Metals Pb Research Articles

Sensitivity of Daphnia magna: Acute Toxicity Evaluation of 22 Metals

Introduction: All potentially toxic metals in the environment can be discharged in the aquatic ecosystems. Daphnia magna is one of the most sensitive species to toxic chemicals in water and is frequently used in toxicological research and environmental monitoring. Material and Methods: Acute toxicity test for twenty-two metals (Pb, Cd, Ni, Hg, Cu, Fe, Co, As, Cr, Mn, Zn, Al, Pd, Na, K, Mo, Mg, Ca, W, Ir, Ti, Ag) was carried out for Daphnia magna. These elements were checked and ranked in terms of decreased immobilization (EC50) after 24Hr and 48Hr and compared with previous studies. Results: The results were categorized into four groups by the 48Hr EC50s values: highly toxic groups (Ag, Hg, Cu, Cd, Pd) [EC50 < 100 μg.l-1], moderately toxics groups Cr, Fe, Ni, Zn and Pb) [100 μg.l-1<EC50 < 1 000 μg.l-1], low toxic groups (Al, Mn, As, Ti, Co, W and Ir) [1000 μg.l-1<EC50 < 100000 μg.l-1], and minimally toxic groups (Na, Mg, K, Ca, and Mo) [EC50 > 100 000 μg.l-1]. Correlation coefficients (r) between EC values and eight physicochemical properties were also examined. The results obtained in this study were weak. Conclusion: This work adds and confirm data about the toxicities of metals in aquatic ecosystems by using a rapid biomonitoring test.

Assessment of trace metal levels in water, sediment and fish tissue from Lake Small Abaya, Ethiopia

The environmental impact of trace metal contamination is a concern for Lake Small Abaya, Ethiopia, because of nearby agricultural and industrial activities. This study assessed the levels of trace metals (Pb, Zn, Cd, Cu, Fe, Mn, and Cr) in water, sediment, and fish samples, as well as the physicochemical parameters of the water. Samples were collected from five sites and analyzed via graphite furnace atomic absorption spectrometry (GFAAS). The mean concentrations in the water were Zn: 0.6971 mg/l, Fe: 0.5628 mg/l, Cu: 0.1168 mg/l, Mn: 0.2129 mg/l, Pb: 0.0057 mg/l, Cr: 0.0021 mg/l, and Cd: 0.0014 mg/l. In the sediments, the mean concentrations were as follows: Fe, 33.066 mg/kg; Zn, 18.263 mg/kg; Mn, 22.777 mg/kg; Cu, 7.5663 mg/kg; Pb, 0.0751 mg/kg; Cr, 0.0233 mg/kg; and Cd, 0.0183 mg/kg. The fish samples presented mean concentrations of Fe: 21.855 mg/kg, Zn: 12.686 mg/kg, Cu: 0.3185 mg/kg, Mn: 0.9181 mg/kg, Pb: 0.0089 mg/kg, Cd: 0.0075 mg/kg, and Cr: 0.0015 mg/kg. All the metal concentrations were generally below the World Health Organization (WHO) regulatory limits. The physicochemical parameters indicated slightly alkaline to neutral conditions, with electrical conductivity and total dissolved solids within acceptable ranges. These findings suggest that current agricultural and industrial activities do not significantly contribute to trace metal pollution. However, continued monitoring and pollution control measures are recommended to ensure the long-term health and sustainability of the lake. This study highlights the importance of effective environmental management strategies to safeguard this crucial aquatic resource.

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.

Comparative analysis of the physicochemical properties and trace metal content of palm oil, from selected markets in Jos south and Jos north LGA, Plateau state, Nigeria

The quality of palm oil samples collected from three different markets in Jos South and Jos North Local Government Area of Plateau State were analyzed and evaluated using standard analytical laboratory procedures. The relative ranges of the physicochemical values obtained were as follows; Moisture Content (MC): 0.56 - 1.89, Iodine value (IV); 51.88 - 55.57 g I2/100g, Peroxide Value (PV): 0.98 - 4.16 mEq02/kg, Saponification Values (SV): 198.46 - 201.54 mgKOH/g, Acid Value (AV): 9.93 - 57.65, and Refractive Index (RI), 1.4576 - 1.4580. The moisture content, iodin value, pH values and acid values were found to exceed the Standard Organization of Nigeria (SON) permissible limits of moisture content (0.29 mgKOH/g), iodine value (45 - 53 mg I2/100g), pH (5 - 7 mg/L), and acid value (0.7 max mg/L) for edible oils respectively while the refractive index, saponification values, peroxide values falls within the SON allowable limits of refractive index (1.4612-1.4707 mg/L), saponification value (195-205 mgKOH/g) and peroxide value (10 mEq02/kg) respectively . The amounts of trace metals (Cu, Zn, Fe, Pb and Cd) determined in the palm oil using the atomic absorption spectrophotometer ranged from Cu(0.34 - 0.52 mg/l), Zn(1.58 - 2.33 mg/l), Fe(19.18 - 26.74 mg/l), Pb(2.87 - 4.06 mg/l) and Cd(1.58 - 2.24 mg/l). However, the levels of Zn, Fe, Pb and Cd exceeded the WHO/FAO recommended values of (1.50, 1.00, 0.05 and 0.02 mg/L) respectively while only Cu concentration was below the WHO/FAO limits of 2.00 mg/L for trace metals in edible palm oil. Consequently, the results of this study shows that the palm oil consumed from these selected markets does not meet the standard quality specification for edible palm oils and hence can post significant health threat to consumers. Therefore, food regulatory agencies should strengthen their surveillance to promote food and health safety of the populace.

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

Metal contamination in mangrove tissues, seeds, and associated sediments from the Vattanam mangrove forest of Palk Bay, southeastern India: An ecological risk assessment

In the present work, the concentrations of toxic heavy metals in mangrove sediments, mangrove leaves, and seeds collected from five stations in the Vattanam mangrove of Palk Bay, southeastern India, as well as the effects of the monsoon season on toxic heavy metals concentrations were determined. The concentrations were 17.5 μg/g for zinc (Zn), 9.11 μg/g for copper (Cu), and 6.03 μg/g for lead (Pb) in sediments; 10.71 μg/g (Zn) and 8.94 μg/g (Cu) in mangrove leaves; and 26.24 μg/g (Zn) and 17.01 μg/g (Cu) in mangrove seeds. At all sampling stations, the Cd concentration was below the limit of detection. These mangroves seem to have adapted successfully to their environment given their selective intake of only essential metals (Cu and Zn) and the restricted movement of non-essential metals (Cd and Pb). The concentrations of metals were below the maximum residual limits regulated by national and international standard limits.

Drill cuttings from oil exploration improve properties of substrate and growth of Ipê-branco ( Tabebuia roseoalba ) seedlings

ABSTRACT More information is needed on the potential of using drill cuttings (crushed rocks) from the oil industry in agriculture and forestry. An experiment in forest nursery was carried out to evaluate the influence of substrates formulated from onshore gravel on characteristics of Ipê-branco (Tabebuia roseoalba) seedlings (i.e., growth, quality, and nutrition). We used five gravimetric proportions of gravel from drill cuttings mixed with Pinus-bark - commercial substrate (Mecplant® Florestal 3): control with only commercial substrate and zero gravel (G0), 2.5 % gravel (G2.5), 5 % gravel (G5), 7.5 % gravel (G7.5), and 10 % gravel (G10). In general, high proportion of drill cuttings increases density and decrease current moisture and total porosity of the formulated substrates. The drill cuttings proportions G2.5, G5 and G7.5 significantly contributed to the available water and readily available water in these substrates, with percentage values ranging 23 – 30 % higher than the G10 substrate. Increasing the gravel proportion generally resulted in increased pH levels, P, Na, K and metals (Cu, Fe, Ni, Mn, Cd, Zn, Cr and Pb), except for Ca and Mg nutrients that decreased. Heavy metal contents in all substrates did not exceed the permissible values in legal standards. The G2.5 and G5 substrates increased by 20 % approximately the stem diameter and height of seedlings, and G2.5 proportion also affected the root dry mass and Dickson quality index, with values two times higher than G0 substrate. Multivariate analysis proved suitable as a complementary approach to evaluate the seedling quality. Drilling cuttings addition, in general, increased the accumulation of nutrients and heavy metals of the Ipê-branco seedlings, and G2.5 and G5 substrates provided the greatest accumulation of the nutrients P, Ca, Pb and Zn in the shoot, while G2.5 proportion contributed with higher accumulation of N, Ca, Fe, Cr, Mn and Pb in the root. Adding drill cuttings as a conditioning component of the substrate at 2.5 and 5 % proportions is a viable alternative for using this residue to produce high-quality Tabebuia roseoalba seedling.

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.

Synthesis, characterization, and performance of MXene-modified PVC membranes for organic and inorganic separation

This study explores the transformation of polyvinyl chloride (PVC) flat sheet membranes for the first time using MXene, a hydrophilic two-dimensional (2D) nanosheet, to enhance ultrafiltration (UF) performance for wastewater treatment. The loading of MXene in the PVC solution was adjusted from 0 to 0.5 g in order to create modified membranes. The properties and performance of these membranes were thoroughly analyzed using field emission scanning electronmicroscopy (FESEM), contact angle (CA) measurements, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), water permeation flux, Bovine serum albumin (BSA) rejection, and Pb metal ions removal tests. Among the developed membranes, the N2-modified PVC membrane, with 0.4 g of MXene, exhibited the most favorable characteristics, including a contact angle of 65.77° and a porosity of .84.8 %. This membrane achieved the highest clean water permeation flux of 201.3 LMH, along with a 99.9 %, 91.03 % BSA and Pb metal ions rejection rate respectively, and a flux recovery ratio (FRR) of 90.2 %. The incorporation of MXene nanosheets significantly enhanced membrane efficiency compared to neat PVC membranes, demonstrating the promising capabilities of MXene-modified PVC membranes for effective wastewater treatment.

Multiple-Integrated Biomarker Indexes to Assess the Responses of the Flatfish Achirus lineatus during Exposure to Light Crude Oil Water Accommodated Fraction.

In the present study, we evaluated the biological response of Achirus lineatus to water accommodated fraction (WAF) of light crude oil (American Petroleum Institute gravity 35°) during a sub-chronic bioassay (14 and 28 days) at two different concentrations: 5% v/v (1.20µg∙L- 1 expressed as total polycyclic aromatic hydrocarbons [∑25 PAH]) and 10% v/v (6.61µg∙L- 1 [∑25 PAH]). The responses were evaluated through the biomarker response index (BRI), the integrated biomarker response (IBRv2) and the bioconcentration factor (BCF). The results showed an increase in biological response in relation to WAF concentration and exposure time, which resulted in a slight and moderate disturbance in the basal condition and bioconcentration level of metals (Pb > Ni > V > Cd) in fish tissue. Results in the present study denote that flatfish such as A. lineatus may be negatively influenced by spilled light crude oil.

Occupational exposure assessment of heavy metals in human scalp hair among tannery workers in Bahir Dar, Ethiopia: Indication of pollution

Ethiopia, is one of the African countries, has immense potential for skins and hides for the leather industries, which will play a crucial role in converting nations into manufacturing-driven economies through industrialization. The chemicals applied in the tanning process are a serious concern for employees and the community if proper safety measures are not taken. The pollution status of employees working in Anbessa and Bahir Dar tannery factories was evaluated by collecting hair samples. After the hair samples washed with acetone, and deionized water, the hair samples were digested with 4 mL of HNO3 and 2 mL of HClO4 for 1:30 h at 250 °C. The levels of metals (Cr, Pb, Zn, Cu, Ni, and Cd) were subsequently analyzed using a Flame Atomic Absorption Spectrophotometer (FAAS). The mean concentrations of Cu, Ni, Zn, Pb, and Cr in the Anbessa tannery factory workers were 17.34–22.75, 16.38–35.03, 235.4–369.2, 30.46–67.31, and 97.56–189.18, respectively, in the various working departments of the factory. Similarly, the concentrations of Cu, Ni, Zn, Cd, Pb, and Cr in the hair of Bahir Dar tannery workers were 30.1–105.9, 17.88–62.20, 216.9–762.1, 0.35–5.21, 33.42–91.42, and 118.5–305.7, respectively. Chromium was found to be the most accumulated metal next to Zn with in both tannery workers that highlighted significant occupational health risks. The principal component analysis (PCA) analysis provide an insights into the interactions between occupational factors and metal exposure. In conclusion, the results of hair analysis from the employees of tannery factories indicates alarming levels of metal exposure, especially for zinc and chromium, which might pose health problems in long time exposure. Thus, it's critical to monitor occupational activities that can harm human health and the environment.

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.

Preparation of Microelectrolysis Filler Using Coal Slag for the Removal of Hazardous Substances in Contaminated Water.

Presently, the utilization of gasification slag in the context of wastewater treatment is constrained. Furthermore, the presence of dye wastewater and wastewater containing hazardous metals represents a significant threat to human health. Accordingly, the present study prepared a microelectrolytic filler (MF) from gasification slag via a high-temperature roasting method and evaluated its degradation performance in water containing organic matter and harmful metal ions. The impact of varying preparation conditions, including initial solution pH and MF dose, on the degradation process was examined. The removal of methyl blue was found to be 92.21% at an initial pH of 2, a reaction time of 300 min and a dosage of 40 g L-1. The removal of Cu(II), Cd(II), and Pb(II) metal ions was 97.32, 96.58, and 99.38%, respectively, at an initial pH of 4, a reaction time of 180 min, and a dosage of 10 g L-1. Following five cycles, the MF process demonstrated continued efficacy in the removal of dyes and heavy metals from the wastewater. A mechanistic analysis revealed that the water treatment process is not a single adsorption process. Instead, it was found that organic macromolecules undergo chain-breaking reactions, while heavy metal ions undergo redox reactions. The wastewater treatment process comprises a number of distinct strategies, including electrochemical reactions, adsorption, flocculation, and precipitation. These findings illustrate the potential of a gasification slag green recycling approach to treat waste with waste, in alignment with the principles of sustainable development.

Air pollution tolerance and metal accumulation potential of some plant species growing in educational institutions of Amritsar, India.

Poor air quality in urban areas increases the exposure of individuals to air pollutants. Hence, it becomes mandatory to grow such plant species that have more potential to tolerate air pollution and can aid in its mitigation. Air pollution tolerance index (APTI) and anticipated performance index (API) are two indices that help in scientific evaluation of plant species before recommending them for plantation. In this study, six plant species from three educational institutions of Amritsar city were screened for their tolerance and performance against air pollution as well as for their capability to act as accumulators of nine metals viz., aluminium (Al), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn). On the basis of APTI, Cassia fistula (C. fistula) was categorized as a tolerant species while Alstonia scholaris (A. scholaris), Cascabela thevetia (C. thevetia), Monoon longifolium (M. longifolium), Pongamia pinnata (P. pinnata) and Syzygium cumini (S. cumini) were categorized as intermediately tolerant plant species. API results suggested that A. scholaris, C. fistula, M. longifolium, P. pinnata and S. cumini should be planted for air pollution mitigation. Geo-accumulation Index (Igeo) results showed that soil samples were moderately contaminated with three (Pb, Cu and Zn) metals. Bioaccumulation factor (BAF), for all metals among six plant species, was found to be less than one implying that these plants were absorbers of metals. Metal Accumulation Index (MAI) indicated that C. thevetia, C. fistula and P. pinnata exhibited relatively higher potential for metal accumulation.

Effect of co-exposure to multiple metals (Pb, Cd, Cr, Hg, Fe, Mn and Ni) and metalloid (As) on liver function in Swiss albino mice.

The study examined the cumulative toxic effect of multiple elements, As, Pb, Cd, Cr, Hg, Fe, Mn and Ni on the liver function and their association with inflammation and apoptosis. To explore the health consequence of simultaneous exposure to multiple metals and metalloid, male and female Swiss Albino mice were randomly divided into 14 groups and subjected to different doses [MPL (maximum permissible limit), 1×, 5×, 10×, 50× or 100×] of metal(loid)s mixture via drinking water for 8weeks. Data showed that combined effect of multiple elements impaired the liver function. This was associated with significant decrease in the antioxidant enzymes and the elevation in lipid peroxidation for high exposure dose of 50× and 100× (p < 0.05). The metal(loid)s mixture exposure led to significant increase (p < 0.05) in cytokines, TNF-α, IL-6 and effector caspases (3 and 6) in exposure groups above 10× dose. Histopathological observation also revealed significant damage in the hepatic tissue on exposure to high dose. Dose dependent accumulation of respective elements (As, Cd, Cr, and Pb) in the liver was observed in each of the exposure groups. However, similar dose related increment was not observed for essential metals such as Ni, Fe and Mn. Differential accumulation of metals in the liver may be attributed to the effect of co-contaminant exposure, which could affect the divalent cation absorption due to antagonism and competitive transport process. Overall findings in this study manifest the complexity of possible joint effect of co-exposure to multiple metals and metalloid on the liver function.

Toxic heavy metals content in different agrochemicals available in markets of Bangladesh and their loads to the agricultural lands.

A study was conducted to determine the concentration of toxic heavy metals in various agrochemicals available in Bangladesh and to assess the burden of these metals on agricultural soils. An atomic absorption spectrophotometer (AAS) was used to measure the content of 4 toxic metals (Cd, Pb, Cr, and Ni) in the aqueous extract of various agrochemicals. There were significant differences in the amounts of Cd, Pb, Cr, and Ni in different brands of insecticides (mean < 0.01, 3.16, 17.32, and 47.33 µgg-1), fungicides (mean 12.42, 10.19, 9.63, and 243.34 µgg-1), phosphatic fertilizers (mean 25.43, < 0.01, 206.33, and 210.69 µgg-1), micronutrient fertilizers (mean 0.68, < 0.01, 43.43, and 65.79 µgg-1), and plant hormones (mean < 0.01, < 0.01, 9.90, and 43.08 µgg-1). The concentrations of Cd and Ni were on anaverage higher in phosphatic fertilizers, which exceeded the maximum acceptable limit of fertilizers in Bangladesh by 2.5 and 4.2 times, respectively. The study also revealed that the burden of toxic heavy metals from agrochemicals on farm soils was in the following order: phosphatic fertilizers > fungicides > micronutrient fertilizers > plant hormones > insecticides. Among the toxic heavy metals, Ni posed the highest burden on Bangladeshi farm soils due to a single application of different agrochemicals in a year. The average total burden of each metal in the soils of Bangladesh showed a decreasing trend in the order of Ni > Cr > Cd > Pb, resulting in a total metal burden of 22.88gyear-1ha-1. Finally, the study recommended that certification about the content of metals be made mandatory for agrochemical manufacturing firms to ensure that their products entering in Bangladeshi markets are free from toxic metals.

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.