Snow cover is known to be an efficient and unique natural archive of atmospheric input and an indicator of ecosystem status. In high latitude regions, thawing of snow provides a sizable contribution ...of dissolved trace metals to the hydrological network. Towards a better understanding of natural and anthropogenic control on heavy metals and metalloid input from the atmosphere to the inland waters of Siberian arctic and subarctic regions, we measured chemical composition of dissolved (<0.22 µm) fractions of snow across a 2800 km south–north gradient in Western Siberia. Iron, Mn, Co, Ni, and Cd demonstrated sizable (by a factor of 4–7) decrease in concentration northward, which can be explained by a decrease in overall population density and the influence of dry aerosol deposition. Many elements (Mn, Ni, Cu, Cd, Pb, As, and Sb) exhibited a prominent local maximum (a factor of 2–3) in the zone of intensive oil and gas extraction (61–62° N latitudinal belt), which can be linked to gas flaring and fly ash deposition. Overall, the snow water chemical composition reflected both local and global (long-range) atmospheric transfer processes. Based on mass balance calculation, we demonstrate that the winter time atmospheric input represents sizable contribution to the riverine export fluxes of dissolved (<0.45 µm) Mn, Co, Zn, Cd, Pb, and Sb during springtime and can appreciably shape the hydrochemical composition of the Ob River main stem and tributaries.
Marine pollutants such as heavy metals (HMs) are considered among the most copious oxidative stress (OS) inducers in marine organisms which leads to reactive oxygen species (ROS) formation. ...Complementary to our previous bioassays studies, the present research focuses on Catalase (CAT), Glutathione S-transferase (GST) and Malondialdehyde (MDA) as oxidative stress biomarkers and the integrated biomarker response (IBR) indexes (IBR.sub.1 and IBR.sub.2) as an ecotoxicological assessment tool in Mytilus galloprovincialis using central composite face centered (CCF) design. The oxidative stress biomarkers were measured in adult mussels (45-55 mm) on 3 days-exposed under different sub-lethal concentrations of cadmium (Cd), zinc (Zn), and copper (Cu). Using multiple regressions, ANOVA analysis revealed that experimental data fitted to second-order (quadratic) polynomial equations. The results showed that types, concentrations and metals combinations has a direct effect in CAT and GST activities, MDA level and IBR indexes. Additionally, metal-metal interactions were found synergistic (supra-additive), antagonistic (infra-additive) or zero interaction in the toxicological effect. As necessary, the optimization of the experimental results was done in order to determine the optimal conditions for the oxidative stress responses and IBR indexes. It was demonstrated that the CCF design combined with the multi-biomarker approach and IBR index can be used as an appropriate tool in ecotoxicological modulation and prediction of oxidative stress and antioxidant status by heavy metals in the mussels Mytilus galloprovincialis.
•Total analysis of heavy metals in river water and sediments were studied.•Elevated levels of metals in water and sediments were observed.•Possible effect of metals in sediments was achieved by CF, ...Igeo and PLI.•Cd and Pb confirmed their serious effect on the aquatic environment.
Contamination of heavy metals in sediment is regarded as a global crisis with a large share in developing countries like Bangladesh. Four heavy metals such as arsenic (As), chromium (Cr), cadmium (Cd) and lead (Pb) in sediments and water were investigated from Karnaphuli River in Bangladesh. The decreasing trend of metals were observed in water as Cr>As>Pb>Cd and in sediment Cr>Pb>As>Cd. The ranges of heavy metals in water were 13.31–53.87, 46.09–112.43, 2.54–18.34 and 5.29–27.45μg/L and in sediments were 11.56–35.48, 37.23–160.32, 0.63–3.56 and 21.98–73.42mg/kg for As, Cr, Cd and Pb. The level of studied metals in water samples exceeded the safe limits of drinking water, indicated that water from this river is not safe for drinking and/or cooking. Contamination factor (CF) confirmed that the sediment samples were moderate to high contamination by As, Cd and Pb. The pollution load index (PLI) values were above one (>1) indicates advanced decline of the sediment quality. This study recommended that continuous monitoring of As, Cd and Pb in water; sediment and other aquatic biota of Karnaphuli River should be directed to assess the risk of these vital metals to safe the ecology in the vicinity of this river.
Food safety is a major concern for the Chinese public. This study collected 465 published papers on heavy metal pollution rates (the ratio of the samples exceeding the Grade II limits for Chinese ...soils, the Soil Environmental Quality Standard-1995) in farmland soil throughout China. The results showed that Cd had the highest pollution rate of 7.75%, followed by Hg, Cu, Ni and Zn, Pb and Cr had the lowest pollution rates at lower than 1%. The total pollution rate in Chinese farmland soil was 10.18%, mainly from Cd, Hg, Cu, and Ni. The human activities of mining and smelting, industry, irrigation by sewage, urban development, and fertilizer application released certain amounts of heavy metals into soil, which resulted in the farmland soil being polluted. Considering the spatial variations of grain production, about 13.86% of grain production was affected due to the heavy metal pollution in farmland soil. These results many provide valuable information for agricultural soil management and protection in China.
The gut microbiome, often referred to as "super organ", comprises up to a hundred trillion microorganisms, and the species diversity may vary from person to person. They perform a decisive role in ...diverse biological functions related to metabolism, immunity and neurological responses. However, the microbiome is sensitive to environmental pollutants, especially heavy metals. There is continuous interaction between heavy metals and the microbiome. Heavy metal exposure retards the growth and changes the structure of the phyla involved in the gut microbiome. Meanwhile, the gut microbiome tries to detoxify the heavy metals by altering the physiological conditions, intestinal permeability, enhancing enzymes for metabolizing heavy metals. This review summarizes the effect of heavy metals in altering the gut microbiome, the mechanism by which gut microbiota detoxifies heavy metals, diseases developed due to heavy metal-induced dysbiosis of the gut microbiome, and the usage of probiotics along with advancements in developing improved recombinant probiotic strains for the remediation of heavy metal toxicity.
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Textile wastewater heavy metal pollution has become a severe environmental problem worldwide. Metal ion inclusion in a dye molecule exhibits a bathochromic shift producing deeper but duller shades, ...which provides excellent colouration. The ejection of a massive volume of wastewater containing heavy metal ions such as Cr (VI), Pb (II), Cd (II) and Zn (II) and metal‐containing dyes are an unavoidable consequence because the textile industry consumes large quantities of water and all these chemicals cannot be combined entirely with fibres during the dyeing process. These high concentrations of chemicals in effluents interfere with the natural water resources, cause severe toxicological implications on the environment with a dramatic impact on human health. This article reviewed the various metal‐containing dye types and their heavy metal ions pollution from entryway to the wastewater, which then briefly explored the effects on human health and the environment. Graphene‐based absorbers, specially graphene oxide (GO) benefits from an ordered structured, high specific surface area, and flexible surface functionalization options, which are indispensable to realize a high performance of heavy metal ion removal. These exceptional adsorption properties of graphene‐based materials support a position of ubiquity in our everyday lives. The collective representation of the textile wastewater‘s effective remediation methods is discussed and focused on the GO‐based adsorption methods. Understanding the critical impact regarding the GO‐based materials established adsorption portfolio for heavy metal ions removal are also discussed. Various heavy‐metal ions and their pollutant effect, ways to remove such heavy metal ions and role of graphene‐based adsorbent including their demand, perspective, limitation, and relative scopes are discussed elaborately in the review.
The growing environmental problems caused by toxic heavy metal ions from the industrial textile activities are now the subject of considerable concern for environmental remediation. Graphene oxide and its related compounds envisage emerging solutions to adsorb those pollutant metal ions.
•We investigated total and speciation of heavy metals in sediments.•Elevated levels of metals in water and sediments were observed.•Cd and Pb were in non-residual while Cr, Ni, Cu and As in the ...residual phase.•Metal effects on sediment were achieved by using CF, Igeo, PLI and EF.•Cd and Pb confirmed the seriousness in the aquatic environment.
The concentration and chemical fractionation of globally alarming six heavy metals (Cr, Ni, Cu, As, Cd and Pb) were measured in surface water and sediment of an urban river in Bangladesh. The decreasing trend of metals were observed in water as Cr>Cu>As>Ni>Pb>Cd and in sediment as Cr>Ni>Cu>Pb>As>Cd. The level of studied metals exceeded the safe limits of drinking water, indicated that water from this river is not safe for drinking and/or cooking purposes. However, the investigated metals showed low mobility except for Cd and Pb which could pose a severe threat to the aquatic environment. Contamination factor (CF) and geoaccumulation index (Igeo) demonstrated that most of the sediment samples were moderately to heavily contaminated by Cr, As, Cd and Pb. The pollution load index (PLI) values were above one (>1) indicates progressive deterioration of the sediment quality. The extent of pollution by heavy metals in the river Korotoa implies that the condition is much frightening to the biota and inhabitants in the vicinity of the river as well.
•Chitosan-modified biochars were synthesized for heavy metal remediation.•Chitosan-modified biochars showed enhanced heavy metal removal ability.•Chitosan-modified biochars reduced toxicity of lead.
...In this work, chitosan-modified biochars were synthesized in efforts to produce a low-cost adsorbent for heavy metal environmental remediation. Characterization results showed that the coating of chitosan on biochar surfaces could improve its performance as a soil amendment or an adsorbent. Batch sorption experiments showed that, compared to the unmodified biochars, almost all the chitosan-modified biochars showed enhanced removal of three metals (i.e., Pb2+, Cu2+, and Cd2+) from solution. Further investigations of lead sorption on chitosan-modified bamboo biochar (i.e., BB-C) indicated that, although sorption kinetics were slow, BB-C had a relatively high Langmuir lead sorption capacity of 14.3mg/g biochar (71.5mg/g chitosan). Sorption of lead on the chitosan-modified biochar greatly reduced its metal toxicity. Both seed germination rate and seedling growth of the Pb-laden BB-C were similar to that of control groups without lead. In addition, uptake of lead by plants was reduced about 60% when lead was sorbed onto the chitosan-modified biochar. This work suggests that chitosan-modified biochars may be used as an effective, low-cost, and environmental-friendly adsorbent to remediate heavy metal contamination in the environment.
The term heavy metals is used as a group name of toxic metals and metalloids (semimetals) causing contaminations and ecotoxicity. In strict chemical sense the density of heavy metals is higher than 5 ...g/cm3. From biological point of view as microelements they can be divided into two major groups. a. For their physiological function organisms and cells require essential microelements such as iron, chromium (III), cobalt, copper, manganese, molidenium, zinc. b. The other group of heavy metals is toxic to the health or environment. Of highest concern are the emissions of As, Cd, Co, Cu, Hg, Mn, Ni, Pb, Sn, Tl. The toxicity of heavy metals is well known at organizational level, while less attention has been paid to their cellular effects. This book describes the toxicity of heavy metals on microorganisms, yeast, plant and animal cells. Other chapters of the book deal with their genotoxic, mutagenic and carcinogenic effects. The toxicity of several metals touch upon the aspects of environmental hazard, ecosystems and human health. Among the cellular responses of heavy metals irregularities in cellular mechanisms such as gene expression, protein folding, stress signaling pathways are among the most important ones. The final chapters deal with biosensors and removal of heavy metals. As everybody is eating, drinking and exposed to heavy metals on a daily basis, the spirit of the book will attract a wide audience.
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