Effects Of Heavy Metal Contamination Research Articles

Integrating Water Quality Index (WQI) and Multivariate Statistics for Regional Surface Water Quality Evaluation: Key Parameter Identification and Human Health Risk Assessment

Assessing regional water quality and evaluating the associated risks to human health posed by aquatic contaminants are paramount for conserving and managing surface water resources and formulating effective local policy decisions. This study utilizes 17 water quality parameters collected monthly from nine national monitoring stations in Nanning City, China, from January 2021 to March 2023, i.e., water temperature (WT), pH, dissolved oxygen (DO), permanganate index (CODMn), chemical oxygen demand (COD), five-day biochemical oxygen demand (BOD5), ammonia nitrogen (NH3-N), total phosphorus (TP), copper (Cu), zinc (Zn), fluoride (F-), selenium (Se), arsenic (As), mercury (Hg), cadmium (Cd), chromium (Cr), and lead (Pb). Analyses were performed utilizing the Water Quality Index (WQI) and multiple stepwise regression to ascertain seasonal and spatial variations in water quality and to identify key water quality parameters. Human health risks were evaluated, focusing on eight heavy metals. The results indicated that the average WQI for the designated area was 94.1, with individual monitoring stations displaying WQIs ranging from 93.22 to 96.44, categorizing the water quality as “excellent”. The WQI exhibited seasonal fluctuations, peaking in spring and winter while decreasing in summer and autumn. All measured parameters met national standards for Class I and II surface waters. The stepwise regression analysis facilitated the construction of minimized WQI models (WQImin) derived from three different training and testing datasets, with a WQImin model incorporating six key parameters, i.e., DO, CODMn, NH3-N, Hg, WT, and Se. The concentration of heavy metals in the water exhibited a sequence of Zn (3.35 µg/L) > Cr (2.00 µg/L) > Cu (1.36 µg/L) > As (1.29 µg/L) > Se (0.32 µg/L) > Pb (0.17 µg/L) > Cd (0.03 µg/L) > Hg (0.01 µg/L), with all metals adhering to the Class I standard. Children are more susceptible to the adverse effects of heavy metal contamination than adults, exhibiting a total environmental health risk of 1.28 times greater. Cr was identified as the predominant contributor to the aggregate health risk, accounting for over 80% of the risk in adults and children, followed by As (19.1%). Future protection efforts are recommended to prioritize the control of Cr and As concentrations in Nanning City.

Inoculation with multifunctional Bacillus sp. NEAU-DCB1-2 mitigates chromium toxicity in pakchoi (Brassica rapa ssp. chinensis) through a multi-level mechanism

Soil chromium (Cr) accumulation is escalating, severely hindering plant growth and development. Plant growth-promoting bacteria (PGPB) have shown potential in enhancing plant tolerance to heavy metals. However, the role and mechanisms of Cr(VI)-reducing PGPB strains in improving the growth of pakchoi under Cr toxicity remain unclear. This study aimed to isolate a Cr(VI)-reducing PGPB strain from Cr-contaminated soil, evaluate its effect on pakchoi growth under Cr(VI) stress, and investigate the mechanisms involved. Our findings showed that Bacillus sp. NEAU-DCB1–2 effectively reduce Cr(VI) to Cr(III) and produced indole-3-acetic acid and siderophores. Under Cr(VI) stress, inoculation with NEAU-DC1–2 significantly promoted seed germination and early growth of pakchoi. In pot experiments, NEAU-DCB1–2 significantly increased biomass accumulation, plant height, and root length of Cr(VI)-treated pakchoi seedlings, while reducing the Cr(VI) content in root, shoot and soil. Moreover, NEAU-DCB1–2 greatly increased catalase, superoxide dismutase, peroxidase, and ascorbate peroxidase activities in seedlings under Cr(VI) stress, thereby reducing malondialdehyde content. Transcriptome analysis indicated substantial alterations in gene expression patterns after inoculation with NEAU-DCB1–2 under Cr(VI) stress. Further analyses revealed that NEAU-DCB1–2 mainly affected the responses of antioxidant system, metal chelation and transport, together with auxin, abscisic acid, and jasmonic acid signaling to Cr(VI) stress. Conclusively, the Cr(VI)-reducing PGPB strain NEAU-DCB1–2 significantly enhances the growth and Cr tolerance of pakchoi through multiple mechanisms, offering a valuable microbial resource for mitigating the adverse effects of heavy metal contamination in agricultural soils on the yield and safety of vegetable crops.

Utilizing machine learning to evaluate heavy metal pollution in the world's largest mangrove forest

The world's largest mangrove forest (Sundarbans) is facing an imminent threat from heavy metal pollution, posing grave ecological and human health risks. Developing an accurate predictive model for heavy metal content in this area has been challenging. In this study, we used machine learning techniques to model sediment pollution by heavy metals in this vital ecosystem. We collected 199 standardized sediment samples to predict the accumulation of eleven heavy metals using ten different machine learning algorithms. Among them, the extremely randomized tree model exhibited the best performance in predicting Fe (0.87), Cr (0.89), Zn (0.85), Ni (0.83), Cu (0.87), Co (0.62), As (0.68), and V (0.90), achieving notable R2 values. On the other hand, the random forest outperformed for predicting Cd (0.72) and Mn (0.91), whereas the decision tree model showed the best performance for Pb (0.73). The feature attribute analysis identified FeV, CrV, CuZn, CoMn, PbCd, and AsCd relationships resembled with correlation coefficients among them. Based on the established models, the prediction of the contamination factor of metals in sediments showed very high Cd contamination (CF ≥ 6). The Moran's I index for Cd, Cr, Pb, and As were 0.71, 0.81, 0.71, and 0.67, respectively, indicating strong positive spatial autocorrelation and suggesting clustering of similar contamination levels. Conclusively, this research provides a comprehensive framework for predicting heavy metal sediment pollution in the Sundarbans, identifying key areas needing urgent conservation. Our findings support the adoption of integrated management strategies and targeted remedial actions to mitigate the harmful effects of heavy metal contamination in this vital ecosystem.

THE IMPACT OF SOIL HEAVY METAL ACCUMULATION ON THE GROWTH OF SUNN HEMP (Crotalaria juncea L.)

Sunn Hemp plants, specifically Crotalaria juncea, are effective in absorbing and reducing the accumulation of heavy metals like cadmium, zinc, lead, and copper in soil. This plant species belongs to the Fabaceae family and is not only important for its phytoremediation capabilities but also for its agricultural value as a fiber and manure crop. Overall, Sunn hemp plants are crucial in mitigating the harmful effects of heavy metal contamination. The experiment was conducted in a greenhouse using a Completed Randomized Design (CRD) with 5 treatments and 6 replications to assess the impact of varying concentrations of heavy metals on Sunn hemp growth. The heavy metals were created by combining Cadmium (Cd), Copper (Cu), Lead (Pb), and Nickel (Ni). Each treatment of heavy metal contamination using 200ml of solution: T0 is the negative control. T1 containing 0.9 (Cd) + 4.0 (Cu) + 0.18 (Pb) + 0.7 (Ni). T2 containing 11.90 (Cd) + 19.80 (Cu) + 36.00 (Pb) + 28.90 (Ni). T3 containing 23.80 (Cd) + 39.60 (Cu) + 72.00 (Pb) + 57.80 (Ni). T4 containing 35.70 (Cd) + 59.40 (Cu) + 108.0 (Pb) + 115.60 (Ni). The study analyzed the impact of heavy metal concentrations on the growth of sunn hemp. Data included soil pH, plant height, flower count, pod count, root and shoot length, fresh and dry weight. Results showed that T4 showed excellent growth performance in terms of height, number of flowers, and dry weight. Sunn hemp has the ability to store heavy metals to a greater extent in its roots and has a remarkable capacity for long-term survival.

Role of Biotechnology and Genetic Engineering in Bioremediation of Cadmium Pollution

Cadmium (Cd) is ubiquitous and an unessential trace element existing in the environment. Anthropogenic activities and applications of synthetic phosphate fertilizers greatly enhance the concentration of Cadmium in the environment, which proves to be carcinogenic. The long-term effects of heavy metals contamination on plants and animals have recently become a major public health concern. Thanks to the application of science and technology, new environmental initiatives can have a lower environmental impact significantly. The role of microbes is very well known and must be considered as potential pollutant removers. Microbial flora can remove heavy metals and oil from contaminated soil and water. In comparison to conventional techniques, bioremediation itself proved to be a more potent technique because the established mechanisms render it ineffective. Biotechnological advancements are inherently harmful to the environment because they have the potential to reduce metal pollution. Pollutants in the environment can be effectively removed using bioremediation. Both native and introduced species can thrive in a microorganism-friendly environment.

Health Effects of Heavy Metal Contamination in Drinking Water

Water is essential for life, be it the life of animals, plants or human beings. It’s our prime duty to protect, manage and preserve the quality of water. Uncontrolled anthropogenic activities have resulted in contamination of fresh water resources thereby affecting the health of living beings. Rampant industrialization is a major environmental problem on the global scale for the pollution of fresh water with toxic effluents containing heavy metals. Contamination of surface water by heavy metals is the greatest quality issues because of their toxic nature, increased release and negative impact on the health of human beings. Water-borne diseases remain one of the major health concerns in the world. Heavy metals are individual metals and metal compounds that can impact human health. Exposure of humans to metals such as antimony, arsenic, barium, cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, selenium, silver, tin, zinc, etc results in chronic and acute toxicities. The toxicity of heavy metals depends on their concentration, period of exposure and route of exposure. Humans are exposed to heavy metals either by inhalation from the atmosphere, intake through drinking water, or by ingestion through the skin by dermal contact. The present review describes the analysis of ‘heavy metal contamination in drinking water’ with reference to definition, sources, health effects on humans and preventive measures. This study suggests that, the best way to get rid of heavy metal contamination in drinking water is to remove toxic heavy metals by using the best water purification system. Also, the ground water resources must be monitored for quality assessment, source identification and bioremediation of heavy metals.

Health effects of heavy metal contaminants Vis-à-Vis microbial response in their bioremediation

Toxic heavy metals are currently significant environmental pollutants as their growing ecotoxicity becomes a serious public health concern. Their multiple application in several fields such as the mining industry, agriculture, medicine, technology and many others, leads to a widespread distribution into the environmental systems. Since toxic metals are not biodegradable, their accumulation in soil, water and air contaminates the food chain, which poses a danger to human health. Because of extensive damage caused by metal intoxication on various organs of the human body, the search for therapeutic methods is very important. Removal of heavy metals from the body is usually carried out by the most common and conventional chelation therapy methods. However, for removal from environment the use of chemical methods is often expensive and can lead to the production of secondary pollutants. There is a remarkable attentiveness with respect to recent progress in heavy metals remediation over the past few decades with special emphasis on bioremediation utilized in various environmental areas. The present review is focused to throw light on the possible sources and related intake routes of the harmful metals, the symptoms of poisoning, their impact on the environment and health and the molecular mechanisms, which threaten human health effects. It also aims to provide an overview of the available studies on microbial bioremediation of heavy metals from the environment, including the mechanisms involved in metal removal and some future directions in microbial biodegradation technology.

Effects of heavy metal contamination on fungal diversity in Pinus brutia shoots

The effects of heavy metal pollution have become a significant global issue in recent years. The primary objective of the present study was to compare the heavy metal concentrations in Pinus brutia shoots grown in an organized industrial zone (OIZ) and a forested area (Adalar) and to examine how these heavy metals affect fungal microbiota. The results achieved here showed that Ni and V concentrations were lower than the detectable limits in both the Adalar and the OIZ region, whereas Se and Cu concentrations were lower than the detectable limits in the shoots collected from the Adalar. Concentrations determined in samples collected from the OIZ were approximately 6 times higher for Cr and 16 times higher for Zn in comparison to the samples collected from the Adalar. Metagenomic analysis revealed that the most common fungal genera were Aureobasidium, Gibberella, Hazslinszkyomyces, Alternaria, Cladosporium, Buckleyzyma, Lasiodiplodia, and Hormonema for the OIZ area and Hormonema, Aureobasidium, Alternaria, Cladosporium, Arthrinium, Fonsecazyma, and Truncatella for the Adalar region. In the future, this study may serve as a reference for the development of innovative strategies for the remediation of heavy metal pollution for a sustainable and clean environment using biological sources.

Spatial distribution of paddy field’s heavy metals diversity contamination in Samarinda using remote sensing imagery

Abstract. Palupi NP, Hardi EH, Fahrunsyah, Rahayu DE, Nugroho RA, Darma S, Idris SD. 2023. Spatial distribution of paddy field’s heavy metals diversity contamination in Samarinda using remote sensing imagery. Biodiversitas 24: 6743-6752. The adverse effects of heavy metal contamination on rice fields posing a significant threat to food safety. This study, conducted from May to July 2023 in Samarinda East Kalimantan, Indonesia, aims to determine the distribution of active rice fields and heavy metal contamination through Kriging's interpolation method. Aerial photographic interpretations, facilitated by ArcGIS 10.4, were performed with 144 sample points within 4 Districts. The content of heavy metals was assessed by Atomic Absorption Spectroscopy at specific wavelengths: 248.3 nm for Fe, 228.8 nm for Pb, 283.3 nm for Cd, 357.9 nm for Cr, 279.5 nm for Mn, 213.9 nm for Zn, and 324.7 nm for Cu, following guidelines of SNI 8910:2021. The research showed that existing rice fields were concentrated in North Samarinda District (380,416 ha), Loa Janan Ilir District (210,133 ha), Sambutan District (404,682 ha), and Palaran District (188,617 ha) with Fe content ranged from 4.976,45 ppm to 16.800,485 ppm, exceeding the critical Fe limit in soil of 500 ppm set by SNI. Mn content ranged from 22.65 ppm to 564.88 ppm, surpassing the critical soil threshold of 0.15 ppm for Mn according to SNI. Cu content varied from 3.32 ppm to 121.75 ppm, exceeding critical Cu limit of 0.04 ppm. Zn content ranged from 8.61 ppm to 223.12 ppm, surpassing the critical limit of Zn's pollution in the soil (0.06 ppm). Pb content ranged from 10.72 ppm to 32,84 ppm, categorized as intermediate compared to the threshold of 0.07 ppm for Pb in soil. Cd content ranged from 0.04 ppm to 0.739 ppm, exceeding the critical limit of 0.01 ppm set by SNI. Cr content was detected to be less than 0.032 ppm, falling into a very low category, with the critical limit for Cr content in soil set at 0.5 ppm according to SNI.

RETRACTED: Using structural equation modeling to assess the genotoxic and mutagenic effects of heavy metal contamination in the freshwater ecosystems: A study involving Oreochromis niloticus in an urban river

Chemical pollutants represent a leading problem for aquatic ecosystems, as they can induce genetic, biochemical, and physiological changes in the species of these ecosystems, thus compromising their adaptability and survival. The Capibaribe River runs through the state of Pernambuco, located in Northeastern Brazil, and passes through areas of agricultural cultivation, densely populated cities, and industrial centers, primarily textiles. Despite its importance, few ecotoxicological studies have been conducted on its environment, and knowledge about pollution patterns and their effects on its biota is still being determined. The objective of this study was to evaluate the water quality and the damage supposed to be caused by pollutants on the DNA specimens of Nile tilapia (Oreochromis niloticus) obtained from seven strategic points of Capibaribe. Tilapia specimens and water were collected during the rainy and dry seasons from 2015 to 2017. The following characteristics were analyzed: physicochemical (six), metal concentration (seven), local pluviosity, micronuclei, and comet assay. The physicochemical and heavy metal analyses were exploratory, whereas the ecotoxicological analyses were hypothetical. To verify this hypothesis, we compared the groups of fish collected to the results of the micronuclei test and comet assay. We created a Structural Equation Model (SEM) to determine how each metal's micronuclei variables, damage index, pluviosity, and concentration were related. Our results demonstrated that the highest values for markers of genetic damage were detected at points with the highest heavy metal concentrations, especially iron, zinc, manganese, chromium, and cadmium. The SEM demonstrated that metals could explain the findings of the genotoxicity markers. Moreover, other pollutants, such as pesticides, should be considered, mainly where the river passes through rural areas. The results presented here demonstrate that the Capibaribe River has different degrees of contamination and confirm our hypothesis.

Effect of heavy metal contamination on soil nematode communities in urban brownfields

Heavy metal contamination in urban brownfields can pose serious threats to the soil ecosystem. Soil nematode communities can respond rapidly to minor alterations in the soil environment over brief time intervals and are extensively employed to track changes in the soil environment. Here, we investigated the impact of heavy metal contamination on soil nematode communities and assessed the ecological risks associated with brownfields. We analyzed heavy metal contamination and soil nematode community structure in a representative urban brownfield and its neighboring urban park. The results showed that the brownfield was predominantly impacted by chromium (Cr) contamination. Plant parasites served as the primary source for soil nematodes in the park, whereas bacterivores fulfilled this role in the brownfield. Omnivores-predators decrease or even disappear with the intensification of heavy metal contamination. Acrobeloides exhibited tolerance to heavy metal contamination. Based on life history strategy, nematode communities could be classified into five colonizer-persister (c-p) groups, and the c-p values were ranked from 1 (short generation time and high colonization ability and fecundity) to 5 (long generation time and low colonization ability and fecundity). Soil nematode communities with c-p values ranging from 1 to 3 exhibited a significant negative correlation with hexavalent chromium [Cr (VI)], while those with c-p values of 4 and 5 (representing high trophic level communities) showed a significant positive correlation. We postulate that bacterivores exhibit superior adaptations to heavy metal contamination. Specific nematode taxa can indicate the pollution status of elements. Soil nematode communities at high trophic levels are powerful indicators of response to Cr (VI) contamination.

Soil Contamination and Human Health: Exploring the Heavy Metal Landscape: A Comprehensive Review

Background: Composting, a cost-effective and efficient method for managing solid waste rich in organic matter, faces challenges when contaminants, particularly heavy metals, are present. These contaminants can significantly impact various environmental aspects and human health. Objective: This study aims to provide a comprehensive review of the effects of heavy metal contamination in compost, focusing on its impact on soil quality, plant growth, aquatic ecosystems, and human health. Methods: An extensive examination of current literature was conducted to analyze the consequences of heavy metal presence in compost. This involved reviewing studies on soil microbial activity, plant health, the accumulation of metals in the food chain, and the resultant effects on animal and human health, as well as on aquatic systems. Results: Elevated levels of heavy metals in compost were found to be toxic to soil microorganisms, vital for numerous soil processes, leading to a reduction in their abundance and functionality. Plants exposed to these metals showed disrupted physiological processes and compromised growth. The absorption of heavy metals by plants leads to their entry into the food chain, posing risks to animal and human health. In aquatic environments, these contaminants contribute to oxidative stress, negatively affecting aquatic life. Conclusion: The presence of heavy metals in compost presents significant environmental and health risks. It is crucial to ensure the absence of such contaminants in compost intended for agricultural use. This study underscores the need for sustainable waste management practices and stringent monitoring of compost quality to safeguard environmental health and human well-being.

Elucidating the effects of heavy metals contamination on vital organ of fish and migratory birds found at fresh water ecosystem

Heavy metal pollution in aquatic environments threatens marine life and lowers the quality of freshwater supplies. This research aimed to quantify the heavy metal concentration in fish, avian tissue, and water of the Mangla reservoir. Concentrations of heavy metals such as Cu, Cd, Cr, and Pb were determined in five vital organs of six species of fishes (Cirrhinus cirrhosis, Catla catla, Hypophthalmichthys molitrix, Wallagu attu, Cyprinus carpio, Sperata seenghala) and five species of migratory birds (Anas strepera, Aythya ferina, Anas platyrhynchos, Anas crecca, Anas clypeata) and water of Mangla dam. Heavy metal concentration was observed with AAS’ help after the samples’ complete chemical digestion. The average concentration of these metals in water samples was higher than the mean values in fish and birds. Heavy metals damaged fish and birds in the same order: Cd > Cu > Cr > Pb. The results of this research will hopefully prompt further consideration on the dangers of heavy metal contamination in freshwater ecosystem.

Impacts of Bamboo Biochar Amendment on Growth, Morphological Traits, and Biomass Allocation of Bambusa balcooa under Copper-Contaminated Soil Conditions

The accumulation of heavy metals in water streams and soil is considered a grave environmental threat that impacts plants and animals. Biochar has recently been widely used to overcome the effects of heavy metal contamination in plants and remediate the soil. A pot-trial study assessed the morphological traits of Bambusa balcooa under copper contamination. Each pot (twenty-four earthen pots) was filled with 7.0 kg of soil and spiked with copper sulfate of 0, 300, 600, and 1200 mg kg-1. Of the total, twelve pots were amended with 7% (w/w of soil) bamboo biochar. Plant samples were harvested after one year (365 days) of treatment for biomass estimation. Data was recorded for different growth and morphological traits such as the number of clums, nodes, leaves, internode length, plant height, leaf area, root length, and dry biomass of root, shoot, and leaf to evaluate the impact of copper with or without bamboo biochar on Bambusa balcooa. The results indicated that the higher concentration of copper suppressed growth parameters such as shoot length, internode length, number of leaves, and leaf area; therefore, growth increment was significantly reduced at ) mg Kg‑1 copper-added soil. Biochar diminishes the impact of Cu stress on plants to some extent as at higher concentrations (600 and 1200 mg kg-1) was enhanced root dry biomass (51 and 148%), shoot dry biomass (42 and 57%), and leaf dry biomass (38 and 48%). Thus, results confirm that biochar amendment under Bambusa balcooa reduces the impact of copper contamination on the plant and increases plant growth by improving soil health, suggesting that bamboo biochar application was effective in metal stabilization, thereby, reducing the bioavailability and phytotoxicity of Cu and can help to restore copper-contaminated soil.

Heavy metal contamination collapses trophic interactions in the soil microbial food web via bottom-up regulation

The soil microbial food web plays a vital role in soil health, nutrient cycling and agricultural productivity. Notably, there is a distinct paucity of information regarding the effects of heavy metal contamination on trophic-level interactions within the microbial food web of agricultural soils, which experience appreciably metal contamination worldwide. Herein, we investigated trophic interactions among predators (protists), their preys (bacteria and fungi) and competitors (nematodes) under four metal contamination levels using high-throughput sequencing and a laboratory verification experiment. Metal contamination decreased growth of protist-preferential prey (e.g., small-sized and gram-negative bacteria), increased the growth of protist-nonpreferential prey (e.g., pathogenic fungi and Actinobacteria), and had a limited effect on the soil protist-competitor (i.e., nematodes). This resulted in a considerable decrease in the diversity and abundance of protistan consumers and a re-arrangement of their interactions with other organisms. From a systemic view, the direct link was weaker between heavy metal contamination and the protist community than the indirect linkage, i.e., metal-induced changes in the prey community. We further validated these results with laboratory incubation trials that documented growth inhibition of protist (Colpoda) and protist-preferential prey (Spingomonas) versus growth stimulation of protist-nonpreferential prey (Arthrobacter) under metal contamination. These findings indicate that metal contamination collapses trophic-level interactions within the soil microbial food web via bottom-up regulation, providing important implications for managing trophic interactions to maintain agricultural ecosystem services under the challenge of worldwide metal contamination.

Ecological Responses of Soil Microbial Communities to Heavy Metal Stress in a Coal-Based Industrial Region in China.

Soil microorganisms play vital roles in ecosystem functions, and soil microbial communities might be affected by heavy metal contamination caused by the anthropogenic activities associated with the coal-based industry. This study explored the effects of heavy metal contamination on soil bacterial and fungal communities surrounding different coal-based industrial fields (the coal mining industry, coal preparation industry, coal-based chemical industry, and coal-fired power industry) in Shanxi province, North China. Moreover, soil samples from farmland and parks away from all the industrial plants were collected as references. The results showed that the concentrations of most heavy metals were greater than the local background values, particularly for arsenic (As), lead (Pb), cadmium (Cd), and mercury (Hg). There were significant differences in soil cellulase and alkaline phosphatase activities among sampling fields. The composition, diversity, and abundance of soil microbial communities among all sampling fields were significantly different, particularly for the fungal community. Actinobacteria, Proteobacteria, Chloroflexi, and Acidobacteria were the predominant bacterial phyla, while Ascomycota, Mortierellomycota, and Basidiomycota dominated the studied fungal community in this coal-based industrially intensive region. A redundancy analysis, variance partitioning analysis, and Spearman correlation analysis revealed that the soil microbial community structure was significantly affected by Cd, total carbon, total nitrogen, and alkaline phosphatase activity. This study profiles the basic features of the soil physicochemical properties, the multiple heavy metal concentrations, and the microbial communities in a coal-based industrial region in North China.

Detoxifying the heavy metals: a multipronged study of tolerance strategies against heavy metals toxicity in plants.

Heavy metal concentrations exceeding permissible limits threaten human life, plant life, and all other life forms. Different natural and anthropogenic activities emit toxic heavy metals in the soil, air, and water. Plants consume toxic heavy metals from their roots and foliar part inside the plant. Heavy metals may interfere with various aspects of the plants, such as biochemistry, bio-molecules, and physiological processes, which usually translate into morphological and anatomical changes. They use various strategies to deal with the toxic effects of heavy metal contamination. Some of these strategies include restricting heavy metals to the cell wall, vascular sequestration, and synthesis of various biochemical compounds, such as phyto-chelators and organic acids, to bind the free moving heavy metal ions so that the toxic effects are minimized. This review focuses on several aspects of genetics, molecular, and cell signaling levels, which integrate to produce a coordinated response to heavy metal toxicity and interpret the exact strategies behind the tolerance of heavy metals stress. It is suggested that various aspects of some model plant species must be thoroughly studied to comprehend the approaches of heavy metal tolerance to put that knowledge into practical use.

Quantitative and Qualitative Assessment of Heavy Metal Risk in a Peri-Urban Area of Central Portugal

Peri-urban areas are characterized by a variety of types of housing, transport infrastructure and multifunctional agriculture, covering extensive areas (ca. 48,000 km2) within the European Union (EU). These areas provide a diverse range of recreation sites and ecosystem services, such as food production. Food security is one of the first priorities for the EU, and there is a critical interface between agriculture and peri-urban land use change. The proximity between urban pollution sources and agricultural areas raises concerns regarding the possible adverse effects of heavy metals contamination on crop quality, and consequent impact on both food security and human health. A field study was performed to assess the risk of soil contamination in a peri-urban area in central Portugal. The total amount and the bioavailable and water-soluble fractions of heavy metals (Cd, Cr, Cu, Pb and Zn) were quantified in the soil samples The results show that heavy metals concentrations were lower than the standard values for soil assessment. However, the bioavailable fraction of Pb was quite variable, depending upon the sampling site. Since only the soluble, exchangeable and chelated metal species in the soils represent the labile fractions available to plants, there is doubt as to how to properly apply the standard values categorized by land utilization to estimate a potential risk relative to metal bioavailability in a multifunctional peri-urban area. It is recommended to standardize a reliable methodology in terms of assessing the risk in soil-crop-human transfer of heavy metals, especially in multifunctional peri-urban areas.

Effect of heavy metal contamination on tomato plant growth, vegetative qualities and accumulation

Effect of heavy metal contamination on tomato plant growth, vegetative qualities and accumulation

Effects of heavy metals contamination on health

Effects of heavy metals contamination on health