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931.
932.
Concentrations of metals and arsenic in farmland soils along the Yanghe River, upstream of Guanting Reservoir, were evaluated using fuzzy comprehensive assessment (FCA). FCA is an emerging methodology for assessing environmental status based on fuzzy logic which can model linguistic data and represent chaotic conditions. The ratio of concentrations of metals and arsenic (As) in surface soils of farmland along the Yanghe River to the corresponding reference values decreased in the order Cd>Zn>Cr>Ni>Pb>Cu>As. Based on the FCA, 86% of surface soils along the Yanghe River were classified as grade C, which is suitable for forestry with a greater absorption capacity, suggesting that most farmland along the Yanghe River has to be abandoned as farmland. In order to improve the quality of soil along the Yanghe River and avoid degeneration of water quality in the river and the Guanting Reservoir, remediation of farmland soils along the river is suggested. 相似文献
933.
Through the practice of vertical greening, which is an important method for modern city greening, a city’s natural geographic conditions and rich plant resources can be efficiently utilized. Using vertical greening to shape the characteristics of a city is a promising method for sustainable development. Integration of vertical greening with urban characteristics offers huge ecological and cultural benefits. Vertical greening was adopted in China much later than other developed cities in the world and is still in the exploratory stage in most of the cities. As one of the pioneer cities to carry out vertical greening in China, Xiamen has managed to project it as one of the city highlights. In this study, we analyzed the problems that Xiamen City faced during its development and the important role vertical greening has played in the urban landscape. In addition, humanistic and ecological benefits of vertical greening are illustrated through an experimental study. 相似文献
934.
镉污染对红壤和潮土微生物的生态毒理效应 总被引:4,自引:0,他引:4
以土壤微生物生物量碳(Cmic)、土壤酶活性及微生物多样性为微生物学指标,以0.01mol·L-1CaCl2作为Cd有效态提取剂,以江西红壤和天津潮土为供试土壤,在室内25℃连续培养28d的条件下探讨了外源Cd对土壤微生物的生态毒理效应。结果表明:1)不同培养时间潮土CaCl2提取态Cd含量均显著低于红壤,潮土微生物受到Cd的抑制作用也明显小于红壤。2)各微生物指标的敏感性不同,并受土壤类型和培养时间的影响,其中,脱氢酶的敏感性强于脲酶,微生物功能多样性指标中BiologEco板上每孔的平均吸光值(AWCD)的敏感性强于Shannon指数;Cmic、脲酶、脱氢酶、AWCD和Shannon指数均在红壤中更为敏感。选取的5个微生物指标对Cd污染都有良好的响应,均可作为Cd污染土壤微生物生态毒理实验中的测试指标。在土壤酶指标中,可优先选取脱氢酶作为测试指标。3)Cd对Cmic、土壤酶、微生物功能多样性的抑制作用存在时间效应。14dCd对Cmic的抑制作用大于28d,而对脲酶和脱氢酶的抑制作用小于28d。建议Cd污染土壤微生物生态毒理实验中将培养时间设置为28d或适当延长。4)28d时,红壤中Cd对Cmic、脱氢酶、脲酶、AWCD、Shannon指数的EC10分别为1.31、0.26、0.93、0.08、22.71mg·kg-1,而在潮土中分别为1.97、0.69、13.12、0.09、>200mg·kg-1。 相似文献
935.
Lin?Luo Zhongjing?WangEmail author 《Frontiers of Environmental Science & Engineering》2013,7(5):756-768
The Hekou-Longmen reach, together with local floods, is the main source area for coarse sedimentations into the Yellow River. When total rainfall slightly increased in the area, discharge dramatically decreased by 40%–70% after the year of 2000, and attracting extensive attention in the context of global climate change. High temporal resolution precipitation (timescales between 1 and 4 h) data from the June to September period from 270 rain gauges over the past three decades was mined in order to help explain the phenomenon. Each rainfall event was classified as light/moderate rain, large rain, heavy rain or rainstorm by the event’s rainfall amount, and further classified as low intensity rain, medium intensity rain and high intensity rain by the event’s rainfall intensity. The Mann-Kendall trend test was applied to detect the presence and significance of monotonic trends, and to find the change points in the mean and variance of the precipitation characteristics series, including the amount, intensity, frequency and duration of each rainfall category. Results show that although the total amount of precipitation has slightly increased, the average rainfall intensity has significantly decreased. The larger change happened in light/moderate rain events and low/medium intensity rain events, and the intensity changes have a great extent occurred around the threshold of Non-Runoff Rainfall regime, which was proposed for the approximate calculation of initial losses. Changes in rainfall distribution between different classes of the Runoff Rainfall regime in the 2000s could lead to 0.9 mm less runoff depth (17.3% of the total reduction) than the 1980–1999 period. The study indicates that changes in hourly precipitation may be responsible for the sharp reduction of discharge. 相似文献
936.
A new procedure combining GC-MS with accelerated solvent extraction for the analysis of phthalic acid esters in contaminated soils 总被引:1,自引:1,他引:0
Tingting MA Ying TENG Peter CHRISTIE Yongming LUO Yongshan CHEN Mao YE Yujuan HUANG 《Frontiers of Environmental Science & Engineering》2013,7(1):31-42
An optimized procedure based on gas chromatography-mass spectrometry (GC-MS) combined with accelerated solvent extraction (ASE) is developed for the analysis of six phthalic acid esters (PAEs), which are priority soil pollutants nominated by United States Environmental Protection Agency (USEPA). Quantification of PAEs in soil employs ultrasonic extraction (UE) (USEPA 3550) and ASE (USEPA 3545), followed by clean up procedures involving three different chromatography columns and two combined elution methods. GC-MS conditions under selected ion monitoring (SIM) mode are described and quality assurance and quality control (QA/QC) criteria with high accuracy and sensitivity for target analytes were achieved. Method reliability is assured with the use of an isotopically labeled PAE, di-n -butyl phthalate-d4 (DnBP-D4), as a surrogate, and benzyl benzoate (BB) as an internal standard, and with the analysis of certified reference materials (CRM). QA/QC for the developed procedure was tested in four PAE-spiked soils and one PAE-contaminated soil. The four spiked soils were originated from typical Chinese agricultural fields and the contaminated soil was obtained from an electronic waste dismantling area. Instrument detection limits (IDLs) for the six PAEs ranged 0.10–0.31 μg·L-1 and method detection limits (MDLs) of the four spiked soils varied from a range of 20–70 μg·kg-1 to a range of 90– 290 μg·kg-1. Linearity of response between 20 μg·L-1 and 2 mg·L-1 was also established and the correlation coefficients (R ) were all>0.998. Spiked soil matrix showed relative recovery rates between 75 and 120% for the six target compounds and about 93% for the surrogate substance. The developed procedure is anticipated to be highly applicable for field surveys of soil PAE pollution in China. 相似文献
937.
938.
For study, the fluoride (F) content and distribution pattern in groundwater of eastern Yunnan and western Guizhou fluorosis
area in southwestern China, the F content of 93 water samples [groundwater (fissure water, cool spring, and hot springs),
rivers water] and 60 rock samples were measured. The result shows the F content of the fissure water and cold spring water
is 0.027–0.47 mg/L, and river water is 0.048–0.224 mg/L. The F content of hot spring water is 1.02–6.907 mg/L. The drinking
water supplied for local resident is mainly from fissure water, cool spring, and river water. And the F content in all of
them is much lower than the Chinese National Standard (1.0 mg/L), which is the safe intake of F in drinking water. The infected
people in eastern Yunnan and western Guizhou fluorosis area have very little F intake from the drinking water. The hot spring
water in fluorosis area of eastern Yunnan and western Guizhou, southwest China has high F content, which is not suitable for
drinking. 相似文献
939.
Guowei Zheng Yanxia jia Xu Zhao Fujuan Zhang Shihong Luo Shenghong Li Weiqi Li 《Chemoecology》2012,22(2):131-138
A phytochemical study of the invasive Eupatorium adenophorum indicated that the plant was rich in a phenolic compound o-coumaric acid (or 2-hydroxycoumaric acid). Biological investigations with the model plant Arabidopsis thaliana and crop plants showed that o-coumaric acid strongly inhibited seed germination, plant growth and root elongation, reduced the photosynthesis in old leaves,
and induced the root cell death and the expression of genes related to senescence, oxidative stress, and systemic acquired
resistance. The phytotoxic effects of o-coumaric acid exhibit selectivity between under- and above-ground parts of test plants and between E. adenophorum and other plants. These results indicate that o-coumaric acid is a potent toxin that might play an important role in the competition of E. adenophorum with its neighboring plants during its invasion and establishment. 相似文献
940.
采用Tessier连续提取法对乌鲁木齐七道湾污水厂夏季和冬季污泥中的Cu、Zn、Pb、Cd进行了含量和形态分析,研究了污泥中重金属的生物有效性。结果表明:该污水厂污泥中重金属含量Zn>Cu>Pb>Cd,4种重金属含量均低于污泥农用污染物控制标准限值。Cu、Zn、Pb主要以残渣态和有机结合态形式存在,Cd主要以残渣态、铁锰氧化态和碳酸盐结合态形式存在。Zn、Cu的生物不可利用态含量高,所占比例在60%以上,对污泥农用有利,Pb、Cd两种元素的生物有效态和潜在有效态之和所占比例在50%以上,有较强的生物可利用性,在污泥农用时存在一定潜在风险。 相似文献