Heavy Metals Pb Research Articles

Mangrove areas, heavy metal (Pb) content in seawater and sediments in the Coastal Area of the Bireuen Fisheries Port

Bireuen Regency has the potential for coastal ecosystem resources. There are two Fish Landing Sites (PPI) with very high activity, namely PPI Peudada and PPI Jangka. The high level of activity leads to concerns about pollution, one of which is the presence of lead (Pb) metal. This research aims to assess the characteristics of mangrove areas, seawater samples for heavy metals Pb, and sediments around the coastal fishing port area of Bireuen Regency. The study was conducted in 2024. Research was carried out at two sampling locations of the Fish Landing Sites (PPI), namely the Peudada Fishing Port and the Jangka Fishing Port using purposive sampling methods. At the BARISTAND (Aceh Research and Industrial Standardization Agency) laboratory, samples were analyzed using an AAS (Atomic Absorption Spectrophotometer). The Pb concentrations in seawater and sediment at first Location (Peudada) were <0.0003 mg/L and 2.60 mg/kg, respectively. At second Location (Jangka), the concentrations were <0.0003 mg/L and 1.78 mg/kg, respectively. Observational results indicate that Pb metal contamination in seawater and sediment at locations 1 and 2 is still below the threshold limit set of Ministry of Environment No. 51 in 2004 and RNO in 1981.

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.

ASSESSMENT OF THE CONCENTRATION OF HEAVY METALS IN ELECTRONIC WASTE DUMP SITE IN ALABA INTERNATIONAL MARKET, LAGOS STATE

This research investigates the concentration of heavy metals (Pb, Cu, Cd, and Ni) at e-waste dump sites in Lagos, Nigeria. Measuring the concentration and distribution of heavy metals across different soil depths and comparing these concentrations in soil and water samples. For this purpose, 78 soil samples were taken from different sampling points, and analyses were carried out following standard procedures. The soil samples retrieved from the e-waste site consistently exhibit a sandy soil texture, as per the USDA classification system. It was found that Cu generally has the highest concentrations in the soil layers (2022.20-2312.67mgkg-1) while Cd generally has the least (16.32-22.62 mgkg-1). The elements observed for this study are Cu > Pd >Ni > Cd. Overall, this comprehensive study provides valuable insights into the environmental contamination and health risks posed by e-waste dump sites, emphasizing the need for effective management strategies to mitigate these risks and protect human health and the environment.

Research on the process of modifying the bio-adsorbent of Sauropus androgynus to treat ion heavy metals Pb2+ in water

Research on the process of modifying the bio-adsorbent of Sauropus androgynus to treat ion heavy metals Pb2+ in water

Environmental Impact of Automobile Wastes on Surface Water Quality in Ebonyi State, Southeast Nigeria

ABSTRACTThe negative impact of operations in informal auto mechanic workshops is a major public health concern, and its effect on surface water pollution cannot be overlooked. This current work evaluates the environmental impact of automobile waste on surface water quality in Ebonyi State, Southeast Nigeria. A total of 108 surface water samples were taken in 2022 and 2023 from Abakaliki, Onueke, and Afikpo streams, and WHO as controls using standard analytical methods. Data sets were analyzed using Fisher's Significance Least Difference (F‐LSD) at the 0.05 probability level. The study showed that surface water appearance was slightly brown, and the observed upstream is acidic in nature, the midstream is alkaline, and the downstream is natural. Water samples from Abakaliki, Onueke, and Afikpo streams were observed to be hard since their concentration levels were above the WHO standard. Furthermore, the high concentrations of heavy metals (Pb and Mn) as well as the oil and grease content indicate that the surface water in the area of study is polluted and its overall quality is degraded. The study therefore concluded that automobile waste had a negative influence on the surface water quality in the study area. Based on these new findings, it is recommended that automobile waste be properly treated and disposed of to avoid their adverse effects on surface water quality. In addition, given the uncontrolled development of these informal auto workshops across the nation in recent years, there is a need for the execution of environmental standards connected to automobile service activities.

Analysis and quantification of selected heavy metals and paraphenylenediamine in commercially available herbal black hair dyes in Sri Lanka

Currently, the use of henna-based herbal black hair dyes is widespread in the community. However, it is important to note that these dyes cannot be classified as completely natural due to the addition of various ingredients to enhance their effectiveness. Most black hair dyes use paraphenylenediamine (PPD) to get a black hue, however, PPD is widely recognized as a contact sensitizer. The toxicity of heavy metals is also prevalent in the cosmetics sector. These metallic elements can permeate the skin and provide widespread exposure throughout the body. Hair dye requires an alkaline pH value because of reactions that occur during the dyeing process, which is incompatible with scalp pH. The varying concentrations of these chemicals and their frequency of usage can result in diverse health issues. The present research implemented High-Performance Liquid Chromatography and Atomic Absorption Spectrometry to quantify the concentrations of PPD and heavy metals (Pb, Cd, and Fe) in seven frequently used brands in Sri Lanka. The lead content in the examined samples exhibited variability, ranging from 0.04 ± 0.01 ppm to 0.28 ± 0.14 ppm. However, all the samples remained below the allowed level of 2 ppm according to the BVL standard. Regarding Cd, certain examined materials surpassed the acceptable thresholds, while others did not and varied between 0 ppm and 2.33 ± 1.92 ppm. Iron was found at a significantly higher concentration compared to the other two heavy metals. A significant quantity of PPD was detected, exceeding the allowable threshold of 6 % according to the European Union legislation. All the samples that were analyzed had a pH value within the alkaline range. The study indicates that herbal dyes generated from natural materials may contain harmful compounds, such as a high concentration of PPD in herbal black hair color potentially inducing sensitization.

Preparation of Zeolite A from Ion-Adsorbing Rare Earth Tailings for Selective Adsorption of Pb2+: An Innovative Approach to Waste Valorization.

Ion-adsorbing rare earth tailings (IRETs) contain a large amount of clay minerals, which are a potential source of silicon and aluminum for the preparation of zeolite materials. The complexity of the tailings' composition and the impurity composition are the main difficulties in the controllable preparation of zeolite. Herein, IRETs were treated by classification activation technology for the preparation of IRET-ZEO, which was used for the removal of heavy metal Pb2+ in water. A new method of resource utilization of ion-type rare earth tailings is realized by "treating waste with waste". The results showed that the IRETs were classified and then thermally activated, and the optimal activation parameter was calcination at 850 °C for 1 h. The optimal NaOH concentration used in the crystallization process was 5 mol/L, with a crystallization time of 3 h and a crystallization temperature of 85 °C, and the crystallization product was zeolite A. The removal rate of the Pb2+ solution with an initial concentration of 100 mg/L was as high as 96.7% in an acidic solution with a pH value from 2 to 5.5. In particular, when the solution pH was higher than 4.2, the adsorption rate of Pb2+ was close to 100%. The IRET-ZEO showed a fast adsorption rate (5 min to reach adsorption equilibrium), a large adsorption capacity (378.35 mg/g), excellent acid resistance, and selectivity and regenerability for Pb2+. This work provides a new strategy for the green resource utilization of IRETs and the treatment of lead-containing wastewater.

Cultivation of Microalgae Mixed Culture from Mahoni Small Lake UI Campus Depok using Zeolite Substrate with Varying Pb Concentration

Research on the cultivation of mixed cultures of Situ (small lake) Mahoni UI Campus Depok has been done. This research was a preliminary study to measure and compare the growth of Situ Mahoni mixed cultures microalgae grown in Bold's Basal Medium (BBM) with addition of zeolite and without addition of zeolite, and varying concentrations of heavy metal Pb. The concentrations of heavy metal Pb used were 0 ppm, 20 ppm, 40 ppm, 60 ppm, 80 ppm, and 100 ppm for two treatments. The results of this research were that the growth of mixed cultures with the addition of zeolite had the highest abundance of 8.800 cells/mL on day 5 (T5) at a Pb concentration of 40 ppm. Meanwhile, the growth of mixed culture without the addition of zeolite had the highest abundance of 21.700 cells/mL on day 10 (T10) at a Pb concentration of 60 ppm. The growth of microalgae mixed cultures in the medium without addition of zeolite was higher than using zeolite. The activation of zeolite pores causes the microalgae growth is relatively lower. This work aimed to study the growth of a mixed cultures microalgae in varying concentrations of Pb with and without the addition of zeolite

Performance and hydration mechanism of MSWI FA-barium slag-based all-solid waste binder

Barium slag (BS) and municipal solid waste incineration fly ash (MSWI FA) are hazardous wastes produced in large quantities, with heavy metals such as Ba, Pb, and Cr significantly exceeding acceptable levels, posing a threat to the ecological environment and living organisms. The development of technologies for the harmless disposal and resource utilization of hazardous waste is a current research focus. This study used BS, blast furnace slag (BFS), MSWI FA, and flue gas desulphurized (FGD) gypsum to replace cement in the preparation of solid waste-based binder. The results indicated that the optimal mass ratio was BS: BFS: FGD gypsum: MSWI FA = 14 %:56 %:20 %:10 %. The compressive strengths of the binder at 3, 7,and 28 days were 23.7 MPa, 30.76 MPa, and 38.65 MPa, respectively. Chinese standard HJ557–2010 was adopted to carry out heavy metal leaching experiment on raw materials, the immobilization efficiency of heavy metals Ba, Pb, and Cr were 99 %, 99 %, and 96 %, respectively, and the leachate toxicity was below the Class III groundwater limit. XRD, FT-IR, TG-DSC, XPS, SEM-EDS and other experimental methods were used to study the effect of BS content on the properties of cementable materials. An appropriate amount of BS hydrolyzes during hydration, releasing Ba²⁺ and OH⁻ ions, which activated the BFS, producing AFt and C–(A)–S–H gel. These products interweaved with material particles to fill the pore spaces, enhancing the binder’s mechanical strength and heavy metal immobilization capability. However, when excessive BS was added, the hydration products favored the formation of FS, leading to a decline in binder performance.

Influence of decades-long irrigation with secondary treated wastewater on soil microbial diversity, resistome dynamics, and antibiotrophy development

In arid and semi-arid regions, the use of treated wastewater (TWW) for irrigation is gaining ground to alleviate pressure on natural water sources. Despite said treatment, the existing methods fail to eliminate potentially dangerous contaminants. As such, this study assessed the impact of long-term TWW irrigation (5 and 25 years) on soil physicochemical properties and bacterial resistance to heavy metals (Pb, Cu, Cd) and antibiotics (tetracycline and amoxicillin). The results revealed heightened salinity and conductivity and reduced pH in irrigated soils. TWW induces harmful effects by reducing microbial density and size, leading to the disappearance of sensitive populations. Conversely, resilient populations, which mainly utilize antibiotics as a carbon source, have adapted. Metagenomic 16S amplicon sequencing analysis demonstrated a shift, notably reducing Actinobacteria, Bacteroidetes, and Firmicutes while increasing Acidobacteriota and Patescibacteria in treated soils. Operational Taxonomic Units affiliated with either Halomonadacea, or Saccharimonadacea and Vicinamibacteracea, were defined as indicators of the absence or presence of TWW contamination, respectively. We conclude that TWW irrigation significantly increases bacterial resistance to heavy metals, whereas the impact of antibiotics is nuanced, with antibiotrophy leveraging lower concentrations in treated soils.

Evaluation of Urbanization Influences on Beach Sediment Contamination with Heavy Metals Along the Littoral Zone of Alexandria City, Egypt

The western coastal area of Alexandria City, Egypt, faces significant environmental challenges due to heavy metal (HM) contamination in beach sediments, driven by intensive urbanization, tourism, commercial harbors, and industrial activities. Therefore, this study focuses on geochemically assessing HM levels in sediment samples from 28 sites and employed various descriptive and multivariate statistical approaches, pollution indices, and sediment quality guidelines (SQGs) to identify pollution hotspots, define contamination grades, and assess the quality of beach sediments. The average concentrations of Cd, Co, Cr, Cu, Pb, and Zn were 25.7, 30, 2.2, 7.5, 2.9, and 8.0 times, respectively, compared to the geochemical background (carbonate sedimentary rocks). et al.-Hanuvil Beach, relatively elevated contents of these metals were recorded. In addition, samples showed Zn levels higher than the corresponding probable effect concentration (PEC) and effect range medium (ERM) values, suggesting adverse impacts on biota. The principal component (PC) analysis revealed the anthropogenic origin of Cd, Co, and Pb in PC1, the mixed origin of Cr, Cu, Mn, and Zn in PC2, and the natural source of Fe in PC3. According to the applied single pollution indices, HM contamination grades were ranked in ascending order of Mn < Fe < Cr < Cd < Cu < Pb < Zn < Co. In conclusion, the HMs (Cu, Zn, Cd, Co, Pb, and Cr) in the study area are anthropogenic, attributed mainly to untreated discharge of municipal and industrial wastewater and solid wastes, atmospheric deposition of air pollutants, and tourism activities.

Spatial Distribution of Physical and Chemical Properties of Deep Sea Water in Xisha, South China Sea

Deep sea water (DSW) is a globally utilized source of renewable energy and other resources. To understand the characteristics of DSW resources in the South China Sea, in July 2022, the Guangzhou Marine Geological Survey (GMGS) investigated temperature, salinity, pH, dissolved oxygen (DO), inorganic salts (DIN, PO43−-P, and SiO3-Si), heavy metals (Hg, Pb, As, and Cd), trace elements (Cu, Zn, Fe, Mn, Ni, Se, and Mo), and other related indicators. The results of this investigation elucidate the horizontal and vertical changes in the physical and chemical properties of deep sea water in the Xisha Sea. The surface seawater quality in Xisha was found to be excellent and to meet first-class seawater survey standards. However, the concentrations of various nutrient salts in the surface layer were relatively low. As the seawater depth increased, different trace elements and heavy metals exhibited variations, and the concentrations of various nutrients also gradually increased.

Novel nanoliter spray enhanced microwave plasma ionization mass spectrometry for the simultaneous detection of heavy metals and organic plasticizers in soil: A case study in a lead-acid battery industrial park

Soil pollution is predominantly attributed to the presence of heavy metal elements and organic compounds; However, current detection methodologies are restricted to the identification of only one of these two sources at a time. A novel analytical approach, known as nanoliter spray enhanced microwave plasma ionization mass spectrometry (Nano-Spray-EMPI-MS), has been developed to facilitate the simultaneous detection of both heavy metals and organic pollutants in soil samples. This technique is characterized by its requirement for minimal sample volumes, thereby allowing for efficient and rapid analysis. The research concentrated on the simultaneous analysis of five heavy metals (Pb, Zn, Cu, Cr, and Ni) and three major phthalates (PAEs), specifically DEHP, DBP, and DMP. The detection and quantification limits for the heavy metals were established to be between 0.16-0.57 and 0.53–1.88 μg L−1, respectively, while the limits for the PAEs ranged from 0.02 to 0.05 and 0.07–0.16 μg L−1. Validation of the method's efficacy in soil detection demonstrated recovery rates of 90.9 %–105.7 % for heavy metals and 89.4 %–97.2 % for PAEs. The application of this method analyzing soil samples collected from an area adjacent to a lead-acid battery industrial park in China revealed varying levels of contamination by both heavy metals and PAEs. Notably, Lead contamination was found to be the most pronounced, with a peak concentration of 862.5 mg kg−1 and a correspondingly high pollution index. These findings are significant for evaluating local ecological risks, pinpointing sources of pollution, and formulating effective pollution management strategies in the region.

Mass flow and ecological risk of heavy metals in anaerobic digestion of food waste

Conversion of food waste (FW) to bioenergy via anaerobic digestion (AD) has become a topic of worldwide research interest. However, the content, distribution, and speciation of heavy metals (HMs) in feedstock and digestate samples throughout the AD process are currently unknown. Especially, the potential ecological risk (PER) of solid digestate with potential of land application was vague. Mass flow of HMs (Cr, Cu, Mn, Ni, Zn, As, Cd, Hg, and Pb) were estimated in a two-stage wet AD of FW plant in Shenzhen, China. Furthermore, the PER of the HMs in solid digestate (SD) was studied. The findings revealed that the variation in the HM contents of the intermediates, as well as the comparatively high HM contents of the SD, were mostly influenced by the total solid contents of the samples, since HMs tend to adhere to the solid matrix. As per mass balance, the Cr and Ni contents of the digestate samples were 4.7 and 5.5 times higher than in the feedstock samples, respectively. The remaining metals were within the range of 82.2126.1 %. Furthermore, the enrichment of HMs in SD must be resolved before reclamation. Moreover, the PER of the HMs in SD was 279.6, considered as a considerable risk level, of which Hg and Cd contributed 46.3 % and 33.6 %, respectively. This research presents a case study for quantitatively assessing the distribution of typical pollutants throughout the AD process, and it offers preliminary data for potential environmental issues caused by digestion product recycling.

Pollution characteristics, bioavailability, and risk assessment of heavy metals in urban road dust from Zhengzhou, China.

To analyze contamination levels, spatial distribution characteristics, bioavailability, and risks of heavy metals (Cr, Ni, Cu, Zn, As, Cd, Hg, and Pb), 65 road dust samples were collected and tested by ICP-MS from Zhengzhou in October 2023. The mean concentrations of most heavy metals, except Ni, exceeded their corresponding background values, with the mean concentration of Cd being 7.43 times that of its background. Spatially, for most heavy metals, higher concentrations were concentrated within the central area, and notable pollution hotspots emerged in proximity to construction area. Cr, Ni, Cu, As, and Pb were mostly bound to residual fraction with lower bioavailability, while Cd and Zn were mainly in exchangeable fraction with higher bioavailability. The enrichment factor, geo-accumulation, contamination factor, and pollution load index indicated that Cd and Hg were highly contaminated, particularly Cd, yet the study area remained moderately polluted. The average RI value of 384.66 indicated a considerate ecological risk, and Cd caused the highest potential ecological risk. Both of the non-carcinogenic and carcinogenic risks were insignificant, however, the human health risk of Cr, As, and Pb demand attention. The research results can provide theoretical basis and data support for the pollution prevention and control of urban environment of Zhengzhou.

Assessing Heavy Metal Contamination in Commonly Used Fertilizers for Polyculture Fish Ponds and Its Implications for Human Health: A Comprehensive Investigation.

Over-fertilizing fish ponds can cause pollution, introducing heavy metals into the food chain and posing health risks. The present study investigated the incidence of heavy metals (Pb, Cu, Cd, and Cr) in commonly applied fertilizers, including nitrogen, phosphorus and potassium (NPK), triple superphosphate (TSP), and di-ammonium phosphate (DAP), and their association with heavy metals in water, sediment, and cultured fish species (Catla catla, Labeo rohita, and Cyprinus carpio) in polyculture fish ponds. The study was conducted over 4months, with four groups in triplicates: control (no fertilizer), group 1 (NPK), group 2 (TSP), and group 3 (DAP). Heavy metal analysis was carried out using atomic absorption spectrophotometry before and after fertilizer application. Significantly (p < 0.05) higher levels of heavy metals were observed in water and sediment after applying fertilizers, with the most pronounced results in group 3 (DAP) followed by group 2 (TSP). The concentration of heavy metals was significantly (p < 0.05) higher in group 3 (DAP) fertilizers compared to other groups. Compared to the control, the concentration and bioaccumulation of heavy metals were significantly (p < 0.05) higher in the fertilizer-applied groups, with notably higher levels in group 3 (DAP). Cluster analysis and the correlation matrix did not show any significant association between the heavy metals and the fertilizers, indicating a complex interplay between the biotic and abiotic factors of the system. The health index (HI) value was < 1 in fish muscles of all studied groups, indicating the fish are safe for consumption. The study recommends monitoring and regulating fertilizer use, especially DAP, to prevent heavy metal contamination, and exploring sustainable alternatives to minimize environmental and health risks.

Evaluation of human and ecological health risks associated with the potentially toxic heavy metals in groundwater of Vellore city, Tamil Nadu, India

Groundwater pollution by heavy metals is a significant and alarming threat globally, through its chronic effect on human health and ecosystem. The current study evaluated the identification and risk assessment of heavy metals in groundwater of the Vellore city, Tamilnadu, India. Groundwater samples were collected from 32 locations over a continuous period of 2022–2023 for every three months on seasonal basis. The samples were analysed for pH, Total Dissolved Solids (TDS), Hardness and heavy metals (Al, As, Ba, Cd, Cu, Pb, Al and Zn). The analysed mean concentrations of these heavy metals were found in the order: As > Cd > Pb > Ba >Zn >Al> Cu. Elevated concentrations of heavy metals were observed in 2022, likely influenced by rainfall and land use patterns. Heavy metals such as Al, As, Pb, and Cd exceeded the BIS limits and whereas Ba, Cu, and Zn concentrations remain within desirable limits. Groundwater Quality Index (GWQI) classified 41% as 'unfit for drinking'. Ecological risk indices (ERI) indicate significant contamination in 34% of samples, with Al and Pb being primary contributors. Non-carcinogenic health risk assessments reveal, chronic hazards, where children facing higher risks followed by men and women groups. Carcinogenic risk assessments indices such as Heavy metal pollution Index (HPI) shown 25% of samples in critical quality, Heavy metal Evaluation Index (HEI) evaluated all samples were in low contamination and Contamination Index (CI) shown 72% samples under high contamination posing high risk to humans. Probable Cancer Risk (PCR) values for As, Pb, and Cd exceed acceptable ranges across all demographic groups posing cancer risk to humans particularly children. The present study highlights the need for groundwater treatment and regulatory interventions to mitigate health and ecological risks due to the contamination of heavy metals in Vellore city.

Stabilization of Arsenic and Heavy Metal Contaminated Soil Using Fishery By-Products and Evaluation of Heavy Metal Uptake in Crops

Objectives : Heavy metals eluted from mine waste pollute surrounding soil and water systems, which can spread to crops and have a harmful effect on the human body. The purpose of this study was to evaluate the feasibility of recycling discarded mussel shells(MS) and manila clam shells (MC) as stabilizers for the immobilization of arsenic(As) and heavy metals(Pb, Zn) in soil.Methods : MS and MC were processed with -#10 mesh natural material, -#20 mesh natural material, and -#10 mesh calcined material and treated at 0-10 wt%. After 1 week or 4 weeks of wet curing, it was eluted with 0.1 N HCl and the concentrations of As, Pb, and Zn in the soil were analyzed through inductively coupled plasma optical emission spectroscopy(ICP-OES) analysis. In addition, red lettuce was cultivated in the stabilized soil and the concentration of heavy metals that were transferred to crops was evaluated. The stabilization mechanism was investigated by scanning electron microscopy-energy dispersive X-ray spectroscopy(SEM-EDX) analysis.Results and Discussion : The stabilization efficiency for arsenic and heavy metals was in the order of natural -#10 mesh &lt; natural -#20 mesh &lt; calcined -#10 mesh. The calcined stabilizer showed a high stabilization efficiency of 98% at a 2 wt% treatment level. Pb was not detected in the red lettuce grown in the stabiliz ed soil, and the standard for leafy vegetables (Pb-0.3 mg/kg or less) was satisfied according to the Ministry of Food and Drug Safety. The SEM-EDX analysis revealed that As was stabilized through Ca-As precipitation and heavy metals(Pb, Zn) were stabilized through pozzolanic reactions.Conclusion : Stabilizers developed from MS and MC can be effectively applied to the stabilization of As and heavy metal-contaminated soil, and are expected to be used as economical and environmentally friendly stabilizers.

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.

Green synthesis of CaO nanoparticles from chicken eggshells: antibacterial, antifungal, and heavy metal (Pb2⁺, Cr2⁺, Cd2⁺ and Hg2⁺) adsorption properties

BackgroundChicken eggshells, a common poultry byproduct, are rich in calcium and provide a sustainable source for producing calcium oxide nanoparticles (CaO NPs). Their use in eco-friendly synthesis aligns with the growing emphasis on sustainable materials for environmental and biomedical applications. Objectives: This study develops an eco-friendly method for synthesizing CaO NPs from chicken eggshells, characterizes their physicochemical properties, and evaluates their antibacterial and antifungal activities. It also tests their effectiveness in removing heavy metal ions (Pb2⁺, Cr2⁺, Cd2⁺, and Hg2⁺) from aqueous solutions.MethodsCaO NPs were synthesized by calcining chicken eggshells at 700°C for 7 h. Comprehensive characterization included analysis of crystalline structure, morphology, optical properties, bandgap energy, chemical composition, and thermal stability. Antibacterial and antifungal activities were tested using the well-agar diffusion method. Batch adsorption experiments evaluated heavy metal ion removal under varying conditions of pH, temperature, stirring time, and adsorbent concentrationResultsThe synthesis produced spherical, single-crystal CaO NPs with diameters ranging from 5 to 30 nm and a crystalline size of approximately 20 nm. The nanoparticles had a bandgap energy of about 4.7 eV. Significant antibacterial activity was observed against Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli, with increasing inhibition zones correlating with nanoparticle concentration. The CaO NPs also effectively inhibited Candida albicans. For efficient metal ion removal, the optimal conditions were found to be 30 min at pH 6 with 40 mg of CaO NPs at 25°C, achieving recovery rates of 98% for Pb2⁺, 97% for Cd2⁺, 97% for Cr2⁺, and 97% for Hg2⁺. For near-complete removal, extending the process to 70 min at pH 6 with 40 mg of CaO NPs at 45°C achieved the highest recovery rates: 99% for Pb2⁺, 98% for Cd2⁺, 99% for Cr2⁺, and 99% for Hg2⁺, though this approach involves higher energy and cost.ConclusionCaO NPs derived from chicken eggshells are effective antibacterial agents and adsorbents for heavy metal removal. These findings highlight their potential for sustainable applications in environmental and biomedical fields.