Analysis of Heavy Metal Content in Soil and Plants in the Dumping Ground of Magnesite Mining Factory Jelšava-Lubeník (Slovakia)

Human health risk assessment due to consumption of dried fish in Chennai, Tamil Nadu, India: a baseline report

The current study sought to determine the levels of radioactivity and heavy metal contamination in 22 dried fish samples collected in Chennai, Tamil Nadu. The study found that there were substantial heavy metals concentrations for Pb, Mn, Cr, Co, and Cd. The concentration of heavy metal Pb being alarmingly high (32.85 to 42.09 mg/kg), followed by Cd (2.18 mg/kg to 3.51 mg/kg) than the permissible limit of WHO (2.17 mg/kg) for Pb and (0.05 mg/kg) for Cd. In terms of radioactivity, the gross alpha activity in the dried fish samples ranged 6.25 ± 0.12 to 48.21 ± 0.11 Bg/kg with an average of 20.35 Bg/kg and with a gross beta activity from 6.48 ± 0.02 to 479.47 ± 0.65 Bg/kg, for an average of 136.83 Bg/kg. The study found that the internal radiation dose that people receive upon consuming the fish species Sphyraena obtusata, Rachycentron canadum, Lepidocephalichthys thermalis, Synodontidae, Carangoides malabaricus, Sardina pilchardus, Scomberomorus commerson, Sillago sihama, Gerres subfasciatus, and Amblypharyngodon mola is above the ICRP-recommended limit of less than 1 mSv/year. Annual gonadal dose equivalent (AGDE) and total excessive lifetime cancer risk (ELCR) ranged 0.488 µSv year-1 and 0.004 µSv year-1 respectively, the values of AGDE being higher than the global average value. The findings of the study indicate that the analyzed dried fish samples are contaminated with Pb and Cd, which shall pose cancer risk to the consumers as a result.

Application and mechanism of carbonate material in the treatment of heavy metal pollution: a review

Among the many heavy metal pollution treatment agents, carbonate materials show strong flexibility and versatility by virtue of their high adsorption capacity for heavy metals and the characteristics of multiple and simple modification methods. It shows good potential for development. This review summarizes the application of carbonate materials in the treatment of heavy metal pollution according to the research of other scholars. It mainly relates to the application of surface-modified, activated, and nano-sized carbonate materials in the treatment of heavy metal pollution in water. Natural carbonate minerals and composite carbonate minerals solidify and stabilize heavy metals in soil. Solidification of heavy metals in hazardous waste solids is by MICP. There are four aspects of calcium carbonate oligomers curing heavy metals in fly ash from waste incineration. The mechanism of treating heavy metals by carbonate in different media was discussed. However, in the complex environment where multiple types of pollutants coexist, questions on how to maintain the efficient processing capacity of carbonate materials and how to use MICP to integrate heavy metal fixation and seepage prevention in solid waste base under complex and changeable natural environment deserve our further consideration. In addition, the use of carbonate materials for the purification of trace radioactive wastewater and the safe treatment of trace radioactive solid waste are also worthy of further exploration.

Spatial variability of heavy metals concentrations in soil of auto-mechanic workshop clusters in Nsukka, Nigeria

The indiscriminate disposal of spent engine oils and other hazardous waste at auto mechanic workshops clusters in Nsukka, Enugu State, Nigeria is an environmental concern. This study examines the concentration of heavy metals in the soil inside the workshop cluster and in the unpolluted soil outside the workshop cluster at approximately 100 m. Ten sampling points were randomly selected from within the cluster and another ten from outside the cluster. Using a hand-held Global Positioning System, the coordinates of the selected points were established and used to create a digital map. Soil samples at depths of 0-30 cm and 30-60 cm, were analyzed for Cu, Fe, Zn, Pb, As and Cd using Spectrophotometer. Moisture content determination and particle size analysis were also done on the samples. Spatial variability of heavy metals concentrations of the studied site was also mapped with ArcGIS 10.2.2 using interpolation methods. Results showed that the soil ranged from sandy loam to sandy clay loam. Cadmium and Zinc had the lowest and highest concentration, respectively, in the studied area. Comparing the concentrations of heavy metals in soils within and outside the auto mechanic cluster revealed notable differences across various depths (0-30 cm and 30-60 cm). The analysis results for soil samples within the cluster exhibited concentration levels (mg/kg) ranging from 0.716-0.751 (Cu), 2.981-3.327 (Fe), 23.464-30.113 (Zn), 1.115-1.21 (Pb), 2.6-2.912 (As), and 0.133-0.365 (Cd) demonstrating a variation pattern in the order of Zn > Fe > As > Pb > Cu > Cd. Conversely, for soil samples outside the cluster, concentration levels (mg/kg) ranged from 0.611-0.618 (Cu), 2.233-2.516 (Fe), 12.841-15.736 (Zn), 0.887-0.903 (Pb), 1.669-1.911 (As), and 0.091-0.091 (Cd). To assess the disparity in heavy metal concentration levels between samples collected within and outside the clusters, ANOVA test was performed. The test showed significant difference in heavy metal concentrations between samples within and outside the auto mechanic cluster (p < 0.05), implying auto mechanic activities significantly impact heavy metal levels within the cluster compared to outside areas. The assessment of soil pollution utilized indices including the Geo-accumulation Index (Igeo), Contamination factor (Cf), and anthropogenic metal concentration (QoC). Zinc, Cadmium, and Arsenic showed the highest contamination factors, indicating significant soil contamination likely due to anthropogenic activities. The concentrations of the metals analyzed were within WHO permissible limits while the metals concentrations were also observed to decrease as depth was increased. Using ArcGIS 10.2.2, spatial maps showing heavy metal distribution were developed, with the Kriging method proving superior. This study suggests that heavy metal levels in the soil at the area be monitored on a regular basis.

Nitric oxide reduces cadmium uptake in wheat (Triticum aestivum L.) by modulating growth, mineral uptake, yield attributes, and antioxidant profile

Wheat (Triticum aestivum L.) is among the plants that are at risk from cadmium (Cd), a hazardous heavy metal that can be fatal due to its rapid absorption and high mobility. Being taken up from the soil and moving to the shoots and roots of edible plants, it enters the food chain and poses a health concern to people worldwide. A strategically important cereal crop, wheat has a demonstrated role in human health systems, particularly in poor nations. In this study, we describe the effects of nitric oxide (NO) on the growth, nutrition, and physiological functions of commercially cultivated wheat cvs. Galaxy 2013 and Akbar 2019 under Cd stress. Four-week-old plants were subjected to Cd (0.5 mM) stress, and after 2 weeks of Cd toxicity, foliar application of nitric oxide (100 and 150 μM) was carried out. As evident from excessive antioxidant production, Cd toxicity increased reactive oxygen species (ROS) level like H2O2 and significantly (p ≤ 0.001) decreased nutrient acquisition, growth, and yield attributes of plants under experiment. The severity of the effect varied between cultivars under investigation. A minimum accumulation of MDA (44%) and H2O2 (55%) was found in the cv. Akbar 2019 under Cd stress, whilst cv. Galaxy 2013 showed the highest accumulation of the oxidative stress indicators malondialdehyde content (MDA) (48%) and H2O2 (60%). Reduced and oxidized glutathione contents were also increased under Cd-induced toxicity. The application of NO resulted in a significant improvement of 22, 25, 25, and 30% in shoot fresh weight, root fresh weight, shoot dry weight, and root dry weight, respectively. Additionally, there was an increased uptake of Ca+2 (16%), K+1 (5%), chlorophyll a (46%), b (32%), a/b ratio (41%), and carotenoid (28%). When compared with Cd-stressed plants, yield parameters like 100 grain weight, number of tillers plant-1, and grain yield plant-1 improved by 14, 17, and 33%, respectively, under NO application. We concluded from the results of this study that NO treatments increased plant development by lowering oxidative stress and limiting Cd uptake. It is inferred from the results of this study that wheat production with reduced heavy metal uptake may be facilitated using NO due to its cytoprotective properties and its interaction with ROS.

Comparison between Variable-Selection Algorithms in PLS Regression with Near-Infrared Spectroscopy to Predict Selected Metals in Soil

Soil is one of the Earth's most important natural resources. The presence of metals can decrease environmental quality if present in excessive amounts. Analyzing soil metal contents can be costly and time consuming, but near-infrared (NIR) spectroscopy coupled with chemometric tools can offer an alternative. The most important multivariate calibration method to predict concentrations or physical, chemical or physicochemical properties as a chemometric tool is partial least-squares (PLS) regression. However, a large number of irrelevant variables may cause problems of accuracy in the predictive chemometric models. Thus, stochastic variable-selection techniques, such as the Firefly algorithm by intervals in PLS (FFiPLS), can provide better solutions for specific problems. This study aimed to evaluate the performance of FFiPLS against deterministic PLS algorithms for the prediction of metals in river basin soils. The samples had their spectra collected from the region of 1000-2500 nm. Predictive models were then built from the spectral data, including PLS, interval-PLS (iPLS), successive projections algorithm for interval selection in PLS (iSPA-PLS), and FFiPLS. The chemometric models were built with raw data and preprocessed data by using different methods such as multiplicative scatter correction (MSC), standard normal variate (SNV), mean centering, adjustment of baseline and smoothing by the Savitzky-Golay method. The elliptical joint confidence region (EJCR) used in each chemometric model presented adequate fit. FFiPLS models of iron and titanium obtained a relative prediction deviation (RPD) of more than 2. The chemometric models for determination of aluminum obtained an RPD of more than 2 in the preprocessed data with SNV, MSC and baseline (offset + linear) and with raw data. The metals Be, Gd and Y failed to obtain adequate models in terms of residual prediction deviation (RPD). These results are associated with the low values of metals in the samples. Considering the complexity of the samples, the relative error of prediction (REP) obtained between 10 and 25% of the values adequate for this type of sample. Root mean square error of calibration and prediction (RMSEC and RMSEP, respectively) presented the same profile as the other quality parameters. The FFiPLS algorithm outperformed deterministic algorithms in the construction of models estimating the content of Al, Be, Gd and Y. This study produced chemometric models with variable selection able to determine metals in the Ipojuca River watershed soils using reflectance-mode NIR spectrometry.

Determination of the Basic Geotechnical Parameters of Blast-Furnace Slag from the Kremnica Region

A decisive aspect of site evaluation for construction is the presence of anthropogenic materials occurring in the geological environment. The geotechnical properties of blast-furnace slag were investigated as a potential substitute for aggregates in the construction industry. The basic geotechnical parameters of the slag were determined, which are critical for evaluating its stability, environmental impact, and usability in geotechnical construction. The research focused on monitoring the physical and mechanical properties of the two samples, and also included mineralogical analysis. The obtained results demonstrated that the slag belongs to the category of poorly graded gravel, G2/GP, and gravel with an admixture of fine-grained soil, G3/G-F. In addition, other important parameters, such as the water disintegration of the slag aggregate, the minimum and maximum bulk densities, the California bearing ratio (CBR), the oedometric modulus (Eoed), and shear tests (the angle of internal friction φ and cohesion c), were determined. The results from this paper provide important information for the proper management of blast-furnace slag so to minimize its environmental impact and achieve sustainability in the mining industry. At the same time, it enables a better understanding of the use of slag as a substitute for aggregates in geotechnical tasks. Despite its local importance in relation to the investigated case, the presented study has significant educational and scientific value for the construction sector, where it is necessary to evaluate anthropogenic activities and materials.

Elemental profile identifies metallurgical pollution in epiphytic lichen Xanthoria parietina and (hypo)xanthine correlates with metals

The accumulation of 55 elements in lichens under the heap of a former nickel smelter (village Dolná Streda, Slovakia) and at eight sites at different distances from the heap plus six sites throughout Slovakia was studied to determine the elemental profile. The major metals in the heap sludge and in the lichens below the heap (Ni, Cr, Fe, Mn, and Co) were surprisingly low in lichens from both the near and far vicinity of the heap (4-25 km), indicating limited airborne spread. However, two different sites with metallurgical activity (another site near the ferroalloy producer in Orava) typically contained the highest amount of individual elements, including rare earth elements, Th, U, Ag, Pd, Bi and Be, and their separation from other sites was confirmed by PCA and HCA analyses. In addition, the amounts of Cd, Ba and Re were highest at sites without a clear source of pollution and further monitoring is needed. It was also an unexpected finding that the enrichment factor calculated using UCC values was increased (often considerably >10) for 12 elements at all 15 sites, indicating eventual anthropogenic contamination with P, Zn, B, As, Sb, Cd, Ag, Bi, Pd, Pt, Te and Re (and other EF values were locally increased). Metabolic analyses showed a negative correlation between some metals and metabolites (ascorbic acid, thiols, phenols and allantoin), but slightly positive (amino acids) or highly positive correlation with purine derivatives hypoxanthine and xanthine. The data suggest that lichens adapt their metabolism to excessive metal loading and that epiphytic lichens are suitable for identifying metal contamination even at apparently clean sites.

Green Synthesis of the Effectively Environmentally Safe Metakaolin-Based Geopolymer for the Removal of Hazardous Industrial Wastes Using Two Different Methods

Untreated wastewater pollution causes environmental degradation, health issues, and ecosystem disruption. Geopolymers offer sustainable, eco-friendly alternatives to traditional cement-based materials for wastewater solidification and removal. In this study, we investigate how wastewater containing organic and inorganic pollutants can be removed using geopolymer mixes based on metakaolin incorporation with cement kiln dust as an eco-friendly material. The present investigation compares the efficacy of two different techniques (solidification and adsorption) for reducing dye contaminants and heavy metals from wastewater using a geopolymer based on metakaolin incorporation with cement kiln dust. This study investigated the adsorption capacity of a geopolymer based on metakaolin incorporating two different ratios (20% and 40% by weight) of cement kiln dust (MC1 and MC2) for the reactive black 5 dyeing bath effluent (RBD) only and in a combination of 1200 mg/L of Pb²⁺ and Cd²⁺, each separately, in aqueous solutions under different adsorption parameters. The results of the adsorption technique for the two prepared geopolymer mixes, MC1 and MC2, show that MC1 has a higher adsorption activity than MC2 toward the reactive black 5 dyeing bath effluent both alone and in combination with Pb²⁺ and Cd²⁺ ions separately. The study also looked at using MC1 mix to stabilize and solidify both the dyeing bath effluent alone and its combination with 1200 mg/L of each heavy metal individually inside the geopolymer matrix for different time intervals up to 60 days of water curing at room temperature. The geopolymer matrix formed during the process was analyzed using FTIR, SEM, and XRD techniques to examine the phases of hydration products formed. The results showed that MC1 effectively adsorbs, stabilizes, and solidifies the dying bath effluent for up to 60 days, even with high heavy metal concentrations. On the other hand, geopolymer mixes showed an increase in mechanical properties when hydration time was increased to 60 days. According to our findings, the type of geopolymer developed from metakaolin and 20 wt.% cement kiln dust has the potential to be employed in the treatment of wastewater because it has good adsorption and solidification activity for the reactive black 5 dye effluent alone and for a mixture of dye pollutants with both Pb²⁺ and Cd²⁺ ions separately. Our results have significant implications for wastewater treatment and environmental remediation efforts, as they offer a sustainable solution for managing hazardous waste materials.

Evaluation of heavy metals contamination in cereals, vegetables and fruits with probabilistic health hazard in a highly polluted megacity

Heavy metals (HMs) contamination in foodstuffs could pose serious health issues for public health and humans are continually exposed to HMs through the consumption of cereals, fruits, and vegetables. The present study was conducted to assess 11 HMs in foodstuffs to investigate pollution levels and health risks to children and adults. The mean contents of Cd, Cr, Cu, Ni, Zn, Fe, Pb, Co, As, Mn and Ba in foodstuffs were 0.69, 2.73, 10.56, 6.60, 14.50, 9.63, 2.75, 0.50, 0.94, 15.39 and 0.43 mg/kg, respectively and the concentration of Cd, Cr, Cu, Ni and Pb were higher than maximum permissible concentrations (MPCs) showing that these foods may be contaminated with metals and constitute a danger to consumers. Vegetables had relatively higher metal contents followed by cereals and fruits. The average value of the Nemerrow composite pollution index (NCPI) for cereals, fruits, and vegetables were 3.99, 6.53, and 11.34, respectively indicating cereal and fruits were moderately contaminated whereas vegetables were heavily contaminated by the studied metals. The total estimated daily and weekly intakes for all studied metals were higher than the maximum tolerable daily intake (MTDI) and provisional tolerance weekly intake (PTWI) recommended by FAO/WHO. The target hazard quotients and hazard index of all studied metals exceeded the standard limit for adults and children suggesting significant non-carcinogenic health hazards. The total cancer risk value of Cd, Cr, Ni, Pb, and As from food intake exceeded the threshold range (1.0E-04), suggesting potential carcinogenic risks. Based on practical and sensible evaluation techniques, the current work will assist policymakers in controlling metal contamination in foodstuffs.

Investigation of phenolic compounds potential to reduce dust pollution of pomegranate trees

The present study was carried out in two seasons from two areas at different distances from the industrial zone of Gabes city which is classified as a Mediterranean host-spot pollution region. Pomegranate tree were highly exposed to various industrial air pollutants containing Zn and Cu. The relation between Zn, Cu, morphological, physiological and biochemical changes induced in pomegranate leaves was evaluated based to the measurement of leaf heavy metals, leaf changes, total phenolic content and quali-quantification of individual phenol profile by LC-ESI-MS.Results showed that the highest levels of metals were found in the closet site to the industrial area. This accumulation varied significantly between areas and seasons and cause significant increase of necrosis leaf area, decrease of leaf area, green leaf area and specific leaf area. LC-ESI-MS analysis showed a spatial and seasonal variation of total phenolic acids and flavonoids which indicate that phenolic compounds are rigorously depending to stressful conditions. A significant positive correlation was found among total Zn, Cu, necrosis, cirsiliol, caffeic and trans-ferulic acids. This accumulation can serve as protective defensive mechanism to minimize the air pollutants effects, chelate Zn and Cu and then to improve the resistance of pomegranate trees.

Ecological Characterization and Bio-Mitigation Potential of Heavy Metal Contamination in Metallurgically Affected Soil

Heavy metals (HMs) remain persistent in soil for a long time and thus present a long-term threat of environmental pollution. In this study, the concentrations of some HMs (As, Cu, Zn, Pb, and Mo) in soil, potentially affected by the ex-operation of a metallurgical plant—specifically, a copper smelter in Alaverdi Town, northeastern Armenia—were measured, based on which, the HM contamination and its ecological, biological, and health effects were assessed. Concentrations of HMs (Cu, Zn, and Pb) were also measured in different plant (leaves) and invertebrate species that occur in the soil over the metallurgical factory site in order to assess the potential for the bioremoval of HMs from the soil. The results showed that the ex-operation of the metallurgical facility created such contamination in the soil that it caused a noticeable loss of invertebrate biomass in the soil and posed ecological, non-carcinogenic (for children), and carcinogenic health hazards. The investigated plant and invertebrate species were characterized by different capacities for the accumulation of HMs from the soil, based on which the plant species Fraxinus excelsior, Acer platanoides, Robinia pseudoacacia, and Aesculus hippocastanum and the invertebrate species Deroceras caucasicum, Limax flavus, and Eisenia rosea are recommended to be used for the selective removal of HMs (Cu, Zn, and Pb) from the soil.

Transfer of Potentially Toxic Elements in the Soil-Plant System in Magnesite Mining and Processing Areas

Mining activities, ore concentrations, and transport processes generate large amounts of pollutants, including hazardous elements, which are released into the environment. This work presents the results of experimental research aimed at evaluating the environmental risks of soil and plant contamination in two magnesite mining and processing areas in the Slovak Republic, and assesses the phytoremediation potential of dominant plant species. Eleven potentially toxic elements in the soil were investigated using X-ray fluorescence spectrometry (Cd, Pb, Cr, Zn, Cu, As, Ni, Mn, Mg, Fe) and atomic absorption spectrometry (Hg). In plants, potentially toxic elements were investigated using inductively coupled plasma mass spectrometry (Cu, As, Cd, Pb) and inductively coupled plasma atomic emission spectrometry (Cr, Zn, Mn, Mg). Selected soil parameters (pH, redox potential, and soil organic matter) were also investigated. Soil contamination was evaluated using environmental indices (geoaccumulation index—Igeo, enrichment factor—EF, contamination factor—Cf, degree of contamination—Cd). The phytoremediation potential of plants was evaluated using the bioconcentration factor (BCF) and the translocation factor (TF). The soil reaction in the studied areas indicated a strong alkalization of the soil. The soils in Jelšava-Lubeník were significantly contaminated with Cr, As, Mn, and Mg. The most significant enrichment based on the average values of EF was found to be in the order of Cd > Mg > Zn > Cu > As > Cr > Ni > Pb > Fe > Hg > Mn. The observed values of Cf and Cd indicated a high degree of soil contamination. In Košice, the soils were found to be significantly contaminated with Cr, Mn, Mg, and Ni. The most significant enrichment was found in the order of Cd > Mn > Ni > Pb > Zn > Mg > Cu > As > Fe > Cr > Hg. Very high Cf was found for Pb and Cr. The results of correlation and hierarchical cluster analyses suggest a similar origin of pollutants caused by significant anthropogenic interventions due to magnesite mining and processing. The investigated dominant plant species, Phragmites australis, Agrostis stolonifera, Elytrigia repens, and Taraxacum officinale are able to accumulate high concentrations of the monitored potentially toxic elements without more serious load or damage. The results of BCF and TF confirmed that P. australis and T. officinale appeared to be suitable accumulators in the phytoextraction process. In the case of E. repens and A. stolonifera it was confirmed that they accumulate and immobilize high concentrations of potentially toxic elements, especially in the roots, establishing the suitability of their use in phytostabilization processes.

Temporal Variations of Heavy Metal Sources in Agricultural Soils in Malta

In the opportunity to understand the benefits of Maltese soil and its importance to our climate, the content of heavy metals—including Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, and Zn—was studied in two fields in proximity in the south-east region of Malta. Analytical determinations were carried out using atomic absorption spectroscopy following heated aqua regia digestion on 50 collected samples using triple repeatability. The decreasing pattern of the concentrations obtained is Fe > Zn > Mn > Sr > Pb > Cu > Ni > Cr > Co. Correlations between pre-harvesting and post-harvesting concentrations were examined to assess lithogenic and anthropogenic relationships. Multivariate analysis including principal component analysis and factor analysis clarified the origin of heavy metals content reviewed. Some of the heavy metals studied showed a dominant relationship between concentration variation and their possible sources. Potential ecological risk assessment demonstrated that the fields reviewed are not contaminated by any of the heavy metals assessed except for Zn which posed a moderate/strong contamination but presented an overall low potential for ecological risk. Concentrations of heavy metals demonstrated no risk to human health and no carcinogenic risk through ingestion and dermal contact with the soil.