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21.
22.
春季黄渤海溶解有机碳的平面分布特征 总被引:1,自引:0,他引:1
依据2010年4~5月对黄渤海调查所得的数据,分析了黄渤海溶解有机碳(dissolved organic carbon,DOC)的含量及其平面分布特征,并对其影响因素进行了初步探讨.结果表明,2010年春季黄渤海DOC的浓度范围为0.96~4.71 mg.L-1,平均浓度为2.27 mg.L-1.平面分布上,DOC整体呈现南北近岸浓度高、中部外海浓度低的特点.在渤海西部近岸、山东半岛东部及长江口东北部均存在高值,尤其是渤海西部近岸,DOC浓度最高达到4.71 mg.L-1,这主要是受河流输入和沿岸流的影响;低值区则主要集中在南黄海中部外海,DOC浓度普遍低于1.50 mg.L-1. 相似文献
23.
24.
余峻才 《安全.健康和环境》2005,5(3):i001-i001
"这件事的责任在我." 这是一句看似简单的话,但真正要把这句话说出口,是需要一定的勇气和责任感的.客观地说,凡是与人有关的事情,一旦出现疏漏,这其中必定与某些人的关系要密切一些,这关系密切的人是应承担相应责任的.但事实上,却常是大事化小,小事化了,最终谁也没有责任,并由此滋生习惯性的推卸责任行为.有些人的习惯性思维是首先千方百计地证明事故如何跟自己没关系,而不是主动地检讨自己可能的过失.事故发生后,为了推卸责任,通常是隐瞒事故真相,设法销毁证据,使事故处理无法真正地吸取教训,导致重复事故的发生.在自己的过失面前,以什么姿态去面对责任?这是对责任心的拷问,也是对起码的职业操守的拷问. 相似文献
25.
Influence of Indian mustard (Brassicajuncea) on rhizosphere soil solution chemistry in long-term contaminated soils: A rhizobox study 总被引:1,自引:0,他引:1
This study investigated the influence of Indian mustard (Brassica juncea) root exudation on soil solution properties (pH, dissolved
organic carbon (DOC), metal solubility) in the rhizosphere using a rhizobox. Measurement was conducted following the cultivation
of Indian mustard in the rhizobox filled four di erent types of heavy metal contaminated soils (two alkaline soils and two acidic
soils). The growth of Indian mustard resulted in a significant increase (by 0.6 pH units) in rhizosphere soil solution pH of acidic
soils and only a slight increase (< 0.1 pH units) in alkaline soils. Furthermore, the DOC concentration increased by 17–156 mg/L
in the rhizosphere regardless of soil type and the extent of contamination, demonstrating the exudation of DOC from root. Ion
chromatographic determination showed a marked increase in the total dissolved organic acids (OAs) in rhizosphere. While root exudates
were observed in all soils, the amount of DOC and OAs in soil solution varied considerably amongst di erent soils, resulting in
significant changes to soil solution metals in the rhizosphere. For example, the soil solution Cd, Cu, Pb, and Zn concentrations increased
in the rhizosphere of alkaline soils compared to bulk soil following plant cultivation. In contrast, the soluble concentrations of Cd, Pb,
and Zn in acidic soils decreased in rhizosphere soil when compared to bulk soils. Besides the influence of pH and DOC on metal
solubility, the increase of heavy metal concentration having high stability constant such as Cu and Pb resulted in a release of Cd and
Zn from solid phase to liquid phase. 相似文献
26.
Co-transport of dissolved organic matter and heavy metals in soils induced
by excessive phosphorus applications 总被引:2,自引:0,他引:2
To evaluate the e ects 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 e ects 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. 相似文献
27.
A strain,USTB-05,isolated from Lake Dianchi,China,degraded the cyanobacterial toxin microcystin-RR(MC-RR) at the rate of 16.7 mg/L per day.Analysis of 16S rDNA sequence showed that the strain was Sphingopyxis sp.Enzymatic degradation pathways for MC-RR by Sphingopyxis sp.USTB-05 were identified.Adda-Arg peptide bond of MC-RR was cleaved and then a hydrogen and a hydroxyl were combined onto the NH 2 group of Adda and the carboxyl group of arginine to form a linear molecule as intermediate product within the ... 相似文献
28.
以铁岭市柴河水库上游集水区域为研究对象,利用铁岭市柴河堡水文站降雨时节实测的暴雨径流数据、泥沙数据、污染物浓度数据进行分析,侧重研究降雨时节暴雨径流量与主要污染物浓度及污染物瞬时流失量之间的关系,以期为柴河流域农业非点源污染控制提供参考。研究结果表明:暴雨期内,非点源污染物浓度及瞬时流失量与径流峰值几乎同步出现,它们之间存在着非常密切的关系。 相似文献
29.
循环经济是实现以环境资源换取经济增长向以环境资源优化经济增长转变的发展模式。定量评价循环经济发展水平是循环经济的基本内容。基于能值理论,运用能值分析方法,从能值流量、经济社会能值、资源利用、环境压力和综合指数5个方面评价了福建省自2000年以来循环经济发展状况。结果表明:福建省经济的发展依靠的是消耗不可更新资源,系统可持续发展能力在不断下降;自然资源相对丰富,但是资源利用率低,净生态效益低下;废弃物还未对环境造成过大压力,环境压力主要来自于经济发展对不可更新资源的依赖以及人口数量的增加。改变经济发展模式,提高资源利用率,减少对不可更新资源利用,加强保护和开发可更新资源,逐步提升循环经济发展水平,是福建省提升可持续发展能力的重点。 相似文献
30.