Source Of Cadmium Research Articles

Tobacco smoke is a likely source of lead and cadmium in settled house dust

IntroductionEnvironmental exposure to lead (Pb) and cadmium (Cd) are risk factors for adverse health outcomes in children and adults. This study examined whether thirdhand smoke residue contributes to Pb and Cd in settled house dust. MethodsParticipants were 60 multiunit housing residents in San Diego, California. All had indoor smoking bans during the study period, and 55 were nonsmokers. Wipe samples from different surfaces and vacuum floor dust samples were analyzed for nicotine, a marker of thirdhand smoke, and for Pb and Cd using liquid chromatography-triple quadrupole mass spectrometry and inductively coupled plasma-mass spectrometry, respectively. ResultsExamined in each sample type separately, Pb and Cd loadings were significantly correlated (r = 0.73, vacuum floor dust; 0.52, floor wipes; 0.72, window sill/trough wipes; all p < 0.0025). Pb and Cd loadings from different sample types were not correlated (all p > 0.30). Nicotine loading in dust was significantly correlated with Pb and Cd loading in dust (r = 0.49 for Pb; r = 0.39 for Cd, all p < 0.0025). Pb and Cd loadings on floor or window surfaces, showed no association with nicotine loading in dust, on floors, or on furniture (all p < 0.30). ConclusionsTobacco smoke is a likely source of Pb and Cd that accumulates in settled house dust in multiunit housing, suggesting that Pb and Cd are constituents of thirdhand smoke that lingers long after smoking has ended.

Lifetime marijuana use in relation to cadmium body burden of US adults: results from the national health and nutrition examination surveys, 2009–2016

ObjectivesLow-level cadmium exposure has been linked to chronic diseases, but the importance of marijuana use as a source of cadmium remains unknown. We aimed to determine the association of marijuana use with blood cadmium (BCd) and urinary cadmium (UCd) levels. MethodsWe abstracted data from the National Health and Nutrition Examination Surveys, 2009–2016. We modeled lifetime marijuana exposure accounting for both duration and frequency of exposure. We used adjusted ratio of geometric means (ARM) and 95% confidence intervals (95% CIs) to compare outcomes among groups of marijuana exposure, relative to never users. The UCd level was adjusted for creatinine excretion. ResultsWe included 163,250 adults (mean age, 38.7 years; 50% women). The ARM of BCd was 1.28 (95% CI = 1.04, 1.57), 1.40 (95% CI = 1.11, 1.76), and 1.77 (95% CI = 1.51, 2.09) in current users with <2 uses per week, 2–3 uses per week, and ≥4 uses per week, respectively. Marijuana use for ≥15 years was associated with both higher cadmium burden in adults with <2 uses per week (ARM of 1.30 (95% CI = 1.04–1.62) for BCd and 1.48 (95% CI: 1.05, 2.09) for UCd or ≥4 uses per week (ARM of 1.69 (95% CI = 1.40, 2.05) for BCd and 1.38 (95% CI = 1.11, 1.72) for UCd. In former users, marijuana use was significantly associated with higher UCd levels in those with ≥15 years of use [ARM of 1.39 (95% CI = 1.14, 1.69) for those with <2 uses/week and 1.51 (95% CI = 1.19, 1.92) for those with ≥4 uses/week]. ConclusionsThe BCd level was higher in both current and former marijuana users than in never users. Marijuana use was also associated with higher UCd levels after a long-term use.

Chemical Speciation and Distribution of Cadmium in Rice Grain and Implications for Bioavailability to Humans.

Consumption of rice (Oryza sativa) is the major dietary source of cadmium (Cd) for populations with rice as the staple. Little is known about the distribution and chemical speciation of Cd in rice grain, which is critical in determining the bioavailability of Cd to humans. We used synchrotron-based techniques for analyses of the speciation and distribution of Cd in rice grain. The majority of the Cd in rice grain was present as Cd-thiolate complexes (66-92%), likely in the form of Cd bound with thiol-rich proteins. The remainder was present as Cd-carboxyl compounds and Cd-histidine. Elemental mapping showed two different patterns of Cd distribution, one with an even distribution throughout the entire grain and the other with a preferential distribution in the outer tissues (aleurone layer and outer starchy endosperm). The distribution pattern is important as it affects the removal of Cd during milling. On average, milling reduced grain Cd concentrations by 23.5% (median of 27.5%), although the range varied widely from a 64.7% decrease to a 22.2% increase, depending upon the concentration of Cd in the bran. We found that the variation in the distribution pattern of Cd in the rice grain was due to a temporal change in the supply of Cd from the soil porewater during grain filling. These results have important implications for Cd bioavailability in human diets.

Dietary exposure assessment of cadmium of adults in Jiangxi Province in 2016

To evaluate dietary exposure of cadmium and their potential health risks of adults in Jiangxi Province. The concentration data of cadmium of 11 kinds of foods were obtained from food safety monitoring in Jiangxi Province in 2012-2017. The food consumption data was obtained from food consumption survey in Jiangxi Province in 2016. Based on the deterministic assessment model, the dietary exposure of cadmium of adults in Jiangxi Province was calculated. The average dietary exposure of cadmium was 18. 426 μg/kg per month, accounting for 73. 7% of the provisional tolerable monthly intake(PTMI). The large portion exposure(P95) of cadmium was 29. 724 μg/kg per month, accounting for 118. 9% of PTMI. The average and the large portion(P95) dietary exposure range of cadmium in different age groups were 16. 224-19. 774 and 24. 059-33. 387 μg/kg per month, respectively. It was indicated that the main dietary sources of cadmium were rice and vegetables, which were contributed more than 92% of total dietary exposure of cadmium. The potential health risks caused by dietary exposure to cadmium of adults in Jiangxi Province was at an acceptable level. But there were some potential health risks in high exposure population.

Appraisal of innovative phytosynthetic CdO NPs from leaf extract of Ocimum Sanctum and their bactericidal activity against different strains

&#x0D; &#x0D; &#x0D; The phytosynthesis of n-type Cadmium Oxide Nanoparticles reduces the toxicity of the substance and makes it Eco-friendly. This Eco-friendly biosynthesis of CdO NPs was synthesized for the first time from the Queen of herbs, Ocimum Sanctum (holy basil).The biosynthesized Cadmium oxide was prepared using Ocimum leaf extract as a reductant and Cadmium Chloride and hydroxide as cadmium and oxide source materials by Co- Precipitation method. Thus obtained Cadmium Oxide Nanoparticles were characterized by different techniques such as X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM),Energy dispersive X-ray spectroscopy(EDS) to study the structural and morphological properties. XRD pattern exhibited the formation of face centered cubic structure of CdO NPs with an average crystalline size of 11.5nm .The chemical bond formation of CdO NPs were confirmed by FTIR spectrum in the range of (400-4000cm-1). The SEM micrographs revealed the predominant formation of Cauliflower shape with a particle size in the range of 61-142nm. The high purity of the biosynthesized nanoparticles were confirmed by EDS analysis. Further it was tested against gram positive and gram negative bacterial strains and showed significant antibacterial activity. This biosynthetic research study opens an innovative window to progress our understanding of how CdO NPs shows resistance to different bacterial strains.&#x0D; &#x0D; &#x0D;

Avoiding Rice-Based Cadmium and Inorganic Arsenic in Infant Diets Through Selection of Products Low in Concentration of These Contaminants

Cadmium in the diet is of concern as it is a renal toxicant and a carcinogen, with a half-life in the body measured in decades. Inorganic arsenic is a chronic carcinogen. For many subpopulations, rice and rice products may be the dominate source of cadmium and inorganic arsenic. In particular, rice porridge, cereal and cake are widely used to feed infants (children < 4.5 years old). In the EU standards for cadmium infant foods in general has been set at 40 μg/kg w.wt., and for inorganic arsenic in rice-based infant foods the standard is 100 μg/kg w.wt.. Here we report cadmium and inorganic arsenic concentrations in rice products marketed for infants, and rice containing products that infants may eat but that are not specifically designated for infants. It was found that while rice-based infant foods conformed to the standards, their non-infant food (generic) analogues did not. Non-infant rice crackers and puffed rice cereals, in particular, had concentrations above these standards for both cadmium and inorganic arsenic. Polished pure rice grain purchased in the UK, but sourced from different countries, was also problematic. Basmati, Italian, Spanish and Thai rice, either exceeded one or the other of the cadmium and inorganic arsenic safety thresholds for infants, or both. Egyptian rice grain was particularly low for both toxins. Therefore, if those responsible for infants want to lower exposure to cadmium and inorganic arsenic, they should stick to foods specifically labeled for infants, or carefully source low cadmium and inorganic arsenic rice-based products that are not specifically labeled as being for infant consumption, or minimize exposure to rice-based foods.

Trace metals in Rio Doce sediments before and after the collapse of the Fundão iron ore tailing dam, Southeastern Brazil

The collapse of the Fundão Dam, in Southeastern Brazil, caused about 50 million m³ of iron ore tailings to sluice down the mountain to Rio Doce, in what is considered the greatest environmental disaster in Brazilian history. The fluvial system received an intense and sudden mudflow that was transported for more than 650 km, before reaching the Atlantic Ocean. Because the area was already impacted by the mineral activities in the region, it becomes essential to evaluate the environmental conditions before the disaster to correctly assess the disaster real damage. This study compares the concentration of trace metals in the sediments of the Rio Doce alluvial plain, before and after the dam collapse, as well as the newly deposited iron ore tailings that became part of the sedimentary framework. The data indicate that the fine particles deposited have since been incorporated into the sandy river sediments. The cadmium and arsenic contents in the sediments increased to levels above the National Environment Council thresholds. The comparison between the levels of trace metals in the situations before and after disaster shows that the mining mud is the source of cadmium while the arsenic was present before the environmental disaster, and its concentration increased due to sediment remobilization. The iron ore tailings deposited on the alluvial sediments also affected the physical parameters since the formed ferruginous crusts waterproofed the ground surface and may, gradually, release toxic metals when exposed to weathering and river reworking.

Metals and Particulates Exposure from a Mobile E-Waste Shredding Truck: A Pilot Study.

The US electronics recycling industry has introduced a novel mobile electronic waste (e-waste) shredding truck service to address increasing needs for secure data destruction of e-waste. These trucks can shred small electronics with data security concerns at remote locations for a wide variety of clients. Shredding jobs usually involve hand-feeding electronic waste (e-waste) for 4-10 h day-1, 1-5 days. Shredding of e-waste has been documented as a source of high metal exposures, especially lead and cadmium. However, no studies have been done to assess exposures on mobile e-waste shredding trucks. We conducted a pilot cross-sectional exposure assessment on a mobile e-waste shredding truck performing a 65-min shredding job (truck back door open and no local exhaust ventilation) in the Greater Boston area in 2019. We collected area air and surface wipe samples for metals along with real-time particulate measurements from different locations. The highest metal air concentrations (e.g. 2.9 µg-lead m-3) were found next and 1.8 m away from the shredder operator inside the semi-trailer. Metal surface contamination was highest near the shredder (e.g. 1190 µg-lead 100 cm-2) and extended to other parts of the truck. Near the shredder, the concentration of ultrafine particles was up to 250 000 particles cm-3 and particulate matter 2.5 mm or less in diameter (PM2.5) was up to 171 µg m-3, and neither returned to background levels after 40 min of inactivity. A diesel-electric generator was used to power the shredder and could have contributed to some of the particulate emissions. We found that mobile e-waste shredding trucks are a source of metals and particulates emissions. We recommend the industry adopts better controls for shredding inside trucks, such as local exhaust ventilation with proper filtration and use of personal protective equipment, to protect workers' health and the environment.

Breeding for low cadmium barley by introgression of a Sukkula-like transposable element.

Barley is the fourth most produced cereal crop in the world and one of the major dietary sources of cadmium (Cd), which poses serious threats to human health. Here, we identify a gene that encodes a P-type heavy metal ATPase 3 (HvHMA3) responsible for grain Cd accumulation in barley. HvHMA3 from the high Cd barley variety Haruna Nijo in Japan and the low Cd variety BCS318 in Afghanistan shared 97% identity at the amino acid level. In addition, the HvHMA3 from both varieties showed similar transport activity for Cd and the same subcellular localization at the tonoplast. However, the expression of HvHMA3 was double in BCS318 than in Haruna Nijo. A 3.3-kilobase Sukkula-like transposable element was found to be inserted upstream of the gene in the low Cd variety, which functioned as a promoter and enhanced the expression of HvHMA3. Introgression of this insertion to an elite barley cultivar through backcrossing resulted in decreased Cd accumulation in the grain grown in Cd-contaminated soil without yield penalty. The decreased Cd accumulation resulting from the insertion was also found in some other barley landraces in the world. Our results indicate that insertion of the Sukkula-like transposable element plays an important role in upregulating HvHMA3 expression.

Overexpression of Rice OsHMA3 in Wheat Greatly Decreases Cadmium Accumulation in Wheat Grains.

Cereals are a major dietary source of the toxic metal cadmium (Cd). Reducing Cd accumulation in cereal crops such as wheat (Triticum aestivum) is important for food safety and human health. In this study, we show that three diverse cultivars of wheat had a high Cd translocation from roots to shoots, similar to a rice (Oryza sativa) cultivar possessing a nonfunctional tonoplast Cd transporter OsHMA3. We investigated the function of TaHMA3 genes in wheat. Three TaHMA3 genes were identified in wheat, all of which encode tonoplast-localized proteins. However, heterologous expression of TaHMA3 genes in yeast showed no transport activities for Cd, which likely explains the low Cd sequestration in wheat roots and subsequently the high Cd translocation to wheat shoots. To increase Cd sequestration in wheat roots, we overexpressed a rice functional OsHMA3 gene in wheat driven by a strong constitutive Ubiquitin promoter. Overexpression of the OsHMA3 gene decreased root-to-shoot Cd translocation in wheat by nearly 10-fold and Cd accumulation in wheat grain by 96%. The results suggest that high Cd translocation is a common trait in wheat caused by a loss of the Cd transport function of TaHMA3 proteins. Transgenic wheat overexpressing a functional OsHMA3 gene offers a highly effective solution to decrease Cd accumulation in wheat grain.

Assessment of cadmium toxicity and its possible effects on goldfish (Carassius auratus), employing microscopy and biochemical techniques.

The present study aimed to evaluate and compare the toxicity level of dietary and waterborne Cadmium (Cd) source on the Goldfish Carassius auratus (C. auratus) using various biochemical and microscopic shreds of evidence. C. auratus were divided into two groups based on Cadmium supplementation methods subjected to the same concentrations in the diet and water; moreover, control (Ctrl) group was set up for comparison. Dietary supplemented group (DSG) group and (Aqueous supplemented groups) ASG were supplied with 0.5% of the Cadmium. Successful completion of the study resulted in the lucrative outcomes, and we noticed significantly high concentrations of Cadmium in the gills of the ASG fish while considerably low levels in the gills of DSG. Histopathological evidence showed clear and distinct changes in the liver cells, dilated sinusoids and unusual occurrence of Kupffer cells were noticed in the AS group fish. At the same time, there were also noticeable changes in the DS group compared to CTRL. Visible changes can be seen on the outer morphology of gills, lamella of ASG and DSG both were shrunk and broken, similar changes were noticed in the muscles myoepithelium. The stress parameters were differentially expressed in both the groups; waterborne Cadmium caused a pronounced release of AST, ALT, cortisol, and glucose concentrations. Comparative mortality showed the highest death rate in the ASG fish compared to DSG fish. The present study depicts the highest toxicity of Cadmium in the soluble Addendum form moreover, administered route and time length are crucial factors.

Leisure craft sacrificial anodes as a source of zinc and cadmium to saline waters

Sacrificial anodes are attached to the hulls of boats and marine structures to prevent corrosion. Their use inevitably leads to release of zinc as well as impurities in the zinc alloy such as cadmium to the saline environment. Risk assessments and source apportionment exercises require accurate assessments of the potential loads of chemicals into the environment. This research has surveyed a wide variety of zinc anodes for their composition to compare against a reported industry standard as well as using differing methodologies to determine the dissolution rate of zinc and cadmium from anodes. A zinc dissolution rate of 477 g/yr/kg of anode is proposed. Although most anodes tested had concentrations of cadmium within the prescribed limits set by the reported standard, calculated leaching rates from laboratory dissolution experiments suggested as much as 400 g per year of cadmium could leach from zinc anodes used on leisure vessels within UK waters.

Cadmium distribution in water, microalgae biomass, and sediment of River Bonan Dolok, Samosir-North Sumatra, Indonesia

River Bonan Dolok in Samosir is located on the watershed of Lake Toba, an ancient volcanic lake in North Sumatra. Some parts of this river bordered with paddy fields, a common source of cadmium through the leaching process, which then released into the water body. Meanwhile, this river has been proposed as endemic fish (called in the local name as Ihan) conservation area and eco-tourism area. Therefore a scientific reference base management concept is needed. Spatial distribution of cadmium (Cd) must be revealed since this metal is very toxic and can be easily transferred and accumulated in the aquatic food chain. This study aims to inform the distribution of Cd in water, microalgae biomass and sediment. All samples were taken compositely from the upper stream (Station 1), Station 2, Station 3, and lower stream (Station 4) in April 2019. The structure of microalgae community is also identified. The results show that Chlorophyte (mostly consisted of Microspora sp) biomass at Station 2, has the highest Cd concentration (0.57 µgCd/g dry weight). While Cyanophyte (dominated by Microcyctis aeruginosa) even observed bloomed at station 4, shows a lower Cd concentration (0.12µgCd/g dry weight). The distribution of Cd in water and sediment (particle size of ≤63 µm) at those sampling stations as well as some water quality also discussed. The range of Cd concentration in water was 0.02 to 0.64 µg Cd/L, while that in sediment was 0.10 to 0.39 µgCd/g dry weight. These data are expected to be used as essential references for developing the management concept of Bonan Dolok ecotourism area in the future.

Clay minerals as a source of cadmium to estuaries

Given the high surface reactivity of clay minerals, it is assumed that flocculation will lead to metal accumulation in marginal marine settings. However, the degree of metal sorption to clays is impacted by solution pH and ionic strength, and it remains unknown whether riverine clays indeed serve as a metal sink once they encounter seawater where pH and ionic strength markedly increase. Here, we conducted cadmium (Cd) adsorption experiments to three types of common clay minerals – kaolinite, illite and montmorillonite. We found that 20–30% of Cd from illite and montmorillonite surfaces were desorbed when transitioning from freshwater to seawater pH and ionic strength conditions, while kaolinite showed no discernible differences. Synchrotron X-ray adsorption spectroscopy confirmed that Cd release corresponded to a change in bonding from outer- to inner-sphere complexes when clays encountered seawater pH and ionic strength conditions. If other trace nutrients (such as Cu, Zn, Co) adsorbed onto riverine clay minerals behave in a similar manner to Cd, we speculate that their desorption in marginal marine settings should exert a significant impact on the productivity of the biosphere.

Source of Cadmium (Cd) In Soils and Its Transfer to Rice and Vegetables: Karotia Union, Tangail

Cadmium is a trace element which is not essential for human being. High cadmium concentration in some rice samples in Bangladesh was reported than that of other countries. This study was carried out to find out the Cd concentration fertilizers, soils, rice and vegetables and along with other chemical properties of Karotia union, Tangail sadar upazila, Tangail. A total of 29 samples were collected among the 14 soils from 7 stations at 0-15 cm and 16-30 cm depth respectively, 5 vegetables, 5 rice and also 4 different countries TSP fertilizers from local market. The Cd concentration values of all soil samples were found between 0.97 to 1.73 mg/kg (0-15 cm) and 0.53 to 0.83 mg/kg (16-30 cm), respectively and the vegetable sample values were found between 0.053 mg/kg to 0.123 mg/kg (d.w.).The rice sample values were found between 0.05 mg/kg to 0.096 mg/kg (d.w.). The fertilizer sample values were found between 20.67 to 92.33 mg/kg. The soil pH values obtained 7.06 to 7.70 (0-15 cm) and 7.48 to 7.88 (16-30 cm) which indicated that the study area soils were neutral to moderately alkaline. The EC values of all soil samples were between 47.67 to 82.67dSm-1 (0-15cm) and 33.33 to 58.33dSm-1 (16-30 cm). The organic matter content of all soils ranged from 0.789 to 0.905% and 0.351 to 0.869% at (0-15 cm and 16-30 cm), respectively. The available sodium (Na) values of soils were found between 1.84 to 1.92 ppm (0-15 cm) and 1.83 to 1.90 ppm (16-30 cm), respectively. The available potassium values ranged from 1.81 to 1.96 ppm (0-15 cm) and 1.84 to 1.97 ppm (16-30cm), respectively. The available calcium values of all soil samples were 1.92 to 1.97 ppm (0-15 cm) and 1.91 to 1.96 ppm (16-30 cm), respectively.

Overexpression of the manganese/cadmium transporter OsNRAMP5 reduces cadmium accumulation in rice grain.

Rice is a major dietary source of the toxic metal cadmium (Cd), and reducing its accumulation in the grain is therefore important for food safety. We selected two cultivars with contrasting Cd accumulation and generated transgenic lines overexpressing OsNRAMP5, which encodes a major influx transporter for manganese (Mn) and Cd. We used two different promoters to control the expression, namely OsActin1 and maize Ubiquitin. Overexpression of OsNRAMP5 increased Cd and Mn uptake into the roots, but markedly decreased Cd accumulation in the shoots, whilst having a relatively small effect on Mn accumulation in the shoots. The overexpressed OsNRAMP5 protein was localized to the plasma membrane of all cell types in the root tips and lateral root primordia without polarity. Synchrotron X-ray fluorescence mapping showed that the overexpression lines accumulated more Cd in the root tips and lateral root primordia compared with the wild-type. When grown in three Cd-contaminated paddy soils, overexpression of OsNRAMP5 decreased concentration of Cd in the grain by 49-94% compared with the wild type. OsNRAMP5-overexpression plants had decreased Cd translocation from roots to shoots as a result of disruption of its radial transport into the stele for xylem loading, demonstrating the effect of transporter localization and polarity on ion homeostasis.

A Comparative Study of the Heavy Metals in the Meat of Chickens in Different Cities of Pakistan. A Review

The quality of food stuff is the main concern of everyone and scientific community is busy in monitoring and ensuring the quality. The aim of this review is study the importance of heavy metals in and the concentrations of these in the meat of chickens. The data of heavy metals concentration (Pb, Cd, Zn, Cu, Ni) in chicken meat determined in various cities of Pakistan such as Karachi, Kohat, Lahore and Kasur city is presented in this review and a comparison study is conducted among the results. The mean accumulation of lead was observed the highest in the research study performed in Lahore of four cities of Pakistan due to the lead contaminated chicken food while that of Karachi was observed the lowest mean level of Pb of all. Kohat was found second to all. The mean concentration of cadmium was observed the highest level in Kohat, because the main source of cadmium is food, among all concerned cities of Pakistan. The research study in Karachi was observed the lowest amount of cadmium in liver. However, no any significant difference of Cd in liver between Lahore and Kasur was observed. The mean concentration of Zn was observed the highest in the liver of Lahore as source of the metals are chicken food than other studies compared. The mean levels of zinc in study of Karachi were observed the lowest of all. On the other hand, the mean accumulation of nickel was observed highest in Karachi due to the industrial wastes that contaminate the chicken food, among the already performed studies of all three cities while Kohat study result was observed the lowest mean concentration of nickel among the three.

A systematic study on chemically deposited cadmium sulfide (CdS) thin film

In this work, the conventional chemical bath deposition (CBD) technique and its growth parameters were systematically studied to deposit CdS thin films on the glass substrate. The samples were prepared using a simple aqueous solution containing cadmium sulfate (CdSO4·8H2O), thiourea [SC(NH2)2], ammonium sulfate [(NH4)2SO4] as a source of cadmium, sulfur, and a complexing agent, respectively. The deposited films were characterized to study the surface morphology, crystallographic structure, chemical composition, optical and electrical properties. Through this study, the structure was determined to cubic with (111) preferential orientation and the crystallinity of the films was improved with the increase of film thickness. The transmission spectra were recorded in the range of wavelength 300–600 nm. The optical bandgap of the optimized CdS films was varied from 2.43 to 2.74 eV. All the films exhibit n-type of conductivity which was found in the order of 10–4 to 10–5 (1/Ω-cm), suggesting that it would be suitable for the buffer layer in thin-film solar cells.

Soil heavy metal contamination assessment in the Hun-Taizi River watershed, China

The Hun-Taizi River watershed includes the main part of the Liaoning central urban agglomeration, which contains six cities with an 80-year industrial history. A total of 272 samples were collected from different land use areas within the study area to estimate the concentration levels, spatial distributions and potential sources of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb) and zinc (Zn) with a geographic information system (GIS), principal component analysis (PCA) and canonical correspondence analysis (CCA). Only the concentration of Cd was over the national standard value (GB 15618–2018). However, the heavy metal concentrations at 24.54%, 71.43%, 63.37%, 85.71, 70.33%, 53.11%, and 72.16% of the sampling points were higher than the local soil background values for As, Cd, Cr, Cu, Hg, Ni, Pb and Zn, respectively, which were used as standard values in this study. The maximal values of Cd (16.61 times higher than the background value) and Hg (12.18 times higher than the background value) had high concentrations, while Cd was present in the study area at higher values than in some other basins in China. Cd was the primary pollutant in the study area due to its concentration and potential ecological risk contribution. The results of the potential ecological risk index (RI) calculation showed that the overall heavy metal pollution level of the soil was considerably high. Three groups of heavy metals with similar distributions and sources were identified through PCA. The results of the CCA showed that the distribution of mines was the strongest factor affecting the distributions of Ni, As, Zn, Pb, and Cd. However, Cu was strongly influenced by the distance to the nearest river. These findings can provide scientific support for critical planning and strategies for soil pollution control and removal to support the sustainable development of the study area.

Blood cadmium levels and sources of exposure in an adult urban population in southern Brazil

BackgroundCadmium (Cd) is a toxic metal that is widely present in the environment due to geologic and anthropogenic sources. Exposures to high Cd levels may cause nephrotoxicity, carcinogenicity, pulmonary and cardiovascular disease, among others. The goal of this study was to investigate in an adult urban population whether an association exists between sources and levels of Cd exposure and blood Cd concentrations. MethodsUsing a census-based design, a total of 959 adults, aged 40 years or older, were randomly selected. Information on socio-demographics, dietary, and lifestyle background was obtained by household interviews. Blood Cd levels were measured by inductively coupled-plasma mass spectrometry. Geometric means (GM) (95% CI) and the 50th percentile were determined, stratified by sex, age, race, education, income class, smoking status, consumption of vegetables, red meat and milk, occupation and blood pressure. To assess the association between Cd exposure and the aforementioned variables, we estimated the geometric mean ratio (GMR) (95%CI) of blood Cd concentrations. Results and conclusionThe geometric mean (95%CI) of blood Cd levels in the total population was 0.25 (0.22, 0.27) ug/dL. In a univariate analysis, significantly higher blood Cd levels were found in men (p < 0.001), current and former smokers (p < 0.001), alcohol drinkers (p < 0.001), those who never or almost never consumed milk (p < 0.001), and in subjects with higher diastolic blood pressure (p = 0.03). Significant correlations were found between the number of cigarettes consumed daily and blood Cd levels. Multivariate analysis confirmed higher blood Cd concentrations were associated with alcohol consumption (GMR 95%CI = 1.28, 1.04–1.59) and in former and current smokers (GMR 95% IC = 1.33, 1.06–1.67 and 4.23, 3.24–5.52, respectively). Our results shed novel information on variables associated with blood Cd levels in an urban Brazilian population, and should encourage additional research to prevent environmental Cd exposure, both in Brazil and globally.