil, is calculated from this equation.


Assuntos
Monitoramento Ambiental/normas , Poluição Ambiental/análise , Metais Pesados/análise , Poluentes do Solo/análise , Solo/química , Azotobacter/isolamento & purificação , Carga Bacteriana , Catalase/análise , Oxirredutases/análise , Microbiologia do Solo
14.
Environ Monit Assess ; 191(8): 527, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31367793

RESUMO

Nowadays, anthropogenic inflow of heavy metals (HM) into the environment far exceeds their natural quantities in Ukraine. The main sources of HM inflow are enterprises that use high-temperature processes in the production cycle-combustion of fuel and thermal processing of raw materials. Examples of such enterprises are Avdiivka Coke and Chemical Plant (the largest in Europe) and the Zmiiv Thermal Power Plant (the largest in Ukraine), which use high-temperature processes associated with the use of black coal that are considered as important sources of heavy metals in the soil. On the basis of analytical data of 3000 samples of surface layer of Ukrainian soils, which form the basis of the nationwide GIS "Microelements in soils of Ukraine," it was established that the spatial distribution of the content of accessible forms of copper in the upper soil layer in Ukraine varies greatly and practically does not depend on the type of soil formation and is determined mainly by geochemical factors such as saturation of parent rocks with copper, as well as anthropogenic influence. The emissions from the Avdiivka Coke and Chemical Plant resulted in the formation of a clearly defined contamination range of soil and vegetation by HM in the adjoining territories exceeding the threshold levels of copper. In the zone of influence of the Zmiiv Thermal Power Plant, the technogenic load on agricultural lands is much less and does not exceed the medical and sanitary indicators of the content of heavy metals in the soils, but due to the high pipe height (180-250 m), the toxic emissions of the enterprise dissipate to a large area and form a regional technogenic background of available copper in soils.


Assuntos
Cobre/análise , Produtos Agrícolas/química , Metais Pesados/análise , Poluentes do Solo/análise , Solo/química , Agricultura , Cobre/química , Monitoramento Ambiental/métodos , Metais Pesados/química , Centrais Elétricas , Ucrânia
15.
Sci Total Environ ; 689: 1037-1043, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31466144

RESUMO

Dissolved organic matter (DOM) elucidated from biochars enhances the dissolution of iron oxides and reduction of iron. However, given that reduction mechanism of iron (Fe(III)) in the practical biochar applications for soil amendment and environmental remediation have not been fully elucidated, this study laid great emphasis on the photo-induced Fe(II) liberated from DOM-Fe(III) complexes. Thus, pyrolysis of biomass was carried out at 300 °C to maximize DOM release from biochars. Moreover, three different biomass samples (rice straw (R), granular sludge (G) from an anaerobic digester, and spent coffee grounds (C)) were chosen as carbon substrates for biochars preparation. To demonstrate the transformation of Fe(III), 1 and 5 wt% biochar was applied to the clean (S1) and arsenic-contaminated (S2) soil with/without the light. The results indicate that the light condition produces more Fe(II). The amount of Fe(II) accounts for 25.3, 28.6, and 30.7% of total iron under the light with 5 wt% GB, RB, and CB in S1, and 10.6, 13.1, and 13.8% in S2. This study demonstrates that Fe(II) is generated more under ultraviolet irradiation than visible light and dark condition. In addition, a control experiment without biochar showed that DOM plays an important role in the reduction of Fe(III). The mobility of arsenic increased under the light condition since the intermediates of DOM photo-degradation accelerates the dissolution of iron oxides and arsenic competes with DOM for the adsorption. Therefore, there was no significant correlation between the elution of arsenic and the formation of Fe(II) during the reductive dissolution of iron oxide under the light condition.


Assuntos
Arsênico/análise , Recuperação e Remediação Ambiental/métodos , Poluentes do Solo/análise , Adsorção , Arsênico/química , Biomassa , Carbono , Carvão Vegetal/química , Compostos Férricos , Ferro/química , Oryza , Oxirredução , Solo/química , Poluentes do Solo/química
16.
Sci Total Environ ; 689: 1244-1254, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31466163

RESUMO

Bioaccessibility (BAC) of fine surface dust (FSD, particle size ≤10 µm) and surface dust samples (particle size ≤250 µm) collected from a gold mining district was used as a tool to determine the portion of arsenic that would be available via simulated lung and gastrointestinal (G.I) fluids. BAC was considered low for both tests (lung 2.7 ±â€¯1%, n = 5 and G.I 3.4 ±â€¯2%, n = 14 for residential surface dust samples). An analytical procedure was developed to further identify arsenic-bearing phases found in FSD samples and analyze the main components that regulate arsenic solubility. Up to five different arsenic-bearing phases were identified among a total of 35 minerals surveyed by scanning electron microscopy-based automated image analysis (Mineral Liberation Analyzer - MLA). Arsenic-bearing Fe oxy-hydroxides and mixed phases comprised the main arsenic phases encountered in FSD samples, thus likely being responsible for regulating arsenic bioaccessibility. Transmission electron microscopy showed that the mixed phases comprised a mix of oriented nanostructure aggregates formed by hematite and goethite entangled with phyllosilicates. The main As-bearing phases identified in FSD samples are similar to those reported in soil samples in the same region. The predominant arsenic-bearing phase encountered in the ore was arsenopyrite, mostly in large particles (>10 µm in size), and therefore unlikely to be found in residential dust. Arsenic intake from both inhalation and ingestion were minimal when compared to total arsenic intake (considering food and water ingestion), which itself was <7% of the value established by the Food and Agriculture Organization of the United Nations Benchmark Dose Lower Confidence Limit (BMDL0.5) of 3.0 µg per kg-1 body weight per day. These results indicated that the relative risks associated with arsenic exposure by inhalation and oral ingestion in this region are low.


Assuntos
Arsênico/análise , Exposição Ambiental/análise , Poluentes do Solo/análise , Poeira/análise , Exposição Ambiental/estatística & dados numéricos , Mineração
17.
Sci Total Environ ; 691: 1072-1081, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31466189

RESUMO

Sulfonamides and their corresponding antibiotic resistance genes (ARGs) are widespread in the environment, which leads to a major threat to global health crisis. Biodegradation plays a major role in sulfonamides removal in soil ecosystem, but the degradation dynamics and the associated functional bacteria in situ remain unclear. In this study, aerobic degradation of sulfadiazine (SDZ) at two dosages (1 and 10 mg/kg) was explored for up to 70 days in two different agricultural soils. The removal of SDZ in all treatments followed first-order multi-compartment model with half-life times of 0.96-2.57 days, and DT50 prolonged with the increase of initial dosage. A total of seven bacterial genera, namely Gaiella, Clostrium_sensu_stricto_1, Tumebacillus, Roseiflexus, Variocorax, Nocardioide and Bacillus, were proposed as the potential SDZ-degraders. sadA gene was for the first time detected in soil samples, but other functional genes might also participate in SDZ degradation. The enrichment of sulfonamide resistance genes was found after 70 days' incubation, which might result in the spread of ARGs in soil. This study can add some new insights towards SDZ degradation in soil ecosystem and provide a potential resource for the bioremediation of SDZ-contaminated soil.


Assuntos
Biodegradação Ambiental , Resistência Microbiana a Medicamentos/genética , Microbiota , Microbiologia do Solo , Poluentes do Solo/análise , Sulfadiazina/análise , Solo , Poluentes do Solo/metabolismo , Sulfadiazina/metabolismo
18.
Ecotoxicol Environ Saf ; 182: 109456, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31398779

RESUMO

The seasonal flooding and drainage process affect the paddy soils, the existence of the iron state either Fe(III) or Fe(II) is the main redox system of paddy soil. Its morphological transformation affects the redox nature of paddy soils, which also affects the distribution of bacterial community diversity. This study based on molecular biological methods (qPCR, Illumina MiSeq sequencing technique) to investigate the effect of Fe(II) and environmental factors on cbbM genes containing carbon fixing microbes. Both Eh5 and pH were reduced with Fe(II) concentrations. The Fe(II) addition significantly affects the cbbM gene copy number in both texture soils. In loamy soil, cbbM gene copy number increased with high addition of Fe(II), while both low and high concentrations significantly reduced the cbbM gene copy number in sandy soil. Chemotrophic bacterial abundance significantly increased by 79.7% and 54.8% with high and low Fe(II) addition in loamy soil while in sandy soil its abundance decreased by 53% and 54% with the low and high Fe(II) accumulation. The phototrophic microbial community increased by 37.8% with low Fe(II) concentration and decreased by 16.2% with a high concentration in loamy soil, while in sandy soil increased by 21% and 14.3% in sandy soil with low and high Fe(II) addition. Chemoheterotrophic carbon fixing bacterial abundance decreased with the Fe(II) accumulation in both soil textures in loamy soil its abundance decreased by 5.8% and 24.8%, while in sand soil 15.7% and 12.8% with low and high Fe(II) concentrations. The Fe(II) concentration and soil textures maybe two of the major factors to shape the bacterial community structure in paddy soils. These results provide a scientific basis for management of paddy soil fertility and it can be beneficial to take measures to ease the greenhouse gases effect.


Assuntos
Ferro/química , Microbiologia do Solo , Bactérias , Carbono , Compostos Férricos/química , Compostos Ferrosos , Inundações , Microbiota , Oryza/química , Oxirredução , Solo/química , Poluentes do Solo/análise
19.
World J Microbiol Biotechnol ; 35(8): 129, 2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31376017

RESUMO

Metal whole-cell biosensors (WCBs) have been reported as very useful tools to detect and quantify the presence of bioavailable fractions of certain metals in water and soil samples. In the current work, two bacterial WCBs able to report Cr(VI) presence and plants growing on Cr(VI)-enriched soil/medium were used to assess the potential transfer of this metal to organisms of higher trophic levels, and the risk of transfer to the food chain. To do it, the functionality of the WCBs within tissues of inoculated plants in contact with Cr(VI)-contaminated soil and water was studied in vitro and in a controlled greenhouse environment. One WCB was the previously described Ochrobactrum tritici pCHRGFP2 and the second, Nitrospirillum amazonense pCHRGFP2, is a newly engineered naturally-occurring endophytic microorganism. Three rice varieties (IAC 4440, BRS 6 CHUÍ, IRGA 425) and one maize variety (1060) were tested as hosts and subjected to Cr(VI) treatments (25 µM), with different results obtained. Inoculation of each WCB into plants exposed to Cr(VI) showed GFP expression within plant tissues. WCBs penetrated the root tissues and later colonized the shoots and leaves. In general, a higher fluorescence signal was detected in roots, together with a higher Cr content and denser WCB colonization. Best fluorescence intensities per plant biomass of shoots were obtained for plant host IRGA 425. Therefore, by analyzing colonized tissues, both WCBs allowed the detection of Cr(VI) contamination in soils and its transfer to plants commonly used in crops for human diet.


Assuntos
Técnicas Biossensoriais/métodos , Cromo/análise , Ochrobactrum/crescimento & desenvolvimento , Oryza/química , Rhodospirillaceae/crescimento & desenvolvimento , Zea mays/química , Disponibilidade Biológica , Engenharia Metabólica , Microscopia de Fluorescência , Ochrobactrum/genética , Ochrobactrum/metabolismo , Oryza/crescimento & desenvolvimento , Oryza/microbiologia , Rhodospirillaceae/genética , Rhodospirillaceae/metabolismo , Poluentes do Solo/análise , Poluentes Químicos da Água/análise , Zea mays/crescimento & desenvolvimento , Zea mays/microbiologia
20.
Environ Monit Assess ; 191(9): 540, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31378832

RESUMO

In this work, we present the results of the investigation of trace elements (Fe, Mg, Ni, Zn, Cu, Cr, Co, Cd, Pb) accumulation potential of Noccaea kovatsii (Heuff.) F. K. Mey., from the Balkan Peninsula. The study included eight populations from ultramafic soils, six from Bosnia and Herzegovina, and two from Serbia. Principal component analysis (PCA) was used to reveal relationships of elements in soil, and Pearson's correlation coefficients for analysing associations of available quantities of elements in soil and those in roots and shoots of N. kovatsii. Uptake and translocation efficiency was assessed by using bioconcentration (BCF) and translocation factors (TF). All the analysed populations of N. kovatsii emerged as strong Ni accumulators, with the highest shoot concentrations of 12,505 mg kg-1. Even thought contents of Zn in plant tissues of N. kovatsii were under the hyperaccumulation level (602 mg kg-1 and 1120 mg kg-1 respectively), BCF was up to 667, indicating that certain surveyed populations have strong accumulative potential for this element.


Assuntos
Brassicaceae/metabolismo , Poluentes do Solo/análise , Solo/química , Oligoelementos/análise , Bósnia e Herzegóvina , Brassicaceae/química , Monitoramento Ambiental , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Brotos de Planta/química , Brotos de Planta/metabolismo , Análise de Componente Principal , Sérvia , Poluentes do Solo/metabolismo , Oligoelementos/metabolismo
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