Total Lead Concentrations Research Articles

The Effect of the Type of Organic Residues and the Level of Lead on the Growth of Yellow Corn mays Zea L.

For the purpose of studying the behavior of lead in the two study soils in Basrah Governorate, southern Iraq, soil samples were collected from two sites in Basrah Governorate (Al-Zubair and Kutayban) with different chemical and physical soil properties, and their content was estimated. Of total lead, a pot experiment was carried out that included growing the yellow corn crop (mays Zea L.) in pots filled with three kg of air-dry soil from the two study soils, treated with organic waste (cow waste and wheat straw waste) at a level of 0.40 tons ha−1. Then lead was added to the two study soils at a level of 0, 50, and 100 mg Pb kg−1 soil. The experiment continued for 60 days, after which plant growth measurements were taken, as well as the amount of total and ready lead remaining in the soil. The results of the study showed that adding lead at a level of 50 mg Pb kg−1 soil significantly increased the total lead concentration compared to the comparison treatment, and the Zubair soil was superior to the Kutayban soil in terms of dry weight and absorbed quantity. The levels of materials added from cow manure and wheat straw to the two soils of the study had a significant effect. In the concentration of lead compared to the comparison treatment, with the difference in the effect of the two substances, the cow manure 40 tons ha−1 outperformed the rest of the treatments and gave the highest growth characteristics, as the dry weight of the plant and the amount absorbed reached 8.806 mg pot−1 and 2.281 mg pot−1, respectively.

Distribution and transformation of potentially toxic elements in cracks under coal mining disturbance in farmland.

The ground cracks resulting from coal mining activities induce alterations in the physical and chemical characteristics of soil. However, limited knowledge exists regarding the impact of subsidence caused by coal mining on the distribution of potentially toxic elements (PTEs) fractions in farmland soil. In this study, we collected 19 soil profiles at varying depths from the soil surface and at horizontal distances of 0, 1, 2, and 5m from the vertical crack. Using BCR extraction fractionation, we determined the geochemical fractions and total concentrations of Chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd) and lead (Pb) to investigate their ecological risk, spatial fraction distribution, and main influencing factors. Results showed that the values of Cd appearing in 68.7% of the samples were higher than 40 and less than 80, presented a moderate ecological risk. Chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), and lead (Pb) were mainly bound to residual fractions (> 60%) with lower mobility and Cd was dominated by F1 (acid-soluble fractions, 50%) and F2 (reducible fractions, 29%) in surface soil (0-20cm). The geochemical fractionation revealed that the mobile fractions (F1-acid-soluble and F2-reducible) of PTEs were primarily located near the crack, influenced by available potassium. In contrast, the less mobile fractions (F3-oxidizable and F4-residual) exhibited higher concentrations at distances of 2 and 5m from the crack, except for arsenic, influenced by the presence of clay particles and available phosphorus.

Phytoremediation potential and vegetation assessment of plant species growing on multi-metals contaminated coal mining site

This study aims to evaluate the plant species potential to accumulate, concentrate and translocate the heavy metals around the coal mining contaminated site with heavy metals at Harnoi, Abbottabad. The phytosociological surveys involve the systematic study of plant communities within the particular area to show their composition, structure and distribution showed that the contaminated coal mining-associated area was poor in vegetation. Among these, 11 plant species with higher important values (IV) are collected with associated soil and analyzed for the total concentrations of Cadmium (Cd), Copper (Cu), Chromium (Cr), Lead (Pb) and Nickel (Ni) using Atomic Spectrophotometer. The phytoremediation indices (BAF, BCF, TF and TI) were used to evaluate the multi-metals hyperaccumulator and stabilizer plant species. Dodonaea viscosa was evaluated as multi-metals (Cd, Cu and Ni) stabilizer. While the Ajuga bracteosa and Sonchus espera, Sisybrium officinale and Platango ovata stabilize Cd and Cr respectively. The other plant species that can stabilize as single heavy metal are Ajuga bracteosa and Sonchus espera (Cd), Sisybrium officinale and Platango ovata (Cr) and Amaranthus spinosus (Ni) respectively. While the multi-metals accumulator plant species are Bidens pilosa (Cu, Pb and Ni), Chenopodium ambrosioides (Cd, Cu and Ni), Amaranthus spinosus (Cd, Cu and Cr), Ajuga bracteosa (Pb and Ni) and Rumex hastatus (Cd and Ni). However, the single heavy metal accumulator plant species are Sonchus espera (Pb), Conyzea Canadensis (Ni), Platango ovata and Malvastrum coromandelianum (Cu) respectively. These plants could find valuable applications in practical phytoremediation for the remediation near mining tailings at Abbottabad. Moreover, the use of local plants is a promising approach not only for in situ accumulation and stabilization of heavy metals but also for tolerance and environmental adaptations in the contaminated area.

Long-term changes in water quality downstream of three abandoned metal mines

Abandoned metal mines pollute rivers with both acidic and circumneutral metal-rich waters, sometimes from well-mapped mines, but often from long-abandoned adits with limited historical records. Changes in water quality over the monitored timescales were calculated for three mines across Wales (Nantymwyn, Parys Mountain and Frongoch), each abandoned since the early 20th century. Using all available spot sampling data provided by the environmental regulator, it was found that there was a sustained input of metals to the receiving watercourses with no or limited reduction in the concentrations from the mines without remediation, despite the passage of time and impacts of weathering. At Nantymwyn, comparison with five months’ sampling in 2019 showed no significant change (p > 0.05) in metal concentrations compared to the same months in 1985. Parys Mountain showed an increase in filtered zinc concentrations of 2 % between 2004 and 2020. At Frongoch, however, a substantial reduction in its environmental impact was observed after remediation, including a 90 % reduction in total lead concentrations. Realisation that the pollution from these sites does not reduce over the decades since abandonment should galvanize the resolve to understand the highest priority sites, and where possible remediate them.

Heavy Metal Pollution in Soils near Ilesha Gold Mining Area, Nigeria

Background The discovery of extensive gold deposits has raised concerns about potential heavy metal contamination in waterways and adjacent soils, particularly in developing nations like Nigeria where environmental regulations may not be stringent enough. Objective A research study was conducted to assess the levels of heavy metals in surface soils (0 to 25 cm deep) across 30 sites within three selected areas (Epe, Igun, and Ijana) located in the gold mining region of Ilesha, Osun State Nigeria. Methods The study employed an atomic absorption spectrophotometer to measure the total concentrations of heavy metals, specifically arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn). Furthermore, the research encompassed an examination of various physicochemical properties of the soil samples, including organic matter content, pH levels, organic carbon content, calcium content, phosphorus levels, cation exchange capacity, and particle size distribution. Results Results showed a range mean concentration with standard deviation of As, Cd, Co, Cr, Cu, Ni, Pb and Zn of 1.0 – 7.1 ± 1.77 mg kg-1, 0.9 – 4.2 ± 0.84 mg kg-1, 1.0 – 6.0 ± 1.29 mg kg-1, 1.1 – 6.4 ± 1.57 mg kg-1, 2.90 – 20.9± 4.00 mg kg-1, 1.1 – 6.4 ±1.56 mg kg-1, 0.7 – 6.7 ±1.26 mg kg-1 and 11.7 – 70.7± 17.75 mg kg-1, respectively. The investigation of soils in three specific locations revealed significant contamination by heavy metals. However, it is worth noting that the concentrations of these metals fell below the established intervention levels outlined by environmental protection agencies such as the World Health Organization and the Food and Agriculture Organization. The distribution of heavy metals and their availability exhibited a direct correlation with the distance from the mining sites, spanning from 0 to 900 meters. Two critical factors influencing the concentration of heavy metals in these areas were identified as soil particle size, specifically the clay percentage, and pH levels. Conclusion Despite the presence of heavy metal pollution in the soils of Epe, Igun, and Ijana, they managed to maintain metal levels below the intervention thresholds set by environmental protection agencies, with the exception of cadmium (Cd).

Preterm Birth and Metal Mixture Exposure among Pregnant Women from the Navajo Birth Cohort Study.

Preterm birth (PTB), defined as birth before 37 wk gestation, is associated with hypertension, diabetes, inadequate prenatal care, unemployment or poverty, and metal exposure. Indigenous individuals are more likely to have maternal risk factors associated with PTB compared with other populations in the United States; however, the role of environmental metals on PTB among pregnant Indigenous women remains uncertain. Previous research identified associations between PTB and individual metals, but there is limited investigation on metal mixtures and this birth outcome. We used a mixtures analysis framework to investigate the association between metal mixtures and PTB among pregnant Indigenous women from the Navajo Birth Cohort Study (NBCS). Maternal urine and blood samples were collected at the time of study enrollment and analyzed for metals by inductively coupled plasma dynamic reaction cell mass spectrometry. Bayesian Profile Regression was used to identify subgroups (clusters) of individuals with similar patterns of coexposure and to model association with PTB. Results indicated six subgroups of maternal participants with distinct exposure profiles, including one group with low exposure to all metals and one group with total arsenic, cadmium, lead, and uranium concentrations exceeding representative concentrations calculated from the National Health and Nutrition Examination Survey (NHANES). Compared with the reference group (i.e., the lowest exposure subgroup), the subgroup with the highest overall exposure had a relative risk of PTB of 2.9 times (95% credible interval: 1.1, 6.1). Exposures in this subgroup were also higher overall than NHANES median values for women 14-45 years of age. Given the wide range of exposures and elevated PTB risk for the most exposed subgroups in a relatively small study, follow-up investigation is recommended to evaluate associations between metal mixture profiles and other birth outcomes and to test hypothesized mechanisms of action for PTB and oxidative stress caused by environmental metals. https://doi.org/10.1289/EHP10361.

ASSESSMENT OF HEAVY METAL POLLUTION IN SOIL AT A REFUSE DUMPSITE IN UNIVERSITY OF CROSS RIVER STATE (UNICROSS), CALABAR, SOUTH-SOUTH, NIGERIA

Total concentration and pollution indices of mercury (Hg), lead (Pb), chromium (Cr), cadmium (Cd), arsenic (As), nickel (Ni), and cobalt (Co) in dumpsite soil located in University of Cross River State, Calabar were evaluated in this work. Soil samples were collected at 0 - 15cm depth from two sampling stations at the dumpsite once in the months of April, August and December, 2021 and analyzed to the closest mg/kg using Atomic Absorption Spectrophotometer (AAS). The concentrations of the heavy metals showed that Cd>Pb>Ni>Cr>As>Co. All the concentrations of the heavy metals examined when compared with those of average value of heavy metals in shale showed that all the metals were lower than their corresponding world average value except Cd. Geoaccumulation index indicated unpolluted to moderately polluted for all metals studied except Cd which indicated strong to very strongly polluted. Contamination factor for Cd indicated very high contamination. Contamination degree for site 1 and 2 indicated considerable degree of contamination and moderate degree of contamination respectively. Pollution load index values investigated were within the baseline level for all the stations. The heavy metal pollution is attributable to the waste deposited at the dumpsite located in the institution. It is recommended that the dumpsite be relocated to another location that is far away from the residential area and from drinking water sources like boreholes.

Evaluation of pollution with some heavy metals for soils and plants of agricultural Locations in Basrah province

To Evaluate the state of pollution with heavy metals (Zn, Cr, Cu, Ni, Pb), ten Locations with different chemical and physical properties were selected from the agricultural Locations of Basrah province: 1/Al-Qurna, 2/Al-Madina, 3/Al-Dair, 4/Al-Haritha, and 5/Karmat Ali (University). ), 6/ Al-Tanuma, 7/ Abu Al-Khasib, 8/ Al-Siba, 9/ Al-Faw and 10/ Al-Zubayr (Al-Burjisiya station) and a site was chosen for comparison, where soil samples were collected from agricultural Locations close to the source of pollution, while plant samples were collected from near and far from the source Pollution and the necessary analyzes were Carried out for the study. The results showed an increase in the concentration of total heavy metals in the soils of most of the study Locations, and they were polluted compared to the comparison treatment. The soils of most agricultural Locations exceeded the internationally permissible limits. The results indicated that the total average concentration of lead, Nickel, copper, chromium and zinc in the Hartha area (the fourth site) was 615.88, 165.55, 390.40, 48.45, 465.83 mg kg-1 soil sequentially, which is higher compared to the average concentration in other agricultural sites, as well as the concentrations of heavy metals increased (Pb, Ni, Cu, Cr, Zn) in plants grown in locations close from the source of pollution. The concentrations of these elements decreased in plants far from the source of pollution. It is noted that the pollution factor (CF) values of Pb and Zn in all study Locations ranged from moderate contamination to very high contamination. Keywords: PLI, pollution Factor (CF), oil installations, soil pollution, plant pollution.

Heavy Metal Contamination Characteristics in Acid Soil-rice Systems and the Corresponding Human Health Risk in a Mining and Smelting Area in Jiangxi Province.

To understand the effects of mining activities on soil cadmium and rice, a typical mining area was selected. The Cd content in a considerable number of soils exceeded the standard limitation GB/T 36,783 - 2018, with a rate of 42.03%. Further analysis revealed soil total Cd content was strongly correlated with soil bioavailability of Cd (R2 0.721**), pH (R2 0.386**) and soil total content of lead(R2 0.678**). It suggests that soil total Cd content and soil pH significantly affect rice Cd levels, and that acid soil increases soil Cd bioavailability [Soil Cd (B)] and accumulation in rice grain. Furthermore, a mathematical dynamic fitting is developed to describe the relationship between rice Cd content, soil pH, and soil Cd bioavailability in acidic soil (pH 5-5.5). Rice Cd content (mg/kg) = - 179.2 + 67.24 × (Soil pH) - 12.81× [Soil Cd (B)] - 6.28 × 153(Soil pH) 2 + 65.79 × [Soil Cd (B)]2. This study identifies the main types of pollutants emitted by industrial activities and recommends Cd as the most concerning pollutant for rice planting and paddy soil.

Study of the concentration level of heavy metals in water and some tissues of common carp, Carpinus carpio L. which is cultured in cages in the Euphrates River

The current study included measuring some chemical and physical properties of the water of the study area and estimating the concentration of three heavy elements (lead, copper, and zinc) in the tissues of the common carp (Gills, muscles, and viscera) of Cyprinus carpio L. Samples were collected from one of the private farms that raise fish in floating cages on the Euphrates River from 11/18/2022 to 4/18/2023. The study also included measuring water temperature, air, turbidity, electrical conductivity, total dissolved solids, pH And dissolved oxygen samples taken from the water were analyzed as well as samples taken from fish tissues on a monthly basis. The results of the study showed that the air temperature ranged between(6.8-10.2)C. Water temperature (17_33), turbidity (6.8_10.2), electrical conductivity (1.04_2.13), total dissolved solids (7752_18730) mg/l, and pH value (7.2_7.82) between neutral to lightly basic. The dissolved oxygen value ranged between (6.78 - 7.92) mg/l during the months of the experiment. The standard methods were used to estimate the concentration of heavy metals in water and tissues by flame atomic absorption spectrometer. The results showed that the highest total concentration of lead, copper and zinc was recorded in the water during the winter season (1.533, 2.300, 6.700) µg/L. Recorded in tissues for lead in the gills and viscera, the highest values were in spring (9.533, 6.500) µg/L, respectively. Copper recorded the highest value in the gills and viscera, respectively, and the concentrations were high in the autumn season (16.793, 18.723) µg/g dry weight, respectively. g dry weight respectively, the results showed that the accumulation of heavy elements was in the following order . 
 Concentrations in the water are zinc < copper < lead
 And in the tissue as follows 
 Gills < muscle < viscera lead 
 gills < viscera < muscle copper 
 Zinc gills < muscle < viscera
 Different densities were also studied to obtain the best culture density. Three densities (21_25_28 fish / m3) were used, with 500 fish for the first treatment, 900 fish for the second treatment, and 1100 fish for the third treatment, with an average weight of (120_140) g. Diet of Iranian origin was used for the three treatments. The results of the statistical analysis showed that there were significant differences during the months of the study, where the highest rate was in the month of March.

An In Vitro Study of the Effects of Temperature and pH on Lead Bioremoval Using Serratia marcescens

Heavy metal contamination of water is a widespread problem in Peru and represents a potential threat to the ecosystem. Bacteria are an ecological alternative to treating these effluents. This research aims to determine the influence of temperature and pH on the lead (Pb) bioremoval in surface water using Serratia marcescens under laboratory conditions. The sample was collected from a stream located in Santiago de Chuco City (Peru). Treatments (T) were carried out by combining pH (5 and 7) and temperature (25, 30, and 35 °C). The bacterial inoculum (S. marcescens) was 3 × 108 CFU/mL, which was constant in all treatments. The lead bioremoval evaluation was performed in an airlift bioreactor and the incubation time was 24 h. The total lead concentration was determined using atomic absorption spectrophotometry. The results show that treatment 6 (temperature: 35 °C, pH: 5, and inoculum: 3 × 108 UFC/mL) showed a better result than the other treatments, with a removal value of 63.94%. Furthermore, the total lead concentration decreased from an initial concentration of 0.268 mg Pb/L to a final value of 0.0964 mg Pb/L. These results are still above the allowed water value (15 µg/L) according to Peruvian standards. On the other hand, temperature and pH influenced lead removal from surface water when S. marcescens was used after a short incubation period (24 h). Although an attempt was made to improve lead bioremoval by varying two parameters, temperature and pH, future research is still needed to investigate the effect of different inoculum concentrations, the use of microbial consortia, and a broader range of physicochemical parameters.

Spatiotemporal variability on local-regional scale in subtidal meiofaunal assemblages along the southern coast of Korea

This study was conducted to investigate the spatiotemporal variability in subtidal meiofaunal assemblages off the southern coast of Korea at local and regional scales. Abiotic and biotic samples were collected by site (three sites at least 10 km apart) within region (three coastal regions at least 50 km apart) over 7 years (2015–2021). The density and taxon richness of meiofaunal assemblages differed significantly among sites, but not among regions or years. The meiofaunal assemblage composition differed significantly among sites, regions, and years. A distance-based multivariate multiple regression analysis revealed that the mean sediment grain size and total nitrogen, lead, nickel, chromium, and aluminum concentrations were key environmental variables determining the variation of the meiofaunal assemblages. This study can provide basic ecological data for understanding the spatiotemporal distribution of meiofauna assemblages and aid in the development of management strategies to mitigate marine pollution on the southern coast of Korea.

Zoning of some physicochemical parameters in the sediments of Meighan wetland in Iran: response to urbanization, industrial, and agricultural activities.

Meighan wetland is located at 8km far away from Arak city with a population of about 600,000 citizens in the center of Iran. Several agricultural activities and industries such as metal, chemical, and mineral, as well as industrial towns, exist around the desired wetland. This research was conducted to measure the sources of chemical contaminants entering the wetland through natural and artificial waterways, to explore the trend of changes in the contaminants, and to prepare the wetland contamination zone map followed by source detection of these contaminants. Sediment samples were taken during 2019-2020 from a depth of 0-30cm from 87 points in the input waterways. The results indicated that the mean total concentrations of cadmium, nickel, lead, zinc, copper, and aluminum in sediments were estimated as 6.7, 93.4, 14.1, 276.4, 34.3, and 22,742.7ppm, respectively. The concentrations of nitrate and phosphate in the sediments were given as 18.6 and 1.8ppm, respectively. The mean comparison indicated that the most significant level of nickel and lead belonged to the input waterways of industrial and urban regions; the maximum cadmium content was seen in the input waterways from the agricultural lands; and the highest level of zinc and aluminum was recorded in the waterways of agricultural-industrial urban regions. There was a significant relationship between the results of classic statistics and zoning found in GIS. Overall, chemical pollutants with the origin of input wastewater from the treatment plant of wastewater and the input waterways from the industrial and urban regions have had the largest share of contamination for Meighan wetland.

Lead Release from Simulated Lead-Containing Jarosite Using Freeze–Thaw Cycling with EDTA

Lead is the primary toxic element found in jarosite residue; it is necessary to synthesize simulated lead-containing jarosite residue (SLJS) to investigate its lead release behavior and predict the slag’s stability and potential for secondary environmental pollution. This study explores the ion release behavior, leaching toxicity, and stability of SLJS during freeze–thaw cycles with EDTA (E-FTC). Experimental results demonstrate that the release of lead, iron, and sulfate from SLJS under E-FTC is contingent upon multiple factors, including solution pH, EDTA concentration, freeze–thaw cycles, freezing temperature, and freeze–thaw mode. Specifically, employing an EDTA concentration of 200 mM, a pH of 6, a freezing temperature of −20 °C, and 12 freeze–thaw cycles, the lead release reaches 15.1 mM, accounting for 94.9% of the total lead content, while iron is negligibly released, thus enabling effective separation of lead from iron. Subsequent to E-FTC, the exchangeable lead content exhibits a substantial reduction, accompanied by a marked increase in residual lead, resulting in a remarkable 98% reduction in leaching toxicity. Moreover, the equilibrium concentration of lead in the continuous stable leaching solution is 0.13 mg/L, significantly below the lead toxicity threshold (5 mg/L). Therefore, environmental stability can be greatly enhanced. This study presents a novel approach for the safe disposal of jarosite residue under mild conditions and at low temperatures, contributing to the broader field of environmentally sustainable waste management.

The Heavy Metals in Human Body Fluids Related to the Tobacco Smoke: A Systematic Review

Metals are a part of trace nutrients necessary for our body. They enter the body and accumulate there in different ways such as drinking water, food, smoking, and the like. In addition, they can lead to harmful health effects. In this study, three databases, including ScienceDirect, PubMed, and Springer, were searched, and articles dealing with the monitoring of metals in human body liquids related to tobacco consumption were selected. The results demonstrated that the total concentration of lead (Pb) and cadmium (Cd) in the hair of children, who were exposed to environmental tobacco smoke (Child E-ETS), was higher than that of children not exposed to tobacco smoke (Child NE-ETS) (4.89 vs. 4.82 µg/g). It was similar for the blood of the children (32.58 vs. 28.3 µg/L). The concentration of Pb, Cd, and arsenic in the blood of adult smokers was significantly higher than that of adult non-smokers (22.07, 1.37, and 22.42 vs. 13.81, 0.57, and 7.51 µg/L). The concentration of the metals in the plasma was higher than the remaining fluids. The concentration of Cd was 0.3286±0.0982 and 0.2759±0.1239 µg/g in the urine of adult smokers and non-smokers, respectively. The results indicated that tobacco smoking could increase some metals in body liquids while decreasing some essential elements of the body, including iron.

Human Health and Ecological Risks Associated with Total and Bioaccessible Concentrations of Cadmium and Lead in Urban Park Soils.

This study investigated the total and bioaccessible concentrations of cadmium (Cd) and lead (Pb) in urban soils and their associated human health and ecological risk. Total and bioaccessible metal concentrations were found within the safe limits except for Cd, surpassing the State Environmental Protection Administration (SEPA) China limit in 9.5% of parks. Bioaccessible concentrations were higher in the gastric (G) phase than the intestinal (I) phase, while Cd showed more bioaccessibility compared to Pb. Bioaccessible concentrations reduced Hazard Quotient (HQing) values by 2-22 times and 0-2 times for children and adults, respectively, while hazard index (HI) declined by 1.7 times, and the mean total bioaccessible risk of Pb decreased by 20.8 times. Further, the study revealed a low level of contamination factor (CF < 1) and a low degree of contamination (CD < 6), and Potential Ecological Risk Index (PERI) values for all the cities were less than 150, indicating low ecological risk.

Estimating the proportion of bioaccessible lead (BaPb) in household dust wipe samples: a comparison of IVBA and PBET methods

Established methods for using standardized dust wipes to collect and measure total lead in household dust are readily available but the use of dust wipes to measure bioaccessible lead (BaPb) is less clear. This study compared two in vitro methods for estimating the proportion of BaPb in dust collected into dust wipes including the US-EPA’s in-vitro bioaccessible assay (IVBA) method at two pH (1.5 and 2.5) values; and the physiologically based extraction test (PBET 2.5 pH). Two types of simulated household dust samples (Pb-soil contaminated and Pb-paint contaminated) each with three Pb concentrations were created. Equal amounts of simulated dust were applied to a smooth surface and collected following the standard EPA dust wipe protocol and were analyzed for BaPb and total Pb (ASTM-E1644-17, ICP-OES). Estimated BaPb levels differed significantly by the method of extraction. Mean percent BaPb were IVBA pH 1.5, > 90% (Pb-paint) and 59–63% (Pb-soil); IVBA pH 2.5 78–86% (Pb-paint) and 45–50% (Pb-soil); PBET pH 2.5 56 to 61% (Pb-paint) and 41–50% Pb-soil). Particularly for lead-paint contaminated dust, PBET showed significantly greater discrimination as suggested by the broader range of BaPb values and closer approximation to total lead concentrations in simulated household dust samples.

Microbiological indicators as sensitive indicators in the assessment of areas contaminated by heavy metals

Context As one of the world’s largest mining spills, the Aznalcóllar pyrite mine accident in Spain in 1998 resulted in ~45 km2 of agricultural soils polluted by arsenic and heavy metals. The Guadiamar Green Corridor (GGC) helped with soil remediation but residual pollution is still detected 20 years later. Aims Several methodologies based on chemical indicators have been used to assess the recovery of these areas. However, simple microbiological indicators (e.g. microbial activity and biomass, and metabolic quotient (qCO2)) are yet to be uesed. The aim of this study was to evaluate areas contaminated by arsenic and heavy metals using microbiological indicators of soil quality. Methods We used a systematic random sampling design to collect soil samples from two soil groups with different recovery trajectories. We analysed the total and water-soluble concentrations of arsenic (As), lead (Pb), copper (Cu), and zinc (Zn), the main soil properties, and bioassays including microbial activity and biomass, and metabolic quotient or microbial stress (qCO2). Key results Twenty years after the accident, soils with As and Pb concentrations that consistently exceeded regulatory levels had altered soil microbial biomass and functioning. Although overall rates of microbial respiration were not significantly different between polluted soils, microbial biomass was lower and qCO2 was higher in the more polluted than in less polluted soils. Conclusions The metabolic quotient and microbial biomass are sensitive indicators in the monitoring over time of soil polluted by arsenic and heavy metals. Implications Microbial indicators must be considered in the assessment of potential ecotoxicity and in the evaluation of soil biological properties influencing soil recovery in the long term.

Analysis of Influencing Factors of Cementitious Material Properties of Lead-Zinc Tailings Based on Orthogonal Tests.

At present, the treatment of tailings is mostly carried out in the form of stacking in tailings ponds, resulting in a huge waste of mineral resources and a major threat to the environment and ecology. Using tailings instead of a part of the cement to make cementitious materials is an effective way to reduce the accumulation of tailings. In this paper, lead-zinc tailings-based cementitious materials were prepared by using lead-zinc tailings, fly ash, and ordinary Portland cement, and the effects of four factors on the mechanical properties of lead-zinc tailings, as well as fly ash content, cement content, and water-binder ratio were studied by orthogonal experiments. The corresponding relationship between the factors and the properties of cementitious materials was determined, and the optimization and prediction of the raw material ratio of lead-zinc tailings-based cementitious materials were realized. The test showed the ratio of raw materials to be at the lowest price ratio. Synchronously the ratio that meets the minimum strength requirements was predicted. When the proportion of fly ash:lead and zinc tailings:cement = 30:40:30 and the water-binder ratio was 0.4, the predicted compressive strength of the prepared cementitious material achieved 22.281 MPa, which meets the strength requirements, while the total content of lead-zinc tailings and fly ash was the highest at this time.

HEAVY METAL CONTENT IN BEEF COLLECTED FROM LOCAL MARKETS OF DHAKA AND ASSESSING THE HEALTH RISK

Around the world, beef is consumed as a healthy source of protein, fat, niacin, vitamins B6, B12, iron, zinc, and phosphorus. There is mounting evidence that beef is becoming increasingly contaminated with heavy metals, particularly lead (Pb) and chromium (Cr). The purpose of this study was to determine the amounts of the lead (Pb) and chromium (Cr) in beef. Five large markets in Dhaka city—Mirpur-1, New Market, Karwan Bazar, Kaptan Bazar, and town hall market of Mohammadpur—were chosen to gather samples of beef. In this study, the Pb and Cr content in beef was estimated by the Zeeman method using graphite furnace atomic absorption spectrophotometer (GFAAS). The microwave digester finished the digestion of beef. The Pb and Cr content in beef were estimated in mg/kg. Total lead (Pb) content in a beef sample of Mirpur -1, New Market, Karwan Bazar, Kaptan Bazar and Mohammadpur was found to be 0.563±0.084, 0.845±0.127, 0.159±0.024, 0.063±0.009 and 0.143±0.021 mg/kg respectively (Minimum detection limit is 0.06 mg/kg). On the other hand, total chromium (Cr) content in beef sample from Mirpur -1 was found below the detection limit of the method (Minimum detection limit is 0.05 mg/kg). The Cr content in beef from New market, Karwan Bazar, Kaptan bazaar and Mohammadpur was found to be 0.05±0.007, 0.052±0.008, 0.121±0.018 and 0.053±0.008 mg/kg respectively. According to Codex Alimentarium Commission (CAC), the acceptable limit of lead content in beef is 0.1 mg/kg and there is no standard for chromium set by international organization like WHO/FAO, CAC. Brazil has set 0.1 mg/kg as permissible chromium content in beef (Ihedioha et al., 2014). Except for Kaptan Bazar, the chromium content was found to be within Brazil's permissible limit. Surprisingly, only Kaptan Bazar had acceptable lead content that was within the CAC limit. Bioresearch Commu. 9(1): 1196-1202, 2023 (January)