Concentrations Of Pb Research Articles

Potentially Toxic Elements (PTEs) Dispersion in Alluvial Deposits from Abandoned Mining Sites

In the watersheds of abandoned mining districts, it is common to find remains of former facilities and waste dams on stream banks and slopes—a situation that results in the transport and accumulation of metal(loid)s in alluvial deposits. To analyze this problem, an area of the former mining district of Linares–La Carolina (southern Spain) was selected to evaluate the contents and distributions of Ag, As, Ba, Cu, and Pb as potentially toxic elements (PTEs) found in the mineral paragenesis. Specifically, this study focused on the Siles Stream, which runs through a sector where underground mining for the exploitation of galena veins generated abundant mining wastes, mainly waste rock and tailings. Thirty-four sediment samples from the stream bed of the Siles Stream and two sediment samples from the Guadiel River, of which it is a tributary, were analyzed. Floodplain sediments were sampled in the stream banks at the middle and lower reaches (11 samples), as well as the riverine soils developed at the mouth of the Siles Stream (22 samples). The analyzed samples presented high levels of PTEs, in most cases with values much higher than the generic reference levels established by European and regional legislation for PTEs in soils. In the case of Pb, the main metal mined in this district, contents of up to 27,074 mg·kg−1 were observed in the stream bed sediments. Very high concentrations of Pb also appeared in the floodplain sediments, with maximum values in the middle course of the stream, where the concentration reached 43,692 mg·kg−1. With respect to the sediments of the Guadiel river bed, the Pb content was 699 mg·kg−1 before the confluence with the stream and 2537 mg·kg−1 downstream, which clearly reflects the influence of the contributions from the Siles Stream. The enrichment factors (EFs) show that the sediments present a severe to very severe anthropogenic influence for Ag, As, Ba, Cu, and Pb. The geoaccumulation index (Igeo) indicates that the entire basin is extremely polluted by Pb, to which As and Ag are added in the middle course of the stream. The potential ecological risk index (RI) and pollution load index (PLI) based on the contamination factor (CF) suggested that metal loads far exceeded the reference values. Selective chemical extraction methods were used to assess the potential bioavailability of these elements in sediment and soil samples. The results showed high concentrations of Pb in the exchangeable fraction, which poses a significant ecological risk and potential human health risks.

Characterization Analysis of Mudstone and Study of Its Pb (II) Adsorption Characteristics in Polluted Water Bodies

In order to explore a medium material for the efficient treatment of Pb(II) pollutants in groundwater, in this paper, mudstone is selected as the medium material, and the morphological structure of the mudstone is characterizes via X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) analyses to study the feasibility of the mudstone adsorbing Pb(II) ions. Then, static adsorption experiments are carried out to investigate the removal effect of mudstone on Pb(II) in aqueous solutions under different conditions and to determine the optimal adsorption conditions. Finally, the results are fitted and analyzed using a thermodynamic model to explore the adsorption mechanism of the mudstone. The main results of this study are as follows. The main mineral composition of the mudstone used in the experiments includes CaCO3, SiO2, CaAl2O4·10H2O, and CaFe4O7. The specific surface area of the mudstone is as high as 23.027 m2·g−1, the pore size is 9.145 nm, and its surface structure is rough, with pores and fissures developed. The pore space and adsorption capacity of the mudstone were enhanced. When 1 g·L−1 of mudstone was added, the pH value of the solution was 6, the reaction time was 60 min, and the initial concentration of Pb(II) was 30 mg·L−1. The removal efficiency of Pb reached 84.5%, and the adsorption amount was 25.352 mg·g−1. For the removal of Pb(II) from the aqueous solution by the mudstone under different concentrations of Pb(II), the reaction was in accordance with the Langmuir adsorption isotherm model, and the maximum adsorption amount reached 54.975 mg·g−1. The relationship between the removal of Pb(II) and the reaction time was in accordance with the pseudo-second-order rate model. The results of this study suggest that mudstone can be used for the removal of Pb(II) from aqueous media.

Human and Ecological Risk Assessment of Soil and Plants Metal Contamination in a Tropical Municipal Solid Waste Dumping Site

ABSTRACT The growing open waste dumpsite contributes to heavy metal leaching, harming public health and ecosystem services. Hence, the study’s novelty lies in its integrated assessment of heavy metal concentration (Cd, Cr, Cu, Fe, Ni, Pb, and Zn) in soil and plants, incorporating risk assessment using both single and combined indexes in the largest active waste dumpsite in Kelantan, Malaysia. Heavy metal in soil samples Cu (164.896 ± 205.096), Pb (122.177 ± 93.309), and Cr (32.74 ± 26.569) were recorded to exceed the standards, while in the studied plants (castor bean, papaya, pea eggplant, and water spinach), Pb concentrations in all plant parts have surpassed the Malaysia Food Regulation (1985) and FAO/WHO guidelines (2016). Translocation factor (TF) in Cu, Cr, and Pb in water spinach and Cr, Cu, and Cd in pea eggplant have TF > 1. Bioconcentration factor (BCF) was < 1 in pea eggplant and water spinach except for Pb in pea eggplant. Correlation analysis revealed a strong correlation between heavy metals in the soil while contrasts in the plants. The potential ecological risk index (PERI) reveals that the soil waste dumpsite is contaminated with heavy metals. The hazard index (HI) and lifetime cancer risk (LCR) values of heavy metals on the soil surface had negligible non-cancer risks posed to adults and indicate that soil ingestion and dermal absorption were the two primary carcinogenic risk exposure routes. These findings implied that Beris Lalang waste dumpsite is a potential source of toxic pollutants to the environment and the local population. It is recommended to conduct a comprehensive feasibility study and design an implementation plan for leachate treatment plant. Additionally, a comprehensive assessment of the specific contaminants present in the leachate and their potential impacts on the environment should be conducted to inform targeted and effective treatment strategies.

Growth and Phytochemistry of Cymbopogon citratus Stapf Inoculated with Plant Growth-Promoting Bacteria under Different Lead Levels.

This study aimed to investigate the phytochemistry of lemongrass (Cymbopogon citratus) inoculated with Azospirillum brasilense and grown in lead (Pb)-contaminated soil to assess its responses to inoculation under different Pb levels. The experimental design was completely randomized in a 2 × 5 factorial scheme: two levels of A. brasilense (absence or presence) and five Pb levels. After four months of treatment, the following were analyzed: total and reducing sugars, total phenolic content, flavonoids, antioxidant activity, antioxidant enzymes, proline, and essential oil (EO) content and composition. Soil Pb levels and A. brasilense inoculation affected phytochemicals in lemongrass plants. Azospirillum inoculation reduced total sugars in the roots at all soil Pb levels, while increasing Pb levels favored a rise in sugar contents. There was an increase in flavonoid content in treatments associated with Pb and inoculated with A. brasilense. Antioxidant capacity was lower at lower Pb levels, regardless of bacterial inoculation. Enzymatic response was mainly affected by Pb concentrations between 50 and 100 mg kg-1 soil. EO content was influenced by soil Pb levels, with higher EO production at 500 mg Pb kg-1 soil and without A. brasilense inoculation. Overall, lemongrass cultivation in Pb-contaminated areas can be an alternative to phytoremediation and EO production for the industry.

Assessment of the accumulation level and ecological risk of heavy metals in surface sediments of Bong Mieu River, Quang Nam Province, Vietnam.

This study assessed the accumulation levels and ecological risks associated with seven heavy metals (As, Pb, Cd, Hg, Cu, Cr, Zn) in the surface sediments of the Bong Mieu River in Quang Nam Province, Vietnam. The sampling encompassed 10 locations (S1-S10), considering areas both impacted and less impacted by gold mining activities. The findings revealed elevated levels of heavy metal pollution and associated ecological risks attributable to gold mining. Heavy metal content varied within specific ranges: As (70.6-341.2 mg/kg), Pb (216.3-504.1 mg/kg), Hg (0.138-0.252 mg/kg), Cd (0.91-1.51mg/kg), Cu (18.3-45.5 mg/kg), Cr (10.5-19.1 mg/kg), and Zn (49.3-84.1 mg/kg). Among these elements, Hg, Cu, Cr, Zn, and Cd adhered to the acceptable limits of VNTR 43:2017/MONRE (VNTR 43:2017/MONRE: National Technical Regulation/Ministry of Natural Resources and Environment of Vietnam). However, As and Pb content at all locations exceeded these limits significantly, with As being 4.1-20 times higher and Pb 2.3-5.5 times higher. The pollution of Pb and As was attributed to waste discharge from gold mining activities, which carry substantial amounts of these metals in various forms. The Igeo indicated heavy pollution of As and Pb in the sediments. Ecological risk factors were ranked as follows: (As) > (Pb) > (Hg) > (Cd) > (Cu) > (Cr) > (Zn). The potential ecological risk (RI) due to combined heavy metal impact varied across locations, with S2 > S8 > S9 > S6 > S7 > S10 > S1 > S3 > S4 > S5, exhibiting low to moderate risk (RI values ranging from 73.4 to 252.8). The study area demonstrated high contamination levels for As and Pb, coupled with low to moderate potential ecological risks.

Heavy metals in tailings and soils in the Pb-Zn mining areas of North-west Türkiye and health risk evaluations

Improper mining waste and tailing management in Pb-Zn mining areas (Balya and Koru) in the north-west Türkiye have not been researched sufficiently. Accordingly, concentrations of heavy metal were determined in mine tailing and soils taken from Balya and Koru, and a health risk evaluation caused by heavy metals was performed. Average Cd, Cr, Cu, Mn, Ni, Pb, and Zn concentrations in mine tailings in Balya are 35.2, 17.8, 354.7, 1735, 10, 10089, 3730 mg kg-1 and these values were determined as 9.9, 8.9, 101.5, 1308, 4.5, 1871, 1375 mg kg-1 in the tailings in Koru, respectively. The concentrations of heavy metals in the soil samples taken from both Balya and Koru were determined to be lower. The evaluation of heavy metals’ health risks was performed according to both non-carcinogenic and carcinogenic effects. The primary route of heavy metals in adults and children has been determined by oral intake. For both children and adults, the order of the carcinogenic effects of heavy metals in mine tailings and soils in Balya and Koru was Cd &amp;gt; Pb &amp;gt; Ni &amp;gt; Cr. As the carcinogenic risk values of Cd and Pb for adults and children in mine tailing and soils in Balya were above the limit value, the children’s Cd carcinogenic risk values were found above the limit value in mine tailing and soils in Koru. The mining area in both Balya and Koru poses a risk to human health since it is close to settlements.

Assessment of essential and potentially toxic metals in raw cow milk from Mukaturi town, Oromia Regional State, Ethiopia

Cow milk is a complete and highly nutritious source of food for humans. However, the quality of milk products has become a significant health concern for consumers, particularly infants and children, in many developing nations, including Ethiopia. The objective of this study was to determine the heavy metal levels in raw cow milk collected from dairy producers and collection centers in Mukaturi town, Ethiopia. Sixty raw cow milk samples (40.0 milk samples from dairy farms and 20.0 milk samples from collection centers) were randomly collected and digested using a mixture of nitric acid (HNO3), hydrogen peroxide (H2O2) and perchloric acid (HClO4) on a hot plate. The amounts of heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in the milk samples were determined using inductively coupled plasma atomic emission spectroscopy (ICP–OES). The findings showed that the average concentrations of Pb (2.31 ± 0.127), Fe (0.566 ± 0.130), Ni (0.210 ± 0.0189), Cd (0.0372 ± 0.0230), Cr (0.369 ± 0.0162), and Co (0.225 ± 0.0150) in mgL−1 were higher than the allowable limits. This could pose a health risk to the public. However, the concentrations of Mn (0.044 ± 0.0369), Cu (0.195 ± 0.0450) and Zn (2.90 ± 0.0570) in mg L−1 were lower than or within the recommended limits and cannot pose any threat to consumers. The validity of the digestion processes was checked by the recovery test. The percentage recoveries of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were found to be in the range of 80.7–122 %, which is within the acceptable range. Therefore, special attention should be given to the continuous monitoring of heavy metal levels in raw milk among dairy producers and collection centers to minimize economic losses and the risk to consumer safety.

An environmentally benign process for effective recovery and solidification of Cr from stainless-steel slag

Stainless-steel slag is a hazardous solid that has caused severe chromium contamination globally. This study proposes an environmentally benign vitrification process for efficient recycling and solidification of Cr from stainless-steel slag using waste copper slag and coal tar residue. The transformation behaviors of heavy metals (Cr, Cu, Pb, Zn) and the Cr toxic leaching mechanism are also determined in this work. The findings indicated that compared with Cu and Fe phases, the Mg(Al,Cr)2O4 and chemically dissolved Cr phases were not easily reduced via coal tar residue, leading to the leaching of highly toxic Cr3+/Cr6+ during the toxicity characteristic leaching procedure (TCLP). Under optimal conditions, 95.56% Cr, 97.71% Fe, and 99.71% Cu could be recovered in the form of high value-added crude stainless-steel, and 99.62% Pb and 99.19% Zn could be enriched in the dust. The furnace slag TCLP result indicated that the leaching concentrations of Cr, Cu, Pb and Zn were 1.82 mg/L, 0.1 mg/L, 0.38 mg/L, and 2.58 mg/L, respectively. More importantly, the concentrations of residual Cr, Cu, Pb and Zn in the furnace slag were only 0.095 wt%, 0.028 wt%, 0.0192 wt%, and 0.011 wt%, respectively. These findings indicate that treated slag can be categorized as general solid waste, minimizing the environmental risks of heavy metals. The results of this study are significant for the sustainable development of the stainless-steel industry and copper metallurgy.

Evaluation of potentially toxic elements in soils developed on limestone and lead-zinc mine sites in parts of southeastern Nigeria

The present study investigated the distribution of elements and potentially toxic elements (PTEs) in soil profiles in the southeastern region of Nigeria, where unrefined and primitive mining practices are common. Soil samples were collected from mine and non-mine sites in Ameka and Nkalagu and analyzed for total elemental concentration using portable X-ray fluorescence (pXRF). The results showed that the Ameka mine-affected soils were heavily polluted, while the Ameka non-mine-affected soils were moderately polluted. The Nkalagu mine and non-mine-affected soils were also moderately polluted. The potential ecological risk (PER) was high in the Ameka mine-affected site due to elevated As, Cu, and Pb levels, while the Ameka non-mine-affected site had a low PER. The enrichment factor (EF) values indicated more enrichment of PTEs in the mine-affected sites compared to the non-mine-affected sites. The geoaccumulation index (Igeo) showed moderate to extreme contamination in the Ameka mine-affected site with Cu, Zn, As, and Pb. In contrast, the Nkalagu mine-affected site had considerably lower contamination. The regression model showed that site characteristics alone were insufficient to explain elements and PTEs distribution, emphasizing the importance of considering soil properties in understanding their spatial patterns. The study highlights the higher concentrations of As, Cu, and Pb in the mine-affected sites compared to the non-mine areas and recommends remediation strategies for these elements and PTEs, especially in the vicinity of mine sites. Further laboratory analysis is recommended to understand the mobility of PTEs with depth for better remediation approaches.

Assessment of Potential Human Health Risk Associated With Heavy Metals in Soil – Vegetables System Irrigated by Rift Valley Lake Ziway, Ethiopia

Metal contamination of vegetables is a major concern, especially in areas where irrigation has been used for a long time. The Central Ethiopian Rift Valley Region is highly affected due to the heavy use of agrochemicals throughout the year. Although some studies have been conducted on the concentration and level of heavy metal pollution, little attention has been paid to their impact on human health. This study determined the concentrations of nine metals (As, Cd, Cr, Co, Cu, Hg, Ni, Pb, and Zn) in a soils and vegetables (tomatoes and onions) irrigated by Lake Ziway, Ethiopia. An inductively coupled plasma optical emission spectrometer (ICP-OES) was used to determine the heavy metal levels. Moreover, the study evaluated the health risks associated with consuming contaminated vegetables by employing major indices, including non-carcinogenic and carcinogenic risks. The results showed that the mean concentrations of Pb, As, Hg, and Cr in all tomato and onion samples and the average Zn, Pb, Cd, and Hg levels in all soil samples exceeded the FAO/WHO threshold. Non-carcinogenic health risk estimates showed that As, Pb, Hg, and Co for children and Pb and Co for adults had THQ values greater than 1, indicating the possibility of systemic health risks. Carcinogenic health risk showed that Ni posed a risk of developing cancer for both adults and children, with values ranging from 10−3 to 10−1. In addition, children are likely to have a higher cancer risk due to exposure to As and Cr. Therefore, it is crucial to raise awareness among stakeholders and implement effective monitoring policies to safeguard public health both within and beyond the study area.

Conversion of metal-enriched magnetite mine tailings into suitable soil for vegetation by phytoremediation process with Bougainvillaea glabra under the influence of Thiobacillus ferroxidance

Magnetite mining is a significant contributor to land deterioration as well as HM-based soil contamination. The characteristics of magnetite mine tailing were examined in the present study, in addition to the positive and sustainable restoration strategy with Bougainvillaea glabra under the influence of Thiobacillus ferroxidance. The traits of test soil analysis findings demonstrated that the majority of the parameters exceeded the allowable limits (For instance: HMs such as Cr, Cu, Zn, Pb, Fe, and Co were found to be 208 ± 2.3, 131.43 ± 1.6, 185.41 ± 3.3, 312 ± 5.11, 956 ± 5.3, and 26.89 ± 2.43 mg kg−1 respectively). T. ferroxidance exhibited impressive HMs tolerance for as much as 800 g mL−1 concentrations of Cr, Cu, Zn, Pb, Fe, and Co. To prevent HMs toxic effects, the HMs contents in test soil were decreased by diluting with normal soil in the ratios of Ex-3 and Ex-2. A typical greenhouse study was carried out to assess the phytoremediation ability of B. glabra across six setups for experiments (Ex-1 to Ex-6). According to the findings of this research, the HMs tolerant T. ferroxidance from Ex-3 and Ex-2 had an outstanding impact on the growth, biomolecules level (such as chlorophylls: 65.84 & 41.1 mg g−1, proteins: 165.1 & 151.1 mg g−1, as well as carbohydrates: 227.4 & 159.3 mg g−1) as well as phytoremediation potential of B. glabra on magnetite mine soil. These findings indicated that a mixture of B. glabra as well as T. ferroxidance might serve as a valuable sustainable agent for removing HMs from contaminated soil.

Exploiting the role of plant growth promoting rhizobacteria in reducing heavy metal toxicity of pepper (Capsicum annuum L.).

Microorganisms are cost-effective and eco-friendly alternative methods for removing heavy metals (HM) from contaminated agricultural soils. Therefore, this study aims to identify and characterize HM-tolerant (HMT) plant growth-promoting rhizobacteria (PGPR) isolated from industry-contaminated soils to determine their impact as bioremediators on HM-stressed pepper plants. Four isolates [Pseudomonas azotoformans (Pa), Serratia rubidaea (Sr), Paenibacillus pabuli (Pp) and Bacillus velezensis (Bv)] were identified based on their remarkable levels of HM tolerance in vitro. Field studies were conducted to evaluate the growth promotion and tolerance to HM toxicity of pepper plants grown in HM-polluted soils. Plants exposed to HM stress showed improved growth, physio-biochemistry, and antioxidant defense system components when treated with any of the individual isolates, in contrast to the control group that did not receive PGPR. The combined treatment of the tested HMT PGPR was, however, relatively superior to other treatments. Compared to no or single PGPR treatment, the consortia (Pa+Sr+Pp+Bv) increased the photosynthetic pigment contents, relative water content, and membrane stability index but lowered the electrolyte leakage and contents of malondialdehyde and hydrogen peroxide by suppressing the (non) enzymatic antioxidants in plant tissues. In pepper, Cd, Cu, Pb, and Ni contents decreased by 88.0-88.5, 63.8-66.5, 66.2-67.0, and 90.2-90.9% in leaves, and 87.2-88.1, 69.4-70.0%, 80.0-81.3, and 92.3%% in fruits, respectively. Thus, these PGPR are highly effective at immobilizing HM and reducing translocation in planta. These findings indicate that the application of HMT PGPR could be a promising "bioremediation" strategy to enhance growth and productivity of crops cultivated in soils contaminated with HM for sustainable agricultural practices.

On the electrokinetic remediation of Pb-contaminated soil: A coupled electro-transport-reaction modelling study based on chemical reaction kinetics

The accumulation of lead (Pb) in soil resulted from industrialization and urbanization poses a threat to human health and the ecosystem. This study proposes a mathematical model for Pb migration and transformation in soil porous media, aiming to guide the design of electrokinetic remediation schemes for Pb-contaminated soils. To improve the validity of the model, the chemical reactions considered in the model are all based on chemical reaction kinetics, which were usually overlooked for model simplification. The model quantitatively describes various physical and chemical processes of Pb at the soil-pore fluid interface and in the pore fluid, including diffusion, electromigration, electroosmosis, electrolytic water reaction, precipitation, adsorption/desorption, protonation/deprotonation reaction, and water self-ionization reaction. The numerical results show that the pH value is a key factor affecting the distribution of Pb in the soil and determining the removal efficiency of Pb. The effects of different enhancement methods on Pb concentration distribution and removal efficiency were evaluated with this model. It was found that placing a cation exchange membrane at the cathode boundary while using 0.01 M nitric acid as anode electrolyte can effectively improve Pb removal efficiency from 3.9% to 93.6%. The developed model can be used to guide the design of the enhanced electrokinetic remediation schemes.

Combating heavy metals in wheat grains under drought – is alien or ancient germplasm a solution to secure food and health?

Alien and ancient wheat germplasms have been utilized to combat diseases and improve yield performance under climate change. However, the potential risk of excessive heavy metal uptake with these germplasms has been less studied. In order to ensure food security, this study aimed to evaluate the levels of cadmium (Cd), lead (Pb) and mercury (Hg) in 30 wheat lines, including modern, old and wheat-rye introgression genotypes grown under three conditions i.e., control, early drought and late drought. The results of this study revealed a generally higher Cd grain accumulation in old and 1R genotypes than in the other genotype groups evaluated here, while old genotypes also showed an excess Pb grain concentration. The induced late drought resulted in an increased Cd uptake in wheat, leading to significantly elevated grain Cd concentration in modern, 1R, 1RS and 2R genotypes, while similar results were not obtained for the other heavy metals e.g. Pb or Hg. Specifically, an old genotype, 207, showed an extremely high Cd value across control and drought conditions. There was a greater genotypic variation in Pb concentration compared to Cd, while consistently high Hg concentrations were observed in several genotypes carrying 1R or 1RS. Some wheat-rye introgression genotypes, particularly those with the 3R chromosome, showed a low Cd accumulation across all treatments. The results from the present study pin-point the necessity of a rigorous assessment of heavy metal accumulation in wheat grain when utilizing ancient and alien genetic resources in breeding for disease resistance, and wheat resilience to environmental stress and climate change. Furthermore, the specific lines identified in this study with elevated heavy metal accumulation should be avoided in breeding programs. Additionally, mechanisms for the found differences in heavy metals accumulation among genotypes and treatments should be further revealed.

Lead Contamination in Meat and Offal from Game (Ruminants), Destined for Raw Feeding of Dogs and Retailed in Austria

Bullet-derived lead (Pb) is a food safety hazard in meat from hunted wild game. Dogs can be exposed to alimentary Pb when fed with meat from wild game. We studied Pb contamination in 47 commercial “bones-and-raw-food” (BARF) packages from wild game meat and offal sold in Austria. Samples were first tested with a metal detector (calibrated for 2.5 mm diameter objects), then by X-ray, and Pb content was determined in sample areas free from metal-dense particles (as assessed in radiographs). Three samples tested positive by the metal detector (particle sizes ranged from 3 mm × 2 mm × 2 mm to 10 mm × 8 mm × 5 mm), with two particles from lead and one from tombac. Metal-dense objects were found in radiographs of 35/47 samples. In 13/47 samples, particles &gt; 1 mm in diameter, and in 33/47 samples, smaller ones (median of five particles per sample) were noted. Lead content was above 1.5 mg/kg wet weight in 19/47 samples and exceeded the limit for general animal feed of 10 mg/kg wet weight in 5 of these 19 samples. The Pb contents as well as the presence of metal particles indicate that there is a feed safety issue in the samples analyzed. By a metal detector, the presence of large fragments was indicated in three samples, which casts doubt on whether all producers use a metal detector to scan the packages before delivery.

Assessment of heavy metals and human health risk associated with the consumption of crops cultivated in industrial areas of Maputo, Mozambique

This study aimed to evaluate heavy metals concentrations in soils and vegetables (cabbage, lettuce, and cassava) cultivated at Matola and Beluluane Industrial Parks, and to assess health risks linked to their consumption through estimated daily intake, hazard index (HI), and incremental lifetime cancer risk. Concentrations of Al, As, Co, Cd, Cr, Ni, Pb, and Zn were determined in the two sites. Soil concentrations of As at Beluluane site and As, Cd, and Cr at Matola site exceeded reference limits of the Food and Agriculture Organization/World Health Organization, showing heavy metal contamination. At Beluluane site, all studied vegetables presented As and Pb levels higher than reference limits, Cd concentrations were higher than the reference limit in cabbage, lettuce, and cassava leaves. At Matola site crops concentrations of As, Cd, Cr, and Pb exceeded the reference limits. Zinc exceeded the reference limit in all crops except in cabbage. HIs for vegetables from Beluluane exceeded 1.0 in cabbage (2.66), lettuce (2.27), and cassava leaves (2.37). Likewise, at Matola, HIs exceeded 1.0 in lettuce (1.67), cassava leaves (1.65), and root tubers (13). We found that vegetables cultivated in industrial parks present high carcinogenic risk due to heavy metal contamination, rendering them unsuitable for human consumption.

Occurrence of heavy metals in sanitary napkins from seven countries: Implication for risk management of female hygiene products

Chemicals in sanitary napkins are easy to enter women's bodies, as these products are in contact with the skin of vagina and vulva directly, which has strong absorption capacity. However, available information regarding the occurrence of metals in sanitary napkins and their potential hazards, remains very limited. This study measured the concentrations of As, Co, Cu, Pb, Cd, Zn, Ni and Cr in sanitary napkins collected from seven countries. Moderate levels of Pb, Cd, Zn and Cr and lower levels of other metals were found, in comparison to the metal concentrations reported for other products previously. Metal concentrations differed by producer, price and fragrance. These metals were originated mainly from the introduction of raw materials and the use of chemical additives during the manufacturing process. Relative to other skin-contacted products, the sanitary napkin contributed more to women's total metal exposure, although the exposure was lower than that of dietary intake. The summed non-carcinogenic risks from six metals and the carcinogenic risks from Pb were acceptable. However, more research is required to investigate metals in sanitary napkins and the associated health risks to women, owing to the variability in the metal concentrations and the complexity of actual exposure.

Analysis of heavy metals and pathogen levels in vegetables cultivated using selected water bodies in urban areas of the Greater Accra Metropolis of Ghana

Open-surfaced water sources have been used to irrigate vegetable farms in cities. Open-surface water often contains unmonitored concentrations of health-threatening contaminants that pose health risks, especially when used to produce vegetables for human consumption. However, information on levels of heavy metals and faecal coliform bacteria in such vegetables in selected sites, especially in Greater Accra Metropolitan Area (GAMA) of Ghana is rare. This study examines the levels of heavy metals and faecal coliform in two vegetables-lettuce and bell pepper - that were cultivated using open-surface wastewater from drains and constructed reservoirs at different locations of the GAMA. Using concurrent mixed methods, questionnaires were administered to 67 vegetable farmers, followed by the collection of vegetable samples from three urban farm sites, Haatso and Dzorwulu and Weija irrigation scheme site (WISS) for laboratory analysis. The concentrations of Lead (Pb), Mercury (Hg) and Cadmium (Cd) were determined using atomic absorption spectroscopy after microwave digestion of the vegetables while total faecal coliform was quantified using MacConkey-Endo broth method. The results from all three sites showed that the concentrations of Cd (=0.001 μg/mg) and Pb (=0.005 μg/mg) in lettuce were within the World Health Organization's (WHO) permissible levels. However, the Hg (≥0.309 μg/mg) and faecal coliform (>5 count/100 ml) in the vegetables from all three sites exceeded the WHO permissible limits. Therefore, consumers of vegetables from such urban farms are exposed to health risks associated with Hg and faecal coliforms. There is the need to intensify education on the health risks of consuming vegetables produced from open-surface water sources from the observed sites. The enforcement of existing phytosanitary standards to enhance food safety and the quality of urban vegetables is also recommended.

Concentrations, source identification and environmental risk assessment of potentially hazardous elements in agricultural soils of Hamedan, west of Iran

ABSTRACT In the current study, a total of 40 agricultural surface soil samples were collected from 40 sites in Hamedan, Iran and the contents of As, Cd, Cr, Cu, Ni, Pb, and Zn were determined by ICP-OES. The average contents of all the analysed elements except Pb were found to be greater than those in the background contents reported for Iran, which could presumably show the anthropogenic sources of these elements. The average EF and PI values decreased in the order of As > Cr > Cu > Cd > Zn > Ni > Pb, while, the rank order of the mean I-geo values followed the order of As > Cr > Cu > Zn > Cd > Ni > Pb. Additionally, the cumulative mean values of RI with 175, demonstrated ‘moderate ecological risk’ across the investigated area. The results of PCC, PCA, and HCA showed that the traffic and agricultural activities could be regarded as the most important anthropogenic factors that affected the content of PTEs in the agricultural soils. In conclusion, an accurate investigation on the probability of the environmental risks due to the agricultural soil pollution by other PTEs and persistent organic pollutants (POPs) is recommended for future works.

Organic Materials Promote Rhododendron simsii Growth and Rhizosphere Soil Properties in a Lead-Zinc Mining Wasteland.

The mining of metal minerals generates considerable mining wasteland areas, which are characterized by poor soil properties that hinder plant growth. In this study, a field plot experiment was carried out in the mining wasteland of the Lanping lead-zinc mine in Yunnan Province to study the effects of applying three organic materials-biochar (B), organic fertilizer (OF), and sludge (S)-at concentrations of 1% (mass fraction), on promoting the soil of mining wasteland and the growth of two plant varieties (Huolieniao and Yingshanhong). The results showed that the amount of available nutrients in the surface soil of a mining wasteland could be considerably increased by S and OF compared to the control check (CK). In the rhizosphere soils of two Rhododendron simsii varieties, the application of S increased the available phosphorus (P) content by 66.4% to 108.8% and the alkali-hydrolyzed nitrogen (N) content by 61.7% to 295.5%. However, the contents of available cadmium (Cd) and available lead (Pb) were reduced by 17.1% to 32.0% and 14.8% to 19.0%, respectively. Moreover, three organic materials increased the photosynthetic rate and biomass of two R. simsii varieties. Specifically, OF and S were found to significantly increase the biomass of R. simsii. Organic materials have direct impacts on the increased plant height and biomass of R. simsii. Additionally, organic materials indirectly contribute to the growth of R. simsii by reducing the content of available Cd and available Pb in rhizosphere soil while increasing the content of available nutrients according to the structural equation model (SEM). Overall, S can stabilize Cd and Pb, increase soil nutrient contents, and promote the growth of R. simsii effectively, and has great potential in the vegetation reconstruction of mining wasteland.