重金属高污染农田土壤EDTA淋洗条件初探

通过室内振荡淋洗试验研究了乙二胺四乙酸二钠(EDTA)浓度、淋洗时间、液固比、淋洗次数对甘肃省白银市某高污染农田土壤中重金属去除效果的影响,并测定了EDTA淋洗前后土壤中重金属形态的变化。结果表明：淋洗剂浓度和液固比越高、淋洗时间越长、淋洗次数越多,对重金属的去除效果越好。在EDTA浓度为5 mmol/L、液固比为2.5、连续振荡淋洗3次、每次1 h时,对土壤中Cd、Cu、Pb、Zn 4种重金属的总去除率分别为 55.2%、21.9%、19.3% 和20.9%,其中Cd 淋洗效率最高。EDTA对土壤中交换态、碳酸盐结合态和铁锰氧化物结合态重金属的去除效果明显,但不能有效去除有机及硫化物态和残余态土壤重金属。     

某PCB厂沉铜冲洗水重金属达标处理技术应用探讨

指出了某厂在PCB生产过程中,排放出多种废水、废液,其中含有高浓度的铜氨、EDTA等络合物,如果此类废水没有得到有效的预处理,将会影响整个工厂污水处理（5000m。／d）系统的正常运行,甚至瘫痪整个污水处理系统。以武汉某电路板公司络合废水预处理工程项目实践为例,处理能力24m。／d,结合沉铜生产工艺特点,总结了处理络合废水中重金属的实用技术。工程实践表明：使用高效MP一10破络剂,可以简单做到过程控制沉铜冲洗水预处理系统出水中的重金属含量,从而确保100％达标。     

Fraction Distributions of Lead,Cadmium, Copper,and Zinc in Metal‐Contaminated Soil before and after Extraction with Disodium Ethylenediaminetetraacetic Acid

Abstract: The fraction distributions of heavy metals have attracted more attention because of the relationship between the toxicity and their speciation. Heavy‐metal fraction distributions in soil contaminated with mine tailings (soil A) and in soil irrigated with mine wastewater (soil B), before and after treatment with disodium ethylenediaminetetraacetic acid (EDTA), were analyzed with Tessier's sequential extraction procedures. The total contents of lead (Pb), cadmium (Cd), copper (Cu), and zinc (Zn) exceeded the maximum permissible levels by 5.1, 33.3, 3.1, and 8.0 times in soil A and by 2.6, 12.0, 0.2, and 1.9 times in soil B, respectively. The results showed that both soils had high levels of heavy‐metal pollution. Although the fractions were found in different distribution before extraction, the residual fraction was found to be the predominant fraction of the four heavy metals. There was a small amount of exchangeable fraction of heavy metals in both contaminated soils. Furthermore, in this study, the extraction efficiencies of Pb, Cd, and Cu were higher than those of Zn. After extraction, the concentrations of exchangeable Pb, Cd, Cu, and Zn increased 84.7 mg·kg^?1, 0.3 mg·kg^?1, 4.1 mg·kg^?1, and 39.9 mg·kg^?1 in soil A and 48.7 mg·kg^?1, 0.6 mg·kg^?1, 2.7 mg·kg^?1, and 44.1 mg·kg^?1 in soil B, respectively. The concentrations of carbonate, iron and manganese oxides, organic matter, and residue of heavy metals decreased. This implies that EDTA increased metal mobility and bioavailability and may lead to groundwater contamination.     

EDTA二钠滴定法测定钙离子含量滴定终点的确定

本文通过对EDTA滴定法测定钙离子含量试验原理的分析提出了正确读取在滴定终点时,所用EDTA二钙溶液溶量的方法,对工地试验现场较精确测定水泥或石灰剂量有一定的意义.     

Effects of ethylenediaminetetraacetic acid on phytate phosphorus utilization and efficiency of microbial phytase in broiler chicks

Previous studies have suggested that organic acids may improve P utilization in animals. To evaluate the ability of ethylenediaminetetraacetic acid (EDTA) to improve phytate P utilization and the possible synergistic effect between EDTA and microbial phytase (MP) an experiment was conducted using 360 Ross 308 broiler chicks. The experiment was carried out using a completely randomized design with a 3*2 factorial arrangement (0, 0.1 and 0.2% EDTA and 0 and 500 IU MP). Four replicate of 15 chicks per each were fed dietary treatments including (i) P-deficient basal diet [0.2% available phosphorus (aP)] (NC); (ii) NC + 500 IU MP per kilogram of diet; (iii) NC + 0.1% EDTA per kilogram of diet; (iv) NC + 0.1% EDTA and 500 IU MP per kilogram of diet; (v) NC + 0.2% EDTA per kilogram; and (vi) NC + 0.2% EDTA + 500 IU MP per kilogram of diet. Weight gain (WG), feed efficiency and serum Ca, P and alkaline phosphatase (ALP) were assessed. Addition of 0.2% EDTA to low aP diets resulted in significantly lower feed consumption (FC) and WG, but 0.1% EDTA did not depress WG compared to NC. Phytase supplementation of P-deficient diets significantly improved WG and feed efficiency, but it had no effect on FC. Microbial phytase supplementation significantly decreased ALP concentration. Results obtained in our study suggest no synergistic effect between phytase and EDTA in broiler chicks.     

Transient expression of an active human interferon-beta in lettuce

Using Agrobacterium mediated transient expression method, plant bivalent expression vector pBI121 containing GUS as a report gene was transformed into lettuce (Lactuca sativa). Through designed orthogonal analysis, intact lettuce leaves infiltrated with 200 μM acetosyringone and 0.8 OD₆₀₀ bacterial suspensions under vacuum for 30 min, then co-cultured at 24 °C for 6 ds produced a maximum GUS protein of 2.5% TSP with 21.39 nmol mg⁻¹ min⁻¹ MU activity, which was 19 times of the control (1.31 nmol mg⁻¹ min⁻¹ MU). Employed these optimized conditions HuIFN-beta was expressed in lettuce leaves. Western blot and antivirus bioactivity analyses confirmed the HuIFN-beta achieved by agrobacterium infiltration had a high biological activity (3.1 × 10⁴ IU/mL). To our knowledge, it is the first detailed orthogonal optimizing study of Agrobacterium mediated transient expression and the first report on the production of the biologically active therapeutic proteins produced by Agrobacterium mediated transient expression in lettuce. In summary, transient expression by Agrobacterium vacuum infiltration can be adopted as an efficient, inexpensive and small-scaled plant expression system for therapeutic protein production.     

Effects of Common Anticoagulants on Routine Plasma Biochemistry of Horse and Comparison with Serum

The effects of various types of anticoagulants on plasma biochemistry have been studied in humans and various animals; however, limited information exists for effects on horse plasma biochemistry. Ten clinically healthy Thoroughbred horses were blood sampled in tubes containing different anticoagulants as well as no anticoagulant. The concentrations of glucose, cholesterol, triglyceride, total bilirubin, blood urea nitrogen (BUN), creatinine, total protein, albumin, calcium, inorganic phosphorus, magnesium and iron, and the activity of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatine kinase (CK), and gamma glutamyl transferase (GGT) were measured. Except for the amounts of inorganic phosphorus, magnesium, and GGT, other measured parameters were significantly lower in citrated plasma than in serum. When corrected for dilution, significant differences were seen for the amounts of glucose, cholesterol, triglyceride, bilirubin, calcium, iron, and the activity of ALT, ALP, and CK in citrated plasma. Most parameters did not show any difference; however, significant decreases in BUN, total bilirubin, ALT, and CK activity were seen when heparin was used as an anticoagulant. When compared with serum, using ethylenediaminetetra-acetic acid (EDTA) as an anticoagulant produced a significant difference in the amounts of measured plasma parameters with the exception of GGT, albumin, creatinine, inorganic phosphorus, and triglyceride.     

Effect of salicylic acid on jasmonic acid-related defense response of pea seedlings to wounding

Interactions between jasmonic acid (JA) and salicylic acid (SA) signaling pathways play important roles in the regulation and fine-tuning of induced defenses which are activated by pathogen, insect attack, or wounding. In this study, endogenous SA and JA level in pea seedlings presented opposite trends in response to wounding. Results exhibited that SA impaired the resistance to wounding of pea seedlings by means of suppressing the action of JA. Based on the fact that the wound-induced PPO activity was suppressed by SA, it could be concluded further that SA had negative effect on JA-related defense response. However, synergy between JA and SA also existed in phenolic metabolism related to PAL. Moreover, endogenous SA and salicylic acid 2-O-β-d-glucose (SAG) levels in wounded pea seedlings also appeared opposite variation tendency, and newly synthesised SAG was detected. In contrast to SA, SAG showed some synergistic action in JA-related defense response in terms of MDA, PPO activity and PAL activity, which was quite different from SA. In conclusion, these results revealed both the negative effect and some synergistic effect of SA on JA-related defense of pea in response to wounding, particularly the role of SAG.     

EDTA辅助小藜修复Pb及Pb-Cd复合污染土壤的研究

通过盆栽试验,研究了Pb及Pb-Cd复合污染土壤添加EDTA（乙二胺四乙酸）对小藜生长和转运、富集Pb、Cd的影响。结果表明,高浓度的EDTA对小藜的生长有抑制作用,Pb及Pb-Cd复合处理下EDTA最佳添加浓度均为2.5 mmol·kg^-1,此时小藜对Pb的转运系数达2.66和2.41,富集系数达1.51和1.82,分别比对照提高554%和493%、8 431%和2 367%;对Cd的转运系数达1.87和3.47,富集系数达1.78和10.8,分别比对照提高165%和355%、77%和283%。2.5 mmol·kg^-1EDTA辅助小藜修复Pb-Cd复合污染土壤的效果优于修复Pb污染土壤的效果。     

EDTA对桑树和任豆幼苗吸收重金属Pb的影响

【目的】研究不同重金属Pb2＋浓度下螯合剂EDTA处理对桑树和任豆幼苗修复土壤中重金属Pb2＋的效果及Pb2＋在植物茎叶及根部积累,以期为重金属污染土壤生态修复及植物资源的合理利用提供理论依据。【方法】用盆栽模拟法,以4L／盆Hoagland营养液作为培养液,培养液中的Pb2＋浓度分别为0、2．5、5．0、10．0、25．0、50．0、100．0、150．0、200．0、250．0mg／L,EDTA的浓度均为0．55mmol／L,以不添加EDTA作对照。分别测定桑苗和任豆幼苗茎叶和根部的Pb2＋浓度。【结果】随着水培液中Pb2＋浓度的增加,桑树和任豆幼苗对Pb2＋的吸收和积累量也逐渐增大;在相同的重金属Pb2＋胁迫背景下,加入EDTA的桑树和任豆幼苗对Pb2＋的吸收量比不添加EDTA的对照组明显增高;桑树和任豆幼苗体内Pb2＋浓度通常为根部〉茎叶,而添加EDTA能加速重金属Pb2＋向茎叶的转运。随着培养液中Pb2＋浓度的增加和时间的延长,Pb2＋在植物根部的积累逐渐增加,而向茎叶的转运则相对减少。【结论】桑树和任豆幼苗具有较强的重金属Pb耐性,而EDTA能促进桑树和任豆幼苗对重金属Pb2＋的吸收,因此,桑树和任豆可作为修复植物应用于重金属污染地区。