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1.
PLoS One ; 15(1): e0227957, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31978135

RESUMO

Hydraulic properties of sandy soil from the Mu Us sandy land of Shaanxi Province were analyzed by using SEM technology. Soil porosity, the water characteristic curve, and unsaturated hydraulic conductivity of aeolian sandy soil with added soft rock were analyzed, and fractal characteristics were established. Soil hydraulic properties revealed the effect of soft rock application on soil structure and hydraulic properties. Mass ratios of soft rock to aeolian sand were 1:5, 1:2, and 1:1. Results showed that the addition of soft rock can significantly increase the bulk density of sandy soil and reduce the total porosity and macroporosity. The mass fraction of water-stable aggregates greater than 0.25mm increases significantly, increasing the fractal dimension of soil pores; reducing the soil saturated water content and saturated hydraulic conductivity. SEM technology and pore fractal theory were used to predict the soil salinity curve and unsaturated hydraulic conductivity of the improved saline soil.

2.
Spectrochim Acta A Mol Biomol Spectrosc ; 226: 117639, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31610465

RESUMO

Soil visible and near infrared (Vis-NIR) has become an applicable and interesting technique to predict soil properties because it is a fast, cost-effective, and non-destruction technique. This study presents an application of diffuse reflectance spectroscopy (DRS) and chemometric techniques for evaluating concentrations of heavy metals in earth-cumulic-orthic-anthrosols soils. 44 soil samples of 0-30 cm were collected from three representative agriculture areas (Fufeng, Yangling, and Wugong transects with 16, 10, and 18 samples, respectively) and analyzed for Cr, Mn, Ni, Cu, Zn, As, Cd, Hg, and Pb by Vis-NIR spectroscopy (350-2500 nm). Average levels of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg, and Pb were 17.95, 274, 12.77, 7.29, 15.81, 7.51, 0.40, 12.58, and 21.05 mg kg-1, respectively. Twenty-four preprocessing methods were extracted sensitive bands. Partial least squares regression (PLSR) used to obtain effective bands and predict soil heavy metals concentrations. The accuracy of the predictive models were assessed in terms of coefficient of determination (R2), the root mean squared error (RMSE), standard error (SE) and the ratio of performance to deviation (RPD). The results revealed that excellent predictions for Hg(Rv2 = 0.99, RPD = 8.59, RMSEP = 0.12, SEP = 0.13), Cr (Rv2 = 0.97, RPD = 5.96, RMSEP = 0.10, SEP = 0.10), Ni (Rv2 = 0.93, RPD = 3.74, RMSEP = 0.13, SEP = 0.13), Pb (Rv2 = 0.97, RPD = 5.57, RMSEP = 0.10, SEP = 0.01), and Cu (Rv2 = 0.92, RPD = 3.38, RMSEP = 0.08, SEP = 0.08). Models for As (Rv2 = 0.87, RPD = 2.58), Mn (Rv2 = 0.80, RPD = 2.09), and Cd (RPD = 2.77) had Rv2 < 0.9 and RPD<3.0, not excellent predictions. For the element of Zn, although Rv2 = 0.91, RPD = 3.13, the offset had too much deviation, and it cannot be considered an excellent model. Therefore, a combination of spectroscopic and chemometric techniques can be applied as a practical, rapid, low-cost and quantitative approach for evaluating soil physical and chemical properties in Shaanxi, China.

3.
Artigo em Inglês | MEDLINE | ID: mdl-31806478

RESUMO

Visible and near-infrared diffuse reflectance spectroscopy (Vis-NIR) has been recognized as a fast method to evaluate the content of soil organic matter (SOM) in various types of soil. The accuracy of Vis-NIR is comparable to conventional laboratory methods for estimating SOM. However, very few studies have applied Vis-NIR to estimate SOM in saline-alkali soil. This study aimed to investigate the efficiency of spectral data for evaluating SOM in saline-alkali soil. Soil samples (n = 291) were collected from the five major saline-alkali soil regions in Shaanxi. SOM was measured using standard methods and the samples were scanned using ASD Fieldspec4 at wavelength of 350-2500 nm to obtain spectral data. Twenty-six pre-processing methods were tested and partial least squares regression (PLSR) was used to estimate SOM. The best preprocessing was R + SG + SNV + FD. The calibration results were Pc = 15, Rc2 = 0.92, RMSEC = 1.11, SEC = 1.12, Slope = 0.92, Offset = 0.45; the validation results were Rv2 = 0.97, RPD = 5.21, RMSEP = 0.38, SEP = 0.38, Slope = 0.97, Offset = 0.17. Therefore, this main objective of the study was to propose an effective approach based on Vis-NIR spectroscopy and Chemometrics for predicting saline-alkali SOM contents in the center of Shaanxi, China.

4.
PeerJ ; 7: e7707, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31576244

RESUMO

The organic carbon mineralization process reflects the release intensity of soil CO2. Therefore, the study of organic carbon mineralization and particle composition analysis of soft rock and sand compound soil can provide technical support and a theoretical basis for soil organic reconstruction (soil structure, materials and biological nutrition). Based on previous research, four treatments were selected: CK (soft rock:sand=0:1), C1 (soft rock:sand=1:5), C2 (soft rock:sand=1:2) and C3 (soft rock:sand=1:1), respectively. Specifically, we analyzed the organic carbon mineralization process and soil particle composition by lye absorption, laser granulometer, and scanning electron microscope. The results showed that there was no significant difference in organic carbon content between C1, C2 , and C3 treatments, but they were significantly higher than in the CK treatment (P < 0.05). The organic carbon mineralization rate in each treatment accords with a logarithmic function throughout the incubation period (P < 0.01), which can be divided into a rapid decline phase in days 1 to 11 followed by a steady decline phase in days 11 to 30. The cumulative mineralization on the 11th day reached 54.96%-74.44% of the total mineralization amount. At the end of the incubation, the cumulative mineralization and potential mineralizable organic carbon content of the C1, C2 and C3 treatments were significantly higher than those of the CK treatment. The cumulative mineralization rate was also the lowest in the C1 and C2 treatment. The turnover rate constant of soil organic carbon in each treatment was significantly lower than that of the CK treatment, and the residence time increased. With the increase of volume fraction of soft rock, the content of silt and clay particles increased gradually, the texture of soil changed from sandy soil to sandy loam, loam , and silty loam, respectively. With the increase of small particles, the structure of soil appear ed to collapse when the volume ratio of soft rock was 50%. A comprehensive mineralization index and scanning electron microscopy analysis, when the ratio of soft rock to sand volume was 1:5-1:2, this can effectively increase the accumulation of soil organic carbon. Then, the distribution of soil particles was more uniform, the soil structure was stable (not collapsed), and the mineralization level of unit organic carbon was lower. Our research results have practical significance for the large area popularization of soft rock and sand compound technology.

5.
Sci Rep ; 9(1): 14719, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31604992

RESUMO

The Mu Us sandy land in China's Shaanxi Province faces a critical water shortage, with its aeolian sandy soil endangering the regional eco-environment. Here we investigated the effects of feldspathic sandstone on water retention in an aeolian sandy soil from the Mu Us sandy land. Feldspathic sandstone and aeolian sandy soil samples were mixed at different mass ratios of 0:1 (control), 1:5 (T1), 1:2 (T2), and 1:1 (T3). Soil-water characteristic curves were determined over low- to medium-suction (1-1000 kPa) and high-suction (1000-140 000 kPa) ranges, by centrifuge and water vapor equilibrium methods, respectively. Results showed that the addition of feldspathic sandstone modified the loose structure of the aeolian sandy soil mainly consisting of sand grains. The van Genuchten model described well the soil-water characteristic curves of all four experimental soils (R2-values > 0.97). Soil water content by treatment was ranked as T2 > T3 > T1 > control at the same low matric suction (1-5 kPa), but this shifted to T2 > T1 > T3 > control at the same medium- to high-suction (5-140 000 kPa). T2 soil had the largest saturated water content, with a relatively high water supply capacity. This soil (T2) also had the largest field capacity, total available water content, and permanent wilting coefficient, which were respectively 17.82%, 11.64%, and 23.11% higher than those of the control (P-values < 0.05). In conclusion, adding the feldspathic sandstone in an appropriate proportion (e.g., 33%) can considerably improve the water retention capacity of aeolian sandy soil in the study area.

6.
PLoS One ; 14(8): e0221925, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31465512

RESUMO

The aim of this study is to explore suitable drip irrigation system on the water saving and high yield of pear-jujube from 2009 to 2012 years in the mountain of northern Shaanxi. The treatments consisted of combinations of 5 drip irrigation systems (DP). The irrigation quota of DP-1, DP-2 and DP-3 treatment was 100 m3 hm-2, 135 m3 hm-2 and 180 m3 hm-2, respectively, irrigated 4 times. The irrigation quota of DP-4 and DP-5 treatment was 135 m3 hm-2 and irrigated 3 and 2times, respectively; and with no irrigation as the control (C). Results indicated that bearing branch length of jujube, fruit set and yield of different drip irrigation system are significantly better than C (P<0.05). Bearing branch length and yield of DP-3 treatment are reached maximum in 2012, which are 22.0 cm and 16772.8 m3 hm-2. And they are increased by 47.7% and 13.2% compared with C, respectively. In addition, the water consumption of different irrigation treatment increases along with the increasing of irrigation amount. And the DP-3 treatment is the highest in different years. The water use efficiency of pear-jujube of low irrigation quota is better than the high irrigation quota. Water use efficiency of 135 m3 hm-2 and irrigated 2 times treatment is the best, which is 1.92 m3 hm-2. Considering the lack of high annual precipitation, we conclude that DP-5 treatment was the best drip irrigation system in the mountain of northern Shaanxi.

7.
Spectrochim Acta A Mol Biomol Spectrosc ; 222: 117202, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31181506

RESUMO

Chlorophyll is an important factor for measuring the normal growth and development status of plants, and it is also of great significance for the management and utilization of agricultural water and fertilizers. In this study, the chlorophyll content of rapeseed leaves was taken as the research object, and the effect of spectral data pretreatment method on the spectral feature extraction and chlorophyll content prediction model was quantitatively studied. ASD FieldSpec Pro (350-2500 nm) spectrometer was used to measure the spectral reflectance of rape leaf samples, and the spectral reflectance characteristics of different chlorophyll contents were analyzed. The Savitzky-Golay nine-point smoothing of the reflectance spectrum was performed, and the first derivation (FD), second derivation (SD), and reciprocal logarithm (LOG)transformation of the reflectance were performed after MSC and SNV preprocessing respectively. The optimal spectral estimation model for chlorophyll was established by PLSR. The results show that: (1) This study was mainly to monitor the chlorophyll content in rape joints during jointing stage, using the correlation between chlorophyll content and hyperspectral characteristics, using MSC, NOR and SNV to pretreat the reflectance spectra and combining different derivations transformations to extract chlorophyll characteristics. (2) Quantitative model of chlorophyll content was established based PLSR, the best preprocessing was R + SG + SNV + LOG+FD, the calibration results was: LVs = 14, Rc2 = 0.97, RMSEC = 4.18, SEC = 4.21, Slope = 0.92, Offset = 2.63; the validation results was: Rv2 = 0.98, RPD = 7.52, RMSEP = 2.94, SEP = 2.98, Slope = 0.98, Offset = 1.43; (3) The optimal estimation model established by different treatment methods has better stability and higher precision, and can rapidly monitor the chlorophyll content of rapeseed in the region.


Assuntos
Brassica napus/química , Clorofila/análise , Folhas de Planta/química , Análise dos Mínimos Quadrados , Espectroscopia de Luz Próxima ao Infravermelho
8.
PLoS One ; 14(4): e0216006, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31002733

RESUMO

[This corrects the article DOI: 10.1371/journal.pone.0211163.].

9.
PLoS One ; 14(4): e0215330, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30998698

RESUMO

To analyze three row orientations (south-north, east-west, southwestern 20°) and two row spacings ('65 + 65', '160 + 40'), we investigated the effect of row orientation and planting pattern on photosynthetic performance, physiological and biochemical indicators related to the aging of leaves. Results revealed that during maturity stage, in north-south and east-west, the initial fluorescence (Fo) at '65 + 65' were higher than those under'160 + 40'; the maximum quantum yield of PS2 photochemistry(ΦP0), basal quantum yield of non-photochemical processes in PS2(ΦN0)of the lower leaves and photosynthetic rate of the upper and ear leaves under'160 + 40'were higher than those under'65 + 65'. The polyphenoloxidase (POD) activities of leaves at different positions under '160 + 40' were higher than that under'65 + 65', while the malondialdehyde (MDA) content was lower. The photosynthesis rate, superoxide dismutase (SOD) and catalase (CAT) activity of leaves at different positions under southwestern 20° '160 + 40' were higher than others. Whilst MDA content '160 + 40' were lower. Therefore, in De Hui City, Jilin Province, southwestern 20° '160 + 40' delayed leaf senescence at the late stage of growth of maize, as well as the effect of increasing maize yield was most obvious.


Assuntos
Produção Agrícola , Fotossíntese , Folhas de Planta/metabolismo , Zea mays/crescimento & desenvolvimento , Fluorescência , Malondialdeído/metabolismo , Proteínas de Plantas/metabolismo , Superóxido Dismutase/metabolismo
10.
Environ Technol ; : 1-11, 2019 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-30961473

RESUMO

Various resources from a municipal wastewater treatment plant (MWTP) are available for microalgae cultivation plants, suggesting that a combination of these technologies can be used to produce microalgae biomass and remove contaminants at a low cost. In this study, the growth performance and nutrient removal efficiency of an indigenous Scenedesmus sp. in various wastewater media with different exchange patterns were investigated firstly, then transferred to a pilot-scale photobioreactor (located inside a MWTP) for bioremediation use. The temperature and pH of the platform were maintained at 15-30°C and 7.6, respectively. The NH4+- N , NO3-- N , and PO43-- P of the wastewater could be reduced to below 0.05, 0.40, and 0.175 mg L-1, respectively. Our results indicate that microalgae cultivation using the resources of a MWTP can achieve high algal biomass productivity and nutrient removal rate. Our study also suggests that efficient technology for controlling zooplankton needs to be developed.

11.
Biomater Sci ; 7(5): 1833-1841, 2019 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-30907899

RESUMO

Uncontrollable hemorrhage is the main cause of death in military and civilian accidents. It is therefore necessary and an urgent requirement to develop a safe and efficient hemostatic material. In this study, the hemostatic performance of frustules of three centric diatom species (Thalassiosira weissflogii, Thalassiosira sp., and Cyclotella cryptica) with similar shapes and different sizes was investigated. The complicated structure of T. weissflogii, leading to its highest BET surface area (169.5 m2 g-1) and liquid absorption (51.4 ± 1.6 times the weight of liquid), exhibited the shortest hemostasis time (158 ± 8.19 s) in in vitro blood coagulation. Thalassiosira sp. had a shorter hemostasis time (167.33 ± 14.74 s) than that of QuikClot® and C. cryptica, indicating that diatom size also played an important role in hemostasis due to the interface reaction between the material and plasma protein. The in vivo hemostasis results further confirmed this conclusion. Diatom frustules also exhibited favorable blood compatibility (<5%), and no significant cell toxicity could be observed from the three frustules. Our results suggest that the coagulation effect of frustules is strengthened upon a decrease in the size and increase in the liquid absorbability. This report provides valuable information for the medical application of diatom frustules in the field of hemorrhage control.


Assuntos
Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Fenômenos Químicos , Diatomáceas/citologia , Hemorragia/tratamento farmacológico , Animais , Materiais Biocompatíveis/uso terapêutico , Materiais Biocompatíveis/toxicidade , Coagulação Sanguínea/efeitos dos fármacos , Parede Celular/química , Hemólise/efeitos dos fármacos , Hemorragia/fisiopatologia , Teste de Materiais , Camundongos , Porosidade , Coelhos , Ratos
13.
Sci Rep ; 9(1): 2200, 2019 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-30778119

RESUMO

Soil structure represents a basis for soil water retention and fertiliser availability. Here, we performed a micromorphological analysis of thin soil sections to evaluate the effects of 10 years of organic planting (OPP), pollution-free planting (PFP), and conventional planting (CPP) on greenhouse soil structure in the North China Plain. We also analysed soil bulk density, soil organic matter (SOM), and wet aggregate stability. The CPP soil microstructure included weakly separated angular block or plate forms and weak development of soil pores (fissured or simply accumulated pores) with the highest bulk density (1.33 g cm-3) and lowest SOM (26.76 g kg-1). Unlike CPP, the OPP soil microstructure was characterised by highly separated granular and aggregated structures and an abundance of plant and animal remains. OPP was associated with the highest total porosity (55.4%), lowest bulk density (1.17 g cm-3), and highest SOM (54.81 g kg-1) in the soil surface layer. OPP also improved the ventilation pore content (proportion of pores >0.1 mm, 44.09%). OPP aggregates showed different hierarchies of crumb microstructure and higher mean weight diameter and geometric mean diameter values than did CPP. These results confirm the benefits of long-term OPP for soil structure and quality in the greenhouse.

14.
J Environ Manage ; 237: 163-169, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30784864

RESUMO

The groundwater is an important route of human exposure to kinds of contaminants. This study was carried out to investigate the occurrence and spatial distribution of groundwater arsenic in the Jinghui irrigation district in Shaanxi Province, China. The water contamination was assessed for drinking purposes by comparing it to national guidelines, and the impacts of arsenic on human health were quantified using the health risk assessment model recommended by the USEPA. The results show that the concentration of groundwater arsenic ranges from 0.0012 to 0.0190 mg/L (average 0.0054 mg/L), and 2.58% of groundwater exceed the national guidelines of 0.01 mg/L for drinking. The carcinogenic risk of arsenic affecting adults has reached 3.50 × 10-4, significantly exceeding the national guideline (1.00 × 10-4.) The health risks resulting from oral exposure are higher than those of dermal exposure. The carcinogenic risk for adults is higher than that for children, while the non-carcinogenic risk for children is higher than that for adults. The area ratio of the carcinogenic risk is 42.82%, and the area of the non-carcinogenic risk is 69.19%. Groundwater arsenic mainly originates from the discharge of industrial wastewater and the slowly release of natural sediments. The results of this study can help to set up suitable management strategies to guarantee water supply and health safety for local residents.


Assuntos
Arsênico , Água Potável , Água Subterrânea , Poluentes Químicos da Água , Adulto , Criança , China , Monitoramento Ambiental , Humanos , Medição de Risco
15.
PLoS One ; 14(1): e0211163, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30682124

RESUMO

Soil microorganisms play a pivotal role in carbon mineralization and their diversity is crucial to the function of soil ecosystems. However, the effects of long-term fertilization on microbial-mediated carbon mineralization are poorly understood. To identify the relative roles of microbes in carbon mineralization of yellow paddies, we investigated the long-term fertilization effects on soil properties and microbial communities and their relationships with carbon mineralization. The treatments included: no fertilization (CK), chemical fertilizer (NPK), organic fertilizer (M), and constant organic-inorganic fertilizer (MNPK). NPK treatment significantly increased soil water content (WC), while M and MNPK treatments significantly increased the content of soil organic carbon (SOC), total nitrogen (TN), soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), and WC. Strong increases in CO2 emissions, potential mineralized carbon, and turnover rate constant were observed in both organic-fertilizer treatments (M and MNPK), relative to the CK treatment. These changes in soil properties can be attributed to the variation in microbial communities. NPK treatment had no significant effect. Different fertilization treatments changed soil microbial community; SOC and SMBN were the most important contributors to the variance in microbial community composition. The variations in community composition did not significant influence carbon mineralization; however, carbon mineralization was significantly influenced by the abundance of several non-dominant bacteria. The results suggest that SOC, SMBN, and non-dominant bacteria (Gemmatimonadetes and Latescibacteria), have a close relationship to carbon mineralization, and should be preferentially considered in predicting carbon mineralization under long-term fertilization.


Assuntos
Biomassa , Carbono/metabolismo , Fertilizantes , Consórcios Microbianos , Microbiologia do Solo , Solo , Fatores de Tempo
16.
Sci Total Environ ; 660: 177-187, 2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30640086

RESUMO

Remote sensing based vegetation index provides a practical method for the monitoring of vegetation dynamics at regional and global scales. Here, using a long-term remotely sensed normalized difference vegetation index (NDVI) dataset, we quantified the vegetation changes in the Loess Plateau (LP) over the last three decades (1982-2015), which includes the period before the Chinese"Grain for Green Program"(GGP) was launched (1982-1999), and the period after the GGP (1999-2015). The correlations between the NDVI and four climate related variables, i.e., precipitation, temperature, root-soil moisture (RSM), and a drought proxy-standardized evapotranspiration deficit index (SEDI), were also examined. The results indicated that, (i) the GGP strongly changed the vegetation in the LP. The growing-season mean NDVI (GSM-NDVI) and the annual mean NDVI (AM-NDVI) decreased slightly before the GGP launched in 1999, with slopes of -3.38×10-3 and-8.00×10-4year-1, respectively. However, they showed slight and significant (p<0.05) increases after the GGP, with slopes of 4.75×10-3 and 2.32×10-3year-1, respectively. (ii) Climate change (i.e., warming and drying) resulted in adverse effects on vegetation in the LP during the period before the GGP. However, the observed changes (i.e., wetting and reduced drought) exerted positive effects on the vegetation during the period after the GGP. (iii) Inter-annual variations of spatially averaged NDVI over the LP were primarily determined by RSM rather than any other climate related variables. In the southeastern LP, the inter-annual variation of GSM-NDVI was mainly determined by precipitation and SEDI, while the inter-annual variation of AM-NDVI was mainly caused by SEDI and RSM. Inter-annual variations of both GSM-NDVI and AM-NDVI were mainly determined by SEDI and RSM in the northwestern LP, and by temperature in the southwestern LP.


Assuntos
Agricultura/métodos , Biota , Mudança Climática , Monitoramento Ambiental , Pradaria , Plantas , China
17.
Bioresour Technol ; 268: 608-615, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30138873

RESUMO

Microalgae possess many advantages, but the lack of a suitable strategy to simultaneously facilitate their low cost cultivation and high value productions limits their commercial applications. In this study, two microalgae strains (RT_C and RT_F) isolated from a municipal wastewater treatment plant were used to establish a two-step wastewater treatment process. During step-1, RT_C was cultivated in composite wastewater due to its high tolerance of sludge centrate; followed by step-2, in which the supernatant generated from RT_C culture was used to cultivate RT_F. The NH4+-N, PO43--P, and COD in the wastewater were removed almost completely using this strategy. Moreover, the majority of the metal ions in the wastewater were absorbed by RT_C during step-1, and thus the powdered RT_F only contained low levels of toxic metals. Our results demonstrate that this two-step process is effective for removing pollutants and while generating a powder sufficiently clean for extracting valuable compounds.


Assuntos
Microalgas , Águas Residuárias , Metais , Esgotos , Purificação da Água
18.
Bull Environ Contam Toxicol ; 101(2): 178-184, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29947911

RESUMO

Mining is considered to be one of the most significant sources of environmental pollution with regard to heavy metals. Mineral mining causes large quantities of mercury, cadmium, and other elements to be released into the environment and naturally poses a serious threat to environment. This paper will analyze the pollution status of agricultural soil caused by the mining of heavy metals in various mining areas in the Xunyang County in the Shaanxi Province of China, an area in famous for its resource mining. Equally, it will look at the potential ecological risk assessment process that is used to analyze the ecological risks of mining heavy metals in agricultural soil located in the surrounding areas. Based on the soil investigation, As pose a moderate ecological risk on the Au mining area. In addition, the Hg metals pose a significantly high potential ecological risk and Cd metals pose a considerable potential ecological risk on the Hg mining area. In the Pb-Zn mining area, a significantly high potential ecological risk was mainly posed by Cd. These results suggest that many heavy metals pose a high potential ecological risk on the agricultural soil in these three mining areas in the Xunyang County, and may cause elevated heavy metal contents in crops, eventually jeopardizing the health of local residents who consume food grown in polluted soil.


Assuntos
Metais Pesados/análise , Poluentes do Solo/análise , Agricultura , China , Produtos Agrícolas , Monitoramento Ambiental/métodos , Poluição Ambiental/análise , Mineração , Medição de Risco
19.
Environ Monit Assess ; 190(7): 380, 2018 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-29872925

RESUMO

The parameters of water contents, oxidation-reduction potential, organic matter, total phosphorus, total nitrogen and heavy metals concentrations of mercury (Hg), cadmium (Cd), lead (Pb), arsenic (As), chromium (Cr), copper (Cu) and zinc (Zn) in surface sediment and their vertical distribution incore sediments of the Heer river were investigated. Evaluation of nutrients and heavy metals in the Heer River sediments was done by pollution index and potential ecological risk index (PERI) method, respectively. Environmental dredging depth was calculated. The parameters pH, water content, total nitrogen (TN), and organic matter (OM) as well as heavy metals decline with the increased depth. Nutrients of TN, total phosphorus (TP), OM, and heavy metals Cd, Cu, and Pb were classified into the same group and there were significant positive correlations according to the principal component analysis and Pearson correlation, implying that they have a common origin. The results of high pollution index value of OM, TP, and TN of surface sediment obtained from this research showed that the Heer River was in serious nutrient pollution. The contributions of individual metals to the potential ecological risk were in the following order: Cd > Cu > Ni > Cr > Zn > As > Pb. Cd presented serious ecological risk and contributed most to the sediments of the Heer River. The ecological risk (RI) was at a considerable high risk level, and therefore, the environmental dredging depth of the Heer River is 94 cm for the purpose of reducing heavy metal contamination of the Heer River.


Assuntos
Monitoramento Ambiental , Sedimentos Geológicos/química , Rios/química , Poluentes Químicos da Água/análise , Arsênico/análise , Cádmio/análise , China , Cromo/análise , Ecologia , Poluição Ambiental/análise , Mercúrio/análise , Metais Pesados/análise , Nitrogênio/análise , Fósforo/análise , Medição de Risco , Zinco/análise
20.
Artigo em Inglês | MEDLINE | ID: mdl-29902769

RESUMO

The storage of soil organic carbon (SOC) should improve soil fertility. Conventional determination of SOC is expensive and tedious. Visible-near infrared reflectance spectroscopy is a practical and cost-effective approach that has been successfully used SOC concentration. Soil spectral inversion model could quickly and efficiently determine SOC content. This paper presents a study dealing with SOC estimation through the combination of soil spectroscopy and stepwise multiple linear regression (SMLR), partial least squares regression (PLSR), principal component regression (PCR). Spectral measurements for 106 soil samples were acquired using an ASD FieldSpec 4 standard-res spectroradiometer (350-2500 nm). Six types of transformations and three regression methods were applied to build for the quantification of different parent materials development soil. The results show that (1)the basaltic volcanic clastics development of SOC spectral response bands located in 500 nm, 800 nm; Trachyte spectral response of the soil quality, and the volcanic clastics development at 405 nm, 465 nm, 575 nm, 1105 nm. (2) Basaltic volcanic debris soil development, first deviation of maximum correlation coefficient is 0.8898; thick surface soil of the development of rocky volcanic debris from bottom reflectivity logarithm of first deviation of maximum correlation coefficient is 0.9029. (3) Soil organic matter content of basaltic volcanic clastics development optimal prediction model based on spectral reflectance inverse logarithms of first deviation of SMLR. Independent variable number is 7, Rv2 = 0.9720, RMSEP = 2.0590, sig = 0.003. Trachyte qualitative volcanic clastics developed soil organic matter content of the optimal prediction model based on spectral reflectance inverse logarithms of first deviation of PLSR. Model number of the independent variables Pc = 5, Rc = 0.9872, Rc2 = 0.9745, RMSEC = 0.4821, SEC = 0.4906, forecasts determine coefficient Rv2 = 0.9702, RMSEP = 0.9563, SEP = 0.9711, Bias = 0.0637.

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