Toxic Metals

The metallothioneins (MT) are small, cysteine-rich heavy metal-binding proteins which participate in an array of protective stress responses. Although a single essential function of MT has not been demonstrated, MT of higher eukaryotes evolved as a mechanism to regulate zinc levels and distribution within cells and organisms. These proteins can also protect against some toxic metals and oxidative stress-inducing agents. In mice, among the four known MT genes, the MT-I and -II genes are most widely expressed. Transcription of these genes is rapidly and dramatically up-regulated in response to zinc and cadmium, as well as in response to agents which cause oxidative stress and/or inflammation. The six zinc-finger metal-responsive transcription factor MTF-1 plays a central role in transcriptional activation of the MT-I gene in response to metals and oxidative stress. Mutation of the MTF-1 gene abolishes these responses, and MTF-1 is induced to bind to the metal response elements in proximal MT promoter in cells treated with zinc or during oxidative stress. The exact molecular mechanisms of action of MTF-1 are not fully understood. Our studies suggest that the DNA-binding activity of MTF-1 in vivo and in vitro is reversibly activated by zinc interactions with the zinc-finger domain. This reflects heterogeneity in the structure and function of the six zinc fingers. We hypothesize that MTF-1 functions as a sensor of free zinc pools in the cell. Changes in free zinc may occur in response to chemically diverse inducers. MTF-1 also exerts effects on MT-I gene transcription which are independent of a large increase in MTF-1 DNA-binding activity. For example, cadmium, which has little effect on the DNA-binding activity of MTF-1 in vivo or in vitro, is a more potent inducer of MT gene expression than is zinc. The basic helix-loop-helix-leucine zipper protein, USF (upstream stimulatory factor family), also plays a role in regulating transcription of the mouse MT-I gene in response to cadmium or H 2 O 2 . Expression of dominant negative USF-1 or deletion of its binding site from the proximal promoter attenuates induction of the mouse MT-I gene. USF apparently functions in this context by interacting with as yet unidentified proteins which bind to an antioxidant response element which overlaps the USF-binding site (USF/ARE). Interestingly, this composite element does not participate in the induction of MT-I gene transcription by zinc or redox-cycling quinones. Thus, regulation of the mouse MT-I gene by metals and oxidative stress involves multiple signaling pathways which depend on the species of metal ion and the nature of the oxidative stress. BIOCHEM PHARMACOL 59;1:95-104, 2000.

In this present work the distribution of heavy metals in sea water and sediments of the Salerno Gulf is measured. The elements determined were Cu, Pb, Cd, Zn and Hg, employing, as instrumental techniques, either differential pulse anodic stripping voltammetry (DPASV) or graphite furnace atomic absorption spectroscopy (GFAAS). A comparison of the results of the two analytical techniques is also made. Mercury determination was carried out employing the cold vapour atomic absorption spectroscopy (CVAAS) technique, with SnCl 2 as the reducing agent. The sample digestion was performed by a new procedure using concentrated suprapure H 2 SO 4-K 2 Cr 2 O 7 mixture. The accuracy and precision of the analytical procedure were evaluated employing Sea Water BCR-CRM 403 and Estuarine Sediment BCR-CRM 277 as reference materials. Accuracy, expressed as relative error e and precision, expressed as relative standard deviation s r , were in order of 2 to 5%. For both matrices, the detection limits, for all the elements, were in the range µg g −1 to ng g −1 .

Lead (Pb) is recognized as one of the most toxic metals. Sources of Pb exposure have been widely documented in North America, and the removal of Pb additives from gasoline was reflected in a dramatic lowering of blood Pb concentration. In Latin America, the removal of Pb from gasoline resulted in decreased exposure, but Pb levels in many areas remain high due to occupational and environmental sources of exposure. While many of the Pb sources have been identified (mining, industries, battery recycling, lead-based paint, ceramics), new ones occasionally crop up. Here we report on blood Pb (B-Pb) levels in remote riverside communities of the Brazilian Amazon. Blood Pb (B-Pb) levels were determined in 448 persons from 12 villages of the Lower Tapajó s River Basin, Pará , Brazil. Socio-demographic and dietary information, as well as occupational, residential and medical history was collected using an interview-administered questionnaire. B-Pb, measured by ICP-MS, showed elevated concentrations.

A small group of Gulf War veterans possess retained fragments of depleted uranium (DU) shrapnel, the long-term health consequences of which are undetermined. We evaluated the clinical health effects of DU exposure in Gulf War veterans compared with nonexposed Gulf War veterans. History and follow-up medical examination were performed on 29 exposed veterans and 38 nonexposed veterans. Outcome measures employed were urinary uranium determinations, clinical laboratory values, and psychiatric and neurocognitive assessment. DU-exposed Gulf War veterans with retained metal shrapnel fragments are excreting elevated levels of urinary uranium 7 years after first exposure (range 0.01-30.7 microg/g creatinine vs 0.01- 0.05 microg/g creatinine in the nonexposed). The persistence of the elevated urine uranium suggests on-going mobilization from a storage depot which results in a chronic systemic exposure. Adverse effects in the kidney, a presumed target organ, are not present at this time, though other effects are observed. Neurocognitive examinations demonstrated a statistical relationship between urine uranium levels and lowered performance on computerized tests assessing performance efficiency. Elevated urinary uranium was statistically related to a high prolactin level (>1.6 ng/ml; P=0.04). More than 7 years after first exposure, DU-exposed Gulf War veterans with retained metal fragments continue to excrete elevated concentrations of urinary uranium. Effects related to this are subtle perturbations in the reproductive and central nervous systems.

Lake Orta (N. Italy) was severely polluted from 1927 by an effluent from a rayon factory, which discharged great amounts of ammonium nitrogen and copper into the lake. In the mid nineteen fifties, some plating factories also started dumping chromium and aluminum. As a result of ammonium oxidation, the lake became very acid and the concentration of metals in the waters reached very high values. Phytoplankton, zooplankton and fish disappeared suddenly from the lake which was by 1930 classified as “sterile”. Later on, about the fifties, a small population of Cyclops abyssorum re-colonised the lake together with some rotifers, in particular Hexarthra fennica. In mid eighties following the introduction of anti-pollution legislation, ammonium loads were greatly reduced and Daphnia obtusa was recorded. The lake waters however were still very acid, prompting the proposal of the Istituto Italiano di Idro-biologia to lime the lake with calcium carbonate to neutralise the excess acidity and re...

Lowland heath is an internationally important habitat type that has greatly declined in abundance throughout Western Europe. In recent years this has led to a growing interest in the restoration of heathland on agricultural land. This generally requires the use of chemical treatments to return soil chemical conditions to those appropriate for the support of heathland ecosystems. However, the potential

Industrial activity has contributed to potentially toxic metal pollution in various ecosystems throughout the world. In this study, the ability of humic and fulvic acids (isolated from lignite with a simple, rapid, and inexpensive method) to reduce toxic metals’ concentration of contaminated water is examined. More specifically, the effect of these compounds is tested on water contaminated (at various concentrations) with Cd, Cr, Cu, Ni, and Pb. The determination is performed by inductively coupled plasma-optical emission spectrometry. The maximum binding capacity is presented by fulvic acids in the following order Cr>Pb>Ni>Cu>Cd (97.8, 96.5, 95.4, 95.1, and 83.3%, respectively), while for humic acids it is Pb>Ni>Cr>Cu>Cd (81.3, 70.7, 68.6, 67.0, and 66.8%, respectively). The binding activity is also tested on water contaminated with two metals simultaneously. In these cases, the existence of two metals in water changes the reduction ability of humic and fulvic acids (positively or negatively).

The main goal of this work was to establish a monitoring network on main rivers of Kosovo. We aim to apply WFD (Water Framework Directive) in Kosovo as soon as possible, and our research could be the first step towards it. Waters of the rivers Drini i Bardhë, Morava e Binçës, Lepenc and Sitnica, which are of supra-regional interest, are investigated systematically. Statistical methods are applied to find locations where integrated water resources management can be suggested. Sediments of these rivers were also investigated at the same monitoring points and results have recently been published by us. In this paper we present results of mass concentrations of ecotoxic metals: Cu(II), Pb(II), Cd(II), Zn(II) and Mn(II) in waters of four main rivers of Kosovo. Results of anomalous concentrations of ecotoxic metals in water are compared with anomalous concentrations of the same elements found in sediments. In Drini i Bardhë River the only anomalous value (for Mn) was found in sediment. In Morava e Binçës extreme values of Cd were found in sediments at the lower stretch of the river. In water anomalous values of Cd, Cu and Mn were found at the upper stretch of the river, which are above permanent toxic values. In Lepenc River anomalies were not found, indicating uncontaminated river. Sitnica River is still polluted at two locations, although most of the industry is closed. Anomalous values of Cd, Pb and Zn were found in sediments and of Pb in water at location S 2 (Fushë Kosovë); at location S 5 (Mitrovicë) anomalous values of Cu, Cd, Pb and Zn were found in sediments and of Cd and Zn in water. Continuation of water and sediment monitoring by Kosovo authorities is highly recommended. Possible remediation at critical locations on Sitnica and Morava e Binçës rivers would be desirable.

Elemental composition of ten samples of instant and roasted ground coffee powders available in markets of India have been analyzed using X-ray fluorescence technique. The samples were analyzed for thirty one elements, out of which major elements were K and Ca. Al, Fe, Ni, Mg, Mn, Sb, Sn and Zn were observed to be present in the smaller quantities. Nonmetals such as S, P and Si were detected in almost all the samples. The samples also showed presence of rare earth metals like W, Zr, Y, Ag, Sr, Rb, Nb and Mo. Toxic metals like Hg and As were not detected in any of the samples, while traces of Cd and Pb were found to be present in four samples each. With the absence of toxic elements coffee can be considered a safe beverage. Detection of radioactive elements U and Th in the coffee samples is an important finding of this research work. Results of elemental analysis of the analyzed coffee samples were correlated to the soil analysis data of their geographical origins. There have been good correlations between elements reported in the soil and those detected in the coffee samples. The motive of the research work is to bring out the goodness of coffee in terms of their elemental composition and also their variation with regard to their geographical origin.

Zinc (Zn) is one of the most important trace elements in the body and it is essential as a catalytic, structural and regulatory ion. It is involved in homeostasis, in immune responses, in oxidative stress, in apoptosis and in ageing. Zinc-binding proteins (metallothioneins, MTs), are protective in situations of stress and in situations of exposure to toxic metals, infections and low Zn nutrition. Metallothioneins play a key role in Zn-related cell homeostasis due to their high affinity for Zn, which is in turn relevant against oxidative stress and immune responses, including natural killer (NK) cell activity and ageing, since NK activity and Zn ion bioavailability decrease in ageing. Physiological supplementation of Zn in ageing and in age-related degenerative diseases corrects immune defects, reduces infection relapse and prevents ageing. Zinc is not stored in the body and excess intakes result in reduced absorption and increased excretion. Nevertheless, there are cases of acute and chronic Zn poisoning.

Comparative evaluation of the toxicity induced by mussels (Mytilus galloprovincialis) from two sites of the Moroccan Atlantic coast in mice. Preliminary studies showed that seawater contains heavy metals from domestic, agricultural and industrial wastes. Marine bivalves concentrate these pollutants by filtration and serve as vectors in human exposure. The objective of this study was to determine the concentration of heavy metals; cadmium (Cd); chromium (Cr), and lead (Pb) in mussels (Mytilus galloprovincialis) collected in two coastal sites; Jorf Lasfar (JL) (neighbouring a phosphate processing platform) and Oualidia (OL) (a vegetable growing area) located at 120 and 190 km south of Casablanca, respectively. Another objective was to test and compare the toxicity of these mussels on mice. The results indicated the presence of heavy metals (Cd, Cr, and Pb) in mussels at different concentrations, depending on the collection period. Higher concentrations were obtained at JL than at OL: for example, Cd concentrations were 80 ± 15 to 199 ± 28 versus 23 ± 5 µg/g mussel dry weight, respectively. Cramming with mussel powder did not increase Cd, Cr, or Pb concentration in either liver or kidneys of treated mice. The relative kidney weights were reduced. Increased glucose urea was observed in animals' urine. Treatment with mussels from OL induced significant reduction (20%) in mice body weight, together with an increase in creatinuria. These results indicate that mussels collected from OL are more harmful than those obtained from JL are. All these mussels should not be recommended for human consumption. To cite this article: K. Moustaid et al., C. R. Biologies 328 (2005).  2005 Académie des sciences. Publié par Elsevier SAS. Tous droits réservés.

The area of study selected in the present investigation was Kasardi River which receives heavy discharge of waste effluent from the nearby Taloja industrial belt which is one of the fastest developing industrial belt of Mumbai. The study was performed to investigate the concentration of toxic heavy metals like chromium (Cr), cadmium (Cd), nickel (Ni), zinc (Zn), copper (Cu), lead (Pb) and iron (Fe) in river. It was observed that concentration of most of these heavy metals were much higher than the maximum permissible limits. These heavy metals have created threat to the aquatic life and through biomagnifications may enter the food chain thereby affecting the human beings as well. The research work was extended further to study the physico-chemical properties like temperature, pH, solid content, chloride, oil / grease content, BOD and COD values of the river water. The authors point out that as India moves towards stricter regulation of industrial effluents to control water pollution, there is a need to implement common objectives, compatible policies and programmes for improvement in the industrial waste water treatment methods.

This study was conducted to assess the potential ecological and human health risk of toxic metals
in agricultural soils near the industrial areas of Bangladesh. In this study, six toxic metals
(chromium, nickel, copper, arsenic, cadmium, and lead) were assessed in 58 soil samples of five
different sampling sites around the industrial areas of Jhenaidah and Kushtia districts in
Bangladesh. Toxic metals were measured using inductively coupled plasma mass spectrometer.
Potential ecological and human health risk were assessed through enrichment factor (EF), contamination
factor (Cf
i ), geoaccumulation index (Igeo), pollution load index (PLI), toxic unit analysis,
chronic daily intake through exposure pathway, hazard quotient, and hazard index. The mean
concentrations of Cr, Ni, Cu, As, Cd, and Pb were found to be 5.78, 21.0, 31.8, 8.05, 1.20, and
19.2 mg/kg, respectively. Metals concentrations were found below the recommended value set
by Dutch standard, Canadian guidelines, and Australian guidelines except Cd. Principal component
analysis indicates that most of the metals in agricultural soils are coming from industrial
sector. The mean values of EF, Igeo, Cf
i, PLI, and toxic units were found safe level for all metals
except Cd. In the view of potential ecological risk (PER), soils from all sampling sites indicated
moderate to very high PER. Total target hazard quotients for all the studied metals in total sampling
sites were <1 and cancer risk values were <10
6 indicating low noncarcinogenic and cancer
risk for adult and children.

Gum kondagogu (Cochlospermum gossypium), an exudates tree gum from India was explored for its potential to decontaminate toxic metal ions in aqueous solution. The toxic metal ions nickel and total chromium biosorption capacity of the gum kondagogu were studied in the batch experimental mode. The optimum conditions of biosorption were determined by investigating pH, contact time, and initial metal ion and biosorbent concentrations. The Freundlich and Langmuir adsorption models were used for the mathematical description of biosorption equilibrium and the data were analyzed on the basis of pseudo-second-order kinetic model. The maximum biosorption capacity of gum kondagogu as calculated by Langmuir model were found to be 50.5 mg g −1 for nickel at pH 5.0 ± 0.1 and 129.8 mg g −1 for total chromium at pH 2.0 ± 0.1, respectively. FTIR, SEM-EDXA and XPS analysis were used to evaluate the binding characteristics of gum kondagogu with metals. The experimental results demonstrate that the metal-ion interaction occurs through ion-exchange, adsorption and precipitation mechanisms.

Comparative evaluation of the toxicity induced by mussels (Mytilus galloprovincialis) from two sites of the Moroccan Atlantic coast in mice. Preliminary studies showed that seawater contains heavy metals from domestic, agricultural and industrial wastes. Marine bivalves concentrate these pollutants by filtration and serve as vectors in human exposure. The objective of this study was to determine the concentration of heavy metals; cadmium (Cd); chromium (Cr), and lead (Pb) in mussels (Mytilus galloprovincialis) collected in two coastal sites; Jorf Lasfar (JL) (neighbouring a phosphate processing platform) and Oualidia (OL) (a vegetable growing area) located at 120 and 190 km south of Casablanca, respectively. Another objective was to test and compare the toxicity of these mussels on mice. The results indicated the presence of heavy metals (Cd, Cr, and Pb) in mussels at different concentrations, depending on the collection period. Higher concentrations were obtained at JL than at OL: for example, Cd concentrations were 80 ± 15 to 199 ± 28 versus 23 ± 5 µg/g mussel dry weight, respectively. Cramming with mussel powder did not increase Cd, Cr, or Pb concentration in either liver or kidneys of treated mice. The relative kidney weights were reduced. Increased glucose urea was observed in animals' urine. Treatment with mussels from OL induced significant reduction (20%) in mice body weight, together with an increase in creatinuria. These results indicate that mussels collected from OL are more harmful than those obtained from JL are. All these mussels should not be recommended for human consumption. To cite this article: K. Moustaid et al., C. R. Biologies 328 (2005).  2005 Académie des sciences. Publié par Elsevier SAS. Tous droits réservés.

Chemolithotrophic bacteria that use sulfate as terminal electron acceptor (sulfate-reducing bacteria) constitute a unique physiological group of microorganisms that couple anaerobic electron transport to ATP synthesis. These bacteria (220 species of 60 genera) can use a large variety of compounds as electron donors and to mediate electron flow they have a vast array of proteins with redox active metal groups. This chapter deals with the distribution in the environment and the major physiological and metabolic characteristics of sulfate-reducing bacteria (SRB). This chapter presents our current knowledge of soluble electron transfer proteins and transmembrane redox complexes that are playing an essential role in the dissimilatory sulfate reduction pathway of SRB of the genus Desulfovibrio. Environmentally important activities displayed by SRB are a consequence of the unique electron transport components or the production of high levels of H(2)S. The capability of SRB to utilize hydro...

Ni-nanoparticles provide efficient catalyst for the reduction of aromatic and aliphatic ketones using ammonium formate or hydrogen (H2) gas as hydrogen donor. Comparative studies were done on both hydrogen donors, i.e. ammonium formate and H2 gas and it was found that ammonium formate was better than H2 gas. This method devoid usage of metal oxide or toxic metals, which are required in excess amount.

Metal pollution is a serious problem for environmental safety and programmes of monitoring and bioremediation are needed. Among the processes of bioremediation, the use of microbes to remove and degrade contaminants is considered a biotechnological approach to clean up polluted environments. The aim of this study was to evaluate the ability of Serratia marcescens in Pb, Cd and Cr removal and the potential use of these bacteria in toxic metal bioremediation from polluted environments. A short-term study (120 min) was carried out to study the bacterial growth in the presence of sub-inhibitory concentrations of each metal analysed and the kinetics of metal biosorption in S. marcescens strain. In addition, metal influence on the biosynthesis of the red pigment &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;prodigiosina&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; by S. marcescens was monitored. The results obtained in this study show metals biosorption by S. marcescens (range: 0.0133-0.213 μg/g for Pb; 0.097-0.1853 μg/g for Cd; and 0.105-0.176 μg/g for Cr) and confirm the possible use of this bacterium to realize bioremediation processes, especially for Pb removal, and as a bioindicator of metal pollution.

Stripping voltammetric techniques are powerful analytical tools that are becoming widely used in various chemical analysis fields. Hence, the objective of this survey is to give a general overview on the scope of the applicability of stripping voltammetric methods in food industries. The applications discussed include recent studies on the utilization of these electroanalytical methods in determination of food contaminants (toxic metals, pesticide, fertilizers and veterinary drugs residuals), trace essential elements, food additive dyes and other organic compounds of biological significance. Tables that give method summaries referenced to the original work are provided.

Physical and chemical properties and the total content of potentially toxic metals (PTMs) in waters and soils were studied from the High Moulouya Valley (Morocco) in order to assess the impact of the past mining activity on their quality and to lay the foundations of a potential reclamation of the area.

A biomonitoring method for the determination of Pb, Cd, and Hg at background levels in whole blood by inductively coupled plasma-mass spectrometry is described. While this method was optimized for assessing Pb, Cd and Hg at environmental levels, it also proved suitable for assessing concentrations associated with occupational exposure. The method requires as little as 200 μl of blood that is diluted 1 + 49 for direct analysis in the inductively coupled plasma-mass spectrometer. Method performance is compared to well-established AAS methods. Initial method validation was accomplished using National Institute of Standards and Technology (NIST) Standard Reference Material 966, Toxic Metals in Bovine Blood. Method detection limits (3s) are 0.05 μg dl − 1 for Pb, 0.09 μg l − 1 for Cd; and 0.17 μg l − 1 for Hg. Repeatability ranged from 1.4% to 2.8% for Pb; 3% to 10% for Cd; and 2.6% to 8.8% for Hg. In contrast, AAS method detection limits were 1 μg dl − 1 , 0.54 μg l − 1 , and 0.6 μg l − 1 , for Pb, Cd, and Hg, respectively. Further performance assessments were conducted over a 2-year period via participation in four international External Quality Assessment Schemes (EQAS) operated specifically for toxic metals in blood. This includes schemes operated by (aand (d) the University of Surrey, Guildford, UK Trace Elements scheme. The EQAS data reflect analytical performance for blind samples analyzed independently by both inductively coupled plasma-mass spectrometry and AAS methods.

Coal-based power generation is a principal source of electricity in India and many other countries. About 15-30% of the total amount of residue generated during coal combustion is fly ash (FA). FA is generally alkaline in nature and contains many toxic metals like Cr, Pb, Hg, As and Cd along with many essential elements like S, B, Ca, Na, Fe, Zn, Mn and P. Dumped FA contaminates the biosphere by mobilization of its fine particles and hazardous metals. Despite the negative environmental impact of FA, coal continues to be a major source of power production in India and therefore FA disposal is a major environmental issue. To overcome this problem, FA dumping sites have been started as a potential resource for biomass production of tree species. Phytoremediation is a strategy that uses plants to degrade, stabilize, and remove contaminants from soils, water and waste FA. Phytomanagement of FA is based on the plants' root systems, high biomass, woody nature, native nature, and resistance to pH, salinity, and toxic metals. Recently Indian researchers mostly from the National Botanical Research Institute have been working on phytoremediation and revegetation of FA dykes, inoculation of bacterial strains for reducing FA stress and biomass production from FA dykes. Many international researchers have worked on reclamation, revegetation and utilization of FA. FA utilization saves resources, mainly land (topsoil), water, coal, limestone and chemical fertilizer. Safe utilization of FA is a major concern around the world and regulatory bodies are enforcing stringent rules for the proper management of FA. This article summarizes various viable avenues in India for FA utilization and environmental management.

The contamination of the environment by toxic metals poses a threat for "Man and biosphere", reducing agricultural productivity and damaging the health of the ecosystem. In developed nations, this problem is being addressed and solved to some extent by using "green technology" involving metal tolerant plants, to clean up the polluted soils. The use of naturally occurring metal tolerant plants and the application of genetic manipulation, should hasten the process of transferring this technology from laboratory to field. Therefore, it is essential to investigate and understand how plants are able to tolerate toxic metals and to identify which metabolic pathways and genes are involved in such a process. Recent advances in knowledge derived from the "omics", have considerable potential in developing this green technology. However, strategies to produce genetically altered plants to remove, destroy or sequester toxic metals from the environment and the long-term implications, must be investigated carefully.

The soil quality of a municipal solid waste dumpsite in Ariara, Aba, southeastern Nigeria was investigated for possible pollution impacts. Samples were collected from three sampling points located within the dumpsite and a control at 0-15, 15-30 and 30-45cm depth profiles. Toxic metals were analyzed with the Atomic Absorption Spectrophotometer. Mean Ni, Fe, Pb, Mn, Zn, Cr and Cd were 2.56 ± 0.6, 314.79 ± 76.1, 17.06 ± 4.3, 102.78 ± 21.2, 90.64 ± 20.4, 22.56 ± 5.0 and 9.25 ± 1.5 mg/kg, while Total Heterotrophic Bacteria (THB), Total Heterotrophic Fungi (THF) and Total Coliforms Bacteria counts (TCB) were 1.6 x 10 6 ± 5.5 x 10 5 , 8.8 x 10 1 ± 2.7 x 10 1 and 1.7 x 10 3 ± 5.3 x 10 2 cfu/g respectively. There were significantly higher concentrations of Fe (Sig. t=0.000), Mn (Sig. t=0.002), Zn (Sig. t=0.018), Cr (Sig. t=0.033) and Cd (Sig. t=0.009) at the impacted than control locations at P<0.05. Zn correlated with THB (r=0.964), THF (r=0.976) and TCB (r=0.987), Cr correlated with THF (r=0.952), Ni correlated with THF (r=-0.956) and TCB (r=-0.976) (P<0.05) and all the metals correlated positively with sand composition (P<0.01). The wastes impacted overlying soil pedons and the high porous sand compositions and high toxic metal levels could make groundwater aquifer of the area vulnerable to pollution from surface point source.

Hexavalent chromium is a well-known highly toxic metal, considered a priority pollutant. Industrial sources of Cr(VI) include leather tanning, cooling tower blowdown, plating, electroplating, anodizing baths, rinse waters, etc. The most common method applied for chromate control is reduction of Cr(VI) to its trivalent form in acid (pH ∼ 2.0) and subsequent hydroxide precipitation of Cr(III) by increasing the pH to ∼9.0-10.0 using lime. Existing overviews of chromium removal only cover selected technologies that have traditionally been used in chromium removal. Far less attention has been paid to adsorption. Herein, we provide the first review article that provides readers an overview of the sorption capacities of commercial developed carbons and other low cost sorbents for chromium remediation.

The soil quality of a municipal solid waste dumpsite in Ariara, Aba, southeastern Nigeria was investigated for possible pollution impacts. Samples were collected from three sampling points located within the dumpsite and a control at 0-15, 15-30 and 30-45cm depth profiles. Toxic metals were analyzed with the Atomic Absorption Spectrophotometer. Mean Ni, Fe, Pb, Mn, Zn, Cr and Cd were 2.56 ± 0.6, 314.79 ± 76.1, 17.06 ± 4.3, 102.78 ± 21.2, 90.64 ± 20.4, 22.56 ± 5.0 and 9.25 ± 1.5 mg/kg, while Total Heterotrophic Bacteria (THB), Total Heterotrophic Fungi (THF) and Total Coliforms Bacteria counts (TCB) were 1.6 x 10 6 ± 5.5 x 10 5 , 8.8 x 10 1 ± 2.7 x 10 1 and 1.7 x 10 3 ± 5.3 x 10 2 cfu/g respectively. There were significantly higher concentrations of Fe (Sig. t=0.000), Mn (Sig. t=0.002), Zn (Sig. t=0.018), Cr (Sig. t=0.033) and Cd (Sig. t=0.009) at the impacted than control locations at P<0.05. Zn correlated with THB (r=0.964), THF (r=0.976) and TCB (r=0.987), Cr correlated with THF (r=0.952), Ni correlated with THF (r=-0.956) and TCB (r=-0.976) (P<0.05) and all the metals correlated positively with sand composition (P<0.01). The wastes impacted overlying soil pedons and the high porous sand compositions and high toxic metal levels could make groundwater aquifer of the area vulnerable to pollution from surface point source.

Exposure to contaminants is one hypothesis proposed to explain the global decline in shorebirds, and this is of particular concern in the arctic. However, little information exists on contaminant levels in arctic-breeding shorebirds, especially in Canada. We studied potential contaminants in three biparental shorebird species nesting in Nunavut, Canada: ruddy turnstones (Arenaria interpres), black-bellied plovers (Pluvialis squatarola) and semipalmated plovers (Charadrius semipalmatus). Blood, feathers and eggs were analyzed for As, Be, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, Se, Tl, V, and Zn. We assessed whether element concentrations a) differed among species and sexes, b) were correlated among pairs and their eggs, and c) were related to fitness endpoints, namely body condition, blood-parasite load, nest survival days, and hatching success. Non-essential elements were found at lower concentrations than essential elements, with the exception of Hg. Maximum Hg levels in blood approached those associated with toxicological effects in other bird species, but other elements were well below known toxicological thresholds. Reproductive success was negatively correlated with paternal Hg and maternal Pb, although these effects were generally weak and varied among tissues. Element levels were positively correlated within pairs for blood-Hg (turnstones) and feather-Ni and Cr (semipalmated plovers); concentrations in eggs and maternal blood were never correlated. Concentrations of many elements differed among species, but there was no evidence that any species had higher overall exposure to non-essential metals. In conclusion, whereas we found little evidence that exposure to the majority of these elements is leading to declines of the species studied here, Hg levels were of potential concern and both Hg and Pb warrant further monitoring.

Hexavalent chromium is a well-known highly toxic metal, considered a priority pollutant. Industrial sources of Cr(VI) include leather tanning, cooling tower blowdown, plating, electroplating, anodizing baths, rinse waters, etc. The most common method applied for chromate control is reduction of Cr(VI) to its trivalent form in acid (pH ∼ 2.0) and subsequent hydroxide precipitation of Cr(III) by increasing the pH to ∼9.0-10.0 using lime. Existing overviews of chromium removal only cover selected technologies that have traditionally been used in chromium removal. Far less attention has been paid to adsorption. Herein, we provide the first review article that provides readers an overview of the sorption capacities of commercial developed carbons and other low cost sorbents for chromium remediation.

Water pollution is one of the major threats to public health in Pakistan. Drinking water quality is poorly managed and monitored. Pakistan ranks at number 80 among 122 nations regarding drinking water quality. Drinking water sources, both surface and groundwater are contaminated with coliforms, toxic metals and pesticides throughout the country. Various drinking water quality parameters set by WHO are frequently violated. Human activities like improper disposal of municipal and industrial effluents and indiscriminate applications of agrochemicals in agriculture are the main factors contributing to the deterioration of water quality. Microbial and chemical pollutants are the main factors responsible exclusively or in combination for various public health problems. This review discusses a detailed layout of drinking water quality in Pakistan with special emphasis on major pollutants, sources of pollution and the consequent health problems. The data presented in this review are extracted from various studies published in national and international journals. Also reports released by the government and non-governmental organizations are included.

Bioremediation is gaining a lot of importance in recent times as an alternate technology for removal of elemental pollutants in soil and water, which require effective methods of decontamination. Phytoremediation-the use of green plants to remove, contain or render harmless environmental pollutants-may offer an effective, environmentally nondestructive and cheap remediation method. The use of genetic engineering to modify plants for metal uptake, transport and sequestration may open up new avenues for enhancing efficiency of phytoremediation. Metal chelator, metal transporter, metallothionein (MT), and phytochelatin (PC) genes have been transferred to plants for improved metal uptake and sequestration. Transgenic plants, which detoxify/accumulate cadmium, lead, mercury, arsenic and selenium have been developed. A better understanding of the mechanisms of rhizosphere interaction, uptake, transport and sequestration of metals in hyperaccumulator plants will lead to designing novel transgenic plants with improved remediation traits. As more genes related to metal metabolism are discovered, facilitated by the genome sequencing projects, new vistas will be opened up for development of efficient transgenic plants for phytoremediation. D

Treatment of polluting discharges from abandoned coal mines in the UK currently produces ca 30,000 t y À1 of hydrous iron oxides (''ochre"), for which there is no major end-use, but which has previously been shown to have potential for removing P from wastewater and agricultural runoff. The efficiency of ochre for P removal from wastewater was investigated in experiments at two sites in the UK: Leitholm in Scotland and Windlestone in England. The three-year experiment at Leitholm involved diverting secondary-treated wastewater effluent through a trough which contained granular and pelletized ochre at different times. In the nine-month experiment at Windlestone, beds of ochre pellets in horizontal and vertical flow configurations were tested. The ochre treatment systems at Leitholm reduced influent concentrations of total P (TP) and TP mass by ca 80% and 50%, respectively, during optimal flow conditions, and achieved a removal rate of up to 65 ± 48 mg TP kg À1 ochre d À1 . There was no detectable release of potentially toxic metals from the ochre during the experiments. P removal rates by concentration were inversely related to flow and declined during the different phases of the experiments, probably due to clogging. At Windlestone, higher removal rates up to 195 mg TP kg À1 ochre d À1 were achieved for short periods of time following cleaning of the experimental system. Ochre has considerable potential to remove P from wastewater in a multi-stage treatment system and has a lifetime estimated to be 10 times longer than other substrates tested for P removal.

Tea (Camellia sinensis L) is one of the most widely popular nonalcoholic beverage, consumed by over twothirds of the world's population due to its medicinal, refreshing and mild stimulant effects. Mainly four types of made tea viz., black or red, oolong, green and white are used for tea infusion (water extract from fermented tea leaf) worldwide. Tea plays a major role in terms of the intake of a number of nutritional trace elements in humans. Besides essential macro-and microelements, experimental studies have demonstrated that the accumulation of significant amount of excess nonessential trace elements in tea leaves may eventually increase the metal body burden in humans. Different literatures have indicated that among different trace elements, levels of aluminium (Al), arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), fluoride (F) manganese (Mn), and nickel (Ni) in different tea infusions were 0.06-16.82 mg L − 1 , trace-1.53 μg L − 1 , trace-0.79 μg L − 1 , below detectable limit-43.2 μg L − 1 , 0.02-40.0 mg L − 1 , 0.2-4.54 mg L − 1 , 0.1-250 mg L − 1 and BDL-0.16 mg L − 1 , respectively. It has also been reported that in some of the tea infusions, toxic metals exceed the maximum permissible limits stipulated for different countries. In the present review, an attempt has been made to update and evaluate the knowledge of the presence of some selected trace elements in tea leaves, made tea and tea infusion, based on the available literature. Existing reports suggested that the presence of trace elements in green tea is lower than the black tea in most cases. However, the available literatures still appear to have some limits and may need more detailed investigations before reaching the conclusions.

The adsorption of lead(II) and cadmium(II) on peels of banana has been studied in batch mode using flame atomic absorption spectroscopy for metal estimation. Concerned parameters like adsorbent dose, pH, contact time and agitation speed were investigated. Langmuir, Freundlich and Temkin isotherms were employed to describe adsorption equilibrium. The maximum amounts of cadmium(II) and lead(II) adsorbed (qm), as evaluated by Langmuir isotherm, were 5.71 mg and 2.18 mg per gram of powder of banana peels, respectively. Study concluded that banana peels, a waste material, have good potential as an adsorbent to remove toxic metals like lead and cadmium from water.

This study was undertaken to evaluate the effect of modified citrus pectin (MCP) on the urinary excretion of toxic elements in healthy individuals. MCP is a reduced molecular weight pectin (weight-average molar mass = = = = = 15400) that is mostly linear homogalacturonan with a 3.8% degree of esterification and approximately 10% rhamnogalacturonan II based on the presence of 2-keto-3-deoxy-octonic acid. Subjects ingested 15 g of MCP (PectaSol ® , EcoNugenics ® Inc., Santa Rosa, California 95407) each day for 5 days and 20 g on day 6. Twentyfour hour urine samples were collected on day 1 and day 6 for comparison with baseline. The urine samples were analysed for toxic and essential elements. In the first 24 h of MCP administration the urinary excretion of arsenic increased significantly (130%, p < < < < < 0.05). On day 6, urinary excretion was increased significantly for cadmium (150%, p < < < < < 0.05). In addition, lead showed a dramatic increase in excretion (560%, p < < < < < 0.08). This pilot trial provides the first evidence that oral administration of MCP increases significantly the urinary excretion of toxic metals in subjects with a 'normal' body load of metals. It is suggested that systemic chelation of toxic metals by MCP may in part be attributable to the presence of rhamnogalacturonan II, which has been shown previously to chelate metals.

Heavy metals accumulate in various tissues and are associated with increases in today's biggest killers: cardiovascular disease and cancer. Reducing these heavy metals from the body has been a challenge to modern day medicine. With the advent of intravenous EDTA chelation, it was possible to remove heavy metals, but this invasive method of heavy metal removal is burdensome and expensive. This review examines the rectal suppository method of chelating and removing toxic metals from the circulation and deposits in tissue storage sites. In preclinical experiments CaNa 2 EDTA (Detoxamin) rectal suppositories were compared to intravenous (IV) administration of C14-labeled calcium disodium ethylenediaminetetraacetate (CaNA 2 EDTA) in order to evaluate the absorption, brain and prostate tissue distribution, and excretion in rats. The absolute bioavailability of CaNa 2 EDTA in blood following rectal dosing was 36.3% of the IV doses route, which confirmed that rectal dosing is an efficient method for delivering EDTA to tissues. Following IV or rectal dosing of C14 labeled CaNa 2 EDTA, the ratio of radioactive EDTA in tissues compared to blood, showed negligible brain localization. However, prostate tissues were found to have a mean ratio of 3.69 via the IV and 13.6 for the rectal route. The half-life of IV administration was found to be approximately 1.5 hours whereas the half-life of rectal administration was over 8 hours. The total recovery of C14 EDTA expressed as percent of administered EDTA IV and rectally was a mean of 47.3% and 30.3%, respectively at eight hours. The suppository formulation of CaNa 2 EDTA was well absorbed; delivering high levels of EDTA to the tissues, prostate in particular (3.5-fold increase over IV administration). In human subjects, adult men with chronic prostatitis and with benign prostate hyperplasia and/or prostate cancer and prostate calculi were treated in an outpatient setting with tetracycline and EDTA suppositories (Detoxamin) for 90 days, and their symptoms and lab results were analyzed. Using the NIH Chronic Prostatitis Symptom Index, statistically significant post-treatment mean reductions in symptoms and pain were found, along with a significant improvement in mean quality of life. Use of the International Prostate Symptom Score also indicated significant reductions in 5/7 symptom categories and significant reduction of mean overall scores. Analysis of blood and stool post-treatment indicated significant changes in mobilized, secreted cations (cadmium, copper, boron, lead, molybdenum, magnesium, and calcium). The blood cholesterol/high density lipoprotein ratio was also significantly decreased. Use of rectal suppositories has proved to be an innovative, effective and simple approach, saving time and money for the patient, and its efficacy and safety have been validated in pre-clinical and clinical studies.

Siderophores are small molecular weight extracellular organic compounds secreted by microorganisms under iron-starved conditions, used by them to chelate and solubilize iron. Though they are specific ferric iron chelator, but is reported that they bind other metals also, such as divalent heavy metals and actinides because of potentially high metal-siderophore stability constants. Thus metal contaminant fate and transport in subsurface environment can be heavily influenced by siderophores. This approach can be successfully used in removing many toxic metals off the soil which poses a serious health threat. Our research focuses on the correlation between cell growth and siderophore production and chemical characterization of the siderophore type. Its also documents the development of an assay method for the screening of different metals for complexation with siderophores based on the Chrome Azurol S (CAS) assay. The present research aims at batch scale mobilization of arsenic from arsenic contaminated soils using siderophore produced by P. azotoformans and thus evaluating its efficiency as compared to Ethylene Diamine Tetra Acetic Acid (EDTA), Citric Acid (CA) for the same. FT-IR spectroscopic studies were carried out to determine the interaction between soil, arsenic and siderophore. Results have shown that the cell growth and siderophore production are inversely related. Characterization of siderophore produced by P. azotoformans has revealed that it is of mixed-type catecholate and hydroxamate. Siderophore was found to complex with heavy metals like Cadmium, Lead, Nickel, Arsenic (III, V), Aluminium, Magnesium Zinc, Copper, Cobalt, Strontium other than Iron. Five washings by siderophore, EDTA, CA removed almost 92.8%, 77.3%, 70.0% arsenic respectively as compared to only 33.8% removal by control. Washing of arsenic contaminated soil with tap water revealed that ≈ 65.8% of arsenic in contaminated soil is in freely available or weakly bound form. The IR spectra revealed that hydrogen bonding exists between siderophore, arsenic and soil. Encouraging results of arsenic removal by biomolecule-siderophore can lead to an emerging tool brimming with opportunities for environmental clean up.

Phytoextraction has emerged as a novel approach to clean up metal-polluted soils in which plants are used to transfer toxic metals from soils to shoots. This review provides a synthesis of current knowledge on phytoextraction of metals from soils and their accumulation in plants. The objective is to integrate soil-related (root exudates and chemical amendments) and biological advances to suggest research needs and future directions. As far as can be deduced from the literature, it will be some time before phytoextraction may be established as a commercial technology. For chemically-assisted phytoextraction, research has not shown easily biodegradable compounds to overcome the risks associated with the use of EDTA for poorly available metals in soils. On the other hand, significant progress has been made on the physiological and molecular aspects regarding tolerance and phytoaccumulation of metals in plants. A multidisciplinary approach is warranted to make phytoextraction a feasible commercial technology to remediate metal-polluted soils.

Chlorination of drinking water is a common practice, used by numerous municipalities in the United States (US) to safeguard their water supplies. However, the chlorine used can chemically react with organic components in the drinking water to produce unwanted chlorination by-products. The objective of this investigation was to evaluate the use of granular activated carbon produced from nutshells (almond, English walnut, pecan) in a point-of-use (POU) water filtration system designated 'Envirofilter' and to determine its efficacy in removing select, potentially carcinogenic chlorination by-products, namely the trihalomethanes (THMs) bromodichloromethane, bromoform and dibromochloromethane. The POU water filtration system that contained the nutshell-based carbons was designated 'Envirofilter' and adsorption efficiencies of this system were compared to that of four commercially available POU home water filter systems, namely, BRITA, Omni Filter, PUR and Teledyne Water Pik. Eight different 'Envirofilters' were constructed of individual or binary mixtures of carbons produced from acid-activated almond or pecan shells and steam-activated pecan or walnut shells and evaluated for adsorption of the three chlorination by-products. The results indicate that only two of the eight 'Envirofilters' failed to remove more THMs than the commercial POU systems. In both cases, these filters contained carbons with either 100% acid-activated almond shells or 100% acid-activated pecan shells. All six of the other filters contained carbons with either 50% or 100% steam-activated pecan shells or steam-activated walnut shells. Therefore, 'Envirofilters' appeared to depend on the presence of steam-activated nutshell carbons for their success. The six effective 'Envirofilters' reduced THM levels to below the Maximum Contaminant Levels (MCL) required by the US Environmental Protection Agency (US EPA). Based on these results, these six 'Envirofilters' may be considered as a replacement for existing commercial filter systems because of their efficacy and projected cost.

The analysis of human biological samples, such as blood, urine, nails, and hair, is generally used for the verification of human exposure to toxic metals. In this review, various spectrometric methods for the determination of cadmium and lead in biological samples are discussed and compared. Several spectrometric techniques are presented and discussed with respect to various characteristics such as sensitivity, selectivity, and cost. Special attention is drawn to the procedures for digestion prior to the determination of cadmium and lead in hair, nails, blood, and urine.