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1.
Chemosphere ; 239: 124798, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31527006

RESUMO

Hexachlorocyclohexane (HCH) and mainly the γ-HCH isomer, namely lindane, were extensively produced and used as pesticides. Huge amounts of wastes, solids and liquids, were disposed of in the surroundings of the production sites. The liquid residuum was a complex mixture of chlorinated organic compounds, COCs, from chlorobenzene to heptachlorocyclohexane. This Dense Non-Aqueous Phase Liquid, DNAPL, migrated by density through the subsurface to greater depths, being trapped or adsorbed into the soil in this movement posing a significant risk to the groundwater. Knowledge of the partitioning in water of COCs in DNAPL is a key issue to determine its fate in the environment. However, there are no data in literature for the partitioning and/or solubility of many of the COCs in this DNAPL, such as pentachlorocyclohexene, hexachlorocyclohexene and heptachlorocyclohexane despite them constitute about 13-30% of the mole fraction of the DNAPLs. In this work, the partitioning to water of COCs in free and those adsorbed onto soil has been studied. In addition, measured and predicted aqueous concentrations of each COC in the DNAPL mixture have been compared. To do this, the solubility of a compound that is a solid crystal when pure at P = 298 K and P = 1 atm has been evaluated considering the approach of sub-cooled liquid state of solid organochlorines. Samples were obtained at Sabiñanigo landfills and soils used had several grain sizes. Transformation in alkaline media of COCs had a positive environmental impact.


Assuntos
Hexaclorocicloexano , Hidrocarbonetos Clorados/química , Poluentes do Solo/química , Halogenação , Hexaclorocicloexano/análogos & derivados , Hexaclorocicloexano/química , Solubilidade , Espanha , Instalações de Eliminação de Resíduos , Água/química , Poluentes Químicos da Água/química
2.
Chemosphere ; 238: 124651, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31472346

RESUMO

A harbour sediment, previously remediated, was tested for soilless strawberry cultivation (Camarosa and Monterey cultivars), as an innovative, cost-effective and environment-friendly approach of sediment management. Sediments were tested as such (TS100) and mixed 1/1 (v/v) with a peat-based commercial substrate (TS50), using the peat-based medium as control (TS0). Substrates were characterized for some physicochemical properties (e.g. density, porosity and water capacity). Minerals (P, Ca, K, Na and Fe), heavy metals (Cu, Zn, Mn, Ni, Cr, Pb and Cd), aliphatic hydrocarbons (C > 12), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dibenzodioxins and dibenzofurans were analysed in substrates and fruits. Sugars and organic acids, including the ascorbic, were also determined in fruits, as quality indicators. Notwithstanding remediation, sediments showed concentrations of Zn (206 mg kg-1), C > 12 (86 mg kg-1) and PAHs (47 mg kg-1) exceeding the limits established by the Italian L.D. 152/2006, regulating the contamination of soil in green areas, thus making its relocation in the environment not permitted as such. No evidence of fruit contamination by Cr, Pb and Cd was highlighted. Moreover, Cu, Zn and Ni fruit concentrations were comparable among treatments. Conversely, Mn showed statistically higher concentrations in TS0 fruits (56-57 mg kg-1) compared to those grown in sediment-based substrates (8-20 mg kg-1). Among organic contaminants, only dioxin-like PCBs were determined in fruits, at toxic equivalent concentrations fourfold lower than the limit established by the European Union. TS100 fruits showed a yield reduction from 40 to 70% for Camarosa and Monterey, but higher sugar and ascorbic acid contents.


Assuntos
Produtos Agrícolas/normas , Monitoramento Ambiental , Fragaria/metabolismo , Frutas/química , Sedimentos Geológicos/química , Produtos Agrícolas/química , Produtos Agrícolas/crescimento & desenvolvimento , Fragaria/química , Itália , Metais Pesados/análise , Minerais/análise , Bifenilos Policlorados/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes do Solo/química
3.
Chemosphere ; 238: 124657, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31473526

RESUMO

This study investigates the degradation of petroleum hydrocarbon in contaminated soil using activated persulfate (PS) with ultrasound (US) and US/Fe. Various controlling factors including different PS dosage, ultrasonic power, pH, soil water ratio and soil particle size were considered. It was found that petroleum hydrocarbon degradation efficiency achieved up to 56.41% and 82.23% in US/PS and US/Fe/PS system, respectively. Based on the experimental results, the reaction rate of US/Fe/PS system was faster than US/PS system and the degradation efficiency enhanced significantly with the increasing ultrasonic power. Changing initial solution pH influenced the petroleum hydrocarbon reaction rate and the best performance would be achieved at pH of 5. The present work identified the main components of petroleum hydrocarbon pollutants in shale gas sites. The mechanism of petroleum hydrocarbon degradation on US/Fe/PS system were analyzed.


Assuntos
Recuperação e Remediação Ambiental/métodos , Hidrocarbonetos/química , Poluição por Petróleo , Poluentes do Solo/química , Poluição Ambiental/análise , Hidrocarbonetos/efeitos da radiação , Gás Natural , Solo , Poluentes do Solo/análise , Poluentes do Solo/efeitos da radiação , Sulfatos/química , Ondas Ultrassônicas , Poluentes Químicos da Água
4.
Ecotoxicol Environ Saf ; 187: 109828, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31639644

RESUMO

Different forms of aluminum (Al) in soil can be toxic to plants and the bacterial community. In our previous study, the distribution and toxicity to plants of soil Al species and soil labile Al fractions were examined. However, the toxicity of different forms of Al on the bacterial community has not been completely studied. In this study, five soil samples (pH: 4.92, 6.17, 6.62, 6.70, 8.51) were collected from Lichuan, China. Tall fescue was planted in rhizosphere boxes with those soils for 120 days. The toxicity of soil Al species and soil labile Al fractions on the bacterial community of near-rhizosphere (NR) soils and far-rhizosphere (FR) soils were analyzed. The effect of different forms of Al on bacterial community between NR and FR soils was small, but the difference was obvious according to the different spatial distribution of samples. An individual bacterial community has eosinophilia, and most bacterial communities are tolerant of heavy metals (e.g., Cu, Zn, Cd). The toxicity of exchangeable Al has a strong effect on the bacterial community. Meanwhile, the toxicity of Al3+ to the bacterial community is strong. In this study, the key finding was that the toxicity of the Al-F- complex toward the bacterial community and plants was different. AlF2+, AlF2+, AlF3, and AlF4- are toxic for the bacterial community, and the correlation decreases with the addition of F-. This finding is of considerable significance to the treatment of acid-contaminated soil and the study of the tolerance mechanism of plants toward Al.


Assuntos
Alumínio/toxicidade , Festuca/microbiologia , Microbiota/efeitos dos fármacos , Microbiologia do Solo , Poluentes do Solo/toxicidade , Alumínio/química , Biodegradação Ambiental , Festuca/metabolismo , Concentração de Íons de Hidrogênio , Metais Pesados/metabolismo , Rizosfera , Solo/química , Poluentes do Solo/química
5.
Ecotoxicol Environ Saf ; 187: 109788, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31648073

RESUMO

The potential threats of microplastics to global health are a new problem. However, little is known about the influence of microplastics on soil organisms. Here, we investigated the effects of low-density polyethylene (LDPE, < 400 µm) on earthworms (Eisenia fetida) under different concentrations (0.1, 0.25, 0.5, 1.0, 1.5 g/kg dry) with three replicates in artificial soil. Results showed that surface damage of earthworms was observed at the concentration of 1.5 g/kg LDPE after exposure 28 days. The microplastics were ingested in a dose-response manner. Smaller sizes of LDPE microplastics were found in the casts of E. fetida, and approximately 30% of the microplastics egested (size < 100 µm) were increased compared with initial microplastics in the soil. The catalase activity and malondialdehyde content increased significantly at the concentration of 1.0 g/kg LDPE after exposure 28 days, and acetylcholine esterase was significantly stimulated at concentrations of 1.5 and 1.0 g/kg LDPE on days 21 and 28, respectively. The results of this study demonstrate the potential risk of LDPE microplastics to E. fetida and may provide a reference for the impact of microplastics on terrestrial creatures.


Assuntos
/toxicidade , Oligoquetos/efeitos dos fármacos , Polietileno/toxicidade , Poluentes do Solo/toxicidade , Solo/química , Animais , Relação Dose-Resposta a Droga , Malondialdeído/metabolismo , Oligoquetos/metabolismo , Tamanho da Partícula , Polietileno/química , Poluentes do Solo/química
6.
Ecotoxicol Environ Saf ; 187: 109829, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31654869

RESUMO

Screening appropriate washing agents to remediate soils contaminated with heavy metals is crucial for decreasing metal hazards posing to environment and human health. In this study, two plant washing agents-water-extracted from Fagopyrum esculentum and Fordiophyton faberi, were applied to remove soil Pb, Zn, and Cd by washing. Results indicated that metal removals augmented with increase of washing solution concentrations, decreased with increasing pH values of the solution and followed the pseudo-second-order model depending on contact duration. At concentration of 50 g/L, pH 3 and contact duration of 120 min, F. esculentum had higher removals of Pb (5.98-6.83%), Zn (21.82-27.94%), and Cd (39.90-40.74%) than those of F. faberi. And metal ions could be removed by binding with carboxyl, hydroxyl, amide, amine and aromatic groups in washing solutions. The potential risks of residual metals declined by 51.35-52.12% for mine soil and 48.51-49.96% for farmland soil with exchangeable and carbonate-bound fractions obviously extracted after a single washing (P < 0.05). And soil organic carbon and nutrients increased to some extent except for total phosphorus and available potassium. Moreover, soil phytotoxicity lowered except that some adverse effects on seed germination existed. Therefore, the water extract from F. esculentum is a promising washing agent for heavy metal removal.


Assuntos
Recuperação e Remediação Ambiental/métodos , Metais Pesados/química , Extratos Vegetais/química , Poluentes do Solo/química , Cádmio/química , Fagopyrum/química , Humanos , Chumbo/química , Chumbo/isolamento & purificação , Myrtales/química , Zinco/química , Zinco/isolamento & purificação
7.
Chemosphere ; 239: 124707, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31479912

RESUMO

Site soils with persistent cyanide compounds (primarily iron-cyanide complex) pose potential hazards to the environment and require remediation before redevelopment. This study evaluated the possibility of thermal treatment on remediation of cyanide-contaminated soils via batch heating experiments spanning a wide temperature range (200-500 °C). The change with operation variables of total cyanide and some reaction intermediates (e.g. CN-) was analyzed in order to elucidate the optimal variables that guarantee cyanide removal while generating no hazardous byproducts. Temperature, heating time and cyanide species have been found to be important parameters influencing removal/destruction of cyanide in soils. For soils bearing K3[Fe(CN)6] and K4[Fe(CN)6], a removal efficiency of >99.9% can be obtained with temperatures over 350 °C at 1 h, while for samples bearing Fe4[Fe(CN)6]3, a higher temperature (>450 °C) is needed to obtain an equivalent efficiency. During heating, the iron-cyanide complexes decomposed, releasing highly toxic free cyanides, which will subsequently be oxidized. However, a small percentage of free cyanide can always be detected as a result of incomplete oxidation, thus caution should be taken to minimize the accumulation of free cyanide during thermal treatment.


Assuntos
Cianetos/análise , Recuperação e Remediação Ambiental/métodos , Poluentes do Solo/análise , Temperatura Ambiente , Cianetos/química , Poluição Ambiental/prevenção & controle , Ferrocianetos/análise , Ferrocianetos/química , Oxirredução , Poluentes do Solo/química
8.
Chemosphere ; 239: 124706, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31493754

RESUMO

The remediation effect of organic acids in heavy metal contaminated soil was widely studied. However, the comprehensive evaluation of organic acids on micro-ecological environment in heavy metal contaminated soil was less known. Herein, this experiment was conducted to investigate the impact of malic acid, citric acid and oxalic acid on soil fertility, cadmium (Cd) speciation and ecotoxicity in contaminated soil. Especially, to evaluate the ecotoxicity of Cd, high-throughput sequencing was used to investigate the soil bacterial community structure and diversity after incubation with organic acids. The results showed that obvious changes in soil pH were not observed. Whereas, the contents of available phosphorus (Olsen-P) and alkali hydrolysable nitrogen (Alkeline-N) evidently increased with a significant difference. Furthermore, compared to control, the proportion of acetic acid-extractable Cd increased by 3.06-6.63%, 6.11-9.43% and 1.91-6.22% respectively in the groups amended with malic acid, citric acid and oxalic acid, which indicated that citric acid did better in improving the availability of Cd than malic acid and oxalic acid. In terms of biological properties, citric acid did best in bacteria count increase, enzyme activities and bacterial community structure improvement. Accordingly, these results provided a better understanding for the influence of organic acids on the micro-ecological environment in Cd contaminated soil, based on physicochemical and biological analysis.


Assuntos
Cádmio/toxicidade , Ácidos Carboxílicos/farmacologia , Recuperação e Remediação Ambiental/métodos , Microbiologia do Solo , Poluentes do Solo/química , Bactérias/efeitos dos fármacos , Cádmio/análise , Cádmio/química , Ácidos Carboxílicos/química , Ácido Cítrico/química , Ácido Cítrico/farmacologia , Ecotoxicologia , Poluição Ambiental/análise , Malatos/química , Malatos/farmacologia , Ácido Oxálico/química , Ácido Oxálico/farmacologia , Solo/química , Poluentes do Solo/análise
9.
Chemosphere ; 239: 124738, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31494316

RESUMO

Stabilization/Solidification (S/S) has been widely used in soil remediation to both improve physical properties and immobilize extensive contaminants. GGBS (granulated ground blast furnace slag)-MgO-CaO (GMCs) was used to treat Pb/Zn contaminated soil. The physical and microstructural characteristics of stabilized/solidified contaminated soil were investigated in this study. Microstructural analysis showed that the main hydration products of GMC treated contaminated soil were C-S-H and hydrotalcite like gels (Ht), which dominated the physical strength of S/S soil. The unconfined compressive strength (UCS) and the leachability of GMC treated contaminated soil were improved with the increase in GMC proportion (5%-15%), curing time (7 days and 28 days) and temperature (5 °C, 21 °C and 45 °C) due to the enhanced hydration. The compressive strengths of the majority mixes met the US EPA criterion (0.35 MPa). The strength of S/S soils was less affected by the increase of curing temperature after a longer curing period (28 days). According to the XRD and SEM results, both Pb and Zn in S/S contaminated soil could be immobilized by the precipitation and the adsorption on the surface of calcium silicate hydrate (C-S-H). Zn can also be incorporated into the structure of C-S-H and Ht. The addition of Pb/Zn decreased the physical strength in the order of: Pb(5000 mg/kg)>Pb(10000 mg/kg)>Zn/Pb(5000 mg/kg)>Pb(20000 mg/kg).


Assuntos
Recuperação e Remediação Ambiental/métodos , Chumbo/química , Poluentes do Solo/química , Solo/química , Zinco/química , Hidróxido de Alumínio/química , Compostos de Cálcio/química , China , Hidróxido de Magnésio/química , Óxido de Magnésio/química , Microscopia Eletrônica de Varredura , Óxidos/química , Silicatos/química , Temperatura Ambiente , Difração de Raios X
10.
Chemosphere ; 239: 124807, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31520982

RESUMO

The characteristics of polyvinylpyrrolidone (PVP)-stabilised nano-zero-valent iron (PVP-NZVI) and its application, combined with surfactant, to trichloroethylene (TCE)-contaminated soil were investigated. Two surfactants (cetyltrimethylammonium bromide [CTAB] and sodium dodecyl sulphate [SDS]) were tested for their ability to enhance the remedial activity of PVP-NZVI in 3 h batch experiments. The prepared PVP-NZVI formed nanoparticles ∼70 nm in diameter. The isoelectric point of PVP-NZVI was about 8.51, similar to the initial pH. X-ray diffraction and X-ray photoelectron spectroscopy analyses revealed that ZVI was the main active component of PVP-NZVI, and carbonised products of the target were observed. The TCE dechlorination efficiency by PVP-NZVI was about 84.73%; the efficiency by PVP-NZVI was about 20% higher when combined with SDS than with CTAB. Therefore, application of PVP-NZVI with SDS represents a potential remediation approach for TCE-contaminated soil.


Assuntos
Recuperação e Remediação Ambiental/métodos , Ferro/química , Solo/química , Tensoativos/química , Tricloroetileno/química , Halogenação , Nanopartículas/química , Espectroscopia Fotoeletrônica , Povidona/química , Dodecilsulfato de Sódio , Poluentes do Solo/química , Poluentes do Solo/isolamento & purificação , Difração de Raios X
11.
Chemosphere ; 239: 124775, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31521931

RESUMO

Enriched levels of thallium (Tl) in the environment are not only derived from anthropogenic sources but also have potential natural origins owing to Tl-rich sulphide mineralization. However, little is known regarding the geochemical fractionations of Tl in contaminated soils from geogenic sources. This study aims to reveal the Tl geochemical fractionations in different types of soils from a large-scale independent Tl mine in southwestern China, via a modified Institute for Reference Materials and Measurement (IRMM) sequential extraction (four-step) scheme. The results revealed that a large percentage of Tl was related to the labile portions (including reducible, weak-acid-exchangeable, and oxidizable fraction) of the soils (68.8-367 mg kg-1). Further analyses by Scanning Transmission Electron Microscopy-Energy Dispersive X-ray Spectrometer (STEM-EDS) found that Tl mainly existed in the Fe-containing minerals (such as jarosite and hematite) with fine particles (∼1 µm). These results highlight that, apart from the anthropogenically induced Tl pollution, the naturally occurring Tl contamination in soils may also pose significant risks to human health and ecological safety. Owing to the relatively high mobility and bioavailability of Tl in the labile fractions, it is important to understand geochemical fractionations of this element for alleviating Tl pollution and effective management of naturally occurring Tl contaminated soils.


Assuntos
Poluentes do Solo/química , Tálio/química , Fracionamento Químico , China , Monitoramento Ambiental/métodos , Compostos Férricos/química , Humanos , Mercúrio/análise , Microscopia Eletrônica de Transmissão e Varredura , Solo/química , Poluentes do Solo/análise , Espectrometria por Raios X , Sulfatos/química , Sulfetos/análise , Tálio/análise
12.
Chemosphere ; 239: 124814, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31527003

RESUMO

The increasing use of zinc oxide nanoparticles (ZnO NPs) in agriculture renders it necessary to evaluate their impact on soil non-target organisms. This work studies Zn availability to earthworms from the ZnO (NP and bulk) applied to two agricultural soils with a different pH at 20, 225, 500, and 1000 mg Zn kg-1. Zn uptakes and the effects on Eisenia andrei, grown under controlled conditions, were determined. Effects were assessed at three levels: organisms, mortality, growth and reproduction; biochemical, catalase and glutathione S-transferase activities, malondialdehyde (MDA), and protein content; cellular in coelomocytes, reactive oxygen species (ROS) generation, lysosomal membrane alterations (RN) and mitochondrial dysfunction (MTT). Available Zn was 100-fold higher in acidic than in calcareous soil and did not differ among ZnO (NP or bulk). Zn in worms was auto-regulated regardless of the soil Zn concentration, pH and ZnO size. Effects on mortality and weight were observed only in the acidic soil at the highest concentration, ZnO NPs reduced survival and body weight, while ZnO bulk reduced body weight. Reproduction parameters in acidic soil were: EC50 (fecundity) 277 and 256 mg Zn kg-1 and EC50 (fertility) 177 and 179 mg Zn kg-1 for ZnO NPs and bulk, respectively, with no found NP-specific effects. No responses of enzymatic activities, MDA and MTT were detected. ROS and RN were altered in the coelomocyte cells of earthworms in the two soils, but effects depended on ZnO size suggesting nanospecific effects. Soil pH governs toxicity more than ZnO size regardless of body Zn concentration.


Assuntos
Agricultura , Nanopartículas/química , Oligoquetos/efeitos dos fármacos , Solo/química , Óxido de Zinco/química , Zinco/farmacocinética , Animais , Peso Corporal/efeitos dos fármacos , Enzimas/metabolismo , Concentração de Íons de Hidrogênio , Poluentes do Solo/química , Poluentes do Solo/toxicidade , Taxa de Sobrevida , Zinco/química , Zinco/toxicidade , Óxido de Zinco/metabolismo , Óxido de Zinco/toxicidade
13.
Chemosphere ; 240: 124827, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31541896

RESUMO

An outdoor macrocosm experiment using Fe-based and organic amendments over 2 years was set up to evaluate the effectiveness of aided-phytostabilisation. For that, a soil contaminated with As- and Cu-rich waste material (∼13000 mg As kg-1 and ∼500 mg Cu kg-1) was treated with combinations of iron sulphate (Fe) with lime, paper mill sludge (PS), holm-oak biochar (BC), olive mill waste compost (OMWC) or green waste compost (GWC). Rye (Secale cereale L.) was grown in the treated and non-treated soils 16 months after addition of the amendments. Arsenic and Cu dynamics in soil were assessed throughout the experiment and soil quality parameters (soil nutrients, organic matter and soil biology) were measured almost two years after addition of the amendments. All treatments resulted in a reduction of soluble and extractable Cu during the experiment and, despite the increase in soil pH (from 5 to 68) and DOC (from 10 up to 50 mg DOC L-1) provoked by the amendments, As was not significantly mobilised in the treated soils. Treatments combining Fe sulphate with the organic materials, especially biochar and both composts, resulted in an increase in soil available nutrients and enhanced rye growth. In this semi-field scale experiment, the combination of Fe sulphate with holm-oak biochar showed the most promising results in terms of soil fertility (nutrient availability), plant As and Cu uptake and soil C sequestration. Further research should focus on monitoring long-term effects of the soil amendments on crops, following repeated applications.


Assuntos
Compostos Ferrosos/química , Secale/química , Poluentes do Solo/química , Fatores de Tempo
14.
Chemosphere ; 240: 124846, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31550594

RESUMO

Cadmium (Cd) precipitation and dissolution in pore water is associated with dissolved organic carbon (DOC)-induced reduction-oxidation of sulfur (S) under waterlogging and is vital for controlling the bioavailability in paddy soil. A 120-day soil incubation experiment, including application of sulfur (S, 30 mg kg-1) and wheat straw (W, 1.0%) alone or in combination (W + S) into Cd-contaminated paddy soil under waterlogging, was conducted to investigate the dynamic of dissolved Cd and its relationship with DOC, S2-, Fe2+, pH, Eh and pe + pH in soil pore water. The results showed that the lowest dissolved Cd concentration was observed in the W + S-treated soil pore water among all treatments when the soil Eh remained at lower values during the period of 15-60 days of incubation, which could be attributed to CdS precipitation and/or co-precipitation of Cd absorbed by FeS2 because of the reduction in sulfur. The application of S resulted in a Cd rebound in the pore water irrespective of W addition when the Eh began to increase from its lowest values during the period of 45-75 days of incubation, and SOB genera were observed in the S added soil. This could be attributed to re-dissolution of the precipitated Cd in soils under the SOB-driven oxidation of sulfide such as CdS and FeS2. In conclusion, DOC-driven reduction-oxidation of sulfur controls Cd dissolution in the pore water of Cd-contaminated paddy soil under waterlogging conditions. Further studies are required to investigate the interaction of sulfur and SOM-induced DOC on Cd bioavailability in rice-planted paddy soils.


Assuntos
Cádmio/uso terapêutico , Poluição Ambiental/efeitos adversos , Poluentes do Solo/química , Enxofre/uso terapêutico , Cádmio/farmacologia , Enxofre/farmacologia , Água
15.
Chemosphere ; 240: 124817, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31561160

RESUMO

A study was conducted on the sorption of 17α-ethynylestradiol (EE2) on five soils formed under different redox conditions: an Arenosol (A_20) with fully aerobic conditions, two Gleysol samples (G_20 and G_40) with suboxic and anoxic conditions and two Histosols (H_20 and H_80) with mostly anoxic conditions. The soils were characterized on the basis of total organic carbon (TOC), specific surface area (SSA) and the Fourier transform infrared spectra of the humic acid and humin fractions (the soil remaining after alkali extraction) of the soil. The maximum adsorption capacity of the soils (Qmax) ranged from 10.7 to 83.6 mg/g in the order G_20 > H_20 > G_40 > A_20 > H_80, which reflected the organic matter content of the soils. The sorption isotherms were found to be nonlinear for all the soil samples, with Freundlich n values of 0.45-0.68. The strong nonlinearity found in the adsorption of the H_80 samples could be attributed to their high hard carbon content, which was confirmed by the high aromaticity of the humin fraction. The maximum sorption capacity (Qmax) of the soils did not increase indefinitely as the organic carbon content of the soils rose. There could be two reasons for this: (i) the large amount of organic matter may reduce the number of binding sites on the surface, and (ii) the decrease in SSA with increasing soil OC content may limit the ability to adsorb EE2 molecules. In anaerobic soil samples, where organic matter accumulation is pronounced, the amount of aromatic and phenolic compounds was higher than in better aerated soil profiles. Strong correlations were found between the amount of aromatic and phenolic compounds in the organic matter and the adsorption of EE2 molecules, indicating that π-π interaction and H-bonding are the dominant sorption mechanisms.


Assuntos
Etinilestradiol/metabolismo , Poluentes do Solo/química , Solo/química , Adsorção , Anaerobiose , Bactérias Aeróbias , Etinilestradiol/análise
16.
Chemosphere ; 240: 124845, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31561162

RESUMO

In the paper, hydrothermally (HT) treated, sulfuric acid (H2SO4), and hydrochloric acid (HCl) washed fly ashes (FA) were used to examine the applied effects with and without biochar (BC) on the bioavailability of heavy metals (HMs) and growth of maize (Zea mays L.) plants in coal-mining contaminated soil. Addition of BC in combination with these processed fly ashes (PFA) significantly increased the soil pH, EC, and soil organic carbon (SOC). Individual application of BC and PFA increased the available contents of Mg, Mn, and Fe, while the combination of BC and PFA significantly decreased the bioavailability of HMs in soil compared to control. The BC + HT-FA and BC + H2SO4-FA were most efficient treatments followed by BC + HCl-FA in promoting plant growth parameters (i.e., fresh and dry biomass, root and shoot lengths), reduction in the uptake of HMs and increase in the uptake of macronutrients. The results established that the combined application of BC and PFA synergistically increased HMs immobilization and maize biomass yields. The lowest transfer rate (TR), bioconcentration factor (BCF), and translocation factor (TF) for Cr, Co, Ni, Cu, Zn, Cd, and Pb were detected in BC + HT-FA, followed by BC + H2SO4-FA and BC + HCl-FA treatments after 60 days of maize crop harvesting. It could be suggested that using BC along with PFA as a soil stabilizer may be a promising source to immobilize HMs in a coal-mining contaminated soil.


Assuntos
Carvão Vegetal/química , Cinza de Carvão/química , Minas de Carvão/métodos , Poluição Ambiental/efeitos adversos , Metais Pesados/química , Poluentes do Solo/química , Solo/química , Zea mays/química , Disponibilidade Biológica
17.
Chemosphere ; 240: 124828, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31568944

RESUMO

Biochar has been recommended as a multi-beneficial amendment for the in situ remediation of heavy metals contaminated soils due to its high recalcitrance, stability, specific surface area and retention capacity, which leads to a long-lasting influence on the immobilization of soil contaminants. The influence of biochar on the availability of heavy metals such as copper is not fully understood and may be related to a change in copper association with soils fractions. Therefore, a long-time laboratory incubation study was set up as a completely randomized design to test the effect of biochar from different sources (coconut husks-CHB, orange bagasse-OBB and sewage sludge-SSB) at two rates of application (30 and 60 t ha-1) on the distribution of copper in a copper-contaminated soil after 24 months incubation. Copper distribution was evaluated through a sequential extraction procedure that fractionated copper into five fractions: F1 (soluble and exchangeable), F2 (specifically bound), F3 (organic matter bound), F4 (Fe and Mn oxide bound) and F5 (residual). Copper availability, soil pH and organic matter were also evaluated. Corn seeds were germinated in the incubated biochar soil to investigate the effect of biochar on seed germination and plantlets characteristics. All biochars increased soil pH and the concentration of oxidizable organic matter, and reduced copper availability after the 24 months incubation. CHB caused a discrete influence on copper distribution among soil fractions. OBB30 increased F1 (54.5%), F3 (24.0%), F4 (32.2%) and F5 (64.1%), and reduced F2 (39.8%); OBB60 reduced F1 (61.8%), F2 (16.5%) and F3 (16.0%) and increased F4 (18.0%) and F5 (84.4%). SSB30 strongly reduced Cu concentration in F1 (96.2%), F2 (34.0%), and F3 (22.2%), and increased F4 (54.4%); SSB60 reduced F1 (57.5%) and F3 (59.4%). Considering the high stability of biochar, the association of copper to the organic fraction leads to a long-time reduction in copper availability in the contaminated soil, which can reduce the cost and increase the efficiency of the remediation process. SSB reduced seed germination but produced vigorous and well-developed plantlets. Therefore, with proper production procedure to reduce the volatile matter content, SSB may not interfere with seed germination and has the greatest potential to be used for the remediation of copper-contaminated sites.


Assuntos
Carvão Vegetal/química , Cobre/química , Poluição Ambiental/efeitos adversos , Sementes/química , Poluentes do Solo/química , Solo/química , Zea mays/química , Germinação
18.
Chemosphere ; 240: 124847, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31568948

RESUMO

Sixteen polycyclic aromatic hydrocarbons (PAHs) proposed by the US EPA as priority were analyzed in air and soil samples in the Southwest of Buenos Aires, Argentina, in order to study the levels, distribution, sources and fugacity ratios of PAHs, evaluating the relationship between them. For this, 10 passive air samplers (XAD-2® resin) were deployed along the area and replaced three-monthly from January to December 2015. PAHs were analyzed through gas chromatography -mass spectrometry (GC-MS). Results obtained showed that total PAHs levels (∑16) ranged from 27.97 to 1052.99 ng m-3 and from 52.40 to 2118.34 ng. g-1 d.w. for air and soil samples, respectively. The highest air- PAHs levels were registered in Bahía Blanca city (1052.99 ng. m-3, d.w.) an urban-industrial site, while the highest soil-PAHs levels were found in La Vitícola (2118.34 ng. g-1, d.w.), a rural location closed to a high traffic national route. For all sites the highest levels were observed during the winter; however, both spatial and temporal variations were only statistically significant for certain specific PAHs. Diagnostic ratios + PCA, determined dominance of pyrolytic sources. Further, data showed that source of PAHs could be attributed to vehicular and industrial emissions (observed in all periods), biomass combustion (linked mainly to warm period) and domestic emissions (linked mainly to cold period). Finally, fugacity ratios resulted <1, indicating that soil and air samples were not in equilibrium for the majority of PAHs determining a net tendency of air PAHs towards deposition while soil acted principally as a sink.


Assuntos
Monitoramento Ambiental/métodos , Hidrocarbonetos Policíclicos Aromáticos/química , Poluentes do Solo/química , Solo/química , Argentina
19.
Chemosphere ; 240: 124873, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31574439

RESUMO

Combined pollution caused by polybrominated diphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs) in mangrove wetlands is serious, with their remediation to be been paid more and more attention. However, little is known about the combined impact of PAHs and mangrove species on removal of PBDEs in contaminated soils. In this study, BDE-209 and pyrene were selected and a 9 months experiment was conducted to explore how BDE-209 removal in contaminated soil varied with pyrene addition and Kandelia obovata planting, and to clarify corresponding microbial responses. Results showed that BDE-209 removals in soil induced by pyrene addition or K. obovata planting were significant and stable after 6 months, with the lowest levels of BDE-209 in combined pyrene addition with K. obovata planting. Unexpected, root uptake of BDE-209 in K. obovata was limited for BDE-209 removal in soil, which was verified by lower total amount of BDE-209 bioaccumulated in K. obovata's root. In soil without K. obovata planting, BDE-209 removal caused by pyrene addition coexisted with changed bacterial abundance at phylum Planctomycetes and Chloroflexi, class Planctomycetacia, and genus Blastopirellula. K. obovata-induced removal of BDE-209 in soil may be related to bacterial enrichment in phylum Proteobacteria, class Gammaproteobacteria and genus Ilumatobacter, Gaiella. Thus, in BDE-209 contaminated soil, microbial community responses induced by pyrene addition and K. obovata planting were different at phylum, class and genus levels. This is the first study demonstrating that pyrene addition and K. obovata planting could improve BDE-209 removal, and differently affected the corresponding responses of microbial communities.


Assuntos
Pirenos/química , Rhizophoraceae/química , Poluentes do Solo/química , Solo/química
20.
Chemosphere ; 239: 124730, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31726518

RESUMO

The impact of electrolytes on the adsorption of emerging pollutants: pharmaceuticals onto layered materials: a raw clay mineral and its nonionic and cationic organoclay derivatives was studied. The selected pharmaceuticals: amoxicillin, norfloxacin, sulfamethoxazole, metoprolol, carbamazepine, and trimethoprim show different electric charges: zwitterionic, anionic, cationic and neutral and hydrophobic character (different LogP). Without any salts, the set of complementary data obtained by UV and infrared spectroscopies, X-ray diffraction points out the importance of the electric charge which represents a key parameter in both the spontaneity and feasibility of the adsorption. In contrast, the hydrophobicity of the analytes plays a minor role but determines the magnitude of the adsorbed amount of pharmaceuticals onto organoclays. With a dual hydrophilic and hydrophobic behavior, nonionic organoclay appears to be the most polyvalent material for the removal of the pharmaceuticals. In the presence of electrolytes (NaCl at a concentration of 1 × 10-2 mol L-1), both nonionic and cationic organoclays show a decrease of their efficiencies, whereas the adsorption is particularly enhanced for Na-Mt except for the cationic species (trimethoprim and metoprolol). Thus, in realistic experimental conditions close to those of natural effluents, raw clay mineral appears as the most appropriate sorbent for the studied pharmaceuticals while it raises the question of the usefulness of organoclays in water remediation strategy.


Assuntos
Eletrólitos/química , Recuperação e Remediação Ambiental/métodos , Preparações Farmacêuticas/análise , Poluentes do Solo/análise , Solo/química , Poluentes Químicos da Água/análise , Adsorção , Amoxicilina/análise , Amoxicilina/química , Carbamazepina/análise , Carbamazepina/química , Cátions/análise , Interações Hidrofóbicas e Hidrofílicas , Metoprolol/análise , Metoprolol/química , Norfloxacino/análise , Norfloxacino/química , Preparações Farmacêuticas/química , Poluentes do Solo/química , Sulfametoxazol/análise , Sulfametoxazol/química , Trimetoprima/análise , Trimetoprima/química , Água/química , Poluentes Químicos da Água/química , Difração de Raios X
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