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Results for “Metals, Heavy”

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PubMed1976

Electromyographic changes in automechanics with increased heavy metal levels.

Twenty automechanics possessing increased whole blood values of one or more of the following heavy metals; chromium, copper, lead, manganese and nickel, were studied for peripheral nerve affection by means of electromyography (both sensoric and motoric nerve potentials were recorded). The heavy metal contents were related to the findings of denervation, distal motor latency, distal sensory latency, motoric and sensoric conduction velocities. Apart from two workers, in whom only lead was assayed, the remaining group of 18 were assayed for all heavy metals under study. Six workers showed increased distal motor and/or sensory latency and seven decreased nerve conduction velocity (four motoric and three sensoric affections). Of the workers with nerve affection, three showed increased levels of lead (nickel and chromium also raised). Four workers showed increased lead, nickel and chromium and one of lead, chromium and manganese. All in all, 10 out of 20 workers (50 percent) with elevated lead levels showed definite signs of peripheral neuropathy and seven out of 14 with raised nickel values showed these signs but they could all be accounted for by the increased lead levels. All except seven workers with raised lead levels in the whole group showed values above the critical limit of 80.0 mug/100 ml in whole blood. The data argue for the highly toxic effect of lead and other heavy metals on the peripheral nervous system and stress the diverse toxic exposure which automechanics undergo during their work. The possibility of there being a synergistic action between heavy metals and components of mineral oil and petroleum is discussed.

Action Potentials↗

PubMed1976

Heavy metal levels and delta-amino-levulinic acid dehydrase levels in peripheral polyneuropathy.

On the basis of assay of heavy metals in whole blood (lead, cadimum, chromium, copper, nickel and manganese) and delta-amino-levulinic-acid dehydrase (ALA-D) and ALA in urine in a normal Danish population, the levels of these clinco-chemical factors were assayed in 23 patients with peripheral neuropathy of unknown etiology. All patients studied showed electro-physiological sign of denervation and/or reduced motor or sensoric nerve conduction velocity. Cadmium and manganese were never found to be increased. In all but four patients, an increase of one or more heavy metals was found. Ten patients showed raised levels of two or more metals, the dominant metal being lead (10 cases), nine patients showed increased in chromium. A significant corrleation was found between increasing lead levels and decreasing ALA-D activity. Although normal concentrations of manganese were found, correlation analysis revealed a significant correlation between increased manganese and decreased ALA-D. The raised values of heavy metals could not be traced to occupational or other exposure to heavy metals and the increased values were not related to tobacco consumption. The findings are discussed in relation to known data on neuropathy and the results seem to indicate a multifactorial patholgenesis of the disease. Among factors contributing to the precipitation of the syndrome may be raised levels of heavy metals.

Adult↗

PubMed2026

Heavy-metal stress shapes habitat-specific microbial survival strategies in estuarine environments.

Estuarine ecosystems face increasing heavy metal pollution from rapid urbanization and industrialization, yet the microbial adaptive strategies to multiple metal stressors across different habitats remain poorly understood. This study investigated the diversity and composition of bacterial and fungal communities across free-living (FL), particle-attached (PA), and sediment (SE) fractions from three estuaries with varying heavy metal contamination, and further investigated functional adaptations of bacterial communities. High-throughput amplicon sequencing revealed habitat-specific communities, with SE hosting the highest alpha diversity and enrichment of metal-resistant genera such as Woeseia and Sva1033. Environmental filtering, particularly by Zn, was the dominant driver shaping bacterial assemblages across all habitats, whereas fungal communities displayed greater stochastic assembly patterns. Analysis of 44 high-quality bacterial metagenome-assembled genomes (MAGs) revealed diverse metal resistance genes (cusA, znuB, and zntA), along with enriched metabolic pathways for carbon, nitrogen, and sulfur cycling. Notably, both active efflux/oxidative stress defense and indirect immobilization mechanisms were observed across all habitats, but their relative importance differed: FL and PA communities exhibited a greater reliance on active metal efflux (czcAB) and oxidative stress defense (trxAB) to maintain intracellular homeostasis, whereas SE communities displayed a stronger genomic potential for sulfate reduction (dsrAB) that may contribute to metal immobilization through sulfide precipitation. This metabolic partitioning highlights the complementary roles of different habitats in mediating metal toxicity and biogeochemical cycling, providing new insights into microbial resilience in polluted estuaries and underscoring the urgency of addressing heavy-metal contamination in these critical ecosystems.

Estuaries↗

PubMed1977

Production of copper coproporphyrin III by Bacillus cereus. II. Regulation of the biosynthesis of coproporphyrin III and its copper complex by oxygen and heavy metal ions.

The effects of oxygen and heavy metal ions on the production of copper coproporphyrin III were studied in Bacillus cereus strain 2. The formation of copper coproporphyrin III was found to be maximum when the cells were cultivated in G-medium at a low level of oxygen supply, but it was suppressed at extremely low oxygen supply levels. When the cells were cultured in metal-free G-medium, neither metal-coproporphyrin III nor coproporphyrin III was formed. In the presence of copper in the medium (400-100 micrometers), the formation of coproporphyrin III copper salt was maximum, but the addition of various heavy metal ions other than copper to the copper-free medium resulted in the formation of neither coproporphyrin III nor its metal chelates. Copper ions appear to be specifically required for coproporphyrin III formation.

Bacillus cereus↗

PubMed2025

Partners in root nodule symbiosis respond uniquely to heavy metal stresses in a host genotype-dependent manner.

The mutualistic symbiosis between legume roots and soil rhizobia culminates in the formation of root nodules, where nitrogen is fixed. Root nodule symbiosis is inhibited by heavy metal stress. In this study, we investigated the relative responses of the symbiotic partners to a non-essential heavy metal cadmium (Cd) and an essential heavy metal zinc (Zn) stress and identified patterns in gene expression. We performed dual transcriptomics in nodules, using the Medicago truncatula-Sinorhizobium meliloti symbiotic system. Phenotypes were measured in the wild-type Medicago truncatula and a mutant in an ABC transporter gene (Mtabcg36), which showed compromised nodule formation in control conditions and further after heavy metal treatment. We observed that the rhizobia were particularly sensitive to Zn in mutant nodules. The greatest degree of differential gene expression in the host plant were observed under Cd and Zn treatments in wild-type nodules. Most Cd-regulated host genes were also differentially regulated by Zn, revealing little discernment between an essential and a non-essential ion under increased exposure. Furthermore, the host response to both the stresses affected auxin and iron homeostasis genes in a host genotype-dependent manner. Our results suggested impaired cadmium export from the mutant nodules. These results have potential implications in agricultural management systems and bioremediation strategies.

Symbiosis↗

PubMed1992

Influence of demetallization of hydrogenated sunflower oil on changes in the forms of heavy metals and their pro-oxidative effects.

The effect of removing heavy metals from hydrogenated sunflower oil using a method based on changes in the contents of the various forms of the heavy metals copper, iron, zinc and nickel and their respective pro-oxidative effects was studied. A high degree of removal of dissociated and bounded ions was observed for hydrogenated oil, while there was no change in the contents of the co-ordination form. The pro-oxidative effect of the dissociated ions and of the bound metal ions in hydrogenated oil decreased nine-fold and seven-fold, respectively, compared with that of the non-hydrogenated oil, as a result of which the oxidation stability of hydrogenated oil increased two-fold. Comparative studies confirmed as appropriate the use of wash waters and auxiliary solutions that do not contain heavy metals for the processing of the hydrogenate after the classical technology.

Copper↗

PubMed1992

[Environmental pollutants and fertility disorders. Heavy metals and minerals].

So far, the influence of lead, cadmium and mercury on human fertility has hardly been considered. First experiences by the authors with the chelating agent 2,3 dimercaptopropane-1-sulfonate (DMPS), which mobilizes heavy metals deposited in the body, seem to favour an association between the body load of heavy metals and complications during the menstrual cycle and during pregnancy. By means of an extensive survey of references, the importance of heavy metals for reproduction is demonstrated. In addition, the deficiency of particular minerals and their interaction with heavy metals are considered. Indications are given for diagnosis and therapy of the exposure to heavy metals. The practical procedure is demonstrated by means of three case studies.

Abnormalities, Drug-Induced↗

PubMed2026

Heavy metal stress in native plant species: investigating phytoremediation potential through physiological and ISSR/SCoT molecular assessments.

In emerging countries, increased industrial activity has a significant impact on economic growth and urban development. However, the acceleration of industrial processes is accompanied by the release of contaminants such as heavy metals. According to the World Health Organization, one-fourth of all human diseases are caused by environmental contaminants, including heavy metals, which can impair numerous organs such as the neurological system, liver, and reproductive systems. This increased efforts to find effective and sustainable methods to remove heavy metals. Phytoremediation is an environmentally benign method of removing heavy metals using specific plants. Thus, from industrially contaminated locations, common native plant species of Lactuca serriola, Sisymbrium irio, Chenopodium murale, and Cynanchum acutum were selected for this study to assess the mechanisms of their molecular and physiological tolerance. Soil and plants were tested for heavy metals (Cd, Pb, and Cu), and contaminated locations were classified as low and highly polluted. Measurements were made of soluble sugar, protein, secondary metabolites, malondialdehyde, and H2O2. Additionally, inter simple sequence repeat (ISSR), start codon targeted (SCoT), and genomic template stability GTS were used. In heavily polluted areas, all plant species exhibit elevated amounts of sugar, proteins, H2O2, MDA, and secondary metabolites, while total phenolics showed a unique significant interaction (plant-location), where Cynanchum exhibited a hyper-stress phenolic accumulation to cope with toxicity, whereas Chenopodium maintained genomic stability with balanced phenolic level. Based on these findings, both Cynanchum acutum and Chenopodium murale demonstrate superior potential for phytoremediation and warrant further investigation for ecological restoration.

Heavy metal↗

PubMed1979

[The levels of heavy metals (Cd, Cu, Hg, Ni, Pb, Zn) in brook trouts from the River Leine in the area of Göttingen (West Germany) (author's transl)].

In order to evaluate the load of heavy metals (Cd, Cu, Hg, Ni, Pb, Zn) imposed on the River Leine by the city of Göttingen (medium-sized town) the content of heavy metals in fish samples (which had been collected at two points on the River Leine, upstream, respectively downstream of Göttingen--Fig. 1) were determined by Atomic Absorption Spectroscopy. Analysis of heavy metals in brook trout (total fish, flesh, and liver) showed a statistically significant definite increase in some heavy metals, caused by the sewage from the city of Göttingen. In the flesh only Cd in the liver Cd, Hg and Zn and in the total fish Cd, Cu and Zn had been increased significantly. All the values of heavy metals in the flesh were lower than the suggested maximum allowable concentrations.

Animals↗

PubMed1977

Heavy metal pollution among autoworkers. II. Cadmium, chromium, copper, manganese, and nickel.

Garages and auto-repair workshops may be polluted with other heavy metals besides lead. Blood of autoworkers with high lead content was analysed for cadmium, chromium, copper manganese, nickel, ALAD activity and carboxyhaemoglobin level. Cadmium and copper levels in blood of autoworkers were comparable with those of the control subjects while chroimium and nickel levels were significantly higher (P less than 0-01 for both metals), and scattered raised values of manganese were found. There was no significant mutual correlation between levels of various heavy metals determined in whole blood. High copper levels were slightly related to decreasing ALAD activity (P less than 0-1). Nineteen per cent of autoworkers were found to have an abnormally blood level of carboxyhaemoglobin. The amount of particulate heavy metal in autoworkshop air was not related to biochemical abnormalities found in the autoworkers. Various sources of pollution of these heavy metals in autoworkshops are discussed.

Adolescent↗

PubMed1992

[Survey of heavy metals in traditional Chinese medicinal preparations].

Traditional Chinese medicinal preparations are still widely used by natives in Taiwan. Some traditional Chinese medicine prepared with ancient formulas have been found to contain some heavy metals. There has been an occasional pediatric case admitted with heavy metal intoxication. In the last two years, we collected 11 ancient formula drug samples from the families of the patients. We detected the heavy metals with an inductively-coupled plasma atomic emission spectrometry and a graphite furnace atomic absorption spectrometry. The final result of our report reveals the problem of heavy metals in traditional Chinese medicinal preparations as being very serious.

Drugs, Chinese Herbal↗

PubMed2026

Biomonitoring of industrial heavy metal pollution via enzymatic and metabolic responses in desert ants (Cataglyphis savignyi) and beetles (Tentyrum sp) as bioindicators.

The current work seeks to evaluate the effectiveness of Cataglyphis saviginyi and Tentyrum sp as indicators of pollution in the city's main industrial regions by analyzing their enzymatic activity and primary metabolites. Soil samples were collected at each site under investigation to analyze soil characteristics and heavy metal content. C. saviginyi and Tentyrum sp were collected across four consecutive seasons (2023-2024) to investigate enzymatic (GPT, GOT, ALP, ACP, LDH) and metabolic (lipid, protein, carbohydrate) biomarkers. The physicochemical properties of the soil differed substantially between the industrial areas and the control site. Soil heavy metal buildup was highest at industrial sites (1 and 4) compared to the control site, with the order being Zn > Cr > Cd > Cu. Heavy metal pollution indices were determined. Increased industrial activity from metal industries, ceramics, and chemical painting companies defines this area, as seen by the high Cdeg, mCd, PI, and PLI values derived for industrial sites 1 and 4. While C. saviginyi and Tentyrum sp deconcentrated and released Cr, Cd, and Zn into the soil via the biological accumulation factor (BAF), Cu acted as a macro-concentrator. Compared with the control site, industrial environments were shown to increase levels of GPT, GOT, LDH, ACP, protein, and carbohydrates in C. saviginyi. However, lipid and ALP activity was suppressed. at industrial sites, Tentyrum sp carbohydrate content was higher than at control sites, but GPT, GOT, ALP, ACP, LDH, protein, and lipid activities were all suppressed. Consequently, enzymatic and metabolic biomarkers proved to be sensitive indicators for assessing industrial heavy metal pollution in desert ecosystems.

Animals↗

PubMed1975

Heavy metal contamination from geothermal sources.

Liquid-dominated hydrothermal reservoirs, which contain saline fluids at high temperatures and pressures, have a significant potential for contamination of the environment by heavy metals. The design of the power conversion cycle in a liquid-dominated geothermal plant is a key factor in determining the impact of the installation. Reinjection of the fluid into the reservoir minimizes heavy metal effluents but is routinely practiced at few installations. Binary power cycles with reinjection would provide even cleaner systems but are not yet ready for commercial application. Vapor-dominated systems, which contain superheated steam, have less potential for contamination but are relatively uncommon. Field data on heavy metal effluents from geothermal plants are sparse and confounded by contributions from "natural" sources such as geysers and hot springs which often exist nearby. Insofar as geothermal power supplies are destined to multiply, much work is required on their environmental effects including those caused by heavy metals.

Air↗

PubMed2026

Persistent antimicrobial resistance during soil remediation driven by residual heavy metal co-selection.

Remediation of heavy metal-contaminated soil is a global priority, particularly as reclaimed land increasingly intersects with urban development and human exposure. However, the ecological consequences of soil remediation, especially its impact on antimicrobial resistance (AMR) as a global health threat, have remained poorly understood. Here, we combined single-cell Raman-D₂O probing with genome-resolved metagenomics to monitor the dynamics of phenotypic and genotypic resistance to metals and antibiotics during a 120-day remediation of soils with three contamination levels from a lead-zinc smelting site. Although chemical remediation substantially reduced bioavailable metals (by 42%-65%), AMR was not diminished. Instead, both phenotypic activity and gene abundance of metal- and antibiotic-resistant microorganisms increased, resulting in a two- to three-fold increase in AMR-associated health risks. Among 76 metagenome assembled genomes (MAGs) from phenotypic resistance communities, all Cd resistance-associated MAGs harbored multidrug resistance genes, half of which were colocalized with metal resistance determinants, and their prevalence continued to rise with remediation. These findings reveal that although remediation alleviates acute metal toxicity, residual low-concentration bioavailable metals sustain evolutionary selection for resistance, highlighting a disconnect between chemical recovery and biological safety. Moreover, the improved soil nutrient and physiochemical properties of remediated soils further promoted the proliferation of antibiotic-resistant bacteria. This study offers new ecological insights into the unintended consequences of anthropogenic interventions, underscoring the need to integrate biological safety into soil health and safety assessments.

Soil Microbiology↗

PubMed1992

Heavy metal tolerance in the fission yeast requires an ATP-binding cassette-type vacuolar membrane transporter.

In response to heavy metal stress, plants and certain fungi, such as the fission yeast Schizosaccharomyces pombe, synthesize small metal-binding peptides known as phytochelatins. We have identified a cadmium sensitive S. pombe mutant deficient in the accumulation of a sulfide-containing phytochelatin-cadmium complex, and have isolated the gene, designated hmt1, that complements this mutant. The deduced protein sequence of the hmt1 gene product shares sequence identity with the family of ABC (ATP-binding cassette)-type transport proteins which includes the mammalian P-glycoproteins and CFTR, suggesting that the encoded product is an integral membrane protein. Analysis of fractionated fission yeast cell components indicates that the HMT1 polypeptide is associated with the vacuolar membrane. Additionally, fission yeast strains harboring an hmt1-expressing multicopy plasmid exhibit enhanced metal tolerance along with a higher intracellular level of cadmium, implying a relationship between HMT1 mediated transport and compartmentalization of heavy metals. This suggests that tissue-specific overproduction of a functional hmt1 product in transgenic plants might be a means to alter the tissue localization of these elements, such as for sequestering heavy metals away from consumable parts of crop plants.

ATP-Binding Cassette Transporters↗

PubMed1992

Heavy metal induced behaviour modulation in mussels: possible neural correlates.

Filtering behaviour of bivalves can be monitored by recording the contraction and relaxation of the adductor muscles, which maintain the filtering activity by closing and opening of the shells having rhythmic and periodic pattern with a time scale of several minutes and hours. Heavy metals (Cu2+, Hg2+, Cd2+, Pb2+, Zn2+) applied into the water for one week cause a clear cut alteration in the adductor's activity characterized in general by changing of the duration of activity and rest. Threshold concentrations affecting the animal's behaviour were 0.005; 0.01 0.05; 0.1 and 10.0 mg/l, respectively. With increasing concentration the duration of activity could be reduced up to 10-20 per cent of the control at application of Cu2+, Hg2+ and Cd2+. Rest periods were also influenced by heavy metals. Wash-out in most cases restored the original activity, sometimes a reverse effect was observed. Since heavy metals, if present in the water, cause reduction of the level of 5HT and DA in the ganglia of mussels and they modulate the chemical sensitivity of molluscan neurons and influence the permeability of various ionic channels, it is suggested that heavy metal ions affect directly both transmitter metabolism and membrane excitability and this way alterations of basic neural mechanisms are responsible in the observed modulation of mussels' behaviour.

Animals↗

PubMed2024

Assessment of antibiotic resistance genes in soils polluted by chemical and technogenic ways with poly-aromatic hydrocarbons and heavy metals.

Anthropogenic activities are leaving lots of chemical footprints on the soil. It alters the physiochemical characteristics of the soil thereby modifying the natural soil microbiome. The prevalence of antimicrobial-resistance microbes in polluted soil has gained attention due to its obvious public health risks. This study focused on assessing the prevalence and distribution of antibiotic-resistance genes in polluted soil ecosystems impacted by industrial enterprises in southern Russia. Metagenomic analysis was conducted on soil samples collected from polluted sites using various approaches, and the prevalence of antibiotic-resistance genes was investigated. The results revealed that efflux-encoding pump sequences were the most widely represented group of genes, while genes whose products replaced antibiotic targets were less represented. The level of soil contamination increased, and there was an increase in the total number of antibiotic-resistance genes in proteobacteria, but a decrease in actinobacteria. The study proposed an optimal mechanism for processing metagenomic data in polluted soil ecosystems, which involves mapping raw reads by the KMA method, followed by a detailed study of specific genes. The study's conclusions provide valuable insights into the prevalence and distribution of antibiotic-resistance genes in polluted soils and have been illustrated in heat maps.

Soil Pollutants↗

PubMed1977

Sedimentary record of heavy metals and polycyclic aromatic hydrocarbons in Lake Constance.

The enrichment of heavy metals and polycyclic aromatic hydrocarbons (PAH) in dated sediments from Lake Constance during the past 75 years corresponds to the general increase of European coal consumption within the same period of time. Coals are assumed to be the main source of heavy-metal enrichment; incomplete combustion (pyrolysis) of coal also seems to be responsible for the very sharp increase of PAH.

Coal↗