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排序方式: 共有356条查询结果,搜索用时 140 毫秒
291.
In order to evaluate the possibility of contamination of soil with trace elements by the application of sludges to soil, the contents of rare earth elements (REEs; La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) and other trace elements (Be, As, Ag, Cd, Sb, Cs, Bi, and U) in wastewater treatment sludges were determined. In sludges of night soil treatment plants (night soil sludges) and sludges of wastewater treatment plants in the food industry (food industry sludges), the distribution patterns of REEs normalized versus average REEs in the continental crust were almost flat. It was considered that the REE patterns of uncontaminated sludges reflected the pattern of the continental crust. The crust-normalized REE patterns of sludges of wastewater treatment plants in the chemical industry (chemical industry sludges) and municipal sewage sludges did not always show flat plots. The sludges that did not show a flat REE pattern were considered to be contaminated with some of the REEs. The coefficient of variation of each element determined among the 10 samples of night soil sludges and the 14 samples of sewage sludges ranged from 34 to 77% and from 26 to 84%, respectively. Among the 10 samples of food industry sludges and the 10 samples of chemical industry sludges, the coefficient ranged from 60 to 143% and from 67 to 172%, respectively. The variations of the content of each element among the food industry sludges or the chemical industry sludges were larger than those among the night soil sludges or the sewage sludges. The contents of Be, As, Cs, REEs, and U in all the sludges were lower than or the same as those in a field soil. Some of the food and chemical industry sludges contained larger amounts of Ag, Cd, and Sb than the soil. All the night soil sludges and sewage sludges contained much larger amounts of Ag and Bi than the soil. 相似文献
292.
Satoru Taniguchi Naoto Yamagata Katsutoshi Sakurai 《Soil Science and Plant Nutrition》2013,59(2):315-324
The hydroxyaluminosilicate (HAS)-montmorillonite (Mt) and hydroxyaluminum (HyA)-Mt complexes are important constituents of soil colloidal complexes in acidic environments. Oxalate and citrate are dominant organic acids in the root exudates of many plants. These acids, among other factors, strongly influence the adsorption behavior of HAS-Mt and HyA-Mt complexes. In this study, we investigated the adsorption phenomena of Cd on the HAS-Mt and HyA-Mt complexes as influenced by oxalate and citrate. Without addition of oxalate and citrate, the adsorption of Cd on Mt was easy. However, in the presence of oxalate and citrate, the adsorption was strongly inhibited. In contrast, the HAS-Mt and HyA-Mt complexes in the absence of oxalate and citrate hardly adsorbed Cd. In the presence of oxalate, the HAS-Mt and HyA-Mt complexes were able to adsorb Cd. Thus, optimal concentration of oxalate for Cd adsorption on both complexes could be determined. Similarly, the HyA-Mt complex showed an optimal concentration of citrate for Cd adsorption. However, the HAS-Mt complex did not adsorb Cd in the presence of citrate. We concluded that the optimal concentrations of oxalate and citrate for Cd adsorption depended on the form of Cd ions and their proportion in the solution. Based on the amount of Cd adsorbed and the distribution of Cd species in the solution, the adsorption of Cd on the HAS-Mt and HyA-Mt complexes took place in various chemical forms. 相似文献
293.
Mary Jane dela Cruz Masao Yoshida Masatsugu Kubota Hiromi Fujita Shigemitsu Arai 《Soil Science and Plant Nutrition》2013,59(6):793-803
Soils of the northwestern part of the Taal Volcano in the Philippines representing four geomorphological units (upper, middle, and lower slopes and alluvial plains) were investigated and related to soil productivity. Results revealed that the soils on the upper and middle slopes contained higher amounts of organic matter and available P and displayed a low P retention together with more favorable physical properties such as loamy soil texture, loose and friable and well-drained soils compared to those on the lower slopes and in the alluvial plains. Due to these favorable soil characteristics, sustained agricultural production was higher at the upper elevations than at the lower elevations. Year-round multistorey / mixed cropping systems of cultivation in the upper and middle landscapes were also made possible because the higher precipitation was evenly distributed coupled with cooler temperatures compared the conditions on the lower slopes and in the alluvial plains. On the other hand, the soils on the lower slopes and in the alluvial plains had a clayey texture and contained a lower amount of organic matter and available P, in addition to the lower precipitation, resulting in reduced land utilization, as indicated by the limited types of crops grown and lower yield of crops. 相似文献
294.
Katsutoshi Sakurai Akinori Nakayama Tsutomu Watanabe Kazutake Kyuma 《Soil Science and Plant Nutrition》2013,59(4):623-633
Influence of Al dissolution on soil ZPC (zero point of charge) measured by a potentio-metric titration (PT) method and a modified salt titration (STPT) method was examined using two strongly weathered soils from Thailand and two volcanic ash soils from Japan. The amount of dissolved Al ions increased with the increase in the concentration of a supporting electrolyte for the strongly weathered soils, while the increase was negligible for the volcanic ash soils. ZPC value of the strongly weathered soils determined by the PT method was lower than that by the STPT method, due to the greater Al dissolution associated with the higher electrolyte concentration used in the PT method. Al ions adsorbed onto the soil surface would shift the ZPC to a higher pH value not as a result of the formation of hydroxy Al polymers, but due to the blocking of permanent negative charge sites, which could otherwise lower the ZPC. The σp value, as a measure of permanent charge or the amount of 11 or O11 adsorbed by a soil required to attain the ZPC, could be used to describe this phenomenon. In the STPT method, the salt concentration was not high enough to causc a significant Al dissolution at the ZPC, which is considered to be a more suitable condition than in the PT method because the ZPC value can be evaluated at a low salt concentration as in the ease of field conditions for crop production. Thus, the STPT method is rccommendcd for the determination of the ZPC. 相似文献
295.
Arai T Tanaka Y Urabe S Kusaba A Tazaki H Ozawa T Kimura N Jung KK Waragaya K Yuyama T Haseba Y Imai S 《Research in veterinary science》2006,81(1):19-23
Plasma metabolite and immunoreactive insulin concentrations and activities of enzymes related to energy metabolism in peripheral leukocytes were measured in growing Holstein calves. A ratio of girth of abdomen divided by girth of thorax (A/T ratio) of calves was significantly elevated after weaning, and the A/T ratio maybe a good indicator to evaluate rumen development. Plasma glucose and free fatty acid concentrations were changed in calves accompanying change in feeding. Activities of lactate dehydrogenase with pyruvate as substrate (LDH-P) and hexokinase (HK) in cytosolic fractions of peripheral leukocytes decreased significantly after weaning the calves reflecting the change of energy source from milk replacer with high percentages of fat and glucose and lactose as absorbable carbohydrate to pelleted feed containing starch as less absorbable carbohydrate and roughage. Some peripheral leukocyte enzymes such as LDH and HK may be good indicators to evaluate changes in energy metabolism of growing calves. 相似文献
296.
Washizu T. Takahashi M. Azakami D. Ikeda M. Arai T. 《Veterinary research communications》2001,25(8):623-629
The activities of the enzymes involved in the malate–aspartate shuttle and the expression of malate dehydrogenase (MDH), a rate-limiting enzyme in the NADH shuttle that produces ATP in glucose metabolism in leukocytes, were determined to investigate the differences in this shuttle system in the peripheral leukocytes of dogs and cats. There were no significant differences between dogs and cats in plasma glucose, immunoreactive insulin, free fatty acid or triglyceride concentrations. The activities of cytosolic and mitochondrial MDH and of mitochondrial glutamate dehydrogenase (GLDH) in canine leukocytes were significantly higher than in feline leukocytes. High activities of MDH in canine leukocytes were confirmed by RT-PCR analysis on the total RNA extracted from leukocytes. It was concluded that there were significant differences between dogs and cats in the NADH shuttle system. 相似文献
297.
M Arai E Stauber C M Shropshire 《Journal of the American Veterinary Medical Association》1992,200(9):1329-1331
Leaves or fruit from 14 plants considered to be toxic to pet birds were administered by gavage to 15 pairs of canaries (Serinus canaria). Each bird was given 0.12 to 0.70 g of plant material. One pair served as a control and was given distilled water. The plant materials were flash-frozen in liquid nitrogen, pulverized, and resuspended in deionized water for administration. Of the plants tested, 5 (oleander, lupine, foxglove, yew leaves, and dieffenbachia) were considered highly toxic and were associated with acute death of birds. The remaining plant samples caused no, or only transient, clinical illness. 相似文献
298.
Washizu T. Kuramoto E. Abe M. Sako T. Arai T. 《Veterinary research communications》1998,22(3):187-192
The activities of Na>+,K>+-ATPase in plasma membrane, of cytosolic enzymes and of glutamate dehydrogenase (GlGD) in mitochondria were measured in leukocytes (WBC) from dogs and cats to clarify the differences in energy metabolism in these cells. Feline WBC had significantly higher activities of hexokinase (HK), pyruvate kinase (PK) and LDH with pyruvate as substrate than did canine WBC. Canine WBC had significantly higher activities of glucokinase (GK) and GlDH than did feline WBC. Feline WBC had unique characteristics of energy metabolism in that the activities of the cytosolic enzymes under anaerobic conditions were significantly higher than those in canine WBC. It therefore appears that there are distinct differences in glucose metabolism in WBC between dogs and cats. WBC enzyme activities are considered to reflect the metabolic state in the whole body of the animal. It is therefore suggested that changes in the activities of certain glycolytic enzymes in WBC may be useful as a diagnostic indicator in some types of metabolic disease in dogs and cats. 相似文献
299.
300.
Kien Chu Ngoc Noi Van Nguyen Bang Nguyen Dinh Son Le Thanh Sota Tanaka Yumei Kang Katsutoshi Sakurai Kōzō Iwasaki 《Water, air, and soil pollution》2009,197(1-4):75-89
This study assessed the arsenic and heavy metal contaminations of agricultural soils around the tin and tungsten mining areas in Dai Tu district in northern Vietnam. Among the examined elements, high total contents of As and Cu were found in the agricultural fields at both tin and tungsten mining sites. Although the major part of the accumulated As and Cu were bound by various soil constituents such as Fe and Mn oxides, organic matter, and clay minerals, increases in water soluble As and Cu were observed, especially for the paddy fields. The results suggest that, in the studied area, As and Cu dispersion from their pollution sources into farmlands is mainly via fluvial transportation of mine waste through streams that cross the paddy fields around the tin mining area, and soil erosion at the tea fields located at lower positions of the slope in the tungsten mining area. 相似文献