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Co-transport of dissolved organic matter and heavy metals in soils induced by excessive phosphorus applications

Journal of Environmental Sciences 2010年第4期22卷 598-606页

作者： mingkui zhang Huimin zhang Department of Natural Resource Science College of Natural Resource and Environmental Sciences Zhejiang University Hangzhou 310029 China. Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition Hangzhou 310029 China

To evaluate the effects of long-term applications of phosphorus fertilizers on mobility of dissolved organic matter （DOM） and heavy metals in agricultural soils, a sandy soil and a loamy soil were spiked with ammonium phosphate at application rates of 0, 25, 50, 100, 250, and 500 mg P per kilogram of soil. A series of 15-cm long soil columns were constructed by packing incubated soils of varying concentrations of P. The soil columns were consecutively leached by simulated rainfalls for six cycles. The contents of water extractable organic carbon in both sandy and loamy soils increased significantly with increasing rates of P applications. Relatively high rates of P applications could induce a marked increase in DOM concentrations in the leachates, the effects were larger with the sandy soil rather than with the loamy soil. Applications of P changed the partitioning of trace metals in the soil solids and the soil solutions. The increased P application rates also seemed to elevate the leaching of Cu, Cd, and Zn from soils. The concentrations of Cu, Cd, and Zn in the leachates were positively correlated with DOM, probably due to the formation of metal-DOM complexes. In contrast, Pb concentrations in the leachates were negatively correlated with DOM, and decreased with increasing rates of P applications. The boosted leaching of DOM induced by high rates of P applications was probably due to the added phosphate ions competing for adsorption sites in the soil solids with the indigenous DOM.

关键词： dissolved organic matter heavy metals phosphorus fertilizer leaching

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Mineral materials as feasible amendments to stabilize heavy metals in polluted urban soils

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Journal of Environmental Sciences 2011年第4期23卷 607-615页

作者： mingkui zhang Jincheng Pu Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition College of Environmental and Resource Sciences Zhejiang University Hangzhou 310058 China.

Four minerals, agricultural limestone （AL）, rock phosphate （RP）, palygorskite （PG）, and calcium magnesium phosphate （CMP）, were evaluated by means of chemical fractions of heavy metals in soils and concentrations of heavy metals in leachates from columns to determine their ability to stabilize heavy metals in polluted urban soils. Two urban soils （calcareous soil and acidic soil） polluted with cadmium, copper, zinc and lead were selected and amended in the laboratory with the mineral materials） for 12 months. Results indicated that application of the mineral materials reduced exchangeable metals in the sequence of Pb, Cd Cu Zn. The reduction of exchangeable fraction of heavy metals in the soils amended with different mineral materials followed the sequence of CMP, PG AL RP. Reductions of heavy metals leached were based on comparison with cumulative totals of heavy metals eluted through 12 pore volumes from an untreated soil. The reductions of the metals eluted from the calcareous soil amended with the RP, AL, PG and CMP were 1.98%, 38.89%, 64.81% and 75.93% for Cd, 8.51%, 40.42%, 60.64% and 55.32% for Cu, 1.76%, 52.94%, 70.00% and 74.12% for Pb, and 28.42%, 52.74%, 64.38% and 49.66% for Zn. Those from the acidic soil amended with the CMP, PG, AL, and RP were 25.65%, 68.06%, 78.01% and 79.06% for Cd, 26.56%, 49.64%, 43.40% and 34.68% for Cu, 44.44%, 33.32%, 61.11% and 69.44% for Pb, and 18.46%, 43.77%, 41.98% and 40.68% for Zn. The CMP and PG treatments were superior to the AL and RP for stabilizing heavy metals in the polluted urban soils.

关键词： heavy metals polluted soil chemical fraction chemical immobilization mineral materials

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Concentrations and chemical forms of potentially toxic metals in road-deposited sediments from different zones of Hangzhou, China

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Journal of Environmental Sciences 2009年第5期21卷 625-631页

作者： zhang mingkui WANG Hao Department of Natural Resource Science College of Natural Resource and Environmental Sciences Zhejiang University Hangzhou 310029 China Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition Hangzhou 310029 China

The 25 road-deposited sediments were collected from five different land-use zones （industrial, residential, commercial, park, and countryside） in Hangzhou, China. The concentrations of metals （Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn） in these samples were determined using ICP-AES after digestion with the mixture of HNO3-HF-HC1 （aqua regia）, and chemically fractionated according to the modified BCR （the European Community Bureau of Reference） sequential extraction procedure. The high metal concentration levels were detected in the sample from industrial zone and commercial zone having heavy traffic. While the low metal levels were noted in the street dust sample from residential zone, park, and countryside zone. The mobility sequence based on the sum of the BCR sequential extraction stages was： Zn （80.28%）, Pb （78.68%）, Cd （77.66%）〉 Cu （73.34%）〉 Mn （67.92%）〉 Co （41.66%）〉 Ni （30.36%）〉 Cr （21.56%）, Fe （20.86%）. Correlation analysis and principal component analysis were applied to the data matrix to evaluate the analytical results and to identify the possible pollution sources of metals. Factor analysis showed that these areas were mainly contaminated by three sources, namely lithology, traffic, and industry.

关键词： heavy metals road-deposited sediment BCR sequential extraction multivariate analysis

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Effect of moisture regime on the redistribution of heavy metals in paddy soil

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Journal of Environmental Sciences 2011年第3期23卷 434-443页

作者： Shunan Zheng mingkui zhang Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition College of Environmental and Resource Sciences Zhejiang University IIangzhou 310029 China Agro-Environmental Protection Institute Ministry of Agriculture Tianjin 300191 China Key Laboratory of Production Environment and Agro-product Safer Ministry of Agriculture Tianjin 300191 China Tianjin Key Laboratory of Agro-environment and Agro-product Safety Tianjin 300191 China

Sequential extraction procedure was applied to assess the dynamics of solid-phase transformation of added Cu, Pb, Cd, and Hg in a typical Chinese paddy soil incubated under three moisture regimes （75% field capacity, wetting-drying cycle, and flooding）. The heavy metals spiked in the soil were time-dependently transferred from the easily extractable fraction （the exchangeable fraction） into less labile fractions （Fe-Mn oxide- and organic matter-bound fractions）, and thus reduced lability of the metals. No significant changes were found for the carbonate-bound and residual fractions of the heavy metals in the soil during the whole incubation. Change rate of the mobility factor （MF）, a proportion of weakly bound fractions （exchangeable and carbonate-bound） in the total metal of soil, reflected the transformation rate of metal speciation from the labile fractions toward stable fractions. It was found that soil moisture regime did not change the direction and pathways of transformation of metal speciation, but it significantly affected the transformation rate. In general, the paddy soil under flooding regime had higher metal reactivity compared with 75% field capacity and wetting-drying cycle regimes, resulting in the more complete movement of metals toward stable fractions. This might be related to the increased pH, precipitation of the metals with sulfides and higher concentration of amorphous Fe oxides under submerged condition.

关键词： heavy metal speciation moisture regime redistribution paddy soil

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Accumulation and relationship of metals in different soil aggregate fractions along soil profiles

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Journal of Environmental Sciences 2022年第5期34卷 47-54页

作者： Qian Shen Mengjie Wu mingkui zhang Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition College of Environmental&Resource SciencesZhejiang UniversityHangzhou 310058China

Different aggregates vary in their ability to retain or adsorb metals in *** soil profiles were sampled from different soil horizons and grouped,and the concentrations of Al,Mg,Ca,Fe,Mn,Cd,Cu and Pb were determined in six sizes of aggregates(>2,2-1,1-0.6,0.6-0.25,0.25-0.053,<0.053 mm).Significantly high(p<0.05)structural stability indexes(SSI)and ag-gregate stability indexes(ASI)were recorded in the topsoil horizon,which may be attributed to the high soil organic matter(SOM)content in aggregates from *** addition,ASI and SSI were positively correlated(r=0.569,p<0.05)with each other,which indicated that the stability of soil aggregates could contribute to the structural stability of bulk ***,accumulation factors(AF),principal component analysis(PCA)and Pearson's correlation co-efficients were used for metal element *** results indicated that SOM was not a key factor affecting the accumulation of Ca,Mg,Al,Fe,Mn,Pb,Cd and Cu in soil *** general,AF values for metal elements in microaggregates(<0.25 mm)were high,which showed that metals preferred to accumulate in fine soil *** PCA and Pearson's correlation coefficients indicated that soil parent materials primarily controlled the distribution of Al,Ca,Fe,Mg and Mn,while materials derived from technogenic sources have important impacts on the distribution of Cd,Cu and Pb in soil aggregates along the soil profile.

关键词： Soil profile Aggregate Structural stability index(SSI) Aggregate stability index(ASI) Metals Accumulation factor(AF)

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Rockburst Intensity Grade Prediction Model Based on Batch Gradient Descent and Multi-Scale Residual Deep Neural Network

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Computer Systems Science & Engineering 2023年第11期47卷 1987-2006页

作者： Yu zhang mingkui zhang Jitao Li Guangshu Chen School of Electrical and Information Engineering Beijing University of Civil Engineering and ArchitectureBeijing100044China Beijing Key Laboratory of Intelligent Processing for Building Big Data Beijing University of Civil Engineering and ArchitectureBeijing100044China State Key Laboratory for GeoMechanics and Deep Underground Engineering China University of Mining&TechnologyBeijing100083China

Rockburst is a phenomenon in which free surfaces are formed during excavation,which subsequently causes the sudden release of energy in the construction of mines and *** rockburst only peels off rock slices without ejection,while severe rockburst causes casualties and property *** frequency and degree of rockburst damage increases with the excavation ***,rockburst is the leading engineering geological hazard in the excavation process,and thus the prediction of its intensity grade is of great significance to the development of geotechnical ***,the prediction of rockburst intensity grade is one problem that needs to be solved *** comprehensively considering the occurrence mechanism of rockburst,this paper selects the stress index(σθ/σc),brittleness index(σ_(c)/σ_(t)),and rock elastic energy index(Wet)as the rockburst evaluation indexes through the Spearman coefficient *** overcomes the low accuracy problem of a single evaluation index prediction *** this,the BGD-MSR-DNN rockburst intensity grade prediction model based on batch gradient descent and a multi-scale residual deep neural network is *** batch gradient descent(BGD)module is used to replace the gradient descent algorithm,which effectively improves the efficiency of the network and reduces the model training ***,the multi-scale residual(MSR)module solves the problem of network degradation when there are too many hidden layers of the deep neural network(DNN),thus improving the model prediction *** experimental results reveal the BGDMSR-DNN model accuracy to reach 97.1%,outperforming other comparable ***,actual projects such as Qinling Tunnel and Daxiangling Tunnel,reached an accuracy of 100%.The model can be applied in mines and tunnel engineering to realize the accurate and rapid prediction of rockburst intensity grade.

关键词： Rockburst prediction rockburst intensity grade deep neural network batch gradient descent multi-scale residual

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Phosphorus Concentration and Forms in Surface and Subsurface Drainage Water from Wetland Rice Fields in the Shaoxing Plain

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Pedosphere 2003年第3期13卷 239-248页

作者： zhang mingkui, JIANG HONG and LIU XINGMEIDepartment of Resource Sciences, College of Resource and Environmental Sciences, Zhejiang University, Hangzhou 310029 (China) Department of Resource Sciences College of Resource and Environmental Sciences Zhejiang UniversityHangzhou 310029 China

Phosphorus (P) is the limiting factor for eutrophication in most freshwater ecosystems. In China, Ptransported from intensively cultivated land has been reported as an important source of P in surface *** this study, we investigated P concentration and forms in surface and subsurface drainage from wetland ricefields in the Shaoxing plain, Zhejiang Province, China. From selected rice fields, surface drainage sampleswere collected at rice-growing, non-growing and fertilization periods, and subsurface drainage samples atdrought and rewetting (irrigation or precipitation after 5～10 d drought period in the surface soils) and wet(drainage under long-term wet soil condition) periods. Water samples were characterized for their totalreactive P (TRP), dissolved reactive P (DRP) and particulate reactive P (PRP). Concentrations of the TRPand DRP in the surface drainage ranged from 0.08 to 1.50 and 0.06 to 1.27 mg L-1, respectively. The TRPand DRP were dependent on field operation activities, and decreased in the order of fertilization period ＞rice-growing period ＞ non-growing period. Phosphorus concentration of runoff receiving P fertilizer can bean environmental concern. The PRP concentration in the surface drainage, ranging from 0.01 to 0.57 mgL-1, accounted for 8%～78% of the TRP. Concentration of the TRP in the subsurface drainage was from0.026 to 0.090 mg L-1, consisting of 29%～90 % of the DRP and 10%～71% of the PRP. In the droughtand rewetting period, the PRP accounted for, on average, 63% of the TRP, much higher than in the wetperiod (23%), suggesting that there was transport of P in preferential flow during drainage events after ashort-term drought period in the surface soils. Therefore, P losses in particulate form may be importantin the subsurface drainage from rice fields when surface soils form cracks and favor rapid flow downwardthrough the soil profiles, suggesting the important role of water-dispersible colloid particles in mediating andco-transporting P in

关键词： drainage phosphorus wetland rice field

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Characterization of Soil Quality Under Vegetable Production Along an Urban-Rural Gradient

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Pedosphere 2003年第2期13卷 173-180页

作者： zhang mingkui, WANG MEIQING, LIU XINGMEI, JIANG HONG and XU JIANMINGCollege of Resource and Environmental Sciences, Zhejiang University, Hangzhou 310029 (China) College of Resource and Environmental Sciences Zhejiang University Hangzhou 310029 (China)

Human activity and urbanization result in urban-rural environmental gradients. Understanding effect of the gradients on soil properties is necessary for management of the soils around urban areas. In this study, soil quality of some vegetable fields was characterized along an urban-rural gradient in Shaoxing County, Zhejiang Province. Fifteen soil physical and chemical properties were evaluated by using principal component *** showed that there was a great variation in the soil quality along the gradient. From rural to urban zones, soil organic matter, water-stable aggregates, cation exchangeable capacity (CEC), total N and P, and available K increased, whereas soil pH value decreased. In addition, Pb, Cu, Ni, Co, Zn and Cr in the soils tended to be accumulated toward the urban zone. Sequential chemical extraction showed that mobility of all the heavy metals in the soils tended to increase from the rural to the urban zones. The variation of soil properties accounted for by the first principal component was significantly explained by the difference in application rates of municipal wastes.

关键词： principal component analysis soil quality urban-rural environmental gradient

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Changes in profile distribution and chemical properties of natural nanoparticles in paddy soils as affected by long-term rice cultivation

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Pedosphere 2021年第5期31卷 659-669页

作者： Dan HUANG Xinyu ZHU Baile XU Yan HE mingkui zhang Fei LIU Zhenghua LIAN Randy ADAHLGREN Philip CBROOKES Jianming XU Institute of Soil and Water Resources and Environmental Science College of Environmental and Resource SciencesZhejiang UniversityHangzhou 310058(China) Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment Hangzhou 310058(China) Department of Land Air and Water ResourcesUniversity of California-DavisDavis CA 95616(USA)

Systematic studies on the genesis,properties,and distribution of natural nanoparticles(NNPs)in soil remain *** study examined a soil chronosequence of continuous paddy field land use for periods ranging from 0 to 1000 years to determine how NNPs in soil changed at the early stages of soil genesis in eastern *** samples were collected from coastal reclaimed paddy fields that were cultivated for 0,50,100,300,700,and 1000 *** nanoparticles were isolated and characterized along with bulk soil samples(<2-mm fraction)for selected physical and chemical *** NNP content increased with increasing soil cultivation age at 60 g m^(-2) year-1,which was related to decreasing soil electrical conductivity(172-1297μS cm^(-1))and NNP zeta potentials(from -22 to -36 mV)with increasing soil cultivation *** in several NNP properties,such as pedogenic iron oxide and total organic carbon contents,were consistent with those of the bulk soils across the soil ***,changes in NNP iron oxide content were obvious and illustrated active chemical weathering,pedogenesis,and potential impacts on the microbial *** analysis demonstrated that the soil cultivation age was the most important factor affecting NNP properties,contributing 60.7% of the total *** and principal component analysis(PCA)revealed splitting of NNP samples into age groups of 50-300 and 700-1000 years,indicating rapid evolution of NNP properties,after an initial period of desalinization(approximately 50 years).Overall,this study provides new insights into NNP evolution in soil during pedogenesis and predicting their influences on agriculture and ecological risks over millennial-scale rice cultivation.

关键词： natural nanoparticle evolution soil chronosequence soil cultivation age soil genesis soil nanoparticles

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Overexpressed SIRT6 ameliorates doxorubicin-induced cardiotoxicity and potentiates the therapeutic efficacy through metabolic remodeling

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Acta Pharmaceutica Sinica B 2023年第6期13卷 2680-2700页

作者： Kezheng Peng Chenye Zeng Yuqi Gao Binliang Liu Liyuan Li Kang Xu Yuemiao Yin Ying Qiu mingkui zhang Fei Ma Zhao Wang The Ministry of Education Key Laboratory of Protein Science School of Pharmaceutical SciencesTsinghua UniversityBeijing 100084China Department of Medical Oncology National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100021China School of Medicine Tsinghua UniversityBeijing 100084China Department of Cardiac Surgery First Hospital of Tsinghua UniversityBeijing 100016China

Since the utilization of anthracyclines in cancer therapy, severe cardiotoxicity has become a major obstacle. The major challenge in treating cancer patients with anthracyclines is minimizing cardiotoxicity without compromising antitumor efficacy. Herein, histone deacetylase SIRT6 expression was reduced in plasma of patients treated with anthracyclines-based chemotherapy regimens. Furthermore,overexpression of SIRT6 alleviated doxorubicin-induced cytotoxicity in cardiomyocytes, and potentiated cytotoxicity of doxorubicin in multiple cancer cell lines. Moreover, SIRT6 overexpression ameliorated doxorubicin-induced cardiotoxicity and potentiated antitumor efficacy of doxorubicin in mice, suggesting that SIRT6 overexpression could be an adjunctive therapeutic strategy during doxorubicin ***, doxorubicin-impaired mitochondria led to decreased mitochondrial respiration and ATP production. And SIRT6 enhanced mitochondrial biogenesis and mitophagy by deacetylating and inhibiting Sgk1. Thus, SIRT6 overexpression coordinated metabolic remodeling from glycolysis to mitochondrial respiration during doxorubicin treatment, which was more conducive to cardiomyocyte metabolism, thus protecting cardiomyocytes but not cancer cells against doxorubicin-induced energy deficiency. In addition, ellagic acid, a natural compound that activates SIRT6, alleviated doxorubicininduced cardiotoxicity and enhanced doxorubicin-mediated tumor regression in tumor-bearing *** findings provide a preclinical rationale for preventing cardiotoxicity by activating SIRT6 in cancer patients undergoing chemotherapy, but also advancing the understanding of the crucial role of SIRT6 in mitochondrial homeostasis.

关键词： SIRT6 Doxorubicin Cardiotoxicity Antitumor efficacy Ellagic acid Mitochondrial homeostasis Glycolysis SGK1

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