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1.
J Environ Manage ; 259: 109674, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32072945

RESUMO

Metals that contaminate soil is one of the major problems seriously affecting sustainable agriculture worldwide. Nickel (Ni) toxicity to agricultural crops is a global problem. Mobility of heavy metals present in contaminated soil can be reduced by the amendment of soil passivators, which will ultimately reduce the risk of them entering the food chain. A greenhouse pot experiment was conducted to investigate the effects of rice straw (RS), biochar derived from rice straw (BI) and calcium carbonate (calcite) on Ni mobility and its up take by maize (Zea maize L.) plant. Maize crop was grown in Ni spiked (100 mg kg-1) soil with three application rates of passivators (equivalent to 0, 1and 2% of each RS, BI and calcite) applied separately to the soil. Results revealed that the post-harvest soil properties (pH, DOC and MBC), plant phenology (plant height, root length, total dry weight) and physiological characteristics were significantly enhanced with passivator application. Additionally, incorporating passivator into the soil reduced Ni mobility (DTPA) by 68%, 88.9% and 79.3%, and leachability (TCLP) by 72.4%, 76.7% and 66.7% for RS, BI and calcite, respectively at 2% application rate. The Ni concentration in the maize shoots reduced by 30%, 95.2% and 95% and in the roots by 56%, 66% and 63.8% with RS, BI and calcite at 2% application rate, respectively. These findings suggest that the application of 2% biochar (BI) is very promising in reducing Ni uptake, and can reduce toxicity to plants, decrease mobility and leachability in the soil.


Assuntos
Oryza , Poluentes do Solo , Carbonato de Cálcio , Carvão Vegetal , Solo , Zea mays
2.
J Environ Manage ; 259: 110018, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32072959

RESUMO

In the study, the dynamics of Sr2+ and geochemically correlated elements (Ca2+, Ba2+, and Y3+) in soil with chelators in the mix (soil to chelator ratio, 1:10; matrix, H2O) were assessed to understand chemical-induced washing remediation of radiogenic waste solids. Specifically, EDTA (2,2',2″,2‴-(ethane-1,2-diyldinitrilo)tetraacetic acid), EDDS (2-[2-(1,2-dicarboxyethylamino)ethylamino]butanedioic acid), GLDA (2-[bis(carboxymethyl)amino]pentanedioic acid), and HIDS (2-(1,2-dicarboxyethylamino)-3-hydroxy-butanedioic acid) are chelators that are used as extractants. The effect of solution pH on chelator-induced extractions of the target elements (t-Es: Sr2+, Ca2+, Ba2+, or Y3+) from soil and stability constants of the t-Es complexes with chelators were used to explain the trends and magnitudes in interactions. Pre- and post-extractive solid-phase speciation was used to define the extent of the competence of each chelator in persuading dissolution of t-Es in the soil. The effects of ultrasonic energy, admixtures of biodegradable chelators, and excess chelators in solution (1:20) were also analyzed on the extractive removal of t-Es from soil. The results indicate that the Sr2+ removal with biodegradable chelators significantly exceeded (approximately 70%) when compared to that of environmentally-persistent EDTA at lower solution pHs and a higher soil to chelator ratio (GLDA > HIDS > EDDS ≈ EDTA). However, the extraction of the geochemically related element was significantly lower.


Assuntos
Recuperação e Remediação Ambiental , Metais Pesados , Poluentes do Solo , Quelantes , Ácido Edético , Solo , Estrôncio
3.
J Environ Manage ; 255: 109896, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32063301

RESUMO

Contamination of soils with poly- and perfluoroalkyl substances (PFAS) has become a challenging issue due to the adverse effects of these substances on both the environment and public health. PFAS have strong chemical structures and their bonding with soil makes them challenging to eliminate from soil environments. Traditional methods of soil remediation have not been successful in their reduction or removal from the environment. This paper provides a comprehensive evaluation of existing and emerging technologies for remediating PFAS contaminated soils with guidance on which approach to use in different contexts. The functions of all remediation technologies, their suitability, limitations, and the scale applied from laboratory to the field are presented as a baseline for understanding the research need for treatment in soil environments. To date, the immobilization method has been a significant part of the remediation solution for PFAS contaminated soils, although its long-term efficiency still needs further investigation. Soil washing and thermal treatment techniques have been tested at the field scale, but they are expensive and energy-intensive due to the use of a large volume of washing solvent and the high melting point of PFAS, respectively; both methods need a large initial investment for their installation. Other remediation technologies, such as chemical oxidation, ball milling, and electron beams, have been progressed in the laboratory. However, additional research is needed to make them feasible, cost-effective and applicable in the field.


Assuntos
Recuperação e Remediação Ambiental , Fluorcarbonetos , Poluentes do Solo , Solo
4.
J Environ Manage ; 255: 109909, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32063303

RESUMO

Soil rehabilitation in the context of the restoration of quarries, dumping sites, or road slopes often requires the prior addition of organic amendments to improve the substrates used for Technosol construction. Bio-wastes coming from advanced Mechanical-Biological Treatment Plants, mainly compost-like-outputs (CLO) and digestates (DGT), are new and suitable sources of organic matter potentially useful as organic amendments for this purpose, in an approach clearly fulfilling the principles of circular economy. In order to assess the suitability of these materials, a complete physicochemical and biological evaluation was carried out, including an ecotoxicological evaluation to discard hazardous effects on key soil fauna groups. Field experiments were also carried out on several road slopes and a dumping site. The stability degree of organic matter and the impurities content could be restricting parameters for the use of CLO in soils. Low stability degree decreased plant development in the initial stages of restoration. Moreover, the high heterogeneity in terms of physicochemical parameters of the different CLOs assessed is a serious constraint to making generalizations about its use. In contrast, composition of DGTs was more stable between plants and batches, and presented low impurities and high N contents that make them more suitable for applying to soil and promoting plant development. Regarding the application rates, DGT application at 20 g kg-1 clearly improved plant growth after sowing, without compromising recruitment. However, application at 80 g kg-1 did not ameliorate seed germination and plant growth, in either CLO or DGT treatments, and increased N-leaching and toxicity risk to soil mesofauna in DGT amended Technosols.


Assuntos
Compostagem , Poluentes do Solo , Desenvolvimento Vegetal , Solo
5.
J Environ Manage ; 255: 109778, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32063315

RESUMO

Waterlogged soils and sediments contaminated with potentially toxic elements (PTEs) constitute a complicated case of degraded areas; their management requires understanding of the dynamic redox-driven PTE mobilization. Such studies about PTE redox-induced dynamics in fishpond sediments are still scarce, but of great importance concerning environmental and human health risk. We studied the redox potential (EH)-induced impacts on the solubility of As, Co, Cu, Mo, Ni, Se, V, and Zn in the sediments of a fish farm in the Nile Delta, Egypt, using an automated apparatus of biogeochemical microcosm. We assessed the fate of elements as affected by the EH-induced changes in pH, Fe, Mn, SO42-, Cl-, and the dissolved aliphatic (DOC) and aromatic (DAC) organic carbon. Sediment redox ranged from -480 mV to +264 mV. Flooding the sediments caused a significant decrease in pH from 8.2 to 5.7. Dissolved concentrations of As, Co, Ni, Se, and Zn, as well as DOC, Fe, and Mn increased under the reducing acidic conditions. The release of As, Co, Ni, Se, and Zn could be attributed to the decrease of EH and the subsequent decrease of pH, as well as to the increase of DOC, and/or the dissolution of Fe-Mn oxides caused by redox reactions. Dissolved concentrations of Cu, Mo, and V increased under oxic conditions and were significantly positive correlated with EH, pH, DAC, and SO42-. This enhancement might be caused by the EH-dependent increase of pH under oxic conditions (particularly for Mo and V), which also led to DAC increase. Sulfide oxidation and the release of the associated elements may have also had a contribution, particularly in the release of Cu. Therefore, the release dynamics of dissolved Cu, Mo, and V in the sediments were controlled, to a certain extent, by the changes of EH/pH, DAC, and sulfur chemistry. We conclude that the biogeochemical differences in the behaviour of the studied elements under variable redox regimes substantially affected the fishponds via possible enhancement of PTE mobilization. Our work shows that the potential environmental risks related to PTE mobilization and fish food security should be taken into consideration for the management of degraded aquaculture systems and waterlogged soils and sediments.


Assuntos
Poluentes do Solo , Poluentes Químicos da Água , Egito , Monitoramento Ambiental , Pesqueiros , Sedimentos Geológicos , Oxirredução , Solo
6.
J Environ Manage ; 258: 110013, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31929055

RESUMO

The effect of competition between isolated petroleum-degrading bacteria (PDB) and indigenous compost microorganisms (ICM) on the efficiency of composting process in bioremediation of petroleum waste sludge (PWS) was investigated. After isolating two native PDB (Acinetobacter radioresistens strain KA5 and Enterobacter hormaechei strain KA6) from PWS, their ability for growth and crude oil degradation was examined in the mineral-based culture (MBC). Then, the PDB isolate were inoculated into the composting experiments and operated for 12 weeks. The results showed that the PDB degraded 21.65-68.73% of crude oil (1-5%) in the MBC after 7 days. The PDB removed 84.30% of total petroleum hydrocarbon (TPHs) in the composting bioreactor containing the initial TPH level of 20 g kg-1. Removal of petroleum hydrocarbons (PHCs) in the composting experiments proceeded according to the first-order kinetics. The computed values of degradation rate constants and half-lives showed a better performance of the PDB than ICM for TPHs removal. This finding suggests that simultaneous application of the PDB and ICM in the composting reactors resulted in a decline in the effectiveness of the PDB which is due to competition between them. The study also verified that the capability of PDB in degrading PHCs can be successfully scaled-up from MBC to composting process.


Assuntos
Compostagem , Petróleo , Poluentes do Solo , Biodegradação Ambiental , Hidrocarbonetos , Minerais , Esgotos , Microbiologia do Solo
7.
J Environ Manage ; 258: 110020, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31929061

RESUMO

Metals that contaminate soil are one of the major problems seriously affecting sustainable agriculture worldwide. Cadmium (Cd) toxicity to agricultural crops is a global problem. Mobility of Cd in contaminated soil can be minimized by the amendment of soil passivators which will ultimately reduce its movement from soil to plants. A pot study was performed to evaluate the impact of sepiolite from 1% to 5% on Cd solubility and its accumulation in spinach tissues. Soil pH, Cd fractionation, Cd accumulation in spinach tissue and Cd adsorption mechanism were determined. Results were recorded that soil pH was increased from 0.3 to 1.0 units with the increasing rate of sepiolite from 1% to 5%. Similarly, Cd contents in acid soluble phase was decreased by 42.8% and increased in residual phase by 35.8% at 5% rate, relative to control. Moreover, the significant reduction in Cd uptake by spinach shoots and roots was occurred by 26.2% and 30.6% at 5% rate, respectively. Furthermore, the maximum Cd adsorption capacity 37.35 mg g-1 was recorded at 5% rate relative to control. The analysis of FTIR, XRD and SEM also confirm the ability of sepiolite for Cd polluted soil restoration and thereby, reduces its phytoavailability in polluted soil to alleviate food security challenges.


Assuntos
Cádmio , Poluentes do Solo , Agricultura , Silicatos de Magnésio , Solo , Spinacia oleracea , Águas Residuárias
8.
J Environ Manage ; 256: 109953, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31989980

RESUMO

The study evaluated plants with phytoremediation potential that occur spontaneously in an area of copper mining tailings in Southern of Brazil. Eleven plant species were investigated for heavy metal concentrations in its biomass. All species showed copper concentrations greater than 100 mg kg-1, and seven species highlighted for copper concentrations between 321 and 586 mg kg-1 and these species showed Cr concentrations between 25 and 440 mg kg-1. The species S. viarum Dunal and B. trimera Less were highlighted showing the highest concentrations of Cr (586 mg kg-1) and Cu (440 mg kg-1), respectively. Seven species showed Pb phytoextraction potential and four species showed Cu phytostabilization potential. It was concluded that the investigated species are adapted to low nutritional conditions and showed tolerance to heavy metals, mainly Cu, Pb and Cr in its biomass.


Assuntos
Metais Pesados , Poluentes do Solo , Biodegradação Ambiental , Brasil , Cobre , Mineração , Raízes de Plantas
9.
Int J Phytoremediation ; 22(3): 236-240, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31997662

RESUMO

In this study, the effects of diesel fuel contamination on common cocklebur (Xanthium strumarium L.) seeds have been investigated. Five levels of contamination were used (0 g, 2.5 g, 5 g, 7.5 g, and 10 g diesel per 100 g of substrate). Germination was significantly reduced only at 7.5 g and 10 g diesel and the highest percentage germination (97%) was recorded at 5 g diesel. Diesel contamination caused a significant reduction in shoot length, but the decline began to be important at 7.5 g diesel. The root length was positively influenced by diesel fuel contamination, the shortest root (12.89 cm) was observed in the control and the longest (19.92 cm) at 5 g diesel. Xanthium strumarium seeds germinated successfully at different levels of contamination, its root length seemed to take advantage of the diesel fuel contamination and its shoot length was mostly affected by the high contamination levels. Therefore, we can propose this plant species as a potential candidate for the phytoremediation of sites contaminated with diesel. Furthermore, the results could help improve our understanding of the behavior of X. strumarium, and its ability to germinate and grow in different soil conditions.


Assuntos
Poluentes do Solo , Xanthium , Biodegradação Ambiental , Gasolina , Germinação
10.
Chemosphere ; 242: 125261, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896178

RESUMO

Seedling establishment consists of the former stage (i.e. skotomorphogenesis) and the latter stage (i.e. photomorphogenesis). Due to specific developmental processes in plants, the two stages may have different sensitivities to antibiotics. Tetracycline (TC), for example, is a major-use antibiotic. Radicle length, the relatively sensitive endpoint in plant skotomorphogenesis, is less sensitive than all of the indices of cotyledon colour and pigments in plant photomorphogenesis to TC stress. In conclusion, we suggest that plant photomorphogenesis may be more sensitive than plant skotomorphogenesis to stresses of antibiotics, but which needs further studies.


Assuntos
Antibacterianos/toxicidade , Brassica rapa/efeitos dos fármacos , Desenvolvimento Vegetal/efeitos dos fármacos , Plântula/efeitos dos fármacos , Poluentes do Solo/toxicidade , Tetraciclina/toxicidade , Proteínas de Arabidopsis/genética , Brassica rapa/crescimento & desenvolvimento , Brassica rapa/efeitos da radiação , Cotilédone/efeitos dos fármacos , Cotilédone/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Luz , Pigmentos Biológicos/biossíntese , Plântula/crescimento & desenvolvimento , Plântula/efeitos da radiação
11.
Chemosphere ; 242: 125255, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896180

RESUMO

A woody-biochar was added to waste biomass during a composting process. The resulting compost-char was amended to a metal contaminated soil and two plant species, L. perenne and E. sativa, were grown in a pot experiment to determine 1) plant survival and stress factors, 2) uptake of metals to plants and, 3) chemical characteristics of sampled soils and pore waters. Compost supplemented with biochar after the composting process were also tested, as well as a commercially available compost, for comparison. Co-composting with biochar hastened the composting process, resulting in a composite material of reduced odour, increased maturity, circum-neutral pH and increased moisture retention than compost (increase by 3% of easily removable water content). When amended to the soil, CaCl2 extractable and pore water metals s were reduced by all compost treatments with little influence of biochar addition at any tested dose. Plant growth success was promoted furthest by the addition of co-composted biochar to the test soil, especially in the case of E. sativa. For both tested plant species significant reductions in plant metal concentrations (e.g. 8-times for Zn) were achieved, against the control soil, by compost, regardless of biochar addition. The results of this study demonstrate that the addition of biochar into the composting process can hasten the stability of the resulting compost-char, with more favourable characteristics as a soil amendment/improver than compost alone. This appears achievable whilst also maintaining the provision of available nutrients to soils and the reduction of metal mobility, and improved conditions for plant establishment.


Assuntos
Brassicaceae/crescimento & desenvolvimento , Carvão Vegetal/química , Compostagem , Lolium/crescimento & desenvolvimento , Metais/análise , Madeira/química , Biodegradação Ambiental , Biomassa , Brassicaceae/química , Lolium/química , Modelos Teóricos , Solo/química , Poluentes do Solo/análise
12.
Chemosphere ; 242: 125281, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896191

RESUMO

In this study, the potential of pulverized waste tires (PWTs), either on their own or mixed with soil (well graded sand), to act as adsorptive fill materials was evaluated by conducting laboratory tests for accessing their adsorption and geotechnical properties. PWT (0, 5, 10, 15, 25, and 100 wt%) was mixed with soil to evaluate the removal of benzene, toluene, ethylbenzene, and xylene (BTEX) components and two heavy metal ions (Pb2+ and Cu2+). Adsorption batch tests were performed to determine the equilibrium sorption capacity of each mixture. Subsequently, compaction, direct shear, and consolidation tests were performed to establish their geotechnical properties. The results showed that BTEX had the strongest affinity based on the uptake capacity by the soil-PWT mixtures. The adsorption of BTEX increased for greater PWT content, with pure PWT having the highest adsorption capacity toward BTEX removal: uptake capacities for xylene, ethylbenzene, toluene, and benzene were 526, 377, 207 and 127 µg/g sorbent, respectively. Heavy metal removal was increased by increasing the amount of PWT up to 10 wt%, and then decreased beyond this ratio. Compacted soil-PWT mixtures comprising 5-25 wt% PWT have relatively low dry unit weight, low compressibility, adequate shear capacity for many load-bearing field applications, and satisfactory adsorption of organic/inorganic contaminants, such that they could also be used as adsorptive fill materials.


Assuntos
Derivados de Benzeno/análise , Metais Pesados/análise , Poluentes do Solo/análise , Resíduos Sólidos/análise , Adsorção , Benzeno/análise , Modelos Teóricos , Eliminação de Resíduos , República da Coreia , Solo/química , Tolueno/análise , Xilenos/análise
13.
Chemosphere ; 242: 125266, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896197

RESUMO

Determining the reliable source contribution and spatial distribution of potentially toxic elements (PTEs) is a focal issue for soil regulation and remediation. For this purpose, three receptor models, US-EPA positive matrix factorization (EPAPMF), weighted alternating least squares positive matrix factorization (WALSPMF), and non-negative constrained absolutely principle analysis (NCAPCA), were used to a dataset consisting of ten PTEs (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, and Zn) for source apportionment. Hazardous areas of ten PTEs were delineated using sequential indicator simulation (SIS) and uncertainty analysis. Three factors for ten PTEs were derived by three receptor models with a one-to-one correspondence between the factors. To obtain more appropriate results, the three receptor models were combined to calculate the ensemble-average source contributions. As, Co, Cr, Cu, Mn, and Ni were derived from a natural source with ensemble-average contributions higher than 85.72%. Cd, Hg, Pb, and Zn were contributed by both parent material and anthropogenic influence. More than half of Hg concentrations were associated with atmospheric deposition caused by human emissions. The concentrations of 28.04% for Cd, 20.74% for Hg, 43.49% for Pb, and 23.71% for Zn were associated with human inputs including agriculture practice, industrial activities, and vehicle emissions. The maps of spatial distribution generated by the SIS indicated that parent materials controlled the spatial distributions of As, Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn. 27.1% and 32.1% of the total area for Cd and Hg were identified as hazardous areas exceeding 1.5 times background values of Shandong province.


Assuntos
Monitoramento Ambiental/métodos , Metais Pesados/análise , Modelos Teóricos , Poluentes do Solo/análise , Solo/química , Agricultura , China , Humanos , Indústrias , Emissões de Veículos/análise
14.
World J Microbiol Biotechnol ; 36(2): 23, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31965334

RESUMO

Arsenic naturally occurs in the earth's crust and can be introduced in the environment by human activities. Agricultural practices in arsenic-contaminated environments pose a threat to human health. The contamination of crops contributes to the metalloid's introduction in the food chain. This study aims to test the hypotheses that the inoculation of a hyperaccumulator rhizobacterial strain, Ochrobactrum tritici As5, to the rhizosphere of rice plants reduces the arsenic presence inside the tissue of the rice plants and reduces the inhibitory effect of the metalloid on the plant's growth parameters. Inoculation of the hyperaccumulating strain O. tritici As5 showed the lowest concentration of arsenic in the plant's tissue (2.6 fold lower than sterile plants), compared to the unmodified type O. tritici SCII24 and sterile rice plants. The inoculation of the type strain SCII24 also led to a decrease in arsenic concentration in the plant tissue compared with sterile plants (1.6 fold lower than sterile plants). The difference in arsenic presence in shoots was smaller among treatment groups than in the roots, showing a similar trend. The inoculation of the hyperaccumulator As5 strain alleviated some of the toxic effects of arsenic on shoot growth compared to inoculation of the unmodified type strain. All these findings together, contribute to our understanding of the interplay between arsenic pollution, plants and their rhizobacteria, especially the role of bioaccumulation of metal(oids) by rhizobacteria, and provide important information on the prevention of arsenic uptake by crops and the development of phytostabilizers.


Assuntos
Arsênico/análise , Ochrobactrum/crescimento & desenvolvimento , Oryza/microbiologia , Arsênico/toxicidade , Biodegradação Ambiental , Produtos Agrícolas/química , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/microbiologia , Ochrobactrum/metabolismo , Oryza/química , Oryza/crescimento & desenvolvimento , Brotos de Planta/química , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/microbiologia , Rizosfera , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
15.
Chemosphere ; 242: 125113, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896177

RESUMO

Health risk associated with drinking water has attracted increasing attention worldwide. Here, we conducted a survey on the main drinking water sources of Dalian in China to clarify the local human health risk associated with heavy metal and pesticide contaminants in the drinking water sources. The results showed that six heavy metals, namely, copper (Cu), zinc (Zn), cadmium (Cd), nickel (Ni), arsenic (As), and mercury (Hg), and two pesticides (atrazine and acetochlor) were detected in water samples, where the highest concentration of Hg (0.0621 µg L-1) exceeded the domestic standard only. In addition to the above-mentioned metals, Cr was also detected in the sediment/soil samples. As to the pesticides, atrazine, acetochlor, hexachlorobenzene, p,p'-DDE, and p,p'-DDD were detected in the sediment/soil samples at ng g-1 levels, and atrazine and acetochlor were found in water samples at ng L-1 levels. The human health risk assessment showed no marked difference in carcinogenic and noncarcinogenic risks from drinking water. Our study approved that hexachlorobenzene and arsenic were the main contributors to human carcinogenic risks, which were calculated at the level of 10-4. Furthermore, sediment and soil ingestion was considered as the major source of human health risk in our study area. This study revealed the current pollution status in the surrounding area of the drinking water source and the main source associated with human health risk, which established a sound basis for further decision-making to take necessary action on pollution control.


Assuntos
Água Potável/química , Exposição Ambiental/estatística & dados numéricos , Poluição Ambiental/estatística & dados numéricos , Metais Pesados/análise , Praguicidas/análise , Arsênico , Cádmio , China , Cobre/análise , Monitoramento Ambiental/métodos , Poluição Ambiental/análise , Humanos , Mercúrio/análise , Compostos Orgânicos , Medição de Risco , Solo , Poluentes do Solo/análise
16.
Chemosphere ; 242: 125237, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896179

RESUMO

The presence of surfactants in biofilters could enhance hydrophobic VOC removal. In this study, blood agar plate, methylene blue agar plate and a culture with n-hexane as the only carbon source were used to screen strains that could biodegrade n-hexane and produce biosurfactants simultaneously. The effects of n-hexane concentration on n-hexane removal and biosurfactant production were also investigated. Results showed that such a strain identified to be Pseudomonas sp. Strain NEE2 was successfully isolated from oil-polluted soils. The biosurfactants production by this strain were dependent on the initial concentration of n-hexane (132-2640 mg/L). At the concentration of 2640 mg/L of n-hexane, the biosurfactants promoted n-hexane removal. At 132 mg/L of n-hexane, n-hexane removal efficiency on day 2 exceeded 60%. The synergistic mechanisms of n-hexane removal and biosurfactant production by Pseudomonas sp. Strain NEE2 were discussed including the enhanced mass transfer from gas to liquid phase, within the biofilm phase and biodegradation at the presence of biosurfactants as well as the consequently enhanced production of the biosurfactants. These results in this study proved that it is possible for microorganisms utilizing the synergistic effect of hydrophobic VOC degradation and biosurfactant production for cost-effective hydrophobic VOC removal in biofilters.


Assuntos
Hexanos/metabolismo , Poluição por Petróleo , Pseudomonas/metabolismo , Poluentes do Solo/metabolismo , Biodegradação Ambiental , Interações Hidrofóbicas e Hidrofílicas , Solo , Tensoativos/química
17.
Environ Monit Assess ; 192(2): 89, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31902034

RESUMO

Soybeans, as legumes, belong among food items that contribute most to the dietary intake of the heavy metal cadmium (Cd). The consumption of soy-based foods may contribute significantly to Cd intake in vegetarians as probably the most frequent consumers of these foods. In this research, the weekly dietary intake of Cd from soy-based foods was investigated in 119 participants (including vegetarians, vegans, and non-vegetarians) in the Czech Republic by means of a semi-quantitative food frequency questionnaire (SFFQ) with personal assistance and the measurement of body weight. Cd content in soy-based foods available on the market was determined by means of atomic absorption spectrometry after microwave digestion. Tofu, as the most frequently consumed food item in the vegetarian/vegan group, contributed most to the total dietary Cd intake. It contained 7.6 ± 0.1 µg Cd/kg, while the highest Cd content was observed in tempeh (18.1 ± 0.4 µg/kg). The highest mean dietary Cd intake per week from soy-based foods was 0.4 µg/kg b.w. and was found in the vegan group. The consumption of soy-based foods was the lowest in the non-vegetarian group as was the dietary intake of Cd, which was 0.04 µg/kg b.w. per week.


Assuntos
Cádmio/análise , Exposição Dietética/estatística & dados numéricos , Contaminação de Alimentos/estatística & dados numéricos , Poluentes do Solo/análise , Alimentos de Soja/análise , Soja/química , Peso Corporal , República Tcheca , Dieta , Monitoramento Ambiental , Fabaceae , Feminino , Humanos , Masculino , Espectrofotometria Atômica , Verduras , Vegetarianos
18.
Environ Monit Assess ; 192(2): 92, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31902037

RESUMO

The aim of the study was monitoring of phthalic acid esters in agricultural soils of the Czech Republic over the period of 6 years, namely dibutyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP). Monitoring took place in twelve regions of the Czech Republic. Soil samples were taken evenly from the top and bottom soil horizons using a zig-zag pattern. Soil samples were taken from arable land, permanent grassland, and hop field. Lyophilisation of the samples was done by ultrasound-assisted extraction using a mixture acetone-hexane (1:1). Phthalic acid esters were analysed using high-performance liquid chromatography with UV detection. Subsequently, the results were statistically compared by analysing the principal components (PCA) to determine the effect of individual factors on the content of phthalic acid esters in agricultural soil. Factors such as precipitation, distance from a pollution source, amount of pesticides, and amount of artificial and organic fertilizers were taken into account. If we compare the concentrations established in this study with the limits set out in the Methodological Instruction of the Ministry of the Environment of the Czech Republic based on RSLs (Regional Screening Levels) issued by the USEPA (United States Environmental Protection Agency), none of these values were exceeded.


Assuntos
Monitoramento Ambiental , Ácidos Ftálicos/análise , Poluentes do Solo/análise , Agricultura , República Tcheca , Dibutilftalato/análise , Dietilexilftalato/análise , Poluição Ambiental/análise , Ésteres/análise , Praguicidas/análise , Solo/química , Estados Unidos
19.
J Environ Manage ; 259: 109991, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31929028

RESUMO

Removing aromatic contaminants from the soil using ultrasonic waves is a new technology with the potential for practical use in industrial scale. In this study, the ultrasonication technology was presumed as a pre-treatment for soils contaminated with phenanthrene. Since the removal of this contaminant from the soil by ultrasonication reduces the cost of treatments such as soil washing, the optimization of independent variables has been investigated in the present study. Effect of variables such as phenanthrene primary concentration (7.5-517.5 mg/kg), ultrasonic power (0-395 W), the volume of water (0-400 mL) and the overall retention time (0-1 h) on the cost-saving of treatment for 100 g soil samples has been presented. The Response Surface Methodology has been used for modeling the results of this research. Based on the results of this research, the optimal conditions have been proposed for maximization of the cost-savings by ultrasonication and minimization of the ultrasonication operating costs. The best proposed conditions to achieve the maximum pollutant removal occurred in soil pretreatments using ultrasonication in water volume of 300 mL, the ultrasonic power of 139W, and 0.5 h process duration, which led to saving of 1.42 ¢/100 g soil for the replacement of the soil washing by the ultrasonication process.


Assuntos
Fenantrenos , Poluentes do Solo , Solo , Água
20.
J Environ Manage ; 259: 110051, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31929031

RESUMO

Soil contamination due to heavy metals is a serious problem worldwide. Leather industry is one of the leading sectors in this regard in Pakistan, discharging heavy metal chromium (Cr) through untreated wastewater. In this study, effect of biochar and elemental sulfur (ES) were evaluated on maize growth, physiology, redox homeostasis and Cr dynamics in tannery polluted soils. Biochar was produced through pyrolysis of sugarcane bagasse at 350 °C and was applied at a rate of 3% (w/w) along with different rates of ES (3 and 6 g kg-1 soil). Results revealed that Cr toxicity in tannery polluted soils negatively affected plant growth, physiological and biochemical attributes. Reduction in plant growth and accumulation of Cr(III) and Cr(VI) in roots and shoots were higher in Sialkot (S) soil compared to Kasur (K) soil. Application of biochar and ES (6 g kg-1) resulted in maximum increase in plant height, biomass, chlorophyll content, photosynthesis, relative water, starch and protein content, as compared to control. While electrolyte leakage, soluble sugars, proline content, lipid peroxidation and antioxidant enzymes (APX, CAT, GSH, GR, GPX, GST and SOD) were decreased by addition of biochar and ES in tannery polluted soils. Similarly, combined application of biochar and ES decreased Cr concentrations in soil, and reduced uptake of Cr(VI) and Cr(III) concentration in roots and shoots of plants in S soil compared with K soil. In conclusion, application of biochar in combination with ES could be considered an interesting environmentally sound option for remediation of tannery polluted soils.


Assuntos
Poluentes do Solo , Zea mays , Antioxidantes , Carvão Vegetal , Cromo , Paquistão , Solo , Enxofre
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