Heavy Metals Cadmium Research Articles

A Ratiometric Fluorescence Probe for Visualized Detection of Heavy Metal Cadmium and Application in Water Samples and Living Cells

Heavy metal cadmium (II) residuals have inflicted severe damage to human health and ecosystems. It has become imperative to devise straightforward and highly selective sensing methods for the detection of Cd2+. In this work, a ratiometric benzothiazole-based fluorescence probe (BQFA) was effortlessly synthesized and characterized using standard optical techniques for the visual detection of Cd2+ with a change in color from blue to green, exhibiting a significant Stokes shift. Moreover, the binding ratio of BQFA to Cd2+ was established as 1:1 by the Job’s plot and was further confirmed by FT-IR and 1HNMR titrations. The ratiometric fluorescence response via the ICT mechanism was confirmed by DFT calculations. Furthermore, the limit of detection for detecting Cd2+ was determined to be 68 nM. Furthermore, it is noteworthy that BQFA showed good performance in real water samples, paper strips, smartphone colorimetric identification, and cell imaging.

Pertubations of Physicochemical Properties and Heavy Metal in the Soil of Coastal Areas of Akwa Ibom State, Nigeria

This study aimed at assessing the concentrations and perturbations of the physicochemical properties and heavy metals in the soil of the coastal regions of Akwa Ibom State, Nigeria. Sampling was carried out across three mangrove locations (Iko Town, Okoroutip and Uta Ewa) in Eastern Obolo, Ibeno and Ikot Abasi Local Government Areas respectively. Four vegetation plots were randomly selected, and within each plot, three belt transects were established. Physicochemical properties [Sand, Clay, Silt, organic carbon (OC), total nitrogen, sulphate and chlorine content] and heavy metals (Arsenic, Silver, Chromium, Copper, Nickel, Lead, Mercury, Cadmium, Titanium, Vanadium and Zinc) were analyzed using standardized methods. Results from this study revealed considerable variations in the physicochemical properties of soil in the study area. The aforementioned heavy metals were present in both wet and dry seasons in considerable concentrations in the soil samples within the study areas. However, were within and below WHO limits. The variations in the physicochemical properties and the presence of these heavy metals in the samples are indicative of an impacted environment unsuitable for the growth and survival of the endemic flora and fauna species of this unique ecosystem. In view of the current knowledge of the role of mangrove ecosystems in blue-economy of the nation and mitigation of ongoing climate change, we advocate a tripartite alliance between the government, multinational companies operating within the area and the various impacted communities that leads to a concerted efforts of constant monitoring and remediation in the reduction of current and future pollutant levels.

Pathological Changes and CYP1A1 Expression as Biomarkers of Pollution in Sarpa Salpa and Diplodus Sargus.

In a marine ecosystem, the most sensitive organisms to environmental changes, mainly to anthropic pressures, are fishes and invertebrates. Therefore, they are considered the ideal targets to indirectly evaluate the health of an entire ecosystem. Teleost fishes, particularly those that occupy the highest trophic levels, can accumulate toxic substances through their diet. In this study, we used two fish species with sedentary behavior and trophic habits, Diplodus sargus and Sarpa salpa, caught in two areas at different anthropic pressures divided into the Gulf of Naples (Na) and the Gulf of Salerno (Sa). This study aimed to correlate the pathological alterations in target organs in both species with known concentrations of polychlorinated biphenyls (PCBs) and heavy metals (lead and cadmium) to the expression of CYP1A1. Histological examination took into consideration circulatory disorders, increase in melanomacrophages (MMs) number, inflammation in kidney and hepatopancreas and gonadal stage maturation. Next, the pathological and morphological changes found were compared to immunohistochemical expression of CYP1A1 in the same samples. Chemical analysis of PCBs, based on 28, 52, 101, 138, 153, and 180 congeners, and heavy metals, were performed on hepatopancreas and muscle samples. Higher median values of PCBs concentration were detected in both species in the Salerno area (8.1 ng/g in Diplodus sargus muscles and 51.1 ng/g in Sarpa salpa hepatopancreas, respectively), although the values were consistently below the legal limits. No critical values were found for lead and cadmium. Therefore, we hypothesized that CYP1A1 and pathological alterations were more expressed in fish from Salerno area. The pathological changes showed a statistically significant difference in inflammation of the kidneys (p < 0.0001) between S. salpa of both Gulfs. In addition, we found a statistically significant difference in the assessment of the increase in MMs/MMCs (p = 0.0384) and circulation disorders (p = 0.0325) of hepatopancreas in D. sargus of both Gulfs. As not all the variables considered showed statistical significance, the analysis of the results does not fully support the correlation between the highest levels of contaminants found in the Salerno area and the expression of CYP1A1. Our data could be a starting point for future studies to better correlate the role of CYP1A1 to pollutants, considering this is the first study involving two of the most common species in the Mediterranean Sea. Thus, future studies could include other species to improve and increase records.

The protective roles of Oryza glumaepatula and phytohormone in enhancing rice tolerance to cadmium stress by regulating gene expression, morphological, physiological, and antioxidant defense system.

The heavy metal cadmium (Cd) is highly poisonous and has received significant attention from environmental scientists due to its harmful impacts on plants. Oryza glumaepatula is a wild rice that contains useful genes against biotic and abiotic stresses. Therefore, the current study used SG007, a single-segment substitution line (SSSL), generated by crossing O. glumaepatula with an elite rice cultivar (HJX74), to evaluate the resistance potential against Cd. Moreover, we assessed the efficacy of strigolactone GR24 (1 μM) against Cd toxicity (100 μM) by investigating physiological, biochemical, and molecular mechanisms in both cultivars (i.e., SG007 and HJX74). The findings of this study revealed that Cd toxicity declined the chlorophyll a, chlorophyll b, and carotenoids by 50%, 20%, and 44% in SG007, and 58%, 39%, and 59% in HJX74 by enhancing electrolyte leakage (EL), malondialdehyde (MDA), and hydrogen peroxide (H2O2) by 113%, 184%, and 119% in SG007 and 248%, 273% and 195% in HJX74, respectively. GR24 improved growth under Cd stress in both cultivars, and SG007 exhibited better plant growth parameters, antioxidant enzymatic activities, nitric oxide synthase (NOS), and nitric oxide (NO) levels than HJX74 under Cd toxicity. GR24 with SG007 regulated expressions of Cd transporters and reduced the cytological disruptions in cell organelles. The combined utilization of SG007 and GR24 reduced Cd accumulation and oxidative stress and improved plant growth parameters and enzymatic activities. In conclusion, our study highlights the potential of utilizing SG007 in conjunction with GR24 as a practical strategy to mitigate Cd pollution in rice. The results not only underscore the beneficial effects of strigolactone GR24 in alleviating Cd-induced stress but also emphasize the valuable genetic traits of O. glumaepatula in developing rice lines with enhanced tolerance to heavy metals, offering broader implications for sustainable agriculture and crop improvement in contaminated environments.

Soil moisture determines the consistency of organic matter decomposition in field and lab test patterns

Litter decomposition serves as the primary process for soil organic matter formation and renewal. However, few studies have been conducted to validate field large-scale litter decomposition patterns. In this study, cotton strips and Solanum nigrum were used to explore the decomposition differences between standardized litter and conventional litter, along with the release of heavy metal Cadmium (Cd). The indoor characteristics of organic matter decomposition were further verified. After 6 months of Cd pretreatment, litter was placed on the surface of soil collected from 15 sites across the China for 3 months of lab tests. The results indicated that the decomposition rates of both litter types were regulated by soil moisture and generally showed a trend of deceleration from east to west, consistent with the field decomposition pattern. In addition, the mass loss of cotton strip was significantly lower than S. nigrum due to the higher Cd concentration. With the decomposition process, both litter types showed a decreasing trend in Cd concentration, especially the cotton strip. Interestingly, our study found soil factors had the highest relative influence on decomposition. A higher soil microbial moisture use efficiency in the mid-latitude region during litter decomposition may be attributed to the adaptability of microorganisms. Our research demonstrated the consistency of lab test patterns with the field experiments, emphasizing the distinctions between standardized and conventional litter. This study not only revealed the influence mechanism of soil moisture and Cd on litter decomposition rate but also emphasized the important role of microorganisms in the litter decomposition process, which provided a new perspective for a deeper understanding of the ecosystem carbon cycle and heavy metal pollution.

Assessment of Heavy Metal (Zinc, Copper, Lead and Cadmium) Contamination in Common Edible Shellfish Species of the Hooghly River and Sunderbans, India

The content of four heavy metals (Zinc, Copper, Lead and Cadmium) in muscles of three shell fish species - prawns -Penaeus monodon and Penaeus indicus and crabs-Scylla serrata, the most prime shellfish food resources of human in the domestic and international market were studied at four stations in the estuarine belt near Bay-of-Bengal which receives wastes of various types from industries and various anthropogenic activities. The samples were digested by acid digestion. The metal contents were quantified using an AAS (Atomic absorption spectrophotometer). The distribution of trace metals accumulated in the muscle tissues of the above mentioned species was in the order- Zn &gt; Cu&gt; Pb&gt; Cd. In the present study, levels of Zinc in the shell fishes ranged from 07.44±0.65 to 128.10 ±2.96 ; Cu ranged from 5 ±0.15 to 99.14 ±1.31; Pb varied from 1.67± 0.14 to 23.99 ± 0.79 and Cd ranged from 1.29± 0.35 to 7.09 ± 0.80.The concentration of the four metals exhibited spatial variation as station 1 &gt;station 2 &gt; station 3 &gt; station 4, which could be a reflection of different bioavailability of metal concentrations in the water body at different stations. The results obtained showed that the metal concentrations in most of the cases were above the threshold value recommended by WHO. Metals such as Cu, Zn, Pb, Cd, can affect various aquatic organisms as well as human being either directly or indirectly as they can enter into the food chain and may be biomagnified at higher trophic levels which is one of the top concerns for human health. Essential heavy metals such as Zinc and Copper are relatively less harmful at low concentration while non-essential metals such as Cd and Pb are highly toxic even at low concentrations.

Measurements of Heavy Elements and Radioactivity Concentration Levels in Types of Fertilizers and Pesticides Commonly Used in Sana’a Yemen

This study aims to measure heavy metals (HMs) concentration and radioactivity concentration levels in fertilizer and pesticide samples collected from local markets in Sana’a, Yemen. Gamma spectroscopy employing a Survey Sodium Iodide NaI (TI) RIIDEYM-G detector was used for radiation and dose assessments. As for heavy metal analyses, this study used Inductively Coupled Optical Emission Spectroscopy (ICP-OES). Thirty samples were collected from local markets in Sana’a, Yemen. Radioactivity measurements show low levels of radioactivity concentration. The average dose rates due to fertilizer and pesticide samples were 1.14 and 1.07 mSv/y, respectively. These values are nearly equal to the recommended annual radiation dose rate limit (1mSv/y) recommended by the International Commission on Radiological Protection (ICRP). For heavy metal analysis, it was found that the average concentrations of heavy metals (HMs) (cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn)) in the fertilizer samples were 1.08 mg/kg, 4.944 mg/kg, 13.8495 mg/kg, 274.371 mg/kg, 3.30446 mg/kg, 15.35686 mg/kg, and 24.4547 mg/kg, respectively. Heavy metal concentrations in fertilizer samples were mainly less than European (EU) guideline limits, with the exception of a few samples. The average concentrations of heavy metals (Cd, Cr, Cu, Fe, Ni, Pb, and Zn) in the pesticide samples were 0.8 mg/kg, 0.5784 mg/kg, 52.280 mg/kg, 73.4651 mg/kg, 2.4482 mg/kg, 3.199 mg/kg, and 1.1309 mg/kg, respectively. The heavy metal concentrations in pesticide samples were less than the corresponding values in fertilizer samples.

Determination of heavy metals and health risk assessment in drinking water in Bukayriyah City, Saudi Arabia

Abstract Heavy metal levels, including arsenic, lead, cadmium, mercury, chromium, and nickel, were analyzed in 124 samples of tap and filtered water obtained from Bukayriyah city, Saudi Arabia, using inductively coupled plasma mass spectrometry. Additionally, measurements of total dissolved solids, conductivity, and pH were also performed. The study also evaluated the potential non-cancer and cancer risks (CRs) associated with the ingestion of these heavy metals for both children and adults. The results indicated that the average concentrations of heavy metals in both tap and filtered water were found to be below the recommended limits set by the World Health Organization and the Gulf Standard Organization. To assess the non-carcinogenic risks, the chronic daily intake (CDI), hazard quotient (HQ), and hazard index were calculated for analyzed metals present in both tap and filtered water. In both the children and adult populations, the CDI indices for heavy metals in tap and filtered water followed the order of Cr &gt; Hg &gt; Ni &gt; Pb &gt; As &gt; Cd. However, it is worth noting that the CDI values for tap water were higher than those for filtered water for both children and adults. The descending order of HQ values is as follows: Hg &gt; Cr &gt; As &gt; Cd &gt; Pb &gt; Ni. This indicates that the HQ values for all metals are below the acceptable limit of 1. These findings confirm that the exposure to the examined metals from both tap and filtered water in Bukayriyah City is within safe limits and poses no non-carcinogenic risks. To assess the carcinogenic risks, the incremental lifetime cancer risk (ILCR) and total carcinogenic risk (TCR) were calculated. The order of ILCR values for both children and adults in tap and filtered water is as follows: Ni &gt; Cr &gt; Cd &gt; As &gt; Pb. All ILCR values were below the acceptable limit of 10−6 to 10−4. However, TCR values exceeded this threshold range only for children exposed to tap water, with a value of 1.43 × 10−4. Thus, children exposed to tap water have a potential risk of developing carcinogenic diseases.

Agro-waste based biomass residues valorization for effective adsorption of heavy metal.

In this experiment four agro-waste based biomass residues (soybean stover-SSb, buckwheat stover-BWb, Artemisia vulgaris- AVb and Chromolaena odorata-COb) was valorized into low cost amendment called biochar followed by compositional characterization for their application in heavy metal removal. Investigation was carried out on the removal of the most common heavy metal ions including arsenic, cadmium, lead, nickel, zinc, and copper through adsorption on four types of biomass valorised biochar. According to preliminary testing, all the biochar was effective to eliminate a mixture of six heavy metals from the aqueous phase, with the removal of arsenic being the most removed and nickel being the least. In comparison to no biochar treatment, the average removal rate of heavy metal from aqueous solution using four distinct types of biochar was 45.75-62.42% (Cd), 43.64-56.33% (Pb), 41.85-59.73% (Ni), 42.87-60.28% (Zn), 45.64-59.51% (Cu), and 49.02-60.53% (As). The percent decrease of cadmium heavy metal adsorption with increase in maximum contaminant level (MCL) from 1- to fivefold was 20.0 (SSb), 20.7 (COb), 21.6 (BWb), and 22.9 (AVb). The results of the dosage study indicated that As adsorption was the most beneficial on all four types of biochar, whereas Ni adsorption was the least effective. With increase in application rate of biochar the heavy metals adsorption (%) was also increased. Four different agro-waste valorized biochar were used to treat the wastewater, and the physical and chemical changes that occurred both before and after the biochar treatment were noted. There was a drop in the wastewater CODT, CODD, TSS, ammonia, TKN, TP and pH values of 79.7-103.5%, 57.7-81.5, 52.3-68.4%, 1.23-2.23%, 14.1-20.6%, and 1.23-3.03%, respectively. Furthermore, after being passed through a biochar, the wastewater's Zn, Pb, Cd, As, Cr and Cu levels decreased by 3.26-6.15%, 0.06-0.34%, 0.01-0.08%, 2.37-3.65%, 3.95-5.53%, and 2.24-3.34%, respectively at 2.5 and 5.0g/litre of wastewater. Thus, in order to comply with regulations for the disposal of wastewater effluent, the process of valorizing biomass into biochar offered enormous potential for the removal of heavy metals in addition to wastewater treatment.

Combined Application of High-Throughput Sequencing and Metabolomics to Evaluate the Microbial Mechanisms of Plant-Growth-Promoting Bacteria in Enhancing the Remediation of Cd-Contaminated Soil by Hybrid Pennisetum

The contamination of soil with the heavy metal cadmium (Cd) is increasingly prominent and severely threatens food security in China. Owing to its low cost, suitable efficacy, and ability to address the shortcomings of plant remediation by enhancing the ability of plants to take up Cd, plant–microbe combination remediation technology has become a research hotspot in heavy metal pollution remediation. A pot experiment was performed to examine the effects of inoculation with the plant-growth-promoting bacterium Brevibacillus sp. SR-9 on the biomass, Cd accumulation, and soil nutrients of hybrid Pennisetum. The purpose of this study was to determine how Brevibacillus sp. SR-9 alleviates stress caused by heavy metal contamination. High-throughput sequencing and metabolomics were used to determine the effects of inoculation on the soil bacterial community composition and microbial metabolic functions associated with hybrid Pennisetum. The results suggest that mutation of Brevibacillus sp. SR-9 effectively alleviates Cd pollution stress, leading to increased biomass and accumulation of Cd in hybrid Pennisetum. The aboveground biomass and the root weight increased by 12.08% and 27.03%, respectively. Additionally, the accumulation of Cd in the aboveground sections and roots increased by 21.16% and 15.50%, respectively. Measurements of the physicochemical properties of the soil revealed that the strain Brevibacillus sp. SR-9 slightly increased the levels of available phosphorus, total nitrogen, total phosphorus, and available potassium. High-throughput DNA sequencing revealed that Brevibacillus sp. SR-9 implantation modified the composition of the soil bacterial community by increasing the average number of Actinobacteria and Bacillus. The total nitrogen content of the soil was positively correlated with the Actinobacteria abundance, total phosphorus level, and available phosphorus level. Metabolomic analysis revealed that inoculation affected the abundance of soil metabolites, and 59 differentially abundant metabolites were identified (p &lt; 0.05). Among these, 14 metabolites presented increased abundance, whereas 45 metabolites presented decreased abundance. Fourteen metabolic pathways were enriched in these metabolites: the folate resistance pathway, the ABC transporter pathway, D-glutamine and D-glutamic acid metabolism, purine metabolism, and pyrimidine metabolism. The abundance of the metabolites was positively correlated with the levels of available phosphorus, total potassium, total phosphorus, and total nitrogen. According to correlation analyses, the development of hybrid Pennisetum and the accumulation of Cd are strongly associated with differentially abundant metabolites, which also impact the abundance of certain bacterial populations. This work revealed that by altering the makeup of microbial communities and their metabolic processes, bacteria that promote plant development can mitigate the stress caused by Cd. These findings reveal the microbiological mechanisms through which these bacteria increase the ability of hybrid Pennisetum to take up the Cd present in contaminated soils.

Machine learning-assisted risk evaluation of heavy metals in the Hainan gold mining region, China.

This study employed machine learning (ML) to thoroughly investigate the impact of informal mining activities on the distribution and pollution status of heavy metals in soils near private gold mines in Hainan Province, southern China, a region known for its ecological sensitivity and economic importance. By systematically collecting surface soil samples and samples at depths of 0.5-1m from 175 drilling sites, a comprehensive quantitative analysis was conducted on major heavy metal elements, including lead (Pb), copper (Cu), cadmium (Cd), nickel (Ni), mercury (Hg), chromium (Cr), arsenic (As), and zinc (Zn). Combined with evaluation methods such as the Pollution Load Index (PLI), Normalized Pollution Index (NIPI), and Ecological Risk Index (ERI), the study revealed a high level of soil pollution at informal mining sites. The findings indicated that the average concentrations of Pb, Cd, Hg, As, and Zn in surface soils significantly exceeded the background values for soils in China, with a pronounced positive correlation observed between these heavy metal elements in both surface and deep soil profiles (r > 0.5). Furthermore, leveraging the heavy metal content in surface soils and the constructed environmental indicators, the predictive accuracy for metal content in deep soils was found to range from R2 = 0.27 to 0.68, suggesting that informal mining activities have led to substantial variations in metal content across different soil profiles. Through the application of a random forest model for predictive analysis of the PLI, NIPI, and ERI, high prediction accuracy was achieved (R2 = 0.78, 0.86, and 0.60, respectively). The study demonstrates that informal mining activities not only elevate the risk of soil pollution but also alter the distribution patterns of heavy metals. Also, this study provides a crucial foundation for the scientific assessment of soil quality and potential environmental hazards, while also affirming the efficacy of ML techniques in forecasting soil quality parameters.

Heavy Metals Analysis of Breweries Effluent used in Soil Cultivated with Glycine Max (L.) Merr. Accessions with Biochar Augmentation

Beer production has promulgated the prevalence of heavy metal contamination in the environment (soil and water bodies). The magnitude of breweries wastewater-effluent effect discharged on soil and its effect on crop quality in terms of growth and physiology must therefore be investigated. This study aims to assess the level of seven heavy metals (HM) (lead (Pb), nickel (Ni), chromium (Cr), copper (Cu), cadmium (Cd), zinc (Zn) and iron (Fe)) in breweries wastewater-effluent and its effect on the growth of Glycine max accessions (TGM-3990, TGM-1348, TGM-1732, TGM-2175 and TGM-928) as well as the influence of biochar soil amendment in the induction of HM tolerance in G. max. Effluent properties were analyzed using the A1 portable TDS/EC meter. HM in the wastewater-effluent was determined using Atomic Absorption Spectrometer (AAS). The experiment was set up in a complete block design. 3 seeds G. max accessions were planted in 7kg of sterilized soil (control, effluent and biochar treatments). Growth parameters were taken using standard methods, while the total photosynthetic pigments (TPP) were determined using the atLeaf chlorophyll meter. The wastewater-effluent recorded an electrical conductivity (EC) of 928µS/cm, total dissolved solids (TDS) (464ppm), Temperature (31.9-32.6°C) and pH (5.37). Results for HM concentration showed; Pb (0.20mg/L), Ni (&lt;0.001mg/L), Cr (0.03mg/L), Cu (&lt;0.001mg/L), Cd (&lt;0.001mg/L), Zn (&lt;0.001mg/L) and Fe (8.74mg/L). The trend shows that Fe˃Pb˃Cr˃Cd˃Cu˃Ni˃Zn. Cr, Cd, Cu, Ni and Zn were significantly below the World Health Organization (WHO) and Waste Water Forum (WWF) permissible limit, while Fe and Pb significantly higher. G. max accessions TGM-928 (80%) and TGM-3990 (80%) had better germination percentage (GP), TGM-1348 (60%) had the lowest GP, while TGM-2175 recorded no germination in all treatments. At 6 weeks after planting (WAP), it was observed that irrigation of G. max accessions with breweries wastewater-effluent significantly (p=0.001) stimulated growth parameters such as shoot length for TGM-3990 which recorded; Treatment=19.53±0.94cm; Control=17.10±0.67cm; Biochar=40.83±1.01cm) while TGM-1732 had the highest shoot growth (T=38.57±1.53cm; C=25.00±0.00cm; B=82.33±5.70cm) when compared to their controls. TGM-3990 (T=32.20mg/kg, C=34.10mg/kg, 43.30mg/kg) recorded the least TPP contents, while TGM-928 (T=51.00mg/kg, C=45.60mg/kg, B=43.50mg/kg) recorded the highest TPP in all treatments. Amelioration of soil with biochar significantly (p=0.001) stimulated growth above the effluent treatment and control. Similar trend was observed for leaf area, petiole length, leaf number, stem girth and internode length. This study has shown that breweries effluent has the potential of growth enhancement in G. max cultivation and in combination biochar application reduces the need for additional fertilizer application.

Effects of cadmium on the intestinal health of the snail Bradybaena ravida Benson.

The heavy metal cadmium (Cd) is a toxic and bioaccumulative metal that can be enriched in the tissues and organs of living organisms through the digestive tract. However, more research is needed to determine whether food-sourced Cd affects the homeostasis of host gut microflora. In this study, the snail Bradybaena ravida (Benson) was used as a model organism fed with mulberry leaves spiked with different concentrations of Cd (0, 0.052, 0.71, and 1.94 mg kg-1). By combining 16S rRNA high-throughput sequencing with biochemical characterization, it was found that there were increases in the overall microbial diversity and abundances of pathogenic bacteria such as Corynebacterium, Enterococcus, Aeromonas, and Rickettsia in the gut of B. ravida after exposure to Cd. However, the abundances of potential Cd-resistant microbes in the host's gut, including Sphingobacterium, Lactococcus, and Chryseobacterium, decreased with increasing Cd concentrations in the mulberry leaves. In addition, there was a significant reduction in activities of energy, nutrient metabolism, and antioxidant enzymes for gut microbiota of snails treated with high concentrations of Cd compared to those with low ones. These findings highlight the interaction of snail gut microbiota with Cd exposure, indicating the potential role of terrestrial animal gut microbiota in environmental monitoring through rapid recognition and response to environmental pollution.

Study on reference material of heavy metals (lead, cadmium, arsenicic, and mercury) in mustard greens by natural infection method

Vegetables are an essential part of daily meals. Each type contains different nutrients and serves various functions, but all provide essential nutrients for human health. Many metal elements are known to play important roles in living organisms and humans. However, heavy metal contamination can be toxic to the body and impact the health of consumers. To ensure the quality of vegetable products, determining the levels of heavy metals (Pb, Cd, As, Hg) is crucial for food safety control in vegetables. Therefore, using heavy metal standard samples (Pb, Cd, As, and Hg) in vegetables provides reference values and accuracy benchmarks for testing results, aiding in precise and objective evaluation during sample testing. This study aims to develop a process for creating standard samples for analyzing heavy metals Pb, Cd, As, and Hg in vegetables using a natural contamination method. The produced samples demonstrated consistency and stability, with an estimated duration of 627 days from the production date. The measurement uncertainty ranges from 7,94% to 15,7%. The values of the standard samples align with the low contamination levels required for analysis, making them suitable for quality control in laboratories. Additionally, the results of this study lay the groundwork for further research into developing other standard samples with diverse matrices and analytical criteria using natural contamination methods.

Smartphone-based portable sensor with Bi-MOF nanocomposite for Cd (II) in vegetable samples

The accumulation of heavy metal cadmium (Cd) in the food chain poses a serious threat to human health, necessitating the development of rapid, on-site, and portable detection methods for Cd (II). Herein, we developed a smartphone-based electrochemical sensor for portable determination of Cd (II) in vegetables using a bismuth metal–organic framework (Bi-MOF) nanocomposite. Prismatic rod-like Bi-MOF was hydrothermally synthesized using trimesic acid as organic ligands, and subsequently, carboxyl-functionalized multi-walled carbon nanotubes (COOH-MWCNTs) were incorporated to form Bi-MOF nanocomposite network. The smartphone-based electrochemical sensor enables rapid, sensitive, and portable detection of Cd (II) in vegetable samples using Bi-MOF/COOH-MWCNTs-modified screen-printed carbon electrodes (SPCE). A comparative analysis of traditional electrochemical sensors coupled with desktop computer for linear voltametric responses for Cd (II) in the range of 0.2–500 ng/mL with a limit of detection (LOD) of 0.07 ng/mL using Bi-MOF/COOH-MWCNTs-modified glassy carbon electrodes (GCE), the portable sensor demonstrated good linear range in 0.7–350 ng/mL with a LOD of 0.22 ng/mL. This work introduces a novel approach for on-site and portable detection of Cd (II) in agricultural products.

Effect of natural aging on biochar physicochemical property and mobility of Cd (II).

This project utilized both field experiment and laboratory analyses to address the gap in understanding regarding the alterations in properties and functions of biochar, and the impact of heavy metal passivation in soil over long-term natural field aging. The study aimed to examine the changes in the physical and chemical characteristics of biochar over an extended period of natural aging. Additionally, it sought to analyze the impact and mechanisms of biochar in reducing of the harmful effects of the heavy metal cadmium (Cd) during the aging process. Both original and aged biochar conformed to the pseudo-second-order kinetics model and the Langmuir model. The aging process enhanced the adsorption of Cd by biochar and mitigated the leaching of Cd2+ into the soil. These findings provide a scientific basis for evaluating biochar's environmental behavior and its potential use in the remediation of soil contaminated with heavy metals.

An integrated novel approach to the environmental health assessment of Bangladesh's coastal ecosystems

The coastal expanse of Bangladesh, situated along the Bay of Bengal, is a susceptible and low-lying area grappling with multiple environmental challenges. Various physicochemical parameters were employed in the assessment of water quality. The CCME Water Quality Index indicated the western coast as 70.13 (Fair), the Central coast as 42.2 (Poor), and the Eastern Coast as 64.6 (Marginal). This outcome was corroborated by the Environmental Quality Index, with the Western Coast ranked as (Good), the Eastern Coast as (Fair), and the Central Coast as (Poor). The analyzed parameters provided insights into pollution levels, water clarity, nutrient dynamics, and the overall health of the coastal ecosystems. Additionally, the study delved into heavy metal concentrations, encompassing arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), manganese (Mn), lead (Pb), and zinc (Zn). The eastern coast exhibited higher contamination compared to the other two regions, emphasizing potential risks to both the environment and human health. This study aimed to evaluate the environmental health risks and water quality in this region, introducing a novel Environmental Health Risk Index (EHRI) to gauge the overall environmental health conditions. According to the EHRI, the Western Coast exhibited good conditions (2.25), while the Central (3.625) and Eastern (3.5) Coasts were classified as not bad, with the Eastern Coast experiencing comparatively lesser impact. Based on these findings, several recommendations emerge, including the implementation of climate change adaptation strategies such as coastal protection measures, the advocacy of sustainable land use practices, and the enhancement of monitoring and management protocols for water quality.

Accumulation of Cd and Pb in soils irrigated with sewage and non-sewage water in Prayagraj, India

Unmanaged agricultural fields and the extended usage of sewage irrigation water can raise the concentration of heavy metals (Cd and Pb) in the soil, turning it into barren soil. The study was conducted during 2022-23 at four sewage and non-sewage irrigated sites in Prayagraj namely Naini, Baxibandh, Rasulabad and Draupadi Ghat. The representative soil samples were taken at depths of 0-15, 15-30, 30-45 and 45-60 cm. Di-acid mixture method was used for the estimation of heavy metals (Cd and Pb) in the soil sample by AAS (Atomic Absorption Spectrophotometer) (AAnalyst600, Perkin Elmer Inc., MA, USA). Contamination factor (CF) and enrichment factor % (EF) of different sites showed various results which fulfill the basic criteria of present and future prospective of research. The highest concentration of Cd and Pb was found in the surface layer (0-15 cm) of sewage and non-sewage irrigated sites at Naini i.e., Cd (4.46±0.42 and 1.05±0.08 mg/kg) and Pb (6.53±0.62 and 1.18±0.12 mg/kg) respectively. The lowest concentration of Cd and Pb was found in the sub-surface layer (45-60 cm) of sewage and non-sewage irrigated sites at Draupadi Ghat i.e., Cd (1.02±0.09 and 0.16±0.01 mg/kg) and Pb (1.68±0.12 and 0.18±0.01 mg/kg) respectively. The concentration of heavy metals cadmium (Cd) and lead (Pb) declined with soil profile depth in both sewage and non-sewage irrigated soils. The long-term persistence of heavy metal contamination in soil can lead to severe issues; therefore, regular monitoring of sewage-irrigated soils is necessary to minimize heavy metal pollution.

Priority areas identification for arable soil pollution prevention based on the accumulative risk of heavy metals

Preventing impending heavy metal pollution in arable soil is crucial for ensuring food security and avoiding challenging remediation. The key to effective prevention strategies lies in proactive identifying currently unpolluted regions that are susceptible to future pollution, which current methods, predicated on the assessment of static pollution status, inadequately characterize the potential accumulative changes in soil heavy metals. In this paper, we proposed a framework for identifying priority areas based on the discrepancy between pollution status and accumulative risk, by considering the specific factors that influence heavy metal accumulation in soil. We applied this framework to a region of Xiangtan County to pinpoint priority areas for preventing impending pollution. The result revealed certain areas exhibited a relatively higher accumulative risk of heavy metal pollution, despite not having reached severe pollution levels for the heavy metals Arsenic (As), Cadmium (Cd), Chromium (Cr), Mercury (Hg), and Lead (Pb), among which the area ratio reached nearly 6 %, 36 %, 1 %, 3 %, 4 %, respectively. The priority areas for preventing Cd pollution were primarily concentrated in the mid-southern, mid-western, and eastern regions, while that of the other four heavy metals were predominantly distributed in the mid-northern regions with varying continuous ranges. Moreover, we prioritized the main pollution risks for comprehensive prevention in the following order: Cd, As, Pb, Hg, and Cr, and investigated the key factors contributing to the pollution of these heavy metals. The insights presented in this study have significant implications for soil environmental quality management, offering valuable guidance for implementing precise measures to prevent heavy metal pollution and efficiently control pollution sources.

The Effect of Heavy Metals in Potato (Solanum tuberosum L.) Genotypes for Some Physiological Parameters

The main aim of this study is to identify physiological characteristics, including Chl a, b, total Chl "a+b" and carotenoids, in potato genotypes under the influence of lead (Pb+2) and cadmium (Cd+2) heavy metals. Two potato genotypes from the Netherlands, Riviera and Agria, were used in the study. Potato tubers were transferred to 2 kg compost pots and placed in a controlled environment with a 12 photoperiod, a day/night temperature of 25/19°C and a relative humidity of 75%. Since Pb+2 and Cd+2 poisoning was greater than in the control and different fractions of heavy metal residues in the substrate were transferred to plant organs, the amounts of these two metals in each treatment (outside the control) were measured. Plant pigments were extracted from fresh leaves in amounts ranging from 60 to 100 mg and these were then extracted into samples containing 80/20% (v/v) acetone/water with 0.5% w/v MgCO3 at room temperature for a full day. Photosynthetic pigments of each sample were extracted three times. The absorbances obtained at 663 nm, 644 nm and 452.5 nm for the maximum absorption of Chl a, Chl b and carotenoids, respectively, were used to measure the amount of chlorophyll and carotenoids. Differences between Pb+2 and Cd+2 and physiological markers were examined with the Duncan Multiple Range test. Information on Pb+2 and Cd+2 content in applications revealed wide variability. When potato genotype seedlings were exposed to varying levels of Pb+2 and Cd+2, the amount of chlorophyll and carotenoids in their leaves was lower than the control group. The results showed that there were significant and statistically significant changes in carotenoid and chlorophyll concentration at the LSD p = 0.01 level. Similar to Pb+2 and Cd+2 inhibiting plant growth, it had a negative effect on photosynthesis as well as chlorophyll and carotenoid contents. Moreover, these effects became more pronounced when the concentrations of two stress factors (Pb+2 and Cd+2) increased.