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盐渍化土壤肥力演变规律研究 总被引：6，自引：0，他引：6
本文是在曲周试验区的长期定位试验和大田调查的基础上 ，研究了盐渍化土壤在改良、利用及培肥过程中，构成土壤肥力的主要因素的演变规律．研 究结果表明：土壤有机质含量从治理初期的小于５ｇ／ｋｇ提高到１５ ｇ／ｋｇ左右；土壤碱解氮从开 始的富氮假象，逐步出现土壤碱解氮含量迅速下降的现象，再缓慢上升到７０～８０ｍｇ／ｋｇ，有 的甚至超过了１３０ ｍｇ／ｋｇ；土壤有效磷含量从２～３ ｍｇ／ｋｇ或者只有０．５～１ ｍｇ／ｋｇ左右，有的 地块近于零提高到１５～２０ ｍｇ／ｋｇ，有的已接近６０ ｍｇ／ｋｇ；土壤速效钾含量则由治理初期的２０ ０ ｍｇ／ｋｇ，下降到３０ ｍｇ／ｋｇ左右；土壤微生物量明显增加，理化性状不断改善，熟化程度逐 步提高；土壤肥力的变化表现出了阶段性特征．提出了盐渍化土壤的合理施肥技术． 相似文献
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钼是生命必需的微量元素，我国土壤含钼范围为０．１－６．０ｍｇ／ｋｇ，有效钼含量从痕迹至０．６５ｍｇ／ｋｇ。农作物正常含钼量０．１－２０ｍｇ／ｋｇ。大豆，玉米，小麦，谷子施钼可使籽粒钼的含量比照增加０．０５６－１２．９ｍｇ／ｋｇ。大豆，小麦施钼比对照可降低硝酸盐，亚硝酸盐含量２．７－６．７％。 相似文献
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紫色土镍对莴笋的毒性临界状态值研究 总被引：3，自引：0，他引：3
以盆栽试验，研究了紫色土中镍对莴笋的毒性统一临界指标。结果表明，以０．０５ｍｏｌ／Ｌ ＣａＣｌ２提取Ｎｉ为指标的土壤Ｎｉ毒性临界状态值在各土壤中可达统一，考虑到土壤伴随元素的影响，可按石灰性和非石灰性紫色土两种情况制定指标，本研究结果是：非石灰性紫色土为（１１．４±０．９２）ｍｇ／ｋｇ土，石灰性紫色土为（１．２±０．１１）ｍｇ／ｋｇ土。 相似文献
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贵州省土壤含硒量及其分布 总被引：14，自引：0，他引：14
贵州省土壤全硒含量的范围为０．０６４－１．３２６ｍｇ／ｋｇ，平均值０．３６９ｍｇ／ｋｇ。全境土壤含硒有由北向东南和随地势下降而逐步增加的趋势。全省可划分为：１．低硒区２．中低硒区３．中硒区４．中高硒区。贵州多数地区土壤属中等含硒水平，少数土壤富硒，同时还有少量缺硒土壤分布。 相似文献
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反相高效液相色谱法检测水,土壤中的除草醚 总被引：3，自引：0，他引：3
介绍了应用反相高效液相色谱检测水，土壤中除草醚的方法。该方法对除草醚在水和土壤中的回收率分别为９９．０％和９２．５％，最小检出浓度分别为１．１×１０＾－２ｍｇ／Ｌ和０．１１ｍｇ／ｋｇ。 相似文献
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用充氧燃烧氟离子电极法测定了安徽产不同品种、不同等级、不同季节和不同地区茶叶中的氟化物，其含量为８．３２－２０８。９１ｍｇ／ｋｇ，发现有显性差异。同时测定了安徽主要水源自来水中含氟量为０．１５－１．０３ｍｇ／Ｌ。并且采用不同饮茶方式研究茶吕中化物含量的变化。 相似文献
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氟氰菊酯在苹果和土壤上的残留动态研究 总被引：1，自引：0，他引：1
本文研究了自然条件下氟氰菊酯在苹果和土壤上的消解规律与最终残留量。结果表明，氟氰菊酯在苹果和土壤上消解较为缓慢，苹果上的半衰期２１．９－２３．６ｄ，土壤上的半衰期为２１．２－２７．８ｄ。在使用浓度为１００－２００ｍｇ／Ｌ，施用２次的情况下，苹果和土壤的最终残留量分别低于０．５和０．０５ｍｇ／ｋｇ。 相似文献
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The extraction of proteins with low fluoride level (LFP) from Antarctic krill (Euphausia superba) was investigated in this work. The optimal conditions for protein solubilization were determined to be pH 11.5 and 4 °C. The proteins were solubilized two times; a water/krill ratio (mL/g) of 6 and a time of 30 min were used for the first step, whereas the second used a water/krill residue ratio (mL/g) of 3 and a time of 30 min. The optimum pH for protein precipitation was 4.6. A LFP with fluoride content of 9.86 mg/kg (dry weight) was finally obtained through a fluoride removal program. The protein yield of LFP was 52.68%. Composition analysis of LFP indicated it was composed of 66.96% of crude proteins (dry weight) and 33.01% of total lipids (dry weight),, and all nine essential amino acids were in sufficient amounts to meet FAO/WHO/UNU requirements for adults and infants. In addition, LFP could be taken as a good source of EPA and DHA for consideration of use as a food item for human consumption. 相似文献
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Bibhash Nath Sudip J. Sahu Joydev Jana Aishwarya Mukherjee-Goswami Sharmi Roy Madhav J. Sarkar Debashis Chatterjee 《Water, air, and soil pollution》2008,190(1-4):95-113
The present study aims to understand the hydrochemistry vis-à-vis As-exposure from drinking groundwater in rural Bengal. The characteristic feature of the groundwaters are low Eh (range, ?151 to ?37 mV; mean, ?68 mV) and nitrate (range, 0.01–1.7 mg/l; mean, 0.14 mg/l) followed by high alkalinity (range, 100–630 mg/l; mean, 301 mg/l), Fe (range, 0.99–38 mg/l; mean, 8.1 mg/l), phosphate (range, 0.01–15 mg/l; mean, 0.54 mg/l), hardness (range, 46–600 mg/l; mean, 245 mg/l) and sulphate (range, 0.19–88 mg/l; mean, 7.2 mg/l), indicating reducing nature of the aquifer. The land use pattern (sanitation, surface water bodies, sanitation coupled with surface water bodies and agricultural lands) demonstrates local enrichment factor for As/Fe in groundwater. Among these, sanitation is the most prevailing where groundwater is generally enriched with As (mean, 269 μg/l) and Fe (mean, 9.8 mg/l). Questionnaire survey highlights that ～70% of the villagers in the study area do not have proper sanitation. This demonstrating the local unsewered sanitation (organic waste, anthropogenic in origin) could also cause As toxicity in rural Bengal. In the agricultural lands, higher mean values of alkalinity, phosphate, sulphate, hardness and electrical conductivity was observed, and could be linked with the excessive use of fertilizers for agricultural production. Bio-markers study indicates that the accumulation of As in hair and nail is related with the construction of exposure scenario with time dimension. The strength and weakness of the on-going West Bengal and Bangladesh drinking water supply scenario and achievability towards alternative options are also evaluated. 相似文献
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Groundwaters contaminated with excess fluoride (above 1.5 mg/L) posed some risks to the public health in India. Methods available for fluoride contaminated water treatment are cogaulation–filtration using alum + lime + bleaching powder (Nalgonda technique) and adsorption using activated alumina. Use of aluminium compounds for water treatment purpose needs replacement on neurological health problem. Objective to this, the synthesis and fluoride adsorption behavior of hydrous ferric oxide (HFO) are reported here. It is seen that fluoride adsorption density varies as a function of pH, contact time, aging time, drying temperature and particle size of HFO. Highest adsorption density for fluoride is found to be at pH 4.0. Effects of competing anions in removing fluoride from solution were tested. Arsenite, arsenate, phosphate and sulfate show strong interfering effect at high anions to fluoride molar ratio in solution. Adsorption of fluoride on HFO follows the Freundlich isotherm and the Lagergren first-order kinetic model. It was also determined that HFO is a better adsorbent in removing fluoride from high fluoride groundwater than some other adsorbents. Regeneration of fluoride-rich HFO results showed that 1.0 M NaOH solution could be used up to a maximum of 75% regeneration. 相似文献
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J R Marzilli F L Acampora L R Alexander M Y Alpert R A Baetz G Bohm J J Donovan A O Landskov F G McNerney P J Simon 《Journal of the Association of Official Analytical Chemists》1984,67(4):682-684
A proposed method using the fluoride (F) ion-selective electrode has been developed for determining the fluoride ion concentration in tablets and solutions containing sodium fluoride. The method has been subjected to collaborative study. Eight samples consisting of 2 authentic fluoride solutions, 2 commercial fluoride solutions, and 4 commercial fluoride tablets were sent to each of 11 collaborators together with a copy of the method. Single assays on the authentic fluoride solutions known to contain 1 mg F/5 mL were performed with average recoveries of 99.5 and 99.6% and relative coefficients of variation (CV) of 2.11 and 1.91%, respectively. Single assays of 2 commercial fluoride solutions declared at 1 mg F/5 mL gave mean values of 0.994 and 0.990 mg and relative CV values of 1.88 and 2.36%, respectively. Single assays of 2 commercial fluoride tablet preparations declared at 0.5 mg F gave mean values of 0.485 and 0.478 mg and relative CV values of 3.12 and 3.71%, respectively. Single assays of 2 commercial fluoride tablet preparations declared at 1 mg F gave mean values of 0.991 and 0.981 mg and relative CV values of 2.99 and 2.85%, respectively. The method has been adopted official first action. 相似文献
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Gisele Cristina dos Santos Bazanella Gabriel Francisco da Silva Angélica Marquetotti Salcedo Vieira Rosangela Bergamasco 《Water, air, and soil pollution》2012,223(9):6083-6093
The occurrence of fluoride in groundwater has been reported in many countries, mainly because the excess fluoride in drinking water can lead to dental or skeletal fluorosis. Fluoride removal by coagulation with Moringa oleifera seeds, followed by separation with membranes, was investigated in this work. Artificially fluoridated water, at a starting fluoride concentration of 10?mg?L?1, was submitted to a coagulation process with aqueous extracts of M. oleifera seeds. The coagulation process was followed by ultrafiltration with membranes at different pressures. The coagulation process with 2.5?g?L?1 of M. oleifera promoted a reduction of 90.90?% in the fluoride content of the treated water, making it possible for poor communities to consume this water. It is noteworthy that the combined coagulation/filtration process using raw coagulant showed the highest values of colour and turbidity, which, however, were still below the limits set for drinking water by Brazilian legislation. The advantage of proposing a sequential process using membrane separation is that it removes colour and turbidity, caused by the use of M. oleifera as a coagulant, resulting in water that meets potability standards. 相似文献
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E. Dotsika D. Poutoukis J. L. Michelot W. Kloppmann 《Water, air, and soil pollution》2006,174(1-4):19-32
Boron is biologically an essential element but is toxic at high concentrations to plants (above approximately 1 mg/L in irrigation water) and probably to humans: The EU Drinking Water Directive fixes a threshold of 1 mg/L and the World Health Organisation (WHO) set a recommended limit at 0.3 mg/L now increased to 0.5 mg/L. Because of this potential toxicity and the need of implementation of EU regulation on national level, the study of the boron levels in both ground- and surface water is of great significance for water management. In Greece, a significant number of thermal, mineral and superficial water springs are found especially in Northern Greece, that present high boron values rendering such water unacceptable according to the European standards. Nevertheless, such ground waters or borehole water with high temperature and high boron content are used for irrigation and drinking purposes, and could therefore have an antagonistic effect on crop yield and health. In order to study the boron contamination and to elucidate the origin of B, we collected a number of hot and fresh water all over Greece. In all the water sampled, the boron concentration exceeds the limit of 0.3 mg/L, which is the former recommended WHO limit. Moreover, in the irrigation water examined, the boron concentration exceeds the value of 0.75 mg/L, which is the limit for sensitive plants (for plants of moderate and plants of high tolerance, these values vary between 0.75–3 and > 3 mg/L respectively). In all cases, elevated boron could be attributed to natural sources, geothermal activity and/or seawater intrusion into the aquifers. This finding has important implications for water management: In a setting of high natural geochemical background values, source control of the pollution is not possible and water managers have to cope with a local to regional geochemical anomaly that implies boron specific water treatment or mixing with unpolluted resources to bring concentrations down. 相似文献
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Monitoring of surface water and shallow aquifers inside and outside of the Los Azufres geothermal fieldduring the period November 1994 to May 1996 led to thedetection of some contamination of surface water andshallow aquifers due to exploitation of the deepbrines. Leaking of evaporation ponds and pipelines,occasionally overflowing of reinjection wells and pondrims as well as outflowing of brines duringrehabilitation or drilling operations, are potentialcontamination sources within the cycle of geothermalproduction.Temporarily and/or permanently increased traceelements concentrations, especially Fe, Mn, F, B, andAs in surface waters within the geothermal field aswell as up to 10 km outside, were observed. Maximumvalues of 125 and 8 mg L-1 were observed for B and As,respectively. The discharge of hypersaline geothermalbrines also causes salinization of surrounding soils.It occasionally happens that cattle drink from thebrines. The use of the river for irrigation anddrinking water supply in the surrounding regions maycause accumulation of toxic elements in the human foodchain or may endanger the public health.The establishment of a closed geothermal productioncycle can be achieved by simple remediationtechniques, such as sealing of the pond walls, removalof overflow channels, direct reinjection without anyreposal time in evaporation ponds, as well as animproved security and control system. 相似文献
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In this research, geological and hydrogeological studies were conducted to determine the source of high arsenic levels in the surficial aquifer of Simav Plain, Kutahya, Turkey. One of the two aquifer systems isolated in the study area was a deep confined aquifer composed of fractured metamorphic rocks that supply hot geothermal fluid. The other one was an unconfined alluvial aquifer, which developed within the graben area as a result of sediment deposition from the highlands. This aquifer serves as the primary water resource within the plain. A water quality sampling campaign conducted in 27 wells drilled in the surficial aquifer has yielded an average arsenic concentration of 99.1 µg/L with a maximum of 561.5 µg/L. Rock and sediment samples supported the fact that local metamorphic rocks contained significant amounts of sulfur minerals where arsenic-containing lenses are present inside. It was also determined that a Cu–Pb–Zn mine was operated in the past in the same formation. Arsenic-containing wastes of this mine were deposited near the Simav district center in an uncontrolled manner. This mined formation had arsenic levels reaching to levels as high as 660 mg/kg, which was found out to be the highest arsenic level in the area. Another potential arsenic source in the study area was the geothermal fluid that was used extensively in three geothermal fields with levels reaching to levels as high as 594 µg/L. Uncontrolled discharges of waste geothermal fluid and overexploitation of groundwater were also found to contribute to arsenic pollution in surface/subsurface waters of the plain. Thus, natural sources and anthropogenic influences of arsenic were found to create high concentrations in local water reserves of the area and influence human health. Consequently, death statistics from the 1995 to 2005 period collected from the area has revealed increased rates of gastrointestinal cancers above Turkish average. 相似文献
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Laxmi Kant Kachhwal Ernest K. Yanful Lisa Lanteigne 《Water, air, and soil pollution》2011,214(1-4):357-382
Environmentally safe disposal of sulfide-rich reactive mine tailings is one of the major challenges facing the mining industry in Canada, Scandinavia, USA, and many other parts of the world. Placing tailings under a water cover is one of the effective methods to reduce the influx of oxygen to the tailings. Wind-induced turbulence and subsequent resuspension of the tailings, however, are major concerns with this approach. In this paper, a study of wind-induced resuspension at the Shebandowan tailings storage facility, northwestern Ontario, Canada, is discussed. The study compares computer modeling of required water cover depths and resuspended tailings concentrations to observed field data. The calculated minimum water cover depths required to eliminate resuspension were found to be higher than the existing implemented water cover depths in each cell. The predicted resuspended tailings concentrations for the west cell were 6?C22?mg/l with an average value of 15?mg/l and, for the east cell, 1?C10?mg/l, with an average of 6.0?mg/l. In comparison, optical backscatter sensors, deployed in situ, recorded average resuspended tailings concentration up to 25?mg/l, indicating that the model results were similar to the field-measured values. Results from sediment trap measurements did not show any correlation between the amount of resuspended tailings and water cover depth. Sediment traps collect not only sediments eroded and suspended at the location of deployment but also those that have been transported from elsewhere and redeposited at the trap location. The amount of resuspension occurring at Shebandowan does not raise a major concern because discharge from the tailings area is collected and managed before it reports to the final effluent. 相似文献