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PubMed2004

Accumulation of heavy metals in some species of lichens in south Tamilnadu, India.

Lichens are lower group of plants. They accumulate heavy metals and have been used as bio-indicators in pollution monitoring. Nine lichen species were collected from urban, rural and hilly areas in the southern part of Tamilnadu. Accumulation of metals differed with species and also with respect to their locations. Among the nine species, Pyxine petricola collected from urban areas showed greater accumulation of the heavy metals i.e., copper, zinc, lead, nickel, chromium and cadmium.

Air Pollutants↗
PubMed1985

Mitochondrial granules: are they reliable markers for heavy metal cations?

Mitochondrial granules have been used as markers for heavy metal cations, but since such granules can also be found in tissues in the absence of such cations, an attempt was made to define conditions under which these different granules might be visualised. The tissue used was the smooth muscle of the central ear artery of the rabbit. In all studies, the presence or absence of mitochondrial granules was determined by several observers, using coded specimens so that the previous treatment of the specimens was not at the time known to the observers. Paired tissues were exposed for 30 or 90 minutes at 20, 30 or 39 degrees C to an incubate containing either 10 mmol/l barium or a control barium-free solution. After fixation in osmium tetroxide, there was no difference between the two groups; in both cases granules appeared more frequently the longer the time and the higher the temperature of incubation. In a further series where glutaraldehyde was the fixative, granules were identified in 23 out of 41 tissues incubated with barium, but in only 1 out of 41 control tissues (P less than 0.001). Electron probe microanalysis showed that granules in osmium-fixed tissues contained osmium as the main element, whereas granules in glutaraldehyde-fixed tissues which had been incubated with barium showed barium as the predominant cation. Thus mitochondrial granules can be reliable markers for heavy metal cations, but only under carefully controlled conditions.

Animals↗
PubMed1987

Toxicities of some heavy metals to the tadpoles of frog, Microhyla ornata (Dumeril & Bibron).

Static bioassays were conducted to determine the relative acute toxicities of five heavy metals (mercury, cadmium, copper, manganese and zinc) to 1-week-old and 4-week-old tadpoles of the frog, Microhyla ornata. Toxic effects were calculated on the basis of LC50 for 24 h, 48 h, 72 h and 96 h exposures at 25.5-26.0 degrees C. Mercury was the most toxic and zinc was the least toxic of the heavy metals tested. The sensitivity of the tadpoles to the heavy metals increased with increased age.

Age Factors↗
PubMed1999

Great and blue tits as indicators of heavy metal contamination in terrestrial ecosystems.

Although there are abundant data on heavy metal contamination in the feathers of seabird species and birds of prey, relatively few studies have addressed the use of passerine birds as indicators of point-source contamination. Concentrations of three essential elements (Al, Zn, and Cu) and two toxic metals (Cd and Pb) were determined in the outer tail feathers of great and blue tits (Parus major and Parus caeruleus), two small insectivorous passerines, at a presumed polluted site (in an urban area close to household waste incinerators) and at a reference site (in a nature reserve). For the great tit, both Cd and Cu levels were significantly higher at the polluted site than in the nature reserve. For the blue tit, Cd, Pb, and Cu levels were significantly higher at the polluted site than at the reference site. There were striking differences in metal levels between blue and great tits inhabiting the same polluted site: lead, zinc, and copper were significantly higher in the smaller blue tit than in the great tit. We suggest that tit (Parus) species, which have been important models in behavioral and ecological research, may be very useful as biomonitors for local contamination.

Animals↗
PubMed2003

Removal of heavy metals by using adsorption on alumina or chitosan.

The removal of heavy metals from wastewater by using activated alumina or chitosan as adsorbers was evaluated. Cd(II) and Cr(III) were employed as models of the behaviour of divalent and trivalent metal ions. The adsorption of Cd(II) and Cr(III) onto the adsorbers evaluated was studied as a function of pH, time, amount of adsorber, concentration of metal ions and sample volume. A 0.4-g portion of activated alumina can retain 0.6 mg Cr(III) and 0.2 mg Cd(II) from 20 mL sample adjusted at pH 4 and stirred for 30 min. It is therefore possible to totally decontaminate 500 mL of a waste containing 5 mg L(-1) Cd(II) and Cr(III) with 10 g alumina. On the other hand, 0.4 g chitosan can totally decontaminate 20 mL of a pH 5 solution containing up to 50 mg L(-1) Cd(II) and Cr(III). A 99.2+/-0.1% retention of Cd(II) and 83+/-1% retention of Cr(III) was obtained from 500 mL of a laboratory waste. The aforementioned strategies were applied for the minimization of analytical chemistry teaching laboratories and atomic spectrometry laboratory wastes. On comparing both adsorbers it can be concluded that chitosan is more preferable than alumina due to the reduced price of chitosan and the absence of side-pollution effects.

Adsorption↗
PubMed2003

Hybrid flotation--membrane filtration process for the removal of heavy metal ions from wastewater.

A promising process for the removal of heavy metal ions from aqueous solutions involves bonding the metals firstly to a special bonding agent and then separating the loaded bonding agents from the wastewater stream by separation processes. For the separation stage, a new hybrid process of flotation and membrane separation has been developed in this work by integrating specially designed submerged microfiltration modules directly into a flotation reactor. This made it possible to combine the advantages of both flotation and membrane separation while overcoming the limitations. The feasibility of this hybrid process was proven using powdered synthetic zeolites as bonding agents. Stable fluxes of up to 80l m(-2)h(-1) were achieved with the ceramic flat-sheet multi-channel membranes applied at low transmembrane pressure (<100 mbar). The process was applied in lab-scale to treat wastewater from the electronics industry. All toxic metals in question, namely copper, nickel and zinc, were reduced from initial concentrations of 474, 3.3 and 167mg x l(-1), respectively, to below 0.05 mg x l(-1), consistently meeting the discharge limits.

Conservation of Natural Resources↗
PubMed2000

Heavy metals in human primary teeth: some factors influencing the metal concentrations.

Human primary teeth have been used as indicators of heavy metal exposure for several decades, but the knowledge about the influence of factors such as tooth type and the presence of caries and roots on metal concentrations is limited. Samples of tooth powder from more than 1200 Norwegian primary teeth without fillings have been analyzed for lead, zinc and cadmium content, and 554 of them for mercury. The material represents all groups of tooth types (incisors, canines and molars), carious and non-carious teeth, and teeth with and without roots. Here we investigate how tooth group and the presence of caries and roots are related to metal concentrations in the teeth. We find that carious teeth have higher metal concentrations than non-carious teeth; the difference was statistically significant for lead, mercury and zinc. Teeth with roots have higher lead and zinc concentrations than teeth without roots. We find differences in metal concentrations between the tooth groups for lead, mercury and zinc. Significant, positive correlations are found between lead and the three other metals and between mercury and zinc. We conclude that metal concentrations in primary teeth are affected by the presence of caries and roots and by tooth group.

Cuspid↗
PubMed2000

[Human biosybstrates in ecologic analytical monitoring of heavy metals].

The authors revealed direct correlation between higher level of some heavy metals in environmental objects, foods and the metals level in human biologic materials. Human biologic materials appeared to reflect total metals intake and to serve objective criteria of environmental pollution.

Environmental Pollutants↗
PubMed2001

In situ bioremediation of soil contaminated with oil and heavy metals.

An experimental plot of soil contaminated with crude oil and heavy metals (copper, zinc and cadmium) was subjected to bioremediation using the activity of the indigenous soil microflora. The oil was light, rich in paraffins and with a very low content of asphaltene-resinous substances. Copper, zinc and cadmium were present mainly as sulfide minerals but also in forms more amenable to biological and chemical leaching. Their contents in the soil exceeded approximately 1.5-3 times the relevant permissible levels. The soil microflora contained different oil-degrading and metal-solubilizing microorganisms. The activity of this microflora was enhanced by suitable changes in the levels of some essential environmental factors such as oxygen, water and nutrient contents in the soil. The oil content in the plot was decreased from the initial 12.50 g/kg dry soil to 1.25 g/kg dry soil within 8 months of treatment. Simultaneously, the contents of copper, zinc and cadmium were decreased below the relevant permissible levels for soil of such type.

Bacteria↗
PubMed2006

[Mechanisms of heavy metal cadmium tolerance in plants].

Cadmium (Cd) is a strongly phytotoxic heavy metal, which inhibits plant growth and even leads to plant death. The main symptoms of Cd(2+) toxicity to plants are stunting and chlorosis. Plant has developed some functions for Cd(2+) tolerance, which include cell wall binding, chelation with phytochelatins (PCs), compartmentation of Cd(2+) in vacuole, and enrichment in leaf trichomes. However, Cd(2+) tolerance in plant is more likely involved in an integrated network of multiple response processes than several isolated functions cited above. In the network, the processes of sulfur metabolism, antioxidative response, and Cd(2+) transport across plasma and vacuole membrane in plant are closely related with Cd(2+) tolerance in plant. The processes of sulfur uptake, assimilation and sequential sulfur metabolism in plant respond to Cd(2+) stress. The expression of sulfur transporters with varied affinity was changed in different ways under Cd(2+) stress, and the high expression of ATP sulfurylase (APS) and adenosine 5' phosphosulfate reductase (APR), which may help to keep the supply of S(2-) for cysteine (Cys) synthesis. The efficiency of Cys synthesis may function in Cd(2+) detoxification, and the up-regulated expression of Ser acetyltransferase (SAT) and O-acetyl-ser (thiol)-lyase (OASTL) has been found in some Cd(2+) treated plants. Reduced glutathione (GSH) is an important antioxidant and the precursor of PCs, glutamylcysteine synthetase (GCS) and glutathione synthetase (GS) catalyze GSH synthesis from Cys, overexpression of the two enzymes can improve Cd(2+) tolerance in plant. PCs are more important Cd(2+) chelators than metallothioneins (MTs) in plants, and the expression of phytochelatin synthase (PCS) responds to Cd(2+) stress. Plant antioxidative system also contributes to Cd(2+) tolerance. The antioxidative response to Cd(2+)-induced oxidative stress varies in different plants and tissues and is also Cd(2+) concentration dependent, and the Cd hyperaccumulator plants show strong tolerance to oxidative stress. Some genes encoded metal transporters with Cd(2+) substrate specificity at plasma and vacuole membranes, which have been isolated and characterized in recent years. These genes play critical roles in Cd(2+) translocation, allocation, and compartmentation in plants. Despite the great progresses made in the field in recent years, there are still some issues which need further exploration, such as the detail of signal transduction and the responses of gene regulation to Cd(2+), the rhizosphere activation and root adsorption to soil Cd(2+), Cd(2+) trafficking in xylem and phloem, Cd(2+) translocation to fruit and seed, and the possible presence of a high-affinity Cd(2+) transporter in Cd hyperaccumulators.

Adenosine Triphosphatases↗
PubMed1987

[Heavy metal exposure of the population in an area of nonferrous metallurgy--a prerequisite for the development of atherosclerotic diseases].

A survey is carried out among the population of a district with nonferrous metallurgy in view of studying the mutual relation between the exposure to heavy metals and some basic risk factors for the development of ischemic disease of the heart. The study pertains to the content of lead, cadmium, copper and zinc in blood and its relation to the serum lipids, glutathione in blood, arterial pressure and age. A higher level of triglycerides and free butyric acids were established in the serum with absence of clinical manifestations as a result of exposure to heavy metals. A significant correlation of cadmium, copper and zinc with serum lipids was found. On the basis of regressive analysis equations for the changes in the biochemical indices are derived under the effect of exposure to heavy metals, as well as for the connection of the arterial pressure with age and serum cholesterol. It is reckon that in clinical healthy young people under the effect of nonoccupational exposure to heavy metals a prerequisite is created for development of atherosclerotic diseases in mature and advanced age. It is recommended that the environmental pollution by nonferrous metallurgy to be accepted as risk factor for development of ischemic disease of the heart and to be taken under consideration in the complex preventive measure for this disease.

Adult↗
PubMed2005

Fecundity of the freshwater fish, Notopterus notopterus (Pallas) in natural and heavy metal contaminated water.

The knowledge of fecundity of fish from a specific aquatic body is extremely important in the successful management and exploitation of its fishery. In the present investigation the fecundity of the freshwater fish, Notopterus notopterus was studied in fish collected from a natural aquatic body (Sirnoor nala) near Gulbarga and also in fish exposed to some heavy metal contamination (HgCl2, CdCl2 and their combination) at sublethal concentration for 15 days in the laboratory. The mathematical relationship between fecundity and total length, body weight, ovary length and ovary weight were determined in both unexposed and exposed fish. The fish, N. notopterus has bigger oocytes and are few in number. Studies in the fish exposed to heavy metals indicate that significant reduction in these parameters after exposure to heavy metals at sublethal concentration was noticed. The fecundity has straight line relationship with total length, body weight, ovary length and ovary weight in control fish which did not alter after heavy metal exposure. This study provides the viability of species in only specific environment.

Animals↗
PubMed2005

Risk perception of heavy metal soil contamination by high-exposed and low-exposed inhabitants: the role of knowledge and emotional concerns.

Soil contaminated with heavy metals is a salient example of environmental risk. Consumption of vegetables cultivated in contaminated soil or direct ingestion of soil by small children can damage health. In contrast to other kinds of pollution or risks such as air pollution or exposure to ozone, the individual risk concerning soil contamination is highly dependent on the way one is exposed to the local source of risk. Thus, we wanted to know if risk perception varies according to the level of exposure. A quasi-experimental, questionnaire-based study was conducted in a community in northwest Switzerland, where the soil is widely contaminated. The level of contamination varies with the distance from the source of the contamination, a metal processing plant. We investigated the perception of risk of heavy-metal-contaminated soil by inhabitants with high-exposure levels (N= 27) and those with low-exposure levels (N= 30). Both groups judged the risk for oneself similarly whereas the low-exposure group, when compared to the high-exposure group, judged perceived risk for other affected people living in their community to be higher. Besides this exposure effect, risk perception was mainly determined by emotional concerns. Participants with higher scores in self-estimated knowledge tended to provide low-risk judgments, were less interested in further information, showed low emotional concern, and thus displayed high risk acceptance. In contrast, actual knowledge showed no correlation with any of theses variables. Judgments on the need for decontamination are determined by risk perception, less application of dissonance-reducing heuristics and commitment to sustainability. The desire for additional information is not affected by missing knowledge but is affected by emotional concerns.

Emotions↗
PubMed2006

Evaluation of heavy metal contamination in Phaeozem of northeast China.

Surface and profile Phaeozem soil samples from 31 locations affected by various anthropogenic activities such as mining, chemical manufacturing, traffic emission and pesticide application were collected in Heilongjiang Province and Jilin Province, northeast China. The range of total concentrations of four heavy metals Cd, Pb, Cu and Zn in the soil was 0.011-3.137, 10.31-62.34, 9.74-51.21 and 39.54-247.59 mg kg(-1), respectively, determined using the acidic digestion procedure. Four methods including single contamination evaluation, background concentration comparison, surface/subsurface concentration comparison and exchangeable fraction evaluation were used to evaluate the extent of metal contamination in Phaeozem. The results indicated that different activities increased the concentrations of the heavy metals in surface soils, where high concentrations of cadmium and lead were found close to chemical plants and in the suburbs of the investigated cities. The four methods showed a general trend of increased soil contamination with heavy metals. Cadmium was of the most concern compared with the other contaminated elements in the study area, due to the long-term phosphatic fertilizer utilization and industrial activities. The proper evaluation method for cadmium contamination was the background concentration comparison, while for zinc and copper was the single contaminative index evaluation. Cadmium and lead could be the potential environmental risk in the Phaeozem area based on the different evaluations.

China↗
PubMed2006

Bioaccumulation of some heavy metals in different tissues of Dicentrarchus labrax L, 1758, Sparus aurata L, 1758 and Mugil cephalus L, 1758 from the Camlik lagoon of the eastern coast of Mediterranean (Turkey).

In this study, bioaccumulation of the heavy metals (Fe, Zn, Cd) in the liver, gill, gonad and muscle tissues of Dicentrarchus labrax, Mugil cephalus and Sparus aurata were investigated seasonally. Camlik is the important fisheries lagoon located in The Iskenderun Bay, Mediterranean coast of Turkey. Due to heavy industrial and agricultural activities in the region, the bay has the polluted coastal waters of Turkey. Therefore, the levels of cadmium, zinc, iron were determined in the muscle in each species because of its importance for human consumption and also the liver, gill, gonad were analysed since these organs tend to accumulate metals. Heavy metal levels were found generally higher in the liver and gill than the gonad and muscle tissues in three species; the levels of all metals in a given tissue were generally higher in Mugil cephalus than the other two species. Data collected in this study suggest that Camlik lagoon is affected by a relatively metal pollution. The concentrations of Zn concentrations in the muscle tissues exceeded the acceptable levels for a food source for human consumption and other metals in the edible parts of the investigated fish were in the permissible safety levels for human uses.

Animals↗
PubMed2005

[Chemical forms of heavy metals in the soils and plants of copper tailings yard].

The study on the chemical forms of heavy metals in the soils and plants at the copper tailings yard in Tongling City indicated that the soils were extremely poor, with organic mater content being 2.6-5.8 g x kg(-1), only 1/15 of the control, while their Cu, Cd, Pb and Zn contents were higher than the control, with Cu 809.30-1395.54 mg x kg(-1) and Cd 3.25-6.35 mg x kg(-1), as 30-60 times as those of the control. The heavy metals contents in Zoysia japonica and Trifolium pratense had a significantly positive correlation with the contents of their exchangeable and organic forms in soils, a significantly or very significantly negative correlation with the forms of Fe-Mn oxides and carbonate, and no correlation with residual form. The main forms of Cu, Zn and Pb in Z. japonica and T. pratense were HAC-and HCl-extractable, and residual. The NaCl-extractable Zn content in the roots, stems and leaves of Z. japonica and T. pratense occupied a higher proportion, while NaCl-extractable Cd was the main form of Cd in both of the plants, not only in their roots but also in their leaves.

China↗
PubMed2000

Evidence for high affinity nickel transporter genes in heavy metal resistant Streptomyces spec.

We have isolated 25 new strains of streptomycetes from soil samples of a polluted site at the former uranium mine, Wismut, in eastern Thuringia, Germany. The strains grew on medium containing 1 mM NiCl2 and thus were resistant to the heavy metal ion. Seven of the strains were further characterized. All of these strains were resistant to heavy metals in various degrees with up to 10 mM resistance against NiCl2 supplied with the liquid minimal growth medium. The high level of resistance prompted us to look for high affinity nickel transporter genes thought to provide a means to eliminate the excess nickel ions form the cells. Degenerate oligonucleotide primers derived from sequences of P-type ATPase transporter genes of Gram negative bacteria identified a fragment which shows deduced amino acid sequence similarities to known high affinity nickel transporters. Investigation of two genes obtained from the isolates Streptomyces spec. E8 and F4 showed high sequence divergence. This was unexpected since a transmissible plasmid had been thought to convey heavy metal resistance.

Amino Acid Sequence↗