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1.
Chemosphere ; 287(Pt 3): 132350, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34582933

RESUMO

A hybridization of managed aquifer recharge (MAR) with pre-oxidation processes was conducted in this study to investigate changes in dissolved organic matter characteristics and the attenuation of selected trace organic contaminants (TrOCs). Potassium permanganate, chlorine, and ozone treatments were used for pre-oxidation, which effectively attenuated some TrOCs, particularly the combination of MAR with ozone achieved 84-99% attenuation. The pre-oxidation step using potassium permanganate showed high removal of carbamazepine (96%). Moreover, MAR was also combined with nanofiltration (NF) as a multi-barrier concept for the removal of persistent TrOCs after MAR. A short-chain polyfluoroalkyl substance (PFAS) was effectively removed after combining MAR columns with NF membranes. Thus, pre-oxidation coupled with MAR followed by NF could potentially enhance the removal of selected TrOCs.


Assuntos
Água Subterrânea , Poluentes Químicos da Água , Purificação da Água , Rios , Areia , Água , Poluentes Químicos da Água/análise
2.
Environ Pollut ; 292(Pt A): 118309, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34626709

RESUMO

A pyrene-degrading consortium OPK containing Mycolicibacterium strains PO1 and PO2, Novosphingobium pentaromativorans PY1 and Bacillus subtilis FW1 effectively biodegraded medium- and long-chain alkanes as well as mixed hydrocarbons in crude oil. The detection of alkB and CYP153 genes in the genome of OPK members supports its phenotypic ability to effectively degrade a broad range of saturated hydrocarbons in crude oil. Zeolite-immobilized OPK was developed as a ready-to-use bioproduct and it exhibited 74% removal of 1000 mg L-1 crude oil within 96 h in sterilized seawater without nutrient supplementation and maintained high crude oil-removal activity under a broad range of pH values (5.0-9.0), temperatures (30-40 °C) and salinities (20-60‰). In addition, the immobilized OPK retained a high crude oil removal efficacy in semicontinuous experiments and showed reusability for at least 5 cycles. Remarkably, bioaugmentation with zeolite-immobilized OPK in sandy soil microcosms significantly increased crude oil (10,000 mg kg-1 soil) removal from 45% to 80.67% within 21 days compared to biostimulation and natural attenuation. Moreover, bioaugmentation with exogenous immobilized OPK stimulated an increase in the relative abundances of Alcanivorax genus, indigenous hydrocarbon-degrading bacteria, which in turn enhanced removal efficiency of crude oil contamination from sandy soil microcosms. The results indicate positive interactions between the bioaugmented immobilized consortium, harboring Mycolicibacterium as a key player, and indigenous Alcanivorax, which exhibited crucial functions for improving crude oil removal efficacy. The knowledge obtained forms an important basis for further synthesis and handling of a promising bio-based product for enhancing the in situ bioremediation of crude oil-polluted marine environments.


Assuntos
Petróleo , Poluentes do Solo , Sphingomonadaceae , Zeolitas , Biodegradação Ambiental , Areia , Solo
3.
Chemosphere ; 286(Pt 3): 131965, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34449324

RESUMO

The production and degradation of plastic remains can result in nanoplastics (NPs) formation. However, insufficient information regarding the environmental behaviors of NPs impedes comprehensive assessment of their significant threats. In this study, the transport behavior of unmodified NPs (PSNPs), carboxyl-modified NPs (PSNPs-COOH), and amino-modified NPs (PSNPs-NH2) was investigated using column experiments in the presence and absence of goethite (GT) and diethylhexyl phthalate (DEHP). Quantum chemical computation was performed to reveal the transport mechanisms. The results showed that GT decreased the transport of NPs and the presence of DEHP decreased it further. Van der Waals forces and small electrostatic interactions coexisted between the PSNPs and GT and caused deposition. Ligand exchange caused greater deposition of PSNPs-COOH on GT-coated sand than that of PSNPs. Although hydrogen bonding existed between the DEHP and NPs with functional groups, an increase in the positive charge and chemical heterogeneity of the collector was the main reason for DEHP promoting the deposition of NPs. Because of low absolute negative zeta potential values, PSNPs-NH2 was sensitive to chemical heterogeneity, and thus fully deposited (over 96.9%) in GT and GT-DEHP-coated columns. Generally, the deposition of NPs due to chemical heterogeneity was more significant than that due to the formation of chemical bonds and van der Waals, electrostatic, and hydrogen interactions. Our results highlight that the surface charge and functional groups significantly influence the transport behaviors of NPs and elucidate the fate of NPs in the terrestrial environment.


Assuntos
Dietilexilftalato , Microplásticos , Plásticos , Poliestirenos , Areia
4.
Chemosphere ; 287(Pt 1): 131889, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34461337

RESUMO

Estimating soil properties is important for maximizing the production of crops in sustainable agriculture. The hyperspectral data next input depends upon the previous one, and the current techniques do not take advantage of this sequential nature of hyperspectral signatures. The variants of RNN can learn the short-term and long-term dependencies between data. This paper proposes a deep learning hybrid framework for quantifying the soil minerals like Clay, CEC, pH of H2O, Nitrogen, Organic Carbon, Sand of European Union from the LUCAS library. The hyperspectral signatures contain the data in the range of 400-2500 nm captured from the FOSS spectroscope in the laboratory. As hyperspectral data is high dimensional, Principal Component Analysis and Locality Preserving Projections are utilized to form the hybrid features, which have low dimensions containing the local and global information of the original dataset. These hybrid features are passed on to Long Short Term Memory Networks, a deep learning framework for building an effective prediction model. The effectiveness of the prepared models is demonstrated by comparing it to existing state-of-the-art techniques.


Assuntos
Redes Neurais de Computação , Solo , Agricultura , União Europeia , Areia
5.
Zootaxa ; 5020(1): 130-140, 2021 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-34810417

RESUMO

As a part of the study of marine nematofauna of a sandy intertidal zone of Jeju Island (South Korea), a number of species have been proven as new for science. Here a new species representing a new genus of the family Microlaimidae (Chromadorea), Jejulaimus sinyangensis gen. n., sp. n. is described. The new monotypic genus is characterized by head set off abruptly from the body; anterior sensilla pattern 6+10, where six outer labial setiform sensilla together with four longer cephalic setiform sensilla are integrated in a common crown; pharyngostoma armed with a dorsal tooth and surrounded by convex muscular pharyngeal tissue, forming an anterior pharyngeal bulb which is distinctly set off from the rest of the pharynx; terminal pharyngeal bulb oval; ventral pore and ampulla of the excretory-secretory gland situated just posterior to the nerve ring; an only anterior testis present. The new genus bears some resemblance to the genera Bolbolaimus, Pseudomicrolaimus and Spirobolbolaimus in having an anterior pharyngeal bulb and in the position of the ventral pore of the excretory/secretory gland, but differs from them by anterior sensilla pattern 6+10, absence of subventral teeth in buccal cavity, and monorchic condition of male reproductive system.


Assuntos
Cromadoria , Nematoides , Animais , Masculino , Faringe , República da Coreia , Areia
6.
Artigo em Inglês | MEDLINE | ID: mdl-34769594

RESUMO

This study focused on the processes of free infiltration, precipitation displacement, and natural attenuation of the LNAPL under the condition of near-surface leakage. Sandbox experiments were performed to explore the migration characteristics of LNAPL in the vadose zone with two media structures and the influences of the soil interface on the migration of LNAPL. The results indicate that the vertical migration velocity of the LNAPL infiltration front in medium and coarse sand was 1 order of magnitude higher than that in fine sand and that the LNAPL accumulated at the coarse-fine interface, which acted as the capillary barrier. Displacement of precipitation for LNAPL had little relationship with rainfall intensity and was obviously affected by medium particle size, where coarse sand (40.78%) > medium sand (20.5%) > fine sand (10%). The natural attenuation rate of the LNAPL in the vadose zone was related to the water content of the media; the natural attenuation rate of fine sand was higher. This study simulated the process of the LNAPL leakage from the near surface into the layered heterogeneous stratum, improved the understanding of the migration of the LNAPL under different stratum conditions, and can provide support for the treatment of LNAPL leakage events in the actual site.


Assuntos
Água Subterrânea , Poluentes do Solo , Poluentes Químicos da Água , Areia , Solo , Poluentes do Solo/análise , Poluentes Químicos da Água/análise
7.
Environ Monit Assess ; 193(12): 780, 2021 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-34748090

RESUMO

This study aims to determine the concentration of potentially toxic elements (PTEs) and rare earth elements (REEs) in Brazilian sandy soils under the Cerrado at the Parnaíba-São Francisco Basin transition. We also explored the geochemical correlation between these elements and pH, cation exchange capacity (CEC), total organic carbon (TOC), sand, clay, oxides from secondary minerals, and chemical index of alteration for each basin. Mineralogical, physical, and chemical analyses were used to examine PTE and REE geochemistry in six sand soil profiles from the Brazilian Cerrado. The background concentrations of these elements are low, but soils from the Parnaíba Basin have higher concentrations of PTEs than soils from the São Francisco Basin. In soils from the Parnaíba Basin, mainly Al2O3 has relevance in the V and Cr geochemistry, as these elements increase with increasing Al2O3 content. On the other hand, the REEs have CEC as a soil attribute of higher relevance in the geochemistry of those elements is soils from the Parnaíba Basin, and this relevance divides the TOC, Fe2O3, and TiO2 minerals from the clay fraction. In soils from the São Francisco Basin, the geochemistry of PTEs is possibly associated with kaolinite, especially Cu, V, and Zn. In contrast, the Ba concentration was associated with the presence of feldspar. Unlike soils from the Parnaíba Basin, the REEs do not correlate with the studied soil attributes, except for Ho and Lu. Ho had a positive association with Al2O3. Ho and Lu are negatively related to the presence of iron oxides.


Assuntos
Metais Terras Raras , Poluentes do Solo , Monitoramento Ambiental , Metais Terras Raras/análise , Areia , Solo , Poluentes do Solo/análise
8.
Int J Syst Evol Microbiol ; 71(10)2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34605765

RESUMO

A Gram-stain-negative, aerobic, motile, short rod-shaped, catalase-negative and oxidase-positive bacterium, strain CAU 1568T, was isolated from marine sediment sand sampled at Sido Island in the Republic of Korea. The optimum conditions for growth were at 25-30 °C, at pH 6.5-8.5 and with 0-4.0 % (w/v) NaCl. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain CAU 1568T was a member of the genus Photobacterium with high similarity to Photobacterium salinisoli JCM 30852T (97.7 %), Photobacterium halotolerans KACC 17089T (97.3 %) and Photobacterium galatheae LMG F28894T (97.3 %). The predominant cellular fatty acids were C16 : 0, summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c) and summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), with Q-8 as the major of isoprenoid quinone. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerols, phosphatidylcholine, phosphatidylethanolamine, phospholipid, two aminophospholipids and three unidentified lipids. The whole genome size of strain CAU 1568T was 4.8 Mb with 50.1 mol% G+C content; including 38 contigs and 4233 protein-coding genes. These taxonomic data support CAU 1568T as representing a novel Photobacterium species, for which the name Photobacterium arenosum sp. nov. is proposed. The type strain of this novel species is CAU 1568T (=KCTC 82404T=MCCC 1K05668T).


Assuntos
Photobacterium , Areia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Sedimentos Geológicos , Photobacterium/genética , Filogenia , RNA Ribossômico 16S/genética , Água do Mar , Análise de Sequência de DNA
9.
Ying Yong Sheng Tai Xue Bao ; 32(8): 2895-2905, 2021 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-34664463

RESUMO

Based on the MODIS NDVI data from 2000 to 2018, we estimated the fractional vegetation cover (FVC) using the dimidiate pixel model and analyzed the spatiotemporal characteristics of FVC in the Beijing-Tianjin sand source region (BTSSR). The geographical detector model was used to estimate the impacts of natural and human factors on FVC spatial distribution at the regional scale. The results showed that the FVC of the BBTSR showed an increasing trend from 2000 to 2018, with an annual growth rate of 0.013·(10 a)-1 and a vegetation increase rate of 8.2%. The area with high FVC was concentrated in the Yanshan Mountain water source protection area, followed by the pastoral transitional zone desertified land control area and the Otindag sandy land area. The area with poor FVC was concentrated in the northern arid grassland area. The explanatory power of driving factors to FVC varied across different regions. Among the natural factors, annual precipitation was the main driving factor for the spatial distribution of FVC in the northern arid grassland area, the Otindag sandy land area and the Yanshan Mountain water source protection area. Slope was the main driving factor for the spatial distribution of FVC in the pastoral transitional zone desertified land control area. Among different human activities, the number of large livestock at the year-end was the main driving factor controlling the spatial distribution of FVC in the northern arid grassland area and the pastoral transitional zone desertified land control area, while population density was the main driving factor controlling the spatial distribution of FVC in the Otindag sandy land area and the Yanshan Mountain water source protection area. There were regional differences in the influen-ce of other factors on FVC spatial distribution. The results of the interaction detector showed that the two-factor interactions were mainly the double-synergy and nonlinear synergy. The interaction of human activities with annual precipitation and slope could more fully explain the spatial variations of FVC. The range of suitable vegetation growth identified by the risk detector was the area with annual precipitation of 316.4-486.0 mm, average relative humidity of 48.4%-57.6%, and average annual temperature of 2.5-7.9 ℃, while other driving factors were different in different zones.


Assuntos
Ecossistema , Areia , Pequim , China , Atividades Humanas , Humanos
10.
Ying Yong Sheng Tai Xue Bao ; 32(9): 3195-3203, 2021 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-34658205

RESUMO

As sand dunes gradually become fixed, soil particle size, soil organic carbon (SOC) and total nitrogen (TN) contents vary across different locations of the dunes. To investigate the spatial variation of soil particle size distribution and soil nutrition in the fixed sand dunes, we examined particle composition, SOC and TC features in different locations of dunes in the Eastern Ningxia. The results showed that the particle sizes of each soil layer were mainly characterized by medium and coarse sands. The SOC and TN contents were higher in surface soil layers, with a maximum of 5.781 and 0.412 g·kg-1, respectively, which were observed in interdune lands and dune ridges, while the leeward slope of the dunes showed the least. The SOC content of both the leeward and windward slope gradually decreased with increasing soil depth along the dune. By contrast, that of the interdune lands decreased first and then increased. At small scale, both the SOC and TN contents showed a clear spatial heterogeneity. There was a positive correlation between soil nutrition contents (SOC and TN) and silt and very fine sand contents in the fixed sand dunes, and a negative correlation with medium and coarse sand contents. Our results implied that soil particle size composition influenced SOC and TN contents. The contents of soil nutrition increased with increa-sing contribution of fine particles, highlighting the role of fine particles in adhesion and accumulation of organic matter.


Assuntos
Carbono , Solo , Nitrogênio/análise , Tamanho da Partícula , Areia
11.
Ying Yong Sheng Tai Xue Bao ; 32(9): 3341-3348, 2021 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-34658221

RESUMO

Crude oil may block soil pores, affect soil water repellency, and change soil water movement. In this study, soil column simulation was used to study the effects of different crude oil pollution levels (0, 0.5%, 1%, 2%, 4%) on the water infiltration processes in loessial soil and aeolian sandy soil. The results showed that soil wetting front speed and infiltration rate of those two soils decreased with increasing crude oil content. The time needed for wetting front reaching the bottom of the soil column was the longest under 4% crude oil polluted soil, which was 4 times and 48 times longer than that of no crude oil polluted soil for loessial soil and aeolian sandy soil, respectively. The cumulative infiltration of loessial soil decreased with increasing crude oil content, while it increased to the max and then decreased as the crude oil content increased in aeolian sandy soil. The cumulative infiltration curves of aeolian sandy soil with high crude oil contents (2% and 4%) presented "up-tail" phenomenon. Kostiakov infiltration model and Philip infiltration model could better fit the infiltration process than Green-Ampt model for loessial soil with different crude oil content. However, the two models could only well fit the infiltration process for aeolian sandy soil with low crude oil content (0, 0.5%, 1%). Crude oil pollution could significantly affect soil water infiltration process, especiall in aeolian sandy soil.


Assuntos
Poluição por Petróleo , Petróleo , Poluentes do Solo , Areia , Solo , Poluentes do Solo/análise
12.
Ying Yong Sheng Tai Xue Bao ; 32(10): 3448-3458, 2021 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-34676705

RESUMO

The Vaganov-Shashkin model was used to simulate the standardized ring-width chrono-logy of Pinus sylvestris var. mongolica on the sandy land in Hulunbuir. The results showed that the fitting degree was better in the period before 2000 than that after 2000. Thus, the simulation results before 2000 were selected to analyze the radial growth. The results showed that the main growing season of P. sylvestris var. mongolica in Hulunbuir Sandy Land was from May to September each year. Temperature had a significant impact on the early and late growth of P. sylvestris var. mongo-lica. In the prosperous period of the growing season, insufficient soil moisture was the main factor restricting the radial growth. The radial growth rates of P. sylvestris var. mongolica in extremely narrow years were more limited by soil moisture than that in extremely wide years. The radial growth rates in the middle of the growing season (from July to August) showed a decreasing trend in wide and narrow years, indicating that the growth of P. sylvestris var. mongolica was affected by drought stress. Our results were consistent with the characteristics of tree-ring physiological models in semi-arid areas of China. The model was applicable to the radial growth simulation of P. sylvestris var. mongolica in Hulunbuir Sandy Land.


Assuntos
Pinus sylvestris , China , Areia , Solo
13.
An Acad Bras Cienc ; 93(4): e20200774, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34705939

RESUMO

This study performs natural sand-based synthesis using the sonochemical route for preparing Zn-doped magnetite nanoparticles. The nanoparticles were dispersed in water as a carrier liquid to form Zn-doped magnetite aqueous ferrofluids. Structural data analysis indicated that the Zn-doped magnetite nanoparticles formed a nanosized spinel structure. With an increase in the Zn content, the lattice parameters of the Zn-doped magnetite nanoparticles tended to increase because Zn2+ has a larger ionic radius than those of Fe3+ and Fe2+. The existence of Zn-O and Fe-O functional groups in tetrahedral and octahedral sites were observed in the wavenumber range of 400-700 cm-1. The primary particles of the Zn-doped magnetite ferrofluids tended to construct chain-like structures with fractal dimensions of 1.2-1.9. The gas-like compression (GMC) plays as a better model than the Langevin theory to fit the saturation magnetization of the ferrofluids. The ferrofluids exhibited a superparamagnetic character, with their magnetization was contributed by aggregation. The Zn-doped magnetite ferrofluids exhibited excellent antibacterial activity against gram-positive and negative bacteria. It is suggested that the presence of the negatively charged surface and the nanoparticle size may contribute to the high antibacterial activity of Zn-doped magnetite ferrofluids and making them potentially suitable for advanced biomedical.


Assuntos
Óxido Ferroso-Férrico , Areia , Antibacterianos/farmacologia , Fenômenos Magnéticos , Água , Zinco
14.
Sensors (Basel) ; 21(20)2021 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-34696127

RESUMO

Sandy range land refers to a major component of grassland area types in the semi-arid area of northern China. Monitoring of vegetation and land surface temperature (LST) using remote sensing technology can help determine the degree of desertification in a regional and/or sub regional scale, as in the Horqin Sandy Land selected in this study. Correlation analysis was performed to examine the relationship between the fractional vegetation coverage (FVC) and the LST within one growing season (from May to August 2017), at different spatial scales. The results showed that the FVC increased from 0.12 in May to 0.29 in August, and the LST increased first and then declined. The highest LST was 41.68 °C in July, while the lowest was 28.62 °C in August. At the grid scale, the LST increased first and then declined with the increase of the FVC on 25 May, 10 June, and 29 August; the FVC ranged from 0.29-0.38, 0.27-0.32, and 0.29-0.38 with the preference of the 'turning point', respectively. A negative correlation was identified between the FVC and the LST and without any 'turning point' in the fitting curve on 28 July. The correlation between FVC and LST complied with the grid scale at the sample area scale. The coupling analysis of landscape pattern expressed by FVC and LST showed that, the landscape evenness, Euclidean nearest neighbor distance, and landscape splitting degree all showed strong coupling correlation in any study period (P). The landscape aggregation of FVC and LST showed a good coupling at the relatively high and low air temperature conditions of P1 and P3. Landscape contagion showed a good coupling between FVC and LST at relatively moderate air temperature condition of P1 and P4. Air temperature conditions and characteristics of vegetation coverage should be considered for a more targeted analysis when analyzing the relationship between FVC and LST and attention should be paid to the timing and type of study area in practical application.


Assuntos
Monitoramento Ambiental , Areia , China , Tecnologia de Sensoriamento Remoto , Temperatura
15.
Molecules ; 26(20)2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34684789

RESUMO

The use of additives has generated significant attention due to their extensive application in the microbially induced calcium carbonate precipitation (MICP) process. This study aims to discuss the effects of Na-montmorillonite (Na-MMT) on CaCO3 crystallization and sandy soil consolidation through the MICP process. Compared with the traditional MICP method, a larger amount of CaCO3 precipitate was obtained. Moreover, the reaction of Ca2+ ions was accelerated, and bacteria were absorbed by a small amount of Na-MMT. Meanwhile, an increase in the total cementing solution (TCS) was not conducive to the previous reaction. This problem was solved by conducting the reaction with Na-MMT. The polymorphs and morphologies of the CaCO3 precipitates were tested by using X-ray diffraction and scanning electron microscopy. Further, when Na-MMT was used, the morphology of CaCO3 changed from an individual precipitate to agglomerations of the precipitate. Compared to the experiments without Na-MMT in the MICP process, the addition of Na-MMT significantly reduced the hydraulic conductivity (HC) of sandy soil consolidated.


Assuntos
Bentonita/metabolismo , Carbonato de Cálcio/metabolismo , Sporosarcina/metabolismo , Bentonita/química , Biotecnologia , Carbonato de Cálcio/isolamento & purificação , Precipitação Química , Cristalização , Microscopia Eletrônica de Varredura , Areia/química , Solo/química , Sporosarcina/crescimento & desenvolvimento , Difração de Raios X
16.
Artigo em Inglês | MEDLINE | ID: mdl-34639414

RESUMO

Sand play may be a significant determinant of health and development in early childhood, but systematically synthesised evidence is absent in the literature. The main objective of this study was to present a planned methodology to systematically review, and synthesise, the evidence regarding sand play and its associations with 0-8-year-old children's health and development. The systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols statement was registered to PROSPERO (CRD42021253852). Literature searches will be conducted using information from eight electronic databases. Studies will be included when participating children were aged 0-8 years, settings provided children with exposure to sand environments and/or materials, and child-level outcomes related to physical, cognitive, and/or social-emotional health and development. The search results will be imported to software; duplicates will be removed; and independent double screening, and study quality assessments using appropriate tools, will be conducted. Synthesis without meta-analysis will be conducted for quantitative studies similar in exposure, outcome, and content analysis to qualitative studies. Our overall confidence in each review finding will be assessed. The findings of this systematic review can inform policy makers and early childhood education teachers about the associations between sand play and children's health and development, and its impact in practice.


Assuntos
Saúde da Criança , Areia , Criança , Pré-Escolar , Humanos , Lactente , Recém-Nascido , Pesquisa Qualitativa , Revisões Sistemáticas como Assunto
17.
Water Res ; 205: 117610, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34649082

RESUMO

Phytotoxins - toxins produced by plants - are contaminants with the potential to impair drinking water quality. They encompass a large group of toxic, partially persistent compounds that have been detected in seepage waters and in shallow wells used for drinking water production. If phytotoxins enter wells used for drinking water production, it is essential to know if the drinking water treatment processes will remove them from the water phase. However, it is currently unknown whether phytotoxins remain stable during traditional groundwater treatment using sand filters as the main treatment process. The objective of this study is to investigate removal potential of phytotoxins in biological sand filters and to asses if the removal potential is similar at different waterworks. Microcosms were set up with filter sand and drinking water collected at different groundwater-based waterworks. To be able to monitor phytotoxin removal ptaquiloside, caudatoside, gramine, sparteine, jacobine N-oxide, senecionine N-oxide and caffeine were applied at initial concentrations of 300 µg L-1, which is approx. two orders of magnitude higher than currently detected in environment, but expected to cover extreme environmental conditions. Removal was monitored over a period of 14 days. Despite the high initial concentration, all filter sands removed ptaquiloside and caudatoside completely from the water phase and at waterworks where pellet softening was implemented (pH 8.4) prior to rapid sand filtration, complete removal occurred within the first 30 min. All filter sands removed gramine and sparteine, primarily by a biological process, while jacobine N-oxide, senecionine N-oxide and caffeine were recalcitrant in the filter sands. During degradation of ptaquiloside and caudatoside we observed formation and subsequent removal of degradation products pterosin B and A. Filter sands with the highest removal potential were characterised by high contents of deposited iron and manganese oxides and hence large specific surface areas. Difference between bacterial communities investigated by 16S rRNA gene analyses did not explain different removal in the filter sands. All five investigated filter sands showed similar degradation patterns regardless of water chemistry and waterworks of origin. In drinking water treatment systems biological sand filters might therefore remove phytotoxin contaminants such as ptaquiloside, caudatoside, gramine, sparteine, while for other compounds e.g. jacobine N-oxide, senecionine N-oxide further investigations involving more advanced treatment options are needed.


Assuntos
Água Potável , Poluentes Químicos da Água , Purificação da Água , Filtração , RNA Ribossômico 16S , Diálise Renal , Areia , Dióxido de Silício , Poluentes Químicos da Água/análise
18.
Environ Sci Process Impacts ; 23(10): 1509-1515, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34669759

RESUMO

Wastewater treatment plants are suspected to be significant point sources of microplastic and nanoplastic particles (NPs) in the environment. As one of the main wastewater treatment processes, advanced oxidation processes (AOPs) may change the physicochemical properties of NPs and further affect their migration. However, limited information is known about the environmental fate of NPs after AOP treatment. In this study, polystyrene nanoparticles were treated using two representative AOPs, Fenton and persulfate treatments, and the migration of the NPs in quartz sand was investigated via column transport experiments. FTIR and XPS analysis indicated that a large number of oxygen-containing groups were generated on the NP surface after AOP treatment leading to lower hydrophobicity and a higher negative charge. Besides, the C/O ratio after Fenton and persulfate treatments was increased from 10.98 to 7.25 and 8.68. Moreover, the NPs after AOP treatment exhibited higher mobility in quartz sand in both ultrapure water and 10 mM NaCl solution. It was more obvious in 10 mM NaCl solution with breakthrough percentages of 79.73% for P-PS, 90.97% for F-PS and 95.67% for N-PS, respectively. These results could be explained by the roles of generated oxygen-containing functional groups; first, the higher negative charge enhanced the electrostatic repulsion between treated NPs and sand; second, lower hydrophobicity improved the binding with water molecules in background solution. This work is helpful in understanding the changes of nanoplastics in AOP treatment and their migration in the natural environment, which has far-reaching influence on the environmental fate and behavior of nanoplastics.


Assuntos
Nanopartículas , Poliestirenos , Plásticos , Quartzo , Areia
19.
J Hazard Mater ; 416: 126231, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492985

RESUMO

Sandy beaches represent environmental compartments particularly vulnerable to litter pollution, and they reflect the magnitude of pollution of adjacent compartments: water and coastal areas. The substitution of conventional polymers by biodegradable materials is generally considered as an alternative for reducing environmental accumulation of plastic debris. The present study is aimed to investigate the degradation of poly(lactic acid), poly(ε-caprolactone), poly(butylenesuccinate adipate) and poly(3-hydroxybutyrate) buried in sand for 267 days, simulating them as beach litter. The analysed polyesters showed different degradation mechanisms and kinetics. PLA is mainly subjected to weathering by physical aging; after an initial faster degradation of the amorphous phase, PCL showed a decrease of its degradation rate; similarly to PCL, the degradation of PBSA started from the amorphous phase; PHB is clearly subjected to biological degradation. The degradation trend of the investigated materials in sand decreased in the order PHB > PBSA > PCL > PLA. PLA, PCL and PBSA did not undergo complete degradation in sand during the testing time.


Assuntos
Poliésteres , Areia , Cinética , Polímeros
20.
Artigo em Inglês | MEDLINE | ID: mdl-34559623

RESUMO

A Gram-positive, aerobic, heterotrophic, non-endospore-forming, rod-shaped and indole-acetic acid-producing strain, designated NEAU-184T, was isolated from marine sand collected in Sanya, PR China, and its taxonomic position was investigated using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequence data indicated that strain NEAU-184T should be assigned to the genus Agromyces and formed a distinct branch with its closest neighbour, Agromyces iriomotensis NBRC 106452T (99.1 %). 2,4-Diaminobutyric acid, d-alanine, d-glutamic acid and glycine were detected in cell-wall hydrolysate and glucose, rhamnose and xylose were detected in whole-cell hydrolysate. The polar lipids were found to contain diphosphatidylglycerol, glycolipid, phosphatidylglycerol and two unidentified lipids. The major menaquinone was MK-12 and the minor menaquinones were MK-13 and MK-11. The predominant fatty acids were anteiso-C17 : 0, anteiso-C15 : 0 and iso-C16 : 0. The DNA G+C content was 71.5 mol%. Furthermore, the strain could be clearly distinguished from its closely related type strains by the combination of DNA-DNA hybridization results and some phenotypic characteristics. Meanwhile, the strain has the ability to produce indole-acetic acid (0.334mg ml-1). Therefore, strain NEAU-184T represents a novel species of the genus Agromyces, for which the name Agromyces mariniharenae sp. nov. is proposed, with strain NEAU-184T (=CGMCC 4.7505T=JCM 32546T) as the type strain.


Assuntos
Ácidos Graxos , Areia , Acetatos , Actinobacteria , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Indóis , Fosfolipídeos , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2
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