Pb Kg-1 Research Articles

Toxic elements in children’s crayons and colored pencils: Bioaccessibility assessment

Crayons and colored pencils for children may contain toxic elements (TEs) exhibiting potential risk for children?s health including cognitive development, after their ingestion, through mouthing and chewing and eventually, their accumulation. The aim of this study was to determine total content of As, Pb, Cr, Cd, Ni and Sb and estimate their bioaccessibility conducting artificial saliva extraction. Sixty samples of colored pencils and crayons from 10 manufacturers were analyzed. Microwave acid assisted digestion followed by inductively coupled plasma optical spectroscopy (ICP-OES) was performed for determination of total content of TEs. Simulation of extraction by artificial saliva was applied to get more reliable data when bioavailability is concerned. The total concentrations of TEs were higher in colored pencils than in crayons and their maximum levels were: 5.78, 9.36, 9.97, 0.615, and 6.63 mg kg-1 for As, Pb, Cr, Cd and Ni, respectively. Concentration of Sb was below the detection limit for all investigated samples. This study showed that concentration of As and Pb in several samples did not comply with European Union regulative. Bioaccessibility study showed the high degree of leaching of Cr and As from pencils, but regardless of extracted portions, concentrations of selected investigated TEs were below allowed levels.

Interactive Effects of Soil Lead and Cadmium on Dry Matter Yield and Metal Content of Indian Mustard (Brassica juncea (L.) Czern)

Lead (Pb) and cadmium (Cd) are known to influence each other’s uptake by plants when they coexist in the soil in significant amounts. This influence can be useful if it is antagonistic but may be detrimental if synergistic. In a screenhouse, interactive effects of soil Cd (0, 10, 25, 50 and 100 mg kg-1) and Pb (0, 25, 50, 100 and 200 mg kg-1) were studied on dry matter yield (DMY), Cd and Pb content in Indian mustard (Brassica juncea (L.) Czern) grown for 60 days in a loamy sand soil. The DMY was recorded and plants were analyzed for total Cd and Pb contents. In equilibrated soil there was significant increase in the mean DTPA-Cd and DTPA-Pb with increase in levels of their respective spiking. The content of DTPA-Cd increased significantly where different combinations of Cd and Pb were applied whereas, DTPA-Pb significantly decreased when Pb was applied in combination with Cd. At Cd+200 mg Pb kg-1 soil and Pb+100 mg Cd kg-1 soil, the mean shoot DMY of Indian mustard decreased by 55.8 and 57.7 per cent, respectively as compared to control. The mean shoot Cd content of Indian mustard increased by 9.9 per cent with application of Cd+200 mg Pb kg-1 soil while the mean Pb content decreased by 10.4 per cent with application of Pb+100 mg Cd kg-1 soil as compared to their respective single treatments. The post-harvest soil DTPA-Cd and Pb decreased as compared to their pre-sowing contents but considerable residual contents still remained in soil. An additive adverse effect of the metals on DMY, Pb and Cd content of the crop was observed.

Direct Ultratrace Detection of Lead in a Single Hair Using Portable Electromagnetic Heating Vaporization-Atmospheric Pressure Glow Discharge-Atomic Emission Spectrometry.

In this paper, the first demonstration of direct ultratrace determination of lead in a single human hair by direct current-atmospheric pressure glow discharge-atomic emission spectrometry (DC-APGD-AES) coupled with electromagnetic heating vaporization (EMV) was described. Only the ultramicro mass of a human hair sample (about 0.15 mg, often a single human hair) was required during the analysis, and fast detection was implemented without tedious pretreatment processes, such as grinding and digestion. A limit of detection (LOD) of 30.8 μg kg-1 (4.8 pg) for Pb was obtained under optimized conditions, which was even equivalent to that of conventional LA-ICP-MS/ETV-ICP-MS/GFAAS. EMV-APGD-AES, meanwhile, can facilitate miniaturization and portability with low power and small size. The accuracy and practicality of the method were verified by the analysis of certified reference materials (CRMs) GBW09101b (human hair) and human hair samples from three volunteers. A simple, efficient, and low-cost method for detecting Pb in human hair has been developed.

The changes of rhizosphere characteristics contributed to enhanced Pb accumulation in Athyrium wardii (Hook.) Makino after nitrilotriacetic acid application.

Chelant-assisted phytoremediation may modify plant rhizosphere, which is closely related to heavy metal (HM) accumulation in plants. This work focused on the effects of nitrilotriacetic acid (NTA) on rhizosphere characteristics to investigate the mechanisms of lead (Pb) accumulation in Athyrium wardii (Hook.) Makino with exposure to 800 mg kg-1 Pb. After NTA application, Pb accumulation in the underground part of A. wardii increased by 14.3%, accompanying with some changes for the rhizosphere soils. Soil pH decreased by 0.37 units, and the dissolved organic carbon (DOC) content in the rhizosphere soils significantly increased by 7.6%. The urease, acid phosphatase, and catalase activities in the rhizosphere soils significantly increased by 104.8%, 19.7%, and 27.1%, respectively. However, a slight inhibition on microbial activities was observed in the rhizosphere of A. wardii after NTA application. Soil respiration decreased by 8.9%, and microbial biomass carbon decreased by 8.9% in the rhizosphere soils, indicating that NTA addition might recruit some microorganisms to maintain rhizosphere functions in Pb-contaminated soils while inhibiting others with low tolerance to Pb. Results suggest that lower pH, more DOC exudation, and higher soil enzyme activities after NTA application contributed to the increase of Pb accumulation in A. wardii. This study gave some preliminary evidence for NTA-assisted Pb remediation by A. wardii by modifying rhizosphere characteristics.

Adsorption Characteristics and Mechanism of Cd and Pb in Tiered Soil Profiles from a Zinc Smelting Site

Vertically tiered soil profiles, comprising miscellaneous fill (S1), plain fill (S2), silty clay (S3), and completely weathered slate (S4), were collected from a zinc smelter site in Zhuzhou City, Hunan Province, and their Cd and Pb adsorption characteristics were examined. Static batch experiments were conducted with different initial Cd and Pb solution concentrations, at temperatures of 288-308 K and pH values of 2-6. The results showed that a pseudo first-order model could be fitted to the kinetics of Cd/Pb adsorption in these soils. The soil profiles had a large retention capacity for Cd and Pb. The Cd and Pb adsorption isotherms for these soils conformed to the Freundlich isotherm, with maximum adsorption at 298 K of 2097-4504 mg ·kg-1 for Cd and 4376-10564 mg ·kg-1 for Pb, based on the Langmuir isotherm. The adsorption capacity of Cd and Pb increased with an increase in initial pH and temperature. The Cd and Pb adsorption process were a spontaneous physical and chemical process, and the soil profiles were ranked by their Cd and Pb adsorption capacities in the following order:completely weathered slate (S4)>miscellaneous fill (S1)>silty clay (S3)>plain fill (S2). The variation in adsorption capacities resulted from the differences in physical and chemical properties of the soil, mainly Fe/Al content and cation exchange capacity. Fourier transform infrared and SEM-EDS analysis showed that the main adsorption mechanism is the exchange of Cd and Pb with Fe/Al, while -OH/C＝O sites in soils were the predominant adsorption sites for Cd and Pb. In the study area, exogenous Cd and Pb discharged by smelting activity accumulated predominantly in surface soil, and their concentration gradually decreased with depth. These results provide a scientific basis for the prevention and control of heavy metal pollution in the soil and groundwater of a smelting site.

EFFECTS OF WASHING TREATMENT ON THE CHARACTERISTICS OF ROADSIDE FRESH FRUITS

R oadside fruits are very possible to be contaminated by heavy metals and microbial contamination, especially fruits that are usually consumed unpeeled , such as grapes, water guava, apples, and starfruit. Heavy metal contaminants that are hazardous to health include lead (Pd), cadmium (Cd), and arsenic (As), while harmful microbial contaminants include Escherichia coli and Salmonella thypi i . This study aims to determine the effect of washing treatment on the characteristics ( heavy metal and microbial contamination ) of some fresh fruit. Washing process using running water and food grade soap. The design of the study used is Randomized Block Design, if it had a significant effect, it was further tested using the Duncan Multiple Range Test (DMRT). The results of study showed that w ashing with food grade soap is preferable, as it shows a significant reduction in the levels of heavy metal and microbiological contents up to 0.000 mg / kg for Pb and Cd; 0.041 mg / kg for As; 0 kol / g for E. coli and 0 kol / 25g for Salmonella thypi i .

Evaluation of sedimentation role of DREISSENA molluscs' population in the process of water quality control in Kakhovka Main Channel (Kherson Region)

Ukraine has a unique natural resources potential and is one of the world's richest agricultural countries in terms of soil composition and land bioproductivity. More than 2/5 of its agricultural land is located within the steppe zone – a zone of unstable and insufficient humidification. The production of agricultural products under arid conditions largely depends on solving the problem of agricultural land artificial irrigation. Due to this, since the 1960s large-scale construction of amelioration facilities took place in Southern Ukraine, including construction of the Kakhovka Reservoir and the Kakhovka Irrigation System, the largest one in Europe. The quality of water intended for irrigation depends on a water source and internal physicochemical/biological processes observed in the amelioration system. The attached bivalve molluscs present an important biotic component of hydrotechnical amelioration systems. They form dense settlements on solid artificial substrates and are usually considered as a source of biological barriers that should be constantly fought against. However, their filtration and sedimentation role can exert influence on the processes of water self-purification. The study aims at evaluating the role of filtering molluscs fouling process when it comes to treatment of irrigation water from suspensions and removal of some heavy metals from the water column. The research is based on the results of field analysis of deposits sedimentation processes in the water column with the help of sedimentation traps at 5 stations along Kakhovka Main Channel. It was found that the total biomass of settlements of attached bivalve molluscs Dreissena polymorpha and Dreissena bugensis that are present in the channel constitutes about 370 – 463 tons and they contribute to precipitation of 11.6 – 27.5 tons of suspended matter to the bottom sediments during summer months. This process is manifested in a decrease of suspended matter concentration in the water along the channel. Together with suspended matter 1.8 – 3.9 kg of Cr, 0.3 – 0.6 kg of Ni, 0.09 – 0.24 kg of Co, 0.08 – 0.18 kg of Pb, 0.088 – 0,144 kg of Cd also join the bottom sediments every month. Thus, the settlements of molluscs attached to the hydraulic structures can be considered as biological amelioration agents contributing to the improvement of irrigation water quality.

Salinization depresses soil enzyme activity in metal-polluted soils through increases in metal mobilization and decreases in microbial biomass.

Salinity may increase metal mobilization with a potentially significant consequence for soil enzymatic activity and nutrient cycling. The goal of this study was to investigate changes in soil enzyme activity in response to salinization of a clay loam soil artificially polluted with cadmium (Cd) and lead (Pb) during a 120-day incubation experiment. Soil samples were polluted with Cd (10 mg Cd kg-1), Pb (150 mg Pb kg-1), and a combination of Cd and Pb, then preincubated for aging and eventually salinized with three levels of NaCl solution (control, low and high). NaCl salinity consistently increased the mobilization of Cd (12-22%) and Pb (5-16%) with greater increases at high (17-22% for Cd, 9-16% for Pb) than low (12% for Cd, 5-7% for Pb) salinity levels. While the increased Cd mobilization was greater in co-polluted (22%) than Cd-polluted (17%) soils, the increase of Pb mobilization was lower in co-polluted (9%) than Pb-polluted (16%) soils at high salinity level. The salinity-induced increases in metal mobilization significantly depressed soil microbial respiration (up to 43%), microbial biomass content (up to 63%), and enzymatic activities (up to 87%). The multivariate analysis further supported that the increased soil electrical conductivity, Cd mobilization, and pH after salinization were the most important factors governing microbial activity and biomass in metal-polluted soils. Results showed that changes in microbial biomass and mobile metal pool with increasing salinity had a major effect on enzyme activities, particularly under the combined metals. This study indicated that the secondary salinization of metal-polluted soils would impose an additional stress on enzymatic activities as biochemical indicators of soil quality, and therefore should be avoided for the maintenance of soil microbial and biochemical functions, especially in arid regions. In metal-polluted soils, the observed responses of extracellular and intracellular enzymes to salinity can be used to advance our knowledge of microbial processes when modeling the carbon and nutrient cycling.

Use of native plants and their associated bacteria rhizobiomes to remediate-restore Draa Sfar and Kettara mining sites, Morocco.

Soil and mine tailings are unreceptive to plant growth representing an imminent threat to the environment and resource sustainability. Using indigenous plants and their associated rhizobacteria to restore mining sites would be an eco-friendly solution to mitigate soil-metal toxicity. Soil prospection from Draa Sfar and Kettara mining sites in Morocco was carried out during different seasons for native plant sampling and rhizobacteria screening. The sites have been colonized by fifteen tolerant plant species having different capacities to accumulate Cu, Zn, and P in their shoots/root systems. In Draa Sfar mine, Suaeda vera J.F. Gmel., Sarcocornia fruticosa (L.) A.J. Scott., and Frankenia corymbosa Desf. accumulated mainly Cu (more than 90mg kg-1), Atriplex halimus L. accumulated Zn (mg kg-1), and Frankenia corymbosa Desf. accumulated Pb (14mg kg-1). As for Kettara mine, Aizoon canariense L. mainly accumulated Zn (270mg kg-1), whereas Forsskalea tenacissima L. was the best shoot Cu accumulator with up to 50mg kg-1, whereas Cu accumulation in roots was 21mg kg-1. The bacterial screening revealed the strains' abilities to tolerate heavy metals up to 50mg kg-1 Cu, 250mg kg-1 Pb, and 150mg kg-1 Zn. Isolated strains belonged mainly to Bacillaceae (73.33%) and Pseudomonadaceae (10%) and expressed different plant growth-promoting traits, alongside their antifungal activity. Results from this study will provide an insight into the ability of native plants and their associated rhizobacteria to serve as a basis for remediation-restoration strategies.

Spirulina platensis Alleviating Effect To Rocket Plant (Eruca Vesicaria ) Grown On A Pb-Polluted Soil

Lead (Pb) is a hazardous heavy metal causing environmental pollution in various sources. A 3-factor pot experiment was conducted to asses the use of Spirulina platensis for alleviating Pb pollution on rocket plant (Eruca vesicaria ) grown in pots (10-kg pot-1). Factors and treatments were (1) Pollution (L): non-polluted (L0) and polluted soil with 400 mg Pb kg-1 (L1) as PbCl2 (2) Priming (P):none (P0), priming (soaking) of rocket seeds in 40 mgL-1(P1) and 80 mgL-1 (P2) (3) .Spirulina foliar spray (F) : with distilled water (F0), 40 mg L-1 (F1) and 80 mgL-1 (F2). Spirulina alleviated contamination andincreased growth and photosynthetic pigments and activity as well as increased activity of carboxylating enzymes (Phosphoenol pyruvate carboxylase (PEPC, EC 4.1.1.31) and ribulose1,5-bisphosphate carboxylase (RuBPC, EC 4.1.1.39) and NPK Highest positive effect was by the the combination of foliar and soaking at 80mg/l of Spirulina platensis solution.

Assessment of selected heavy metal concentrations in soils from a mining area in Minna, Niger state.

The study investigated the contents of selected heavy metals in top soils and sub-soils around the vicinity of artisanal gold mining site in Minna, Niger state, using standard procedures. Digestion was done using HNO3-H2O2-HCl and heavy metal content using atomic absorption spectrometer. The results obtained showed some extent of contamination with mean values of 2.87 ± 0.17mg kg-1, 286.21 ± 0.20mg kg-1, 15,375.46 ± 0.52mg kg-1, 2233.60 ± 0.46mg kg-1, and 131.71 ± 0.15mg kg-1 for Cd, Zn, Fe, Mn, and Pb, respectively. The surrounding environment (50m away from the gold mining site) also showed significant contamination with mean values of 2.77 ± 0.17mg kg-1, 295.27 ± 0.20mg kg-1, 11,523.64 ± 0.25mg kg-1, 1956.50 ± 0.54mg kg-1, and 74.63 ± 0.15mg kg-1 for Cd, Zn, Fe, Mn, and Pb, respectively. The values obtained were significantly higher when compared with those from the control soil samples. With the exception of Pb and Mn, the values of the other metals investigated were all below the WHO permissible limit. The trend of contamination with respect to contamination factor was in the order: Zn > Fe > Pb > Mn > Cd. The high contents of Pb and Mn in this area therefore show the need for more studies and immediate intervention measures.

Vermicompost Buffering Capacity to Reduce Acidification of Pb and Cd Contaminated Inceptisols and Entisols

Contamination of heavy metals on the soil leads to an increase in its acidity. Vermicompost application is commonly used to improve the properties of soil. The study was carried out to determine the reduction of the acidity in Pb and Cd contaminated soils under the application of vermicompost. Two laboratory experiments were set using Completely Randomized Design (CRD) with two factors. The first factor was soil samples, vis Inceptisols, and Entisols, and the second factor was the rates of vermicompost, consisted of 0, 5, 10, 15 g kg-1. The treatment combination was repeated three times. The soils were pretreated with 10 mg kg-1 Pb or Cd using Pb(NO3)2 and Cd(NO3)2. Three hundred kg soil sample was incorporated with vermicompost and placed in a 500 ml plastic bottle. The mixtures were incubated for eight weeks, and the moisture of the soil was maintained at field capacity. The acidity and soil temperature were monitored every week. The study indicated that Pb contaminated soil acidity increased to the sixth week of the incubation and decreased afterward. However, the acidity of Cd contaminated soil was consistently increased during the incubation. Treatment of vermicompost significantly lowered the acidity of both Pb and Cd contaminated soils. Contaminated Entisols had a higher response to the application of vermicompost than that of Inceptisols. This finding is significant in assessing acidity risk and possible management intervention for Pb and Cd contaminated soils.

Atmospheric emission inventory of hazardous air pollutants from biomass direct-fired power plants in China: Historical trends, spatial variation characteristics, and future perspectives

The agricultural and forestry biomass direct-fired power generation represents an important technology to promote the low-carbon energy transition and agricultural waste reuse in China. In recent years, emissions of hazardous air pollutants (HAPs) caused by the rapid biomass industrialization have attracted increasing attention. To investigate the characteristics of HAPs emitted from biomass power plants in China, a multiple-year comprehensive emission inventory including NOx, SO2, PM, PM10, PM2.5, and trace elements (As, Cd, Cr, Cu, Hg, Pb, Zn) has been established for the period of 2006–2017. As a result of the emission standard (GB13223-2011), emissions of conventional HAPs have declined since 2014. The results show that national total emissions in 2017 were estimated at 29,516.0 t of NOx, 14,192.1 t of SO2, 4100.7 t of PM, 2353.9 t of PM10, 1630.6 t of PM2.5, 3057.2 kg of As, 1622.8 kg of Cd, 8285.8 kg of Cr, 54,443.4 kg of Cu, 132.9 kg of Hg, 66,325.8 kg of Pb, and 175,587.9 kg of Zn, respectively. The majority of HAPs emissions have been concentrated in eastern, northeastern, and central areas of mainland China. Shandong, Heilongjiang, and Anhui represent the top three provinces with the highest HAPs emissions from 2012 to 2017. Besides, the future emissions in 2025 and 2035 under the ultra-low emission policy are predicted with scenario analysis.

Bioaccumulation and Human Risk Assessment of Heavy Metals in Oreochromis niloticus and Clarias gariepinus Fish Species from the Golinga Reservoir, Ghana

ABSTRACT The Nile tilapia (Oreochromis niloticus) and African catfish (Clarias gariepinus) from the Golinga reservoir in Northern Ghana are consumed as an alternative source of protein. In the current study, levels of selected metals (As, Cd, Fe, Co, Cr, Cu, Mn, Mo, Ni and Pb) in the two fish species and the fish condition were determined, and potential human health effects assessed. The metal concentrations in the edible fish muscles ranged from 0.16 mg kg-1 (Mn) to 101 mg kg-1 (Pb). The weight-length relationships showed that both fish were growing isometrically, and bioaccumulation of metals from the reservoir was considered insignificant with bioconcentration factors below 100 except for Mn, whose value was 161 in the gills of Oreochromis niloticus. The health risk assessment showed that Pb, Cd and As had Target Hazard Quotient values above 1 for both fish species, with that of As being as high as 19.6 for Oreochromis niloticus. The target cancer risk values for As, Cd, Cr and Pb were above the non-risk threshold of <10-6, indicating the risk of cancer developing over the years due to fish consumption. The metal concentration in the fish in the reservoir should therefore be constantly monitored and potential health risks associated with frequent consumption of the fish assessed. Keywords: fish; health risk assessment; Nile tilapia; Target Hazard Quotient; trace metals

Alleviation of lead toxicity and phytostimulation in perennial ryegrass by the Pb-resistant fungus Trichoderma asperellum SD-5.

Lead (Pb), a highly toxic metal ion, is detrimental to plants and humans. Existing botanical techniques for Pb-contaminated soil remediation are limited in their efficiency. Here, we investigated the use of the fungus Trichoderma asperellum Samuels, Lieckf & Nirenberg SD-5, which we identified previously as being Pb-resistant, for phytoremediation and for its effects on plant growth, Pb adsorption, and physiological responses in perennial ryegrass (Lolium perenne L. 'Lark'). We set up four soil treatments: CK (uncontaminated by Pb), T1 (1000 mg kg-1 Pb), T2 (1:9 ratio of sawdust to T1), and T3 (T2 inoculated with T. asperellum SD-5). A pot experiment revealed that the addition of the Pb-resistant microorganism promoted growth and increased biomass in ryegrass under Pb stress, in addition to significantly enhancing photosynthesis by increasing the leaf chlorophyll content and improving the total protein content and expression of the pAPX, POD, SOD, and GPX genes, evidence of an improved antioxidant system and the alleviation of Pb stress. We demonstrated that Pb-resistant microorganisms can enhance Pb extraction from the soil, thus improving remediation. Mitigation mechanisms operating at the physiological and gene expression levels were also determined, providing a scientific basis for the role of combined plant-microorganism methods in remediating Pb-contaminated soil.

Status, source, human health risk assessment of potential toxic elements (PTEs), and Pb isotope characteristics in urban surface soil, case study: Arak city, Iran.

The current study was conducted to assess the level of potentially toxic elements (PTEs) contamination (Cu, Pb, Zn, Cr, As, Cd, and Ni) in surface soils from Arak city. Arak, which is an industrial city, is a prominent center of chemicals, metal/electric, manufacturing factories, and other industries. Forty-three surface soil samples were collected from 0-20cm after removing the visible surface contamination in the dry season in June 2017. Metal concentrations were found highly variable, ranging from 174-3950mg/kg for Cu, 181-3740mg/kg for Pb, 48-186mg/kg for Zn, 105-1721mg/kg for Ni, 0.8-0.9mg/kg for As, 114-1624mg/kg for Cr, and 3.45-12.36mg/kg for Cd. The results of geochemical fraction indicated that the main components of Pb, Cr, and Zn at most of the sampling sites are Fe-Mn bound/reducible. Meanwhile, the residual fraction is the dominant fraction of sequence extraction for Ni, Cu, and Cd. Higher values of reducible bound for Pb, Cr, and Zn, as well as a considerable percentage of Ni, Cu, and Cd, imply that the main source of the studied PTEs (except As) in the study area is both anthropogenic and geogenic inputs. The results of principal component analysis (PCA), correlation analysis, enrichment factor (EF), enrichment index (EI), and top enrichment factor (TEF) confirm that Pb, Ni, Cu, Cr, Cd, and Zn had a similar anthropogenic source which is confirmed by geochemical fractionation analysis. Carcinogenic risks (CR) of studied PTEs were estimated to be higher than the target limit of 1.0E-06, for adults and children except for Cr with values of 5.91E-04, and 3.81E-04 for children and adults, respectively. Higher CR values of Cr compared to other PTEs in Arak surface soil demonstrate that living target populations, including children and adults, particularly children, are more at risk of carcinogenic risks of PTEs. 206Pb/207Pb ratios of the collected samples indicated that Pb in Arak surface sample was derived from industrial inputs and deposition, as well as re-suspension vehicle exhaust emission from previously leaded gasoline. The findings concerning the applied end-member contribution of geogenic and industrial and vehicle emission represented that the contribution could vary from 68.0% to 15% (mean: 39.3) for industrial emission, 65% to 19% for vehicle exhaust (mean: 39), and 46% to 10% (mean: 21.6) for geogenic sources.

Health risk assessment of potentially toxic elements in common cultivated rice (Oryza sativa) emphasis on environmental pollution

Heavy metal accumulation and contamination is a global serious dilemma due to toxicity, abiotic characteristics, abundant resources, and cumulative behavior of heavy metals. This evaluation aimed at measuring and evaluating seven heavy metals (Ni, Cu, As, Zn, Pb, Cr, and Cd) content in rice (Oryza sativa) and associated health risks was carried out for consumers in Khuzestan Province, Iran. We choose 20 stations in 5 strategic regions of rice cultivation. The average carcinogenic risk of arsenic by rice consumption in Khuzestan Province was estimated to be 3 adults and 4 children per 10,000 populations. The average concentrations of heavy metals in rice and rice field soils were as follows: In rice: Ni (0.38 ± 0.25), Cu (5.29 ± 3.04), As (0.087 ± 0.066), Zn (17.89 ± 3.35), Pb (0.17 ± 0.08), Cr (0.69 ± 0.25) and Cd (0.058 ± 0.027) mg kg-1.In soils: Ni (49.32 ± 16.71), Cu (36.69 ± 19.74), As (5.02 ± 3.42), Zn (71.20 ± 12.72), Pb (10.99 ± 4.299), Cr (81.23 ± 22.31), and Cd (0.18 ± 0.072) mg kg-1, respectively. Nickel showed the highest standard deviation of the SPI with an average of 2.38 ± 0.81. The average CPI for rice was in the following descending order: Cd (0.95 ± 0.45)> Ni (0.92 ± 0.64)> Pb (0.84 ± 0.41)> Cr (0.69 ± 0.25)> As (0.65 ± 0.52)> Cu (0.53 ± 0.31)> Zn (0.36 ± 0.068). Cadmium and nickel respectively showed the highest and lowest BAF with an average of 0.302 and 0.0067. According to the US Environmental Protection Agency (USEPA) classification, the overall HI for adults in four regions was at Level 3 (medium) and for children in two regions at Level 4 (high). The corresponding values for cadmium were 5 adults and 8 children per 100,000 populations. This means that rice consumption in Khuzestan Province could cause cancer during the lifetime of rice consumers.

An Overview of Cadmium, Chromium, and Lead Content in Bivalves Consumed by the Community of Santa Rosa Island (Ecuador) and Its Health Risk Assessment

Santa Rosa Island community members derive their income and livelihoods from bio-aquatic resources, principally bivalves of the genus Anadara, both for subsistence use and commercial purposes. Bivalve mollusks have a sedentary lifestyle and feed by filtering water, meaning they absorb all surrounding substances, including harmful elements like toxic metals. This study aimed to analyze different-sized samples of Anadara tuberculosa and Anadara similis, sediment, and Rhizophora mangle leaves to determine their total amount of cadmium, lead, and chromium as a first approach to the evaluation of the health risk related to the consumption of bivalves. For both species from four sampling sites, the results revealed metal concentrations in the bivalves between 0.211 and 0.948 mg·kg-1, 0.038 and 0.730 mg·kg-1, and 0.067 and 0.923 mg·kg-1 for Cd, Cr, and Pb, respectively. The calculated potential risk (>1) for cadmium, considering all body weights, showed a high health risk for consumers. In the case of lead, the results showed a high health risk in children. There was no risk found for chromium. For sediments, the mean values were 2.14, 29.99, and 12.37 mg·kg-1 and for the Rhizophora mangle leaves were 2.23, 4.22, and 3.35 mg·kg-1 for Cd, Cr, and Pb, respectively. These results did not show a relation with the metal content in bivalves.

An overview of cadmium, chromium, and lead content in bivalves consumed by the community of Santa Rosa Island (Ecuador) and its health risk assessment

Santa Rosa Island community members derive their income and livelihoods from bio-aquatic resources, principally bivalves of the genus Anadara, both for subsistence use and commercial purposes. Bivalve mollusks have a sedentary lifestyle and feed by filtering water, meaning they absorb all surrounding substances, including harmful elements like toxic metals. This study aimed to analyze different-sized samples of Anadara tuberculosa and Anadara similis, sediment, and Rhizophora mangle leaves to determine their total amount of cadmium, lead, and chromium as a first approach to the evaluation of the health risk related to the consumption of bivalves. For both species from four sampling sites, the results revealed metal concentrations in the bivalves between 0.211 and 0.948 mg·kg-1, 0.038 and 0.730 mg·kg-1, and 0.067 and 0.923 mg·kg-1 for Cd, Cr, and Pb, respectively. The calculated potential risk (>1) for cadmium, considering all body weights, showed a high health risk for consumers. In the case of lead, the results showed a high health risk in children. There was no risk found for chromium. For sediments, the mean values were 2.14, 29.99, and 12.37 mg·kg-1 and for the Rhizophora mangle leaves were 2.23, 4.22, and 3.35 mg·kg-1 for Cd, Cr, and Pb, respectively. These results did not show a relation with the metal content in bivalves.

Potential role of compost mixed biochar with rhizobacteria in mitigating lead toxicity in spinach

Consumption of heavy metals, especially lead (Pb) contaminated food is a serious threat to human health. Higher Pb uptake by the plant affects the quality, growth and yield of crops. However, inoculation of plant growth-promoting rhizobacteria (PGPR) along with a mixture of organic amendments and biochar could be an effective way to overcome the problem of Pb toxicity. That’s why current pot experiment was conducted to investigate the effect of compost mixed biochar (CB) and ACC deaminase producing PGPR on growth and yield of spinach plants under artificially induced Pb toxicity. Six different treatments i.e., control, Alcaligenes faecalis (PGPR1), Bacillus amyloliquefaciens (PGPR2), compost + biochar (CB), PGPR1 + CB and PGPR2 + CB were applied under 250 mg Pb kg-1 soil. Results showed that inoculation of PGPRs (Alcaligenes faecalis and Bacillus amyloliquefaciens) alone and along with CB significantly enhanced root fresh (47%) and dry weight (31%), potassium concentration (11%) in the spinach plant. Whereas, CB + Bacillus amyloliquefaciens significantly decreased (43%) the concentration of Pb in the spinach root over control. In conclusion, CB + Bacillus amyloliquefaciens has the potential to mitigate the Pb induced toxicity in the spinach. The obtained result can be further used in the planning and execution of rhizobacteria and compost mixed biochar-based soil amendment.