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氢化物原子荧光法测定化探样品中的砷、锑、铋、汞,用HCl-H_2O_2浸取溶矿,加热时间短,成本低.在盐酸介质中加热,H_2O_2氧化HCl而自行分解.溶解完全,与王水溶矿结果一致。另外,可避免用王水溶样后,残余硝酸破坏还原剂硫脲(析出单体硫)对测定砷、锑、铋、汞的影响,所以更具有优越性。 相似文献
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采用比色管水浴消解法消解土壤样品,以原子荧光光度法测定土壤中的汞.结果表明,该方法具有快速方便、准确性好、灵敏度高等优点,是较好的测定方法. 相似文献
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生物多样性是人类赖以生存与发展的基础。中国生物多样性保护优先区域集中分布着中国绝大多数的生物物种,如何保护好这些区域的生态系统和生物多样性,是实现可持续发展急需解决的问题。本文基于2010年和2015年的2期土地利用/覆被数据,应用人类干扰指数,分析了中国生物多样性保护优先区域人类干扰的程度及变化。结果表明：① 2015年中国生物多样性保护优先区域人类干扰程度以微度和轻度为主,15个优先区处于微度干扰,占优先区总面积的84.10%,13个处于轻度干扰,占优先区总面积的6.65%;华北平原黄土高原区和华东华中丘陵平原区人类干扰程度较高,而西南高山峡谷区、蒙新高原荒漠区和青藏高原高寒区人类干扰程度很低;② 2010-2015年,占优先区总面积84.54%的区域人类干扰程度基本持衡,人类干扰程度发生增加和下降的面积大致冲抵,生物多样性保护优先区域整体变化不大,华南低山丘陵区和东北山地平原区人类干扰程度较高,且升幅超过1%,华北平原黄土高原区降幅最大,为0.15%;③ 人类干扰程度较高且变化幅度大的区域,主要受经济发展对生态系统干扰及土地利用程度加深的影响,对农田、居民点及工矿交通用地的需求增加,退耕还林等部分生态工程实施有利于减少人类对生态系统的干扰程度。总体上看,全国32个生物多样性保护优先区域整体上人类干扰程度较低且变化幅度较小,且人类干扰程度高的区域分布较集中,说明国家生态保护各项政策与措施的实施对生物多样性保护起到了良好的促进作用,有利于生物多样性的保护。 相似文献
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本文详细研究了氢化物原子荧光法测定硒和碲的工作条件及其它元素的干扰情况。发现通过加入铁盐及提高试液酸度可以较好地消除干扰。拟定了以逆王水加硝酸钾分解样品,用5mol·L~(-1)盐酸提取,用同一溶液对硒:碲进行原子荧光测定的方法,方法简便、快速、成本低、灵敏度高。硒和碲的检出限分别为8.6×10~(-10)g和2.21×10~(-10)g。 相似文献
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氯化亚锡还原冷蒸汽无色散原子荧光光谱法测定痕量汞,采用硫酸、双氧水、王水逐次加入低温分析样品,可以保证样品分解完全又可避免汞的损失。汞的检出限为6.0×10~(-10)g,精密度RSD％=4.1。该方法操作简便,快速、准确、费用低,可应用于大批量地球化学样品的分析。 相似文献
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为了对比不同类型烃源岩样品在不同的热解模拟实验条件下生油和生气的活化能,选取渤中地区多个湖相泥质烃源岩原岩和干酪根样品进行了开放体系无水热解和封闭体系加水热解实验,烃源岩样品取自不同的洼陷和烃源层位,具有不同的有机质丰度、类型和成熟度。对比结果表明,有机质类型和成熟度对烃源岩生油活化能有重要影响,平均生油活化能随有机质类型变差和成熟度增大而增大。不同的洼陷、烃源层位和样品类型对平均生油活化能无明显影响,而样品类型则影响活化能的分布,原岩活化能分布相比干酪根更加集中。处于成熟阶段烃源岩的生气活化能比处于低熟阶段烃源岩的生油活化能高11~17 kJ/mol。相对于开放体系无水热解实验,封闭体系加水热解实验活化能分布集中且能够包含初次裂解和二次裂解过程。本研究应用封闭体系加水热解模拟实验,分别选择低熟烃源岩原岩样品和成熟烃源岩干酪根样品进行生油和生气活化能研究,取得了良好的效果。 相似文献
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According to the historical changes of coastal lines, seven soil sampling districts, from land to sea, were arranged in Dongtai City, Jiangsu Province to sample soils from surface and profile. Concentrations of seven major heavy metals （HMs）, granularity, pH, organic matters and C/N of the soil samples were analyzed. Results show that concentrations of heavy metals in agricultural land present a certain spatial variance, decreasing from land to sea. Pollution assessment indicates that the agricultural soils were not polluted by HMs, but the potential pollution of Cu and Hg needs to be alerted. Different HMs accumulate in the surface and sub-surface of the soil profiles, and concentrations of Hg and Pb decrease significantly with the increment of soil depth. Concentrations of HMs exhibit a significantly negative correlation to pH, but have no significant relation with organic matters in soil. Principle component analysis show that the concentrations of HMs relate to the land use history. Concentrations of Hg, Ni and Cr in soil are closely related with land use history, and concentrations of Pb, Cu and Cr are affected by land use history as well as other factors. However, there is no significant relation between concentration of As and land use history. 相似文献
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Role of organic acids in desorption of mercury from contaminated soils in eastern Shandong Province, China 总被引：2，自引：0，他引：2
Batch experiments were conducted to study the effects of low-molecular-weight organic acids(LMWOAs) on desorption of Hg from two kinds of soils in the eastern Shandong Province,China.Of all LMWOAs,oxalic and citric acids were chosen as the representatives in this experiment because they are most common in soils.Desorption of Hg increases with the increase of extracting time,until the highest desorption amount at 6-8 h,and then declines.It indicates that timeliness is very important when organic acids are used for phytoremediation in contaminated soils.When the concentrations of organic acids increase from 1.0 mmol/L to 10.0 mmol/L,Hg desorption increases significantly regardless of oxalic or citric acid.Compared with oxalic acid,citric acid is more effective to enhance the desorption of Hg,especially from fluvo-aquic soil.With the increase of initial pH value from 3 to 8,Hg desorption decreases directly in the presence of oxalic acid.However,Hg desorption first decreases,then increases,and eventually decreases again in the presence of citric acid due to the variation of competitive ability between chelating of citric acid and adsorption of soil in different pH values.Citric acid showed greater ability to release Hg from soils than oxalic acid.According to the results of the present study,it is found that the bioavailabilities of heavy metal can be improved with selecting suitable types and concentrations of organic acid amendment and reasonable soil condition. 相似文献
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《中国海洋湖沼学报》2021,(5)
The ocean is an important inventory of anthropogenic mercury(Hg),yet the history of anthropogenic Hg accumulation in the ocean remains largely unexplored.Deep-sea corals are an emerging archive of past ocean chemistry,which take in sinking or suspended particulate organic matter as their food sources.Such organic matter would exchange Hg with the local seawater before being consumed by the deepsea corals.As such,the organics preserved in the coral skeleton may record the Hg evolution of the ambient seawater during the time of coral growth.Here,we report the first data on Hg concentrations variability of a deep-sea proteinaceous coral in the oligotrophic North Pacific at the water depth of 1 249 m,in attempt to understand the transfer of anthropogenic Hg into the deep Pacific ocean over the last seven centuries.We find that the Hg concentrations of different coral growth layers have remained relatively constant albeit with considerable short-term variability through time.The overall stable Hg concentration of the last seven centuries recorded in our sample suggests that anthropogenic pollution is not yet a clearly resolvable component in the deep oligotrophic North Pacific waters,in agreement with rece nt estimation from modelling works and observational studies of modern seawater profiles.As there is hardly an unambiguous way to separate anthropogenic Hg from the natural background based on recent seawater profiles,our historical data provide valuable information helping to understand the oceanic cycle of Hg through time. 相似文献
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Oskar Bojko Cezary Kabala Łukasz Mendyk Maciej Markiewicz Magdalena Pagacz-Kostrzewa Bartłomiej Glina 《山地科学学报》2017,14(12):2391-2405
Global and local climate changes could disturb carbon sequestration and carbon stocks in forest soils. Thus, it is important to characterize the stability of soil organic matter and the dynamics of soil organic carbon (SOC) fractions in forest ecosystems. This study had two aims: (1) to evaluate the effects of altitude and vegetation on the content of labile and stabile forms of organic carbon in the mountain soils; and (2) to assess the impact of the properties of soil organic matter on the SOC pools under changing environmental conditions. The studies were conducted in the Karkonosze Mountains (SW Poland, Central Europe). The content of the most labile fraction of carbon (dissolved organic carbon, DOC) decreases with altitude, but the content of fulvic acids (FA), clearly increases in the zone above 1000 m asl, while the stabile fraction (humins, non-hydrolyzing carbon) significantly decreases. A higher contribution of stabile forms was found in soils under coniferous forests (Norway spruce), while a smaller - under deciduous forests (European beech) and on grasslands. The expected climate change and the ongoing land use transformations in the zone above 1000 m asl may lead to a substantial increase in the stable humus fraction (mainly of a non-hydrolyzing carbon) and an increase in the SOC pools, even if humus acids are characterized by a lower maturity and greater mobility favorable to soil podzolization. In the lower zone (below 1000 m asl), a decrease in the most stable humus forms can be expected, accompanied by an increase of DOC contribution, which will result in a reduction in SOC pools. Overall, the expected prevailing (spatial) effect is a decreasing contribution of the most stable humus fractions, which will be associated with a reduction in the SOC pools in medium-high mountains of temperate zone of Central Europe. 相似文献
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样品经低温稀王水溶解 ,在选定的仪器条件下 ,用氯化亚锡还原 ,测定汞的吸收峰值。方法简便、快速、价廉 ,适用于大批化探样品的测定。 相似文献
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The lowest addition of mercury (0.1 ug Hg 1−1) was used in CEEs for research on mercury flux, speciation and budget. The removal behavior of mercury by phytoplankton in
water columns of CEEs can be described by first order kinetic equations for total and particulate mercury in the CEE spiked
by mercury. The removal rate of mercury in water columns depends on the size and productivity of phytoplanton in a water column
to which mercuric ions were added. A 4.4 day half-life time and a 2.8 day half-life time for total and particulate mercury
respectively was obtained in diatom bloom. During microflagellate bloom a 30 day total mercury half-life time was estimated
with increase of particulate mercury in the water column. The 0.010 ug Hg cm−2y−1 mercury flux rate that was attained in the control bag agreed with the values from field measurements in Saanich Inlet where
the bags were launched.
The proportion of total mercury to dissolved and particulate mercury depended also on the size, productivity, and concentration
of mercury in a water column. A more or less constant distribution of mercury species in the control bag was observed as follows:
dissolved Hg 0.73, particulate Hg 0.27, inorganic Hg 0.42, dissolved organic Hg 0.31. After spiking with mercury, the particulate
mercury rose rapidly and reached to over 70% of the total mercury.
The concentration factor of mercury by phytoplankton in the CEEs in the order of 105 was consistent with the results from field measurements in Saanich Inlet.
The mercury recovery from the water column, sediment, water with sediment, and the CEE bag walls was only 52.3% of total mercury
spiked in the CEE. The losses of mercury by vaporization into the ambient air and diffusion through the wall of the enclosure
should be considered.
This paper was published in Chinese inOcean. Limn. Sinica,17(4):307–317, 1986. 相似文献
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This study reports the geochemical characteristics of zinc (Zn), copper (Cu), lead (Pb), nickel (Ni), mercury (Hg), iron (Fe),
and manganese (Mn) in the riparian sediment pore water of the Songhua River, Northeast China. In total, 36 pore water samples
and 18 surface water samples from three typical sections were collected and analyzed in June 2009. Cluster analysis of heavy
metals was performed to analyze the pollution sources of the metals. Results showed that Hg concentrations in the pore water
were greater than those in the surface water, indicating a potential ability of Hg release from riparian sediment system to
river water. However, concentrations of Fe and Mn in the surface water were greater than those in the pore water, demonstrating
that the microenvironments of riparian and riverbed sediment systems were quite different. Variations of Zn, Cu, Pb and Ni
between the surface and the pore water were different in each section. Most metals had similar horizontal and profile distribution
characteristics in the three sections except for Zn and Ni. Hg, Fe and Mn concentrations in the pore water increased gradually
with the increase in horizontal distance from water body, in contrast to this, Cu decreased, and Pb presented a fluctuating
trend. With the increase in depth, Pb and Fe, Cu and Mn showed the same trends, and Hg showed a variable trend. The above
distribution characteristics could mainly be attributed to the properties and the interactions of metals, pH and oxidation-reduction
conditions, and the complex pollution sources and hydrologic regime in history. The probable sources of metals include the
historical and ongoing discharge of industrial wastewater, mining activities, sewage irrigation for agricultural production,
and atmospheric deposition from coal-fired plants. 相似文献
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根据郑州市东北郊不同污水灌区、不同深度的土壤采样分析结果,计算了重金属元素在土壤中的概率分布类型及环境背景值,论述了重金属元素对土壤的污染特点及其对农作物生长的影响,并指出了汞污染土壤的普遍性和对粮食及蔬菜质量所造成的危害。 相似文献