Total Cadmium Concentrations Research Articles

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.

Exposure to iodine, essential and non-essential trace element through seaweed consumption in humans

Seaweed consumption has gained popularity due to its nutritional value and potential health benefits. However, concerns regarding the bioaccumulation of several trace elements highlight the need for comprehensive studies on exposure associated with seaweed consumption. To address this gap in knowledge, we carried out a feeding intervention study of three common edible seaweeds (Nori, Kombu, and Wakame) in 11 volunteers, aiming to elucidate the extent of both beneficial and harmful trace element exposure through seaweed consumption in humans. Concentrations of total arsenic, cobalt, copper, cadmium, iodine, molybdenum, selenium, and zinc were measured in urine samples before and following seaweed consumption. Elements concentrations were also measured in the seaweeds provided for the study. Descriptive analysis for each element were conducted and we used quantile g-computation approach to assess the association between the 8-element mixture and seaweed consumption. Differences in urine element concentrations and seaweed consumption were analyzed using generalized estimating equations (GEE). Urinary concentrations of iodine and total arsenic increased after seaweed consumption. When we analyze the 8-element mixture, the largest weight was observed for iodine after Kombu consumption while for total arsenic was observed after Wakame consumption. Similar results were observed when we compared the mean differences between the elements before and after seaweed consumption through the GEE. Seaweed consumption relates with increased urinary iodine and total arsenic concentrations, particularly after Kombu and Wakame consumption.

Prevention of Cadmium Contamination by Microbial Inoculant and Its Potential Mechanism

Cadmium is the main heavy metal contaminant of food in the world. The extent of cadmium pollution in peanut in China remains unclear. To determine the cadmium pollution level in peanut, samples from the main producing regions in China were assessed. The findings revealed that the cadmium pollution level in Chinese peanuts was relatively low. Moreover, the Aflatoxin Rhizobia Couple B. amyloliquefaciens, B. laterosporu, B. mucilaginosus, E. ludwiggi (ARC-BBBE) microbial inoculants on cadmium contamination in peanut were evaluated. The fertilization methods were categorized into conventional fertilization and conventional fertilization supplemented with 60 kg/hectare of microbial inoculant ARC-BBBE as the base fertilizer. The cadmium contents in the soil and peanut plant parts were detected and analyzed. The results demonstrated that the microbial inoculant ARC-BBBE significantly reduced the total cadmium content in peanut, as well as the available cadmium and exchangeable cadmium in soil. Furthermore, the pH and urease and alkaline phosphatase activities in soil were significantly enhanced, suggesting that the microbial inoculant ARC-BBBE decreased cadmium content in soil and reduced the cadmium uptake by plants through a combination of the action of the bacteria itself and the secretion of extracellular substances. This ultimately achieves the goal of reducing the cadmium content in peanut seeds.

Associations among global long interspersed nuclear element-1 DNA methylation, metal exposure, and chronic kidney disease.

Long interspersed nuclear element-1 (LINE-1) methylation serves as an indicator of global DNA methylation. This study explored the correlation between LINE-1 methylation and chronic kidney disease (CKD). We also evaluated whether LINE-1 methylation could modify the association between CKD and metal exposure. A total of 213 patients with clinically defined CKD, without hemodialysis and 416 age and sex matched controls were recruited. Levels of LINE-1 methylation, total urinary arsenic, blood lead, blood cadmium, and plasma selenium were assessed. The results reveal a positive association between LINE-1 methylation and CKD, with an odds ratio (OR) of 5.30 (95% confidence interval: 2.81 to 9.99). Total urinary arsenic and blood cadmium concentrations were positively related with LINE-1 methylation. This study was the first to observe that low plasma selenium, high blood cadmium, and high blood lead levels significantly and additively interact with increased LINE-1 methylation to increase the OR of CKD. Additionally, high LINE-1 methylation interacted multiplicatively with low plasma selenium to increase the OR of CKD (p < 0.001). This study highlighted the significant association between LINE-1 hypermethylation and CKD. Furthermore, the results demonstrate that LINE-1 methylation can interact with high blood cadmium or low plasma selenium to affect CKD risk.

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.

Identification of the succinate-CoA ligase protein gene family reveals that TaSUCL1-1 positively regulate cadmium resistance in wheat

The Succinate-CoA ligase (SUCL1) gene family is involved in energy metabolism, phytohormone signaling, and plant growth, development, and tolerance to stress. This is the first study to analyze the SUCL1 gene family in wheat (Triticum aestivum). 17 TaSUCL1 genes were identified in the complete genome sequence and classified into five subfamilies based on related genes found in three other species. The 17 TaSUCL1 genes were unevenly distributed across 11 chromosomes, and the collinearity of these genes was further investigated. Through using real-time qPCR (RT-qPCR) analysis, we identified the expression patterns of the TaSUCL1 genes under various tissues and different heavy metal stress conditions. The functions of selected TaSUCL1-1 gene were investigated by RNA interference (RNAi). This study provided a comprehensive analysis of the TaSUCL1 gene family. Within the TaSUCL1 genes, the exon-intron structure and motif composition exhibited significant similarity among members of the same evolutionary branch. Homology analysis and phylogenetic comparison of the SUCL1 genes in different plants offered valuable insights for studying the evolutionary characteristics of the SUCL1 genes. The expression levels of the TaSUCL1 genes in different tissues and under various metal stress conditions reveal its important role in plant growth and development. Gene function analysis demonstrated that TaSUCL1-1 silenced wheat plants exhibited a decrease in the total cadmium (Cd) concentrations and gene expression levels compared to the wild type (WT). Additionally, TaSUCL1-1 belonging to class c physically interacts with the β-amylase protein TaBMY1 as verified by yeast two-hybridization. This research provides a useful resource for further study of the function and molecular genetic mechanism of the SUCL1 gene family members.

Exposure of the general French population to metals and metalloids in 2014–2016: Results from the Esteban study

BackgroundThe purpose of the Esteban study was to describe levels of various biomarkers of exposure to several environmental pollutants, including metals and metalloids, among the French population. This paper describes the distribution of concentrations of 28 metals and metalloids in two different populations, and estimates the main determinants of exposure to total arsenic, the sum of inorganic arsenic (iAs) and its two metabolites monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), cadmium, chromium, copper, mercury and nickel. MethodsEsteban is a cross-sectional study conducted between 2014 and 2016 on a random sample of 2503 adults (18–74 years old) and 1104 children (6–17 years old) from the general population. The data collected included biological samples (blood, hair, and urines), socio-demographic characteristics, environmental and occupational exposure, and information on dietary factors and lifestyle. The geometric mean and percentiles of the distribution were estimated for each metal. Multivariate analyses were performed to identify the determinants of exposure using a generalized linear model. ResultsOnly four metals had a quantification rate below 90% in adults (beryllium, iridium, palladium, and platinum), and three metals in children (beryllium, iridium, and platinum). The concentrations of total arsenic, cadmium, chromium and mercury were higher than those found in most international studies. The determinants significantly associated with exposure were mainly diet and smoking. ConclusionsEsteban provided a nationwide description of 28 metal and metalloid exposure levels for adults (some never measured before) and for the first time in children. The study results highlighted widespread exposure to several metals and metalloids. These results could be used to advocate public health decisions for continued efforts to reduce harmful exposure to toxic metals. The Reference values (RV95) built from Esteban could also be used to support future government strategies.

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).

Cd-contaminated soil remediation using MgFe2O4/chitosan carbon aerogel beads

The immobilization of cadmium in soil to reduce its bioavailability is a common approach in soil remediation. However, fluctuations in soil pH, redox potential, and microbial activity can still lead to cadmium release. To address this challenge, MgFe2O4/chitosan carbon aerogel beads (MCSCA) were synthesized for in-situ remediation to remove Cd from the soil. A two-week remediation period was conducted to assess the effectiveness of MCSCA in Cd-contaminated soil. Different proportions (1%, 2%, and 3% by soil weight) of MCSCA were incorporated into the soil for remediation, followed by MCSCA separation through water flotation. The results demonstrated that after three remediation cycles, 55.46%, 72.27%, and 75.70% of the total cadmium were removed by 1%, 2%, and 3% MCSCA additions, respectively, corresponding to the removal of 76.51%, 87.39%, and 90.28% of bioavailable cadmium. Regeneration of MCSCA was accomplished using 0.1 M HCl, achieving cadmium desorption rates of 97.14%, 96.43%, and 90.48% for 1%, 2%, and 3% MCSCA additions, respectively. The regenerated MCSCA maintained higher remediation efficiency, removing 62.72%, 75.20%, and 80.96% of bioavailable cadmium even after three cycles, with MCSCA recovery rates of 94.40%, 92.30%, and 91.40%, respectively. In a pot experiment, pakchoi plants grown in soil post three rounds of remediation with different ratios (1%, 2%, and 3%) of MCSCA xhibited reductions in total cadmium content by 44.75%, 59.38%, and 69.88%, respectively, compared to plants grown in Cd-contaminated soil. In summary, this study underscores the effectiveness of MCSCA in remediating Cd-contaminated soils, offering a promising approach for soil remediation.

Hydraulic control on sedimentation processes and bottom sediments chemistry of Sulejów Reservoir in Poland

Abstract The Sulejów reservoir is one of the largest reservoirs in Poland and is exposed to a large flux of nutrients from both point and diffuse sources, which leads to an excessive amount of eutrophication and cyanobacteria bloom. The underlying inspiration for this paper was to use a 1D HEC-RAS hydrodynamic model to improve the knowledge of sedimentation conditions and the chemistry of bottom sediments in the context of reservoir eutrophication and algae bloom. Field sampling was performed, and chemical concentrations of Total Organic Carbon, Total Phosphorus, and Cadmium were measured in samples from bottom sediments. The deepest parts of the reservoir and the presence of sediment traps coincide with the highest concentrations of organic carbon, nutrients, and heavy metals. The paper has shown that reservoir hydrodynamic modelling and precise bathymetry maps provide very valuable information that can be used for the interpretation of bottom sediment chemistry patterns and for understanding the conditions of sedimentation.

Human health risk assessment of intake Cd and Cu from agricultural soils in Mostar and Tomislavgrad

The aim of the research was to determine the total content of cadmium (Cd) and copper (Cu) in agricultural soils and to determine the potential toxicity of different intake routes for children and adults. Two locations were selected (Tomislavgrad and Mostar) where field crops were grown. Taking soil samples and determining the content of Cd and Cu was carried out according to the Instructions on determining the permitted amounts of harmful and dangerous substances in the soil and their testing methods (Official Gazette of FBiH, no. 96/22). A health risk assessment model based on the guidelines of the US Environmental Protection Agency (USEPA, 1996; USEPA, 2002; USEPA, 2011) was used to calculate the human health risk assessment. The measured values of the total content of copper and cadmium at the Tomislavgrad location are in accordance with the prescribed limit values. The copper content at the Mostar location was 205.90 mg/kg, which is above the limit value, and the cadmium content is in accordance with the prescribed limit values. When the HI value is less than 1, then there is no risk to human health, but if the values are greater than 1, then there is concern about non-carcinogenic risks (USEPA, 2004). The USEPA considers a carcinogenic risk in the range of 1×10–6 to 1×10−4 to be acceptable to human health. Calculations for non-carcinogenic and cancerous health risks were following the limit values.

Pollution Levels of Three Heavy Elements and some Environmental Factors for Mud Farm Water North of Thi-Qar

The current study was conducted to determine the levels of pollution of the three heavy elements, and some environmental factors for the water of a mud farm north of Thi Qar district of Shatrah, at the village of Al-Ajja Al-Buhan, near Hor Al-Ghomqa, it is 55 km away from the center of Al-Nasiriyah, from 5/11/2022 to 5/4/2023. The study included measuring the temperature of water and air, turbidity, electrical connection, salinity, total dissolved solids, pH and dissolved oxygen. Water samples were analyzed on a monthly basis. The results of the study showed that the air temperature ranged between 22-30 °C, the water temperature ranges between 17-20°C, turbidity ranges from 8.11-11.3 NTU, the electrical conductivity of the salinity recorded values ranging from 1.19-1.99 μS/cm, total dissolved solids recorded values ranging between 6543 - 11165 mg / L, the pH values range from 7.17-7.98, between neutral to lightly basic, dissolved oxygen values ranged between 6.77-8.9 mg/L during the months of the experiment. Standard methods were used to estimate the concentrations of heavy metals in water, by flame atomic absorption spectrophotometer. The results showed that the highest total concentration of zinc, copper and cadmium, recorded in water during the months of the year amounted to 22.89, 1.99 and 2.99 μg / L, respectively. The results showed that the accumulation of elements heavy was, concentrations in the water of zinc > copper > cadmium.

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.

Study of the Heavy Metals Concentration Level in the Water and Sediment and some Tissues of the Grass Carp Ctenopharyngodon idella V. Cultured in Cages in the Euphrates River

The current study was conducted in Thi Qar Governorate, Nasiriyah city on one of the private farms, grass carp were cultured, to determine the effect of some heavy elements (cadmium, copper and zinc) in the water and sediments of the Euphrates River, measuring the concentration of elements in some parts (gills, muscles and viscera) of grass carp fish. Water, sediment and fish samples were collected monthly from 11/8/2022 to 4/8/2023. The study also included field tests such as air and water temperature measurements, the air temperature ranged between 11-29 C, and the water temperature ranged between 9-25 C. Heavy metals were measured in water, sediment and fish tissues by flame atomic absorption spectrometer. The results showed the highest total concentration of cadmium in the water during April and copper in February and April, as for zinc, it recorded the highest concentration during April. The highest concentration of cadmium was recorded in the gills and muscles during April. The highest concentration of cadmium in the guts was recorded in the winter. Copper had the highest concentration in the gills and muscles during April. Zinc recorded high concentrations in the viscera, muscles and gills. As for the sediments, the values of cadmium ranged from 0.104-0.223 μg/L. Copper recorded values ranging between 5.07-13.2 μg/L. Zinc values ranged between 29.87-59.2 μg/L. The results showed that the accumulation of heavy elements was as follows: Concentrations in the water of zinc>cadmium>copper. Concentrations in the sediments of zinc> copper>cadmium. In tissues: Cadmium viscera>gills>muscle. gillscopper>viscera>muscles. Viscera>gills>muscles.

The Influence of Industrial Residues of Phosphate Fertilizers Complexes on Content of Phosphor, Cadmium and Lead in Soil and Water

The study was carried out in Al-Qaim region near by the factory of fertilizer about 420 km west of Baghdad. Samples of soils were taken by depths of (0-0.20), (0.20-0.40) and (0.40-0.60) m with three directions (N north, S south, E east) according to the direction of annuity wind. Soil samples were taken at three distances from the factory (500, 1000, and1500) m. Samples of water were taken from three sources; wells, acidic and alkaline water from the factory. The aim of this paper was to study the influence of residue of phosphate fertilizer factory in content of Phosphor, Cadmium and Lead of soil and water. The results showed that the highest values of available phosphorus were 956.80 and 528.46 mg l-1 for distances 1500 and 1000 m, at depths of 0.4-0.6 m in the N1 directions as well as for N1 and S1 directions at the depth of 0-0.2. The highest total cadmium content was 4 mg l-1 for 500 m distance with the N1 direction at depth of 0-0.2m respectively. available cadmium was found in small quantity and consider negligible. The available lead was 83 and 0.45 mg l-1, for 1000 and 500 m distances in the direction of N1 for the depths of 0-0.2 and 0.2-0.4m respectively.

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&gt;Pb&gt;Ni&gt;Cr&gt;As&gt;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.

The effects of earthworm inoculation on cadmium-contaminated rice field in Southern China: a pot experiment and a field test.

Currently, the effects of earthworm inoculation on cadmium-contaminated rice field remain unclear. In this study, four treatments were tested, including rice monoculture (CK), earthworm inoculation with low density (L, 30 g/m2), middle density (M, 60 g/m2), and high density (H, 90 g/m2). The pot and field experiment were conducted in Hunan Province, China. In the pot experiment, the H treatment significantly decreased the available cadmium concentration in 0 ~ 20 cm soil by 5.21% ~ 16.51%, and the M treatment significantly decreased in 0 ~ 10 cm soil by 7.29% ~ 8.96%. The H treatment significantly decreased the total cadmium concentration in 0 ~ 5 cm soil by 10.36%. Moreover, the earthworm inoculation treatments significantly reduced cadmium accumulation in rice organs. In the field experiment, the M and H treatment decreased the available cadmium concentration in 0 ~ 20 cm soil by 14.05% ~ 47.52% and the H treatment decreased the total cadmium concentration in 0 ~ 20 cm soil by 0.78% ~ 5.75% although there was no significant difference. Furthermore, the earthworm inoculation treatments significantly decreased cadmium accumulation in part of rice organs. In conclusion, this study recommends that earthworm inoculation is an effective method of controlling cadmium contamination for rice production.

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.

Applicability of Compost and Mineral Materials for Reducing the Effect of Diesel Oil on Trace Element Content in Soil.

Petroleum-derived substances have become the factor adversely affecting the soil quality and, also, crop production. However, the ability to immobilise contaminants is limited in anthropogenically altered soils. Therefore, a study was undertaken to evaluate the effects of soil contamination with diesel oil (0, 2.5, 5 and 10 cm3 kg-1) on the contents of trace elements in the soil and determine the suitability of different neutralising materials (compost, bentonite and calcium oxide) for the in situ stabilisation of soil contaminated with this petroleum derivative. In the soil contaminated with the highest dose of diesel oil (10 cm3 kg-1), a decrease in chromium, zinc and cobalt and an increase in the total nickel, iron and cadmium concentrations were found in the series without the addition of neutralising materials. Remediation with compost and mineral materials contributed to a significant reduction of nickel and iron, as well as cobalt, in soil (calcium oxide only). All materials used contributed to an increase in cadmium, chromium, manganese and copper in the soil. The above-mentioned materials (most notably calcium oxide) can be successfully used to reduce the effect of diesel oil on the contents of some trace elements in soil.

Levels of Arsenic, Cadmium, and Mercury in Urine of Indigenous People Living Close to Oil Extraction Areas in the Peruvian Amazon.

Levels of Arsenic, Cadmium, and Mercury in Urine of Indigenous People Living Close to Oil Extraction Areas in the Peruvian Amazon.