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1.
Environ Monit Assess ; 193(5): 245, 2021 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-33821384

RESUMEN

Studies to assess variability factors of heavy metals in soils are essential to understand their behavior in the environment and for the assessment of contaminated areas. In this context, this research aimed to study the factors that influence the variability of heavy metal levels and their bioavailability in pasture areas in the Alturas de Nazareno region, Mayabeque, Cuba, as well as the transfer to plants. Forty-five points were distributed in a natural pasture and at two depths (0-20 and 20-40 cm) as a function of relief and soil type. Pseudo-total heavy metal contents were determined according to method 3051A of USEPA, geochemical fractionation according to the Community Bureau of Reference method, and plant digestion according to method 3052 of USEPA. Soil samples were separated into two groups, according to cluster analysis. The type of soil associated with the pH and Ca attributes were the factors that most influenced the variability of the total and bioavailable levels of metals in natural pasture soils in the region of Alturas de Nazareno. Group 1 showed the lowest heavy metal contents and the highest pH and calcium values, which were predominantly associated with carbonate soils. Group 2 had the highest contents of heavy metals and Fe, corresponding mainly to the soil Ferralítico Rojo. The concentration of metals in plants was directly related to their bioavailable content in the soil, where G2 represents the group with the highest risk of transferring metals to the food chain.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Cuba , Monitoreo del Ambiente , Metales Pesados/análisis , Suelo , Contaminantes del Suelo/análisis
2.
Environ Monit Assess ; 193(5): 256, 2021 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-33835289

RESUMEN

Naturally elevated contents of copper (Cu) and nickel (Ni) are found in soils worldwide, and their potential toxicity is better understood when geochemical reactive fractions are identified and monitored. Thus, this study aimed to assess the bioavailability of Cu and Ni and estimate environmental risks in naturally metal-enriched soils of Carajás Mining Province, Eastern Amazon, Brazil. For that, 58 surficial soil samples were analyzed for their extractable contents of Cu and Ni by Mehlich 1. Next, 13 soil samples were selected for additional single and sequential extractions, for the determination of metal content in the shoots of grasses naturally growing in these soils and for calculating the risk assessment code. Despite the naturally high total concentrations, the contents of easily available Cu and Ni are a minor fraction of total concentrations (up to 10.15%), and the reducible oxide and residual pools hold the major proportion of total content of metals. This contributed to low bioavailability, low environmental risk, and also to low concentrations of these metals on grasses collected in the field. Soil organic matter, Fe2O3, Al2O3 and clay content have a dominant role in metals retention on studied soils. Our findings on the bioavailability of Cu and Ni in a region of great economic relevance for Brazil are important not only for predicting the elements' behavior in the soil-plant system but also for refining risk assessments and to provide useful data for environmental quality monitoring.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Disponibilidad Biológica , Brasil , Cobre/análisis , Monitoreo del Ambiente , Metales Pesados/análisis , Níquel , Suelo , Contaminantes del Suelo/análisis
3.
Environ Monit Assess ; 193(5): 259, 2021 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-33837853

RESUMEN

Soil salinity is a major issue causing land degradation in coastal areas. In this study, we assessed the land use and soil salinity changes in Djilor district (Senegal) using remote sensing and field data. We performed land use land cover changes for the years 1984, 1994, 2007, and 2017. Electrical conductivity was measured from 300 soil samples collected at the study area; this, together with elevation, distance to river, Normalized Difference Vegetation Index (NDVI), Salinity Index (SI), and Soil-Adjusted Vegetation Index (SAVI), was used to build the salinity model using a multiple regression analysis. Supervised classification and intensity analysis were applied to determine the annual change area and the variation of gains and losses. The results showed that croplands recorded the highest gain (17%) throughout the period 1984-2017, while forest recorded 3%. The fastest annual area of change occurred during the period 1984-1994. The salinity model showed a high potential for mapping saline areas (R2 = 0.73 and RMSE = 0.68). Regarding salinity change, the slightly saline areas (2 < EC < 4 dS/m) increased by 42% whereas highly saline (EC > 8 dS/m) and moderately saline (4 < EC < 8 dS/m) areas decreased by 23% and 26%, respectively, in 2017. Additionally, the increasing salt content is less dominant in vegetated areas compared with non-vegetated areas. Nonetheless, the highly concentrated salty areas can be restored using salt-resistant plants (e.g., Eucalyptus sp., Tamarix sp.). This study gives more insights on land use planning and salinity management for improving farmers' resilience in coastal regions.


Asunto(s)
Salinidad , Suelo , Monitoreo del Ambiente , Ríos , Senegal
4.
Environ Pollut ; 276: 116696, 2021 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-33744496

RESUMEN

It is a common practice to maintain soil fertility based on the paddy-upland rotation with green manure in the subtropical region of China. However, rare studies are known about greenhouse gas (GHG) emissions from the paddy-upland rotation with green manure incorporation. Therefore, we conducted a field experiment of two years to compared with the effect of two kinds of green manure (CV: Chinese milk vetch and OR: Oilseed rape), and two kinds of cropping system (DR: double rice system and PR: paddy-upland rotation) on greenhouse gases emissions. We have found that the annual accumulation of CH4 of Chinese milk vetch-rice-sweet potato || soybean was significantly reduced by 32.95%∼63.22% compared with other treatments, mainly because Chinese milk vetch reduced the abundance of methanogens by reducing soil C/N ratio. Meanwhile increasing soil permeability resulting from paddy-upland rotation also reduced soil CH4 emission. However, The annual accumulation of N2O of Chinese milk vetch-rice-sweet potato || soybean was increased by 17.39%∼870.11% compared with other treatments, mainly attributed to paddy-upland rotation decreased soil pH and nosZ abundance and increased nirK and nirS, thus enhancing N2O emission, meanwhile the Chinese milk vetch incorporation and its interaction with the paddy-upland rotation has greatly enhanced the contents of NO3--N and abundance of ammonia-oxidizing archaea (AOA). The area-scaled global warming potential (GWP) and the biomass-scaled greenhouse gas emissions intensity (GHGI) of Chinese milk vetch-rice-sweet potato || soybean was reduced by 19.01%∼50.69% and 5.38%∼35.77% respectively. Thereby, the Chinese milk vetch-rice-sweet potato || soybean cropping system was suitable for agricultural sustainable development.


Asunto(s)
Astrágalo (Planta) , Gases de Efecto Invernadero , Oryza , Agricultura , China , Calentamiento Global , Metano/análisis , Óxido Nitroso/análisis , Rotación , Suelo
5.
J Environ Manage ; 286: 112227, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33647673

RESUMEN

Mining activity and abandoned mine land are one of the major sources of heavy metal pollution. Thus, ecological rehabilitation of abandoned mine lands is crucial to control heavy metal pollution. This research aims to explore the influencing factors and effects of different vegetation on copper (Cu) accumulation and soil amelioration. In this study, the abandoned land of Tongguanshan Cu mine in Tongling city, Anhui province, China, was chosen as the test area, and nine sampling points were established. Samples of soil and plants were collected from each plot, and the impacts of Cu pollution on soil enzymes and other features were analyzed, as well as the correlation between Cu accumulation of different plants and soil properties. The results showed that Cu content of soil in the Tongguanshan area varied greatly with the depth of the soil profile. Moreover, Cu in the soil can inhibit soil enzyme activities; and the correlation coefficients of total soil Cu with urease and catalase were -0.83 and -0.73, respectively. Clearly, the accumulation of Cu in plants was positively correlated with Cu content in soil. It was found that Pueraria lobata had the best remediation effect on soil Cu pollution in a short period of time. Hence the preliminary tests clearly indicate that phytoremediation in abandoned mine lands can not only reduce heavy metal pollution, but also enhance soil nutrition and enzyme activity, helping to ameliorate degraded land and promote regional socioeconomic sustainable development.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , China , Cobre , Monitoreo del Ambiente , Metales Pesados/análisis , Minería , Suelo , Contaminantes del Suelo/análisis
6.
Ecotoxicol Environ Saf ; 214: 112049, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33647852

RESUMEN

The disposal of untreated sanitary sewage in the soil has several consequences for human health and leads to environmental risks; thus, it is necessary investigating, monitoring and remediating the affected sites. The aims of the current study are to evaluate ecotoxicological effects on Eisenia andrei earthworms exposed to soil subjected to sources of sanitary sewage discharge and to investigate whether prevention values established by the Brazilian legislation for soil quality, associated with the incidence of chemical substances in it, are satisfactory enough to assure the necessary quality for different organisms. Earthworms' behavior, reproduction, acetylcholinesterase activity, catalase, superoxide dismutase and malondialdehyde levels were evaluated. The reproduction and behavior of earthworms exposed to sanitary sewage were adversely affected. Increased superoxide dismutase and catalase activity acted as antioxidant defense mechanism. Significantly increased lipid peroxidation levels and acetylcholinesterase activity inhibition have indicated lipid peroxidation in cell membrane and neurotransmission changes, respectively. Results have confirmed that sanitary sewage induced oxidative stress in earthworms. In addition, based on biochemical data analysis, the integrated biomarker response (IBR) has evidenced different toxicity levels in earthworms between the investigated points. Finally, results have indicated that effluents released into the soil, without proper treatment, lead to contaminant accumulation due to soil saturation and it can hinder different processes and biological development taking place in the soil. In addition, the current study has shown that physical-chemical analyses alone are not enough to assess soil quality, since it is also requires adopting an ecotoxicological approach. Brazilian legislation focused on soil quality must be revised and new guiding values must be proposed.


Asunto(s)
Oligoquetos/fisiología , Contaminantes del Suelo/análisis , Animales , Antioxidantes/metabolismo , Brasil , Catalasa/metabolismo , Ecotoxicología , Contaminación Ambiental/análisis , Humanos , Malondialdehído/metabolismo , Oligoquetos/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Aguas del Alcantarillado , Suelo/química , Superóxido Dismutasa/metabolismo
7.
J Environ Manage ; 286: 112194, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33652255

RESUMEN

Silvopastoralism in New Zealand's highly erodible hill country is an important form of erosion and sediment control. Yet, there has been little quantitative work to establish the effectiveness of space-planted trees in reducing shallow landslide erosion. We propose a method to provide high-resolution spatially explicit individual tree influence models at landscape scale for the dominant species in pastoral hill country. The combined hydrological and mechanical influence of trees on slopes is inferred through the spatial relationship between trees and landslide erosion. First, we delineate individual tree crowns and classify these into four dominant species classes found in New Zealand's pastoral hill country. This is the first species classification of individual trees at landscape scale in New Zealand using freely accessible data, achieving an overall accuracy of 92.6%. Second, we develop tree influence models for each species class by means of inductive inference. The inferred empirical tree influence models largely agree with the shape and distribution of existing physical root reinforcement models. Of exotic species that were planted for erosion and sediment control, poplars (Populus spp.) and willows (Salix spp.) make up 51% (109,000 trees) in pastoral hill country at a mean density of 3.2 trees/ha. In line with previous studies, poplars and willows have the greatest contribution to slope stability with an average maximum effective distance of 20 m. Yet, native kanuka (Kunzea spp.) is the most abundant woody vegetation species in pastoral hill country within the study area, with an average of 24.1 stems per ha (sph), providing an important soil conservation function. A large proportion (56% or 212.5 km2) of pastoral hill-country in the study area remains untreated. The tree influence models presented in this study can be integrated into landslide susceptibility modelling in silvopastoral landscapes to both quantify the reduction in landslide susceptibility achieved and support targeted erosion and sediment mitigation plans.


Asunto(s)
Deslizamientos de Tierra , Árboles , Hidrología , Nueva Zelanda , Suelo
8.
Bioresour Technol ; 329: 124902, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33657500

RESUMEN

The purpose of this study is to explore the action characteristics of metabolic regulators like adenosine tri-phosphate (ATP) and malonic acid (MA) during rice straw (RS) and fruit and vegetable waste (FVW) composting. Results showed that due to the easy degradation difference, ATP and MA reduced CO2 emission in RS and FVW, respectively. Moreover, adding ATP and MA increased humic acids (HA) content in FVW more significantly (p < 0.05), especially for ATP. However, adding MA accelerated organic matter degradation during RS composting, which was basically consistent with CO2 emission, but it was not effective in promoting HA formation. Furthermore, the microbial community was reshaped by adding ATP and MA. Eventually, structural equation model further confirmed that adding metabolic regulators enhanced the biotic and abiotic pathways of HA formation, and the promotion effect of adding ATP was more obvious. The study has great practical significance for the dispose of agricultural waste.


Asunto(s)
Compostaje , Oryza , Carbono , Sustancias Húmicas/análisis , Suelo
9.
Bioresour Technol ; 329: 124896, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33657502

RESUMEN

The aim of this study was to evaluate nitrogen pollution risks from distinct materials composting with the discrepancy of component, including chicken manure, municipal solid and straw waste (CM, MSW, SW). Results showed total nitrogen maximum mean concentrations were observed in CM (39.57 g/kg). Pollution risks in CM were continuous, while MSW and SW mainly concentrated during heating phases. Microbial analysis confirmed that pollution risks from ammonification and nitrification were more prevalent in CM. The risks of pollution caused by nitrate reduction accompanied N2O were the most serious in MSW. The multifunctional nitrogen-related microbes Pseudomonas and Bacillus were affected by microenvironments and contributed to different pollution risks. Furthermore, PICRUSt analysis identified the "inferred" key genes (pmoC-amoC, nrfH, nifD etc.) related to nitrogen pollution risks. This study evaluated nitrogen pollution risks and proposed the future directions, providing theoretical basis and feasible optimization measures for the mitigation of nitrogen pollution during composting.


Asunto(s)
Compostaje , Animales , Contaminación Ambiental , Estiércol , Nitrificación , Nitrógeno/análisis , Suelo
10.
J Environ Manage ; 286: 112211, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33667819

RESUMEN

Urban community gardeners employ a range of best practices that limit crop contamination by toxicants like lead (Pb). While Pb root uptake is generally low, the relative significance of various Pb deposition processes and the effectiveness of best practices in reducing these processes have not been sufficiently characterized. This study compared leafy lettuce (Lactuca sativa) grown in high Pb (1150 mg/kg) and low Pb (90 mg/kg) soils, under three different soil cover conditions: 1) bare soil, 2) mulch cover to limit splash, and 3) mulch cover under hoophouses to limit splash and air deposition, in a New York City (NYC) community garden and a rural site in Ithaca, New York (NY). The lettuces were further compared to greenhouse (Ithaca) and supermarket (NYC) samples. Atmospheric deposition was monitored by passive trap collection through funnel samplers. Results show that in low Pb soils, splash and atmospheric deposition accounted for 84 and 78% of lettuce Pb in NYC and Ithaca, respectively. In high Pb soils, splash and atmospheric deposition accounted for 88 and 93% of Pb on lettuces, with splash being the dominant mechanism. Soil covers were shown to be effective at significantly (p < 0.05) reducing lettuce Pb contamination, and mulching is strongly recommended as a best practice.


Asunto(s)
Contaminantes del Suelo , Suelo , Plomo , Lechuga , Ciudad de Nueva York , Contaminantes del Suelo/análisis
11.
J Environ Manage ; 286: 112191, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33667822

RESUMEN

The sustainable land management program (SLMP) of Ethiopia aims to improve livelihoods and create resilient communities and landscape to climate change. Soil organic carbon (SOC) sequestration is one of the key co-benefits of the SLMP. The objective of this study was to estimate the spatial dynamics of SOC in 2010 and 2018 (before and after SLMP) and identify the SOC sequestration hotspots at landscape scale in four selected SLMP watersheds in the Ethiopian highlands. The specific objectives were to: 1) comparatively evaluate SOC sequestration estimation model building strategies using either a single watershed, a combined dataset from all watersheds, and leave-one-watershed-out using Random Forest (RF) model; 2) map SOC stock of 2010 and 2018 to estimate amount of SOC sequestration and potential; 3) evaluate the impacts of SLM practices on SOC in four SLMP watersheds. A total of 397 auger composite samples from the topsoil (0-20 cm depth) were collected in 2010, and the same number of samples were collected from the same locations in 2018. We used simple statistics to assess the SOC change between the two periods, and machine learning models to predict SOC stock spatially. The study showed that statistically significant variation (P < 0.05) of SOC was observed between the two years in two watersheds (Gafera and Adi Tsegora) whereas the differences were not significant in the other two watersheds (Yesir and Azugashuba). Comparative analysis of model-setups shows that a combined dataset from all the four watersheds to train and test RF outperform the other two strategies (a single watershed alone and a leave-one-watershed-out to train and test RF) during the testing dataset. Thus, this approach was used to predict SOC stock before (2010) and after (2018) land management interventions and to derive the SOC sequestration maps. We estimated the sequestrated, achievable and target level of SOC stock spatially in the four watersheds. We assessed the impact of SLM practices, specifically bunds, terraces, biological and various forms of tillage practices on SOC using partial dependency algorithms of prediction models. No tillage (NT) increased SOC in all watersheds. The combination of physical and biological interventions ("bunds + vegetations" or "terraces + vegetations") resulted in the highest SOC stock, followed by the biological intervention. The achievable SOC stock analysis showed that further SOC stock sequestration of up to 13.7 Mg C ha--1 may be possible in the Adi Tsegora, 15.8 Mg C ha-1 in Gafera, 33.2 Mg C ha-1 in Azuga suba and 34.7 Mg C ha-1 in Yesir watersheds.


Asunto(s)
Carbono , Suelo , Agricultura , Secuestro de Carbono , Conservación de los Recursos Naturales , Etiopía
12.
J Environ Radioact ; 232: 106570, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33677137

RESUMEN

A revision of the International Atomic Energy Agency (IAEA) Technical Report Series No. 472 (TRS 472) transfer parameter data for root uptake of radionuclides by crops in tropical environments was conducted under the IAEA Modelling and Data for Radiological Impact Assessments (MODARIA II) programme (2016-2019). Data on concentration ratios between plant and soil (CRplant-soil) were collated and summarised following a specific data selection process based on the Köppen-Geiger classification of tropical (class A) climates. An overview of the data collation and analysis methods is presented together with a comparison of CRplant-soil values between the revised tropical dataset and TRS 472 datasets. The revised dataset of CRplant-soil values for tropical environments is part of the IAEA MODARIA II programme Technical Document on soil to plant transfer of radionuclides in non-temperate environments.


Asunto(s)
Energía Nuclear , Monitoreo de Radiación , Contaminantes Radiactivos del Suelo , Radioisótopos/análisis , Suelo , Contaminantes Radiactivos del Suelo/análisis
13.
J Environ Manage ; 286: 112272, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33677337

RESUMEN

The recycling of biogas residues resulting from the anaerobic digestion of organic waste on agricultural land is among the means to reduce chemical fertilizer use and combat climate change. This in sacco decomposition study investigates (1) the potential of the granulated biogas residue fraction to provide nutrients and enhance soil carbon sequestration when utilized as exogenous organic matter in grassland soils, and (2) the impact of different nitrogen fertilizers on the organic matter decomposition and nutrient release processes. The experiment was conducted in two permanent grasslands of the Greater Region over one management period using rooibos tea as a comparator material. The decomposition and chemical changes of the two materials after incubation in the soil were assessed by measuring the mass loss, total carbon and nitrogen status, and fibre composition in cellulose, hemicellulose and lignin. Overall, after the incubation period, granulated biogas residue maintained up to 68% of its total mass, organic matter and total carbon; increased its content in recalcitrant organic matter by up to 45% and released 45% of its total nitrogen. Granulated biogas residue demonstrated resilience and a higher response uniformity when exposed to different nitrogen fertilizers, as opposed to the comparator material of rooibos tea. However, the magnitude of fertilizer-type effect varied, with ammonium nitrate and the combinatorial treatment of raw biogas residue mixed with urea leading to the highest organic matter loss from the bags. Our findings suggest that granulated biogas residue is a biofertilizer with the potential to supply nutrients to soil biota over time, and promote carbon sequestration in grassland soils, and thereby advance agricultural sustainability while contributing to climate change mitigation.


Asunto(s)
Secuestro de Carbono , Suelo , Agricultura , Biocombustibles , Carbono , Fertilizantes/análisis , Pradera , Nitrógeno/análisis
14.
J Environ Radioact ; 232: 106567, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33689934

RESUMEN

Sorption hypotheses and models are required for the prediction of 137Cs migration in soils contaminated after nuclear reactor accidents and nuclear weapons tests. In assessment models, the Kd (distribution coefficient) hypothesis for sorption, which assumes that sorption is instantaneous, linear and reversible, has often been coupled with the convection-diffusion equation (CDE) to model 137Cs migration. However, it fails to describe 137Cs migration velocities which often decrease with time. Alternative equilibrium-kinetic (EK) hypotheses of 137Cs sorption/desorption have been suggested by laboratory experiments but have not been fully validated in field conditions. This work addressed the influence and magnitude of non-equilibrium 137Cs sorption in field conditions by reinterpreting, with an inverse approach, series of 137Cs profiles measured in mineral soils of forest plots located in Fukushima Prefecture (2013-2018). Our results show that the inclusion of non-equilibrium sorption significantly improves, compared to the equilibrium hypothesis, the realism of simulated 137Cs profiles. Fitted sorption parameters suggest a fast sorption kinetic (half-time of 1-7 h) and a pseudo-irreversible desorption rate (half-time of 3.2 × 100-3.4 × 106 years), whereas equilibrium sorption (4.0 × 10-3 L kg-1 on average) only affects a negligible portion of 137Cs inventory. By June 2011, such EK parameters fitted on our plots realistically reproduced profiles measured in the same forest study site (Takahashi et al., 2015). Predictive modeling of 137Cs profiles in soil suggests a strong persistence of the surface 137Cs contamination by 2030, with exponential profiles consistent with those reported after the Chernobyl accident. This study demonstrates that hypotheses and parameters of 137Cs sorption can be partially inferred from in situ measurements. However, further experiments in controlled conditions are required to better estimate the sorption parameters and to identify the processes behind non-equilibrium sorption.


Asunto(s)
Accidente Nuclear de Fukushima , Monitoreo de Radiación , Contaminantes Radiactivos del Suelo , Radioisótopos de Cesio/análisis , Japón , Minerales , Suelo , Contaminantes Radiactivos del Suelo/análisis
15.
Bioresour Technol ; 329: 124914, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33690057

RESUMEN

The aim of this study was to investigate the pathways and mechanisms of nitrogen transformation during the composting process, by adding diatomite (0%, 2.5%, 5%, 10%, 15% and 20%) into initial mixtures of pig manure and sawdust. The results revealed that diatomite facilitated the conversion from NH4+-N to amino acid nitrogen and hydrolysis undefined nitrogen, then reduced NH3 and N2O emission by 8.63-35.29% and 14.34-73.21%, respectively. Moreover, the structure and abundance of nitrogen functional genes provided evidence for nitrogen loss. Furthermore, compared with the control (0.03), the treatment blended with 10% diatomite (T3) had the highest value in composting score (-1.27). Additionally, the ratio of carbon and nitrogen (57.30%) was vital for reducing nitrogen loss among all physio-chemical parameters in this study. In conclusion, adding diatomite was a practical way to enhance nitrogen conservation and increase quality of end products, and the optimum added dosage was at 10%.


Asunto(s)
Compostaje , Estiércol , Animales , Tierra de Diatomeas , Nitrógeno , Suelo , Porcinos
16.
Ecotoxicol Environ Saf ; 214: 111994, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33711576

RESUMEN

This study investigated the vermicomposting of spent drilling fluid (SDF) from the nature-gas industry mixed with cow dung in 0% (T1), 20% (T2), 30% (T3), 40% (T4), 50% (T5), and 60% (T6) ratio employing Eisenia fetida under a 6 weeks trial. Eisenia. fetida showed better growth and reproduction performances in the first three vermireactors (T1-T3), and the mortality was higher in the vermireactors that contained more spent drilling fluid (≥40%). Vermicomposting results in a decrease in total organic carbon, C/N ratio, and an increase in EC, total nitrogen, total phosphorous, total potassium compared to their initial values. The RadViz and VizRank showed that vermicomposting results in a greater impact on the C/N ratio (15.24-35.48%) and EC (7.29-26.45%) compared to other parameters. Activities of urease and alkaline phosphatase during vermicomposting initially increased and then declined suggesting vermicompost maturity. Also, seed germination, mitotic index and chromosomal abnormality assays using cowpea signified that the vermicomposts T2 is suitable for agricultural use due to the lower phytotoxicity and cytotoxicity. The results indicated that SDF could be converted into good quality manure by vermicomposting if mixed up to 20% with cow dung.


Asunto(s)
Compostaje/métodos , Oligoquetos , Animales , Biodegradación Ambiental , Bovinos , Estudios de Factibilidad , Heces , Femenino , Estiércol , Nitrógeno , Fósforo , Reproducción , Suelo
17.
Bioresour Technol ; 329: 124923, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33711715

RESUMEN

The aim of this study was to identify critical driving factors and pathways of mitigating heavy metals (HM) bioavailability during biochar/montmorillonite-amended composting: emphasize on the interaction effect between organic constituents and functional bacteria. Organic components, such as humus (HS), humic (HA) and fulvic acid (FA) and dissolved organic carbon (DOC), exhibited indivisible links with Cu and Zn speciation, which confirmed their vital roles on deactivating Cu and Zn. Network analysis indicated that biochar/montmorillonite obviously increased the diversity of Cu resistant/actor and Zn actor bacteria, which aided in HM passivation. Although multiple pathways were involved in regulating Cu/Zn passivation, the interaction of bacteria and organic constituents was the most critical driving factor. Given that, promoting potential HM resistant/actor bacteria utilizing and transforming low-humification organic fractions coupling with elevating high-humification constituents were the optimal pathway. This study is helpful to practical application of biochar/montmorillonite to inactivate HM for industrial composting.


Asunto(s)
Compostaje , Metales Pesados , Bacterias , Bentonita , Carbón Orgánico , Metales Pesados/análisis , Suelo
18.
J Environ Radioact ; 232: 106568, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33740532

RESUMEN

In the present study, 137Cs and 238U activity concentrations, 234U/238U activity ratio, and 235U/238U isotope ratio were measured in fifteen soil samples collected from the exclusion zone around the Fukushima Daiichi Nuclear Power Station (FDNPS). The 137Cs activity concentrations of Fukushima-accident contaminated soil samples ranged from 29.9 to 4780 kBq kg-1 with a mean of 2007 kBq kg-1. On the other hand, the 238U activity concentrations of these soil samples ranged from 5.2 to 22.4 Bq kg-1 with a mean of 13.2 Bq kg-1. The activity ratios of 234U/238U ranged from 0.973 to 1.023. The 235U/238U isotope ratios of these exclusion zone soil samples varied from 0.007246 to 0.007260, and they were similar to the natural terrestrial ratio confirming the natural origin. Using isotope dilution technique, the 235U/137Cs activity ratio was theoretically estimated for highly 137Cs contaminated soil samples from Fukushima exclusion zone ranged from 5.01 × 10-8 - 6.16 × 10-7 with a mean value of 2.51 × 10-7.


Asunto(s)
Accidente Nuclear de Fukushima , Monitoreo de Radiación , Contaminantes Radiactivos del Suelo , Uranio , Radioisótopos de Cesio/análisis , Japón , Espectrometría de Masas , Plasma/química , Suelo , Contaminantes Radiactivos del Suelo/análisis , Uranio/análisis
19.
Zootaxa ; 4920(1): zootaxa.4920.1.3, 2021 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-33756675

RESUMEN

Three new species of oribatid mites of the family Galumnidae are described from soil and coniferous litter of Hogsback State Forest, Eastern Cape Province, South Africa. Pilogalumna hogsbackensis sp. nov. differs from Pilogalumna tenuiclava and P. ornatula by the presence of elongate oval postanal porose area and narrowly unilaterally dilated bothridial head. Pergalumna amatholensis sp. nov. differs from Pergalumna distincta by the presence of smaller body size, rounded rostrum, unilaterally dilated bothridial head, one pair of notogastral porose areas Aa, and the localization of opisthonotal gland opening and lyrifissure im. Stictozetes ihaguensis sp. nov. differs from all species of the genus by presence of bothridial seta with narrowly dilated head and median pore in both genders. An identification key to known species of Stictozetes is presented.


Asunto(s)
Ácaros , Animales , Tamaño Corporal , Femenino , Bosques , Masculino , Suelo , Sudáfrica
20.
Zootaxa ; 4941(2): zootaxa.4941.2.1, 2021 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-33756937

RESUMEN

Four new species of zerconid mites of the genus Halozercon are described and illustrated based on material collected from litter and soil in Altai and Tuva mountains, South Siberia, Russia-H. alataus sp. n., H. gryphus sp. n., H. kumir sp. n. and H. aesopi sp. n. Morphological characters for the new Halozercon species are given. A key for all known species of Halozercon is attached.


Asunto(s)
Ácaros , Animales , Federación de Rusia , Siberia , Suelo
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