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91.
92.
Fengzu Zhang Sufang Fan Shaowen Liu Xuesheng Li Canping Pan 《Environmental monitoring and assessment》2013,185(11):9101-9109
A modified LC-MS method for the analysis of mepiquat residue in wheat, potato, and soil was developed and validated. A hydrophilic interaction liquid chromatographic column has been successfully used to retain and separate the mepiquat. Mepiquat residue dynamics and final residues in supervised field trials at Good Agricultural Practice (GAP) conditions in wheat, potato, and soil were studied. The limits of quantification for mepiquat in all samples were all 0.007 mg kg?1, which were lower than their maximum residue limits. At fortification levels of 0.04, 0.2, and 2 mg kg?1 in all samples, recoveries ranged from 77.5 to 116.4 % with relative standard deviations of 0.4–7.9 % (n?=?5). The dissipation half-lives (T 1/2) of mepiquat in soil (wheat), wheat plants, soil (potato), and potato plants were 4.5–6.3, 3.0–5.6, 2.2–4.6, and 2.4–3.2 days, respectively. The final residues of mepiquat were below 0.153 mg kg?1 in soil (wheat), 0.052–1.900 mg kg?1 in wheat, below 0.072 mg kg?1 in soil (potato), and below 1.173 mg kg?1 in potato at harvest time. Moreover, pesticide risk assessment for all the detected residues was conducted. A maximum 0.0012 % of acceptable daily intake (150 mg kg?1) for national estimated daily intake indicated low dietary risk of these products. 相似文献
93.
Xu Bentuo Wu Minghong Pan Chenyuan Sun Yan Yuan Debao Tang Liang Xu Gang 《Environmental science and pollution research international》2017,24(16):14409-14416
Environmental Science and Pollution Research - Hydroxylated polyhalodiphenyl ethers (HO-PXDEs) have attracted considerable scientific interest as examples of emerging aquatic pollutants. However, a... 相似文献
94.
Chen B Pan Y Wang J Fu Z Zhang Y Zhou Y 《Environmental monitoring and assessment》2012,184(6):3545-3556
Evenly distributed sampling design is generally considered as an efficient sampling design. It is widely used in sampling
for the environmental survey. In this paper, we present a novel method for generating N evenly distributed samples within a given irregular polygon via simulating the movements of some ideal homogeneous point
charges. Initially, charges are randomly put into the sampling region; then, they are freed and held orderly; and after enough
runs, the charges will finally reach a stable state with all of them having a zero resultant force and velocity; and so they
distribute evenly within the region. Their layout can thus be considered as an evenly distributed sampling design. The main
advantages of this method are: (1) it is easy to understand and implement; (2) it is efficient in both running and generating
better designs. Analysis and experimental results indicate that this method is an efficient and robust method for generating
even sampling designs for 2D polygonal sampling region. 相似文献
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97.
长江流域商品粮基地建设与农业持续发展 总被引:6,自引:4,他引:2
长江流域横跨我国中亚热带,光、热、水气候资源及其时空组合优势明显,土地自然生产力较高。粮食生产在全国占有重要地位。但由于流域内山地比重大,人口稠密,人均土地资源偏少,在现有耕地资源有限和粮食市场不稳等的多重压力下,历史时期内形成的“南粮北调”正逐渐被“北粮南调”所取代。在分析长江流域粮食生产现状和近二十年来商品粮基地建设对粮食生产的促进作用的基础上,从流域经济持续发展角度,提出了发挥长江流域粮食生 相似文献
98.
The effect and mechanism of inorganic carbon (IC) on the biodegradation of dimethyl phthalate (DMP) by a green microalga Closterium lunula was investigated. The growth of this microalga and the biodegradation of DMP were significantly enhanced when the initial IC was increased. An intermediate product of DMP biodegradation was identified as phthalic acid (PA) that was accumulated and caused a sharp decrease in pH of microalgal culture medium, which inhibited both the growth of microalga and the biodegradation of DMP. A suggested second-order kinetic equation of organic pollutant biodegradation by microalgae (-dC/dt = kNr) fitted well with the experimental data. The increase of IC caused a decline in biodegradation rate constant for organic carbon (k) and an increase in growth (N) by supplying a favorite carbon source and mitigating the decrease of pH. As the net effect, the overall biodegradation rate of DMP was promoted as IC increased, which was dominated by the increase of microalgal growth. 相似文献
99.
Rapid degradation of butachlor in wheat rhizosphere soil 总被引:16,自引:0,他引:16
The degradative characteristics of butachlor in non-rhizosphere, wheat rhizosphere, and inoculated rhizosphere soils were measured. The rate constants for the degradation of butachlor in non-rhizosphere, rhizosphere, and inoculated rhizosphere soils were measured to be 0.0385, 0.0902, 0.1091 at 1 mg/kg, 0.0348, 0.0629, 0.2355 at 10 mg/kg, and 0.0299, 0.0386, 0.0642 at 100 mg/kg, respectively. The corresponding half-lives for butachlor in the soils were calculated to be 18.0, 7.7, 6.3 days at 1 mg/kg, 19.9, 11.0, 2.9 days at 10 mg/kg, and 23.2, 18.0, 10.8 days at 100 mg/kg, respectively. The experimental results show that the degradation of butachlor can be enhanced greatly in wheat rhizosphere, and especially in the rhizosphere inoculated with the bacterial community designated HD which is capable of degrading butachlor. It could be concluded that rhizosphere soil inoculated with microorganisms-degrading target herbicides is a useful pathway to achieve rapid degradation of the herbicides in soil. 相似文献
100.