heavy metals in soils alloway 1990

... their stability and transportability. Settling rate experiments (Figure 2.2) indicated a decline in the concentration of kaolinitic colloids remaining in suspension at pH <5.5 compared to the ... found in an acidified sandy aquifer [18]. Organic colloid migration following humus disintegration has been found to be the main transport mechanism for Pb in subsoils of forested ecosystems in Switzerland ... have increased the soluble metal load. These findings clearly demonstrate the role of colloid mineralogical composition on their ability to induce and mediate the transport of heavy metals in subsurface

Ngày tải lên: 11/08/2014, 10:22

... another interact through covalent terms. Choosing the atomic charges remains an important step in developing an interatomic potential, however. Charges are either determined empirically by adjusting ... available to interested researchers include GAMESS (see Quantum Chemistry Program Exchange, Indiana University), Spartan (Wavefunc- tion, Inc.), Jaguar (Schrodinger, Inc.), Q-CHEM (Q-Chem, Inc.), Parallel ... of copper in the environment.86–88 The main thrust of our research will be trying to incorporate mineral surfaces into the aqueous-phase models we have presented here Generating accurate

Ngày tải lên: 11/08/2014, 10:22

... sediment–water interface, in Advances in. .. mediated mineral formation: Insights into manganese(II) oxidation from molecular genetic and biochemical studies, in Geomicrobiology: Interactions ... gene cluster involved in manganese oxidation by spores of the marine Bacillus sp strain SG-1, J Bacteriol., 178 , 35 17, 1996 Verity, R., Investigations of Manganese Oxidizing Bacteria, ... Complexation Modeling Hydrous Ferric Oxide, John Wiley & Sons, New York, 1990 Friedl, G., Wehrli, B., and Manceau, A., Solid phases in the cycling of manganese in eutrophic lakes: New insights

Ngày tải lên: 11/08/2014, 10:22

... in identifying Zn-bearing phases in the subsoil, indicating that Zn was not found in abundant portions in any one phase Aluminum, Si, and Fe in the maps in the subsurface soil indicated ... other minerals in the matrix which may cause fluorescence, resulting in an interference with the spectrum of the central element of interest (e.g., for Co and Ni in samples containing Fe oxides in ... 8 Zinc Speciation in Contaminated Soils Combining Direct and Indirect Characterization Methods Darryl Roberts, Andreas C. Scheinost, and Donald L. Sparks CONTENTS 8.1 Introduction

Ngày tải lên: 11/08/2014, 10:22

... 199 2 35 Kretzschmar, R and Voegelin, A., Modeling competitive sorption and release of heavy metals in soils, in Heavy Metals Release in Soils, Selim, H.M and Sparks, D.L., ... Cd and Zn decreased following saturation, and Ni decreased in two of the three soils. These decreases in metal solubility coincided with a pH increase in all three soils, and were attributed ... released metals to soil solids following dissolution of the Mn oxide. Trace metals initially associated with the Mn oxide fraction may also be retained by specific adsorption reactions, 19 involving

Ngày tải lên: 11/08/2014, 10:22

... contained many diverse metal-chelating groups responsible for the decreasing metal sorption in soils In most agricultural soils with pH ranging from 5 to 8, such as soils containing ... the HiB fraction mainly consisted of the N-containing group, including most amino acids, amino sugar, low-molecular-weight amines, and pyridine, while the HiA fraction contained the component ... to the mineral surfaces. Therefore, composting organic wastes would increase the adsorption of DOM on soils because of the increase in aromatic carbon-containing compounds after composting (Liang

Ngày tải lên: 11/08/2014, 10:22

... require a thin coating of a conductive substance to eliminate charging artifacts Metal coating (e.g., Au/Pd) can increase both the SE and BSE signals for high-resolution imaging, but may interfere ... with performing microanalysis by increasing electron backscattering at the expense of specimen x-rays while producing x-rays characteristic of the metal coating Therefore,... containing layer ... particles are moving rapidly. Scattering intensity measurements are taken at short time intervals relative to the diffusive motion of colloidal particles, resulting in high initial correlation

Ngày tải lên: 11/08/2014, 10:22

... contents in soils (Huang et al 2007; Khan et al 2008; Zhao et al 2007) The total contents of heavy metals provide information on the accumulation of heavy metals in soils However, the mobility of metals ... industrial activities including copper and lead casting, phosphorous fertilizer production, chemical manufacturing, etc., has been indicated to have introduced heavy metals into water and soil ... studies mainly addressed total metal concentrations in the soils (Ho and Egashira 2001; Trinh and Wada 2004; Le 2002); no detailed investigation of contents and chemical forms of heavy metals in soils

Ngày tải lên: 14/12/2017, 17:50

... for the determination of heavy metals in reed plants (Phragmites australis) Anal Chim Acta 497(1):191–198 Kachenko AG, Singh B (2006) Heavy metals contamination in vegetables grown in urban and ... assessment of heavy metals in some tea marketed in Nigeria-Bioaccumulation of heavy metals in tea Health 2(09):1097–1100 Sharma RK, Agrawal M, Marshall F (2007) Heavy metal contamination of soil ... the degree of contamination and daily intake of toxic heavy metals via tea (3); to measure the interaction of heavy metal concentrations in fresh tea leaves, processed tea and soils from tea plantations

Ngày tải lên: 29/05/2020, 14:09

... plants to high concentrations of heavy metals in their tissues as well as in soil. This chapter presents the results of investigations of these heavy metals in the wetland and the rates of filtration. ... the. .. ranging from a minimum of 522 g-dm/m2 to a maximum of 1 798 g-dm/m2 Dominant plants in each plot are given in Appendix Table A9.16 Concentration of Heavy Metals in Plant Tissues ... mine waters flowing into the wetland was monitored from 1977 to 1990, and the results were compared with the historical records. The ability of wetland plants to remove heavy metals from flowing

Ngày tải lên: 18/06/2014, 19:20

... 122 HEAVY METALS IN THE ENVIRONMENT: USING WETLANDS FOR THEIR REMOVAL recognized as part of the economy through their work in filtering toxic substances such as heavy metals. Increasingly, ... discounting/income capitalization formula is given in Appendix A11. METHODS The first step in valuing the work of the wetland in retaining lead was to quantify the amount of lead actually held in ... reported in the U.S... time is in nite, the damage is also regarded as in nite since it continues in perpetuity This is in contrast with the mainstream economic notion of discounting

Ngày tải lên: 18/06/2014, 19:20

... ANALYSIS Mining Law of 1972 The statutes that govern lead mining today date back to the General Mining Law of 1972. In passing this law, Congress intended to protect the rights of individuals ... benefits of mining and selling lead and lead products were large, and the cost of damaged ecosystems seemed minor. The regulations governing the mining and processing of lead were few, as seen in Table ... purposes in the economy. But, because the economic drain from waste is small in the beginning and the price of obtaining new resources is low, recycling is slow to develop and the benefits of recycling

Ngày tải lên: 18/06/2014, 19:20

... leaf area index of floating vegetation was measured using a line-intercept transect 5 m in length. The intercept lengths were recorded for individual leaves of Nymphaea . Totals of intercept ... DIVERSITY INDICES Diversity was calculated using three indices. The Shannon diversity index is given by where H ′ is the information in bits per individual, p i is the proportion of individuals ... 1973). Fine particulates were removed in the field by partially submerging and agitating the bucket, taking care not to allow exchange of materials except through the sieve bottom. Remaining material

Ngày tải lên: 18/06/2014, 19:20

... low intakes (deficiency) or excess intakes (toxicity) In deriving the limits of the AROI, uncertainties in the data as well as the variability in the intakes of individuals within ... leading to reduced availability Copper uptake in the gut is inhibited by high zinc intakes Both a direct interaction and an interaction mediated by metallothionein induction may explain this ... transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming, and recording, or by any information storage and retrieval system, without permission in writing

Ngày tải lên: 11/08/2014, 15:20

... new information about the environmental chemistry of heavy metals results from continuing improvements in trace element analytical research. This is particularly true in the fields of heavy metals ... are important in prioritizing contaminants for regulation. Routine monitoring of regulated contaminants ensures compliance with allowed levels and can indicate a hazardous situation. In addition, ... chapter is to give an overview of the principal analytical methods used in environmental sciences for heavy metals determination. The monitoring of trace metals in the environment has been a subject

Ngày tải lên: 11/08/2014, 15:20

... in vivo 4.4 Protein-Protein Interactions Heavy metals have been shown to in uence protein-protein interactions One example is the disruption of the E-cadherin/catenin cell adhesion complex ... again depending on their membrane potential (41). There are intracellular changes in Ca 2ϩ concentration in response to toxic insult as heavy metals are postulated to interfere with the Ca in? ??ux ... and intracellular stability of newly synthesized proteins. An interesting new finding is the linkage between heavy metal–induced toxicity and the function of the ubi- quitin-proteasome system in

Ngày tải lên: 11/08/2014, 15:20

... Experimental studies in animals suggest that the absorption of indium from the gastrointestinal tract is about 2% (9). Since, like aluminum, indium occurs in the earth’s crust in silicates, such ... ϽϽ1%, occur in aluminum and zinc ores. In contrast to cadmium, indium has few industrial or medical applications and, in consequence, it has attracted little environmental or toxicological interest ... Dekker, Inc. aluminumandgallium,toGroup13oftheperiodictable(Fig.1),andincommon with these latter metals the predominant oxidation state is In( III) (7). In the earth’s crust traces of indium,

Ngày tải lên: 11/08/2014, 15:20

... production using metals, such as for certain chromium pigments or nickel-containing catalysts, have been associated with human cancer (6). Individuals involved in certain mining processes and in iron ... resulted in the more rapid onset and increased malignancy... species include nickel, chromium, copper, and iron Some evidence indicates that metals can replace zinc in DNA-binding zinc finger ... agent as a carcin- ogen was that of skin tumors in humans undergoing oral therapy with medicinal arsenical preparations for various diseases, including, in fact, cancers (22). Inha- lation exposure

Ngày tải lên: 11/08/2014, 15:20

... preservation industries as well as the use of the preserved wood products. Mining and smelting of ore minerals including sulfides of copper, lead, and zinc, as well as gold processing, have contributed ... converting these into a less mobile chemical form and/or by binding them within an insoluble matrix offering low leaching characteristics Chemical fixation processes have been applied both in situ ... silver, zinc, and lead mining (1 26, 127), leach As into the aquifers and cause natural As contamination in the drinking water wells of the region Groundwater is the. .. (lowland) in

Ngày tải lên: 11/08/2014, 15:20