Mehlich 3 soil test extractant: A modification of Mehlich 2 extractant

Abstract

The objectives of this study were to modify the Mehlich 2 (M2) extractant to include Cu among the extractable nutrients, retain or enhance the wide range of soils for which it is suitable and minimize it's corrosive properties. The substitution of nitrate for chloride anions and the addition of EDTA accomplished those objectives. The new extracting solution, already designated Mehlich 3 (M3) is composed of 0.2N CH₃COOH‐0.25N NH₄N0₃‐0.015NNH₄F‐0.013NHN0₃‐0.001M EDTA. Extractions from 105 soils using M3, M2, Bray 1 (Bl) and Ammonium Acetate (AA) were compared to evaluate the new extractant. The quantity of F extracted by M3 exceeded that by M2 20% and that by Bl 4% but the results from all extractions were highly correlated. Extractions of both K and Mg by M3 were 6–8% higher than those by AA and 3–4% higher than those by M2, but, again, there was high correlation among methods. Addition of EDTA increased Cu extractions by 170%, Mn by 50% and Zn by 25%. Cu extractions by M3 correlated with those from the Mehlich‐Bowling method. High correlations between Mn, as well as Zn, extracted by M3 and M2 were shown.     

Critical Soil Zinc Deficiency Concentration and Tissue Iron: Zinc Ratio as a Diagnostic Tool for Prediction of Zinc Deficiency in Corn

ABSTRACT

Zinc (Zn) fertilizer application is most economic if based on soil test and plant analysis information. The aim of this study was to determine the soil test [diethylenetrinitrilopentaacetate (DTPA) and ethylenetriaminepentaacetic acid (EDTA) extractable] Zn-critical levels and tissue Fe/Zn ratio for corn (Zea mays L.). A greenhouse experiment with 12 soil series and two Zn fertilizer treatments (0 and 15 mg Zn kg^?1 as zinc sulfate) was conducted. Critical Zn deficiency levels were determined using the Cate-Nelson procedure. Relative corn yield varied from 0.59 to 1.64. Critical deficiency levels based on the Cate-Nelson method were 1.50 and 1.17 mg kg^?1 for DTPA and EDTA-extracted soil Zn, respectively. No accurate critical deficiency level could be established using the shoot Zn concentrations. The critical iron (Fe)/Zn ratio in the corn shoot was 3.9. Values greater than 3.9 indicate hidden Zn deficiency and probable response to applied Zn.     

Influence of graded EDTA applications on mobilization and translocation of trace elements—a soil column experiment

Increasing concerns about potential environmental effects of ethylenediaminetetraacetic acid (EDTA) accumulation in soils require better understanding of its behavior and its effect on trace element mobilization. In this study we investigated the effect of EDTA on soil trace element mobilization in undisturbed soil columns taken from a heavy metal contaminated field. The columns were leached by EDTA solutions of different concentrations under unsaturated, steady‐state conditions. The transport of trace elements (Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sn, Zn) and EDTA was monitored by regularly collecting the leachates. After the termination of the leaching experiment the soil columns were divided into 5 layers to determine trace elements and EDTA concentrations in the soil. The results revealed that the soil analysis alone was not suitable to infer mobilization or immobilization patterns in relation to the EDTA concentration, as the mobilized fraction was too small in relation to the total trace metal concentrations in the soil. Analysis of the leachates displayed that after 2–4 pore volumes the EDTA output concentration reached about 80% of the input concentration. The trace element concentrations in the leachates showed that some elements were mobilized by EDTA (Cd, Cu, Fe, Pb, Co, Ni, Zn) while others were immobilized (Mn, Cr, Mo, Sn) in the soil columns after EDTA application.     

Bioaccumulation of gold in macrofungi and ectomycorrhizae from the vicinity of the Mokrsko gold deposit, Czech Republic

Samples of macrofungi collected in the vicinity of the Mokrsko gold deposit were analyzed for Au by INAA and ICP-MS. Ectomycorrhizal fungi yielded from 0.88 to 564 μg kg⁻¹ Au (dry weight) in 79 samples. Saprobic fungi (75 samples) from the same locations yielded significantly higher concentrations: 3-7739 μg kg⁻¹ Au (dry weight), with the highest contents in Lycoperdon perlatum. These are the highest recorded concentrations of Au in naturally-occurring fungi/vascular plants. Concentrations of Au in ectomycorrhizae were approximately 4-10 times higher than those in fine roots. It appears that saprobic fungi, namely several terrestrial saprobes of the genera Agaricus and Lycoperdon, are more efficient than ectomycorrhizal fungi at taking up Au, probably assisted by other microbiota and/or by a range of naturally-occurring compounds that have yet to be identified. The present data demonstrate that macrofungi are involved in the biogeochemical cycling of Au.     

鸡蛋壳壳膜及表面角质层去除方法的优化与比较

本文拟对EDTA法、蛋白酶K法和NaOH法去除鸡蛋壳壳膜及表面角质层的条件进行优化并比较,以期获得分离蛋壳有机层和矿化晶体层的有效方法。通过SS-550扫描式电子显微镜观察发现,EDTA法中以5%EDTA处理鸡蛋壳30min的效果相对较好,能去除蛋壳内膜及尽可能多的外膜,但是表面角质层的去除效果较弱;蛋白酶K法中以50μg/mL蛋白酶K孵育鸡蛋壳48h的效果相对较好,能完全去除表面角质层和蛋壳内膜,但蛋壳外膜尚不能彻底去除干净;而NaOH法中则以2%NaOH于99℃中煮鸡蛋壳17min的效果最理想,既能彻底去除壳膜又能完全去除表面角质层。3种方法相比,去除鸡蛋壳壳膜及角质层的理想方法是于99℃的2%NaOH中煮17min。     

Novel chelant‐based washing method for soil contaminated with Pb and other metals: A pilot‐scale study

Remediation with chelants can restore metal‐contaminated soils for use as a natural resource. Calcareous soil from Meza Valley, Slovenia, and acidic soils from Arnoldstein, Austria, and Pribram, Czech Republic (with 1,028, 862, and 926 mg ∙Pb∙kg⁻¹, respectively), were washed with 60–100 mmol EDTA per kilogram of air‐dried soil in series of 30 batches (50 kg soil batch⁻¹). The approach involves a novel reaction that incorporates alkaline substitution, precipitation and adsorption of toxic metals on polysaccharides, and chelant acidic precipitation via 83% EDTA (on average) and complete process water recycling (no wastewater was generated). The pH gradient was imposed by Ca(OH)₂ and H₂SO₄, and excess reagent was removed with the remediated soil as CaSO₄, thereby preventing the salification of the recycled waters. Remediation removed 60%, 78%, and 71% of the Pb from the Meza, Arnoldstein, and Pribram soils, respectively, and reduced the Pb bioaccessibility levels in the simulated human gastrointestinal phase by 5.0, 7.7, and 8.1 times. Residual emissions (EDTA, toxic metals) were reduced with soil aging and remediated soil deposition on a reactive permeable barrier. The solid waste generated from the process totaled 10.8 kg tons⁻¹ of the air‐dried soil, and the material/energy costs of remediation reached 20.6 € tons⁻¹. These results demonstrate the robustness, efficiency, and safety of this novel approach.     

对EDTA滴定法测定硫酸盐方法的探讨

通过对EDTA滴定法测定硫酸根方法的探讨，认为通过电导率的大小估算水样中硫酸盐的含量，对准确测定水样中的硫酸盐含量至关重要．在实际操作分析中更加简便。     

部分金属离子及EDTA对瘦肉型猪(PIC344)精液酸性磷酸酶活性与荧光光谱的影响

研究了K+、Mg2+、Ni2+、Zn2+、Mn2+、Fe2+、Cd2+、Ca2+、Cu2+9种金属离子及EDTA对瘦肉型猪(PIC344)精液酸性磷酸酶(ACPase)活力的影响,发现K+、Mg2+、Ca2+、Ni2+、Mn2+对ACPase有不同程度的激活作用。Cu2+、Cd2+、Fe2+、Zn2+对ACPase有不同程度的抑制作用。同一浓度范围内的金属离子对ACPase的激活作用强弱依次为Mg2+>Ni2+>Mn2+>K+>Ca2+,对ACPase的抑制作用强弱依次为Cu2+>Cd2+>Fe2+>Zn2+。利用双倒数作图法研究了Cu2+、Cd2+对酶的作用,结果表明这2种抑制剂对酶的抑制作用为非竞争性抑制,用Dixon作图法求得其抑制常数Ki值分别为0.58×103mol/L、9.44×103mol/L。研究了Mg2+、Ca2+、Cd2+、Cu2+对酶荧光光谱的影响,结果表明:Mg2+、Ca2+、Cd2+、Cu2+引起酶荧光发射光谱强度降低,最大发射波长不变,说明这些金属离子对酶的构象有不同程度的影响。     

The effects of different anticoagulants on routine canine plasma biochemistry

The effects of heparin, ethylenediaminetetraacetic acid (EDTA), sodium citrate and sodium fluoride/potassium oxalate on plasma biochemistry results in dogs were studied and compared with serum. Blood specimens from 10 apparently clinical healthy dogs were collected and placed in different tubes containing each anticoagulant tested. Differences in albumin, acetylcholinesterase, ionized calcium and potassium were found between serum and heparinized plasma. Most metabolites and enzymes did not show any variation, but significant decreases in electrolytes, alkaline phosphatase, acetylcholinesterase, bile acids, fructosamine and albumin were found when EDTA was used. Sodium citrate produced a 10-15% decrease in most metabolites and enzymes, possibly due to a sample dilution effect. Sodium fluoride/potassium oxalate produced haemolysis which may have influenced changes in some biochemical parameters.     

Topical effect of various agents on gelatinase activity in the tear film of normal dogs

OBJECTIVE: To evaluate the topical effect of various agents, currently used in the treatment of melting ulcers, on gelatinase activity present in the tear film of normal dogs. ANIMAL STUDIED: Eight normal adult beagles. PROCEDURES: Each animal received the following agents: cyclosporine A 1%, N-acetylcysteine 10%, ciprofloxacin 0.3%, ethylenediaminetetraacetic acid (EDTA) 1%, doxycycline 0.001%, polysulfated glycosaminoglycans (PSGAG) 5%, autoserum, and artificial tears during a 48-h period following a Latin square design. Tear samples were collected with micro-capillary pipettes following a corneal surface irrigation of each eye with sterile saline on four different occasions. Basal and total gelatinase activities were evaluated by optical density after processing in a commercial gelatinase activity assay. From the optical density ratio, a semi-quantitative measure of gelatinase activity was obtained. Basal and total activities were measured in all samples. RESULTS: The lowest total gelatinase activity, representing a percent decline in the enzyme activity although not significant, was observed 1 h after the last treatment in seven out of the eight ophthalmic agents; EDTA (68%), ciprofloxacin (76%), cyclosporine A (68%), doxycycline (47%), artificial tears (26%), PSGAG (25%), and N-acetylcysteine (20%). However, only the reduction observed with EDTA 6 h after the last treatment was significantly lower compared to the reduction observed with the artificial tears. CONCLUSION: This study indicated that only EDTA was able to significantly reduce the gelatinase activity in a persistent manner in the tear film of normal canine eyes. Further studies will be required to evaluate the effect of EDTA under ulcerative conditions and to more accurately ascertain the potential in vivo effect of the other agents.