High Levels Of Zn Research Articles

Role of environmental factors & oxidative stress with respect to in vitro fertilization outcome.

Background & objectives:Oxidative stress, lifestyle factors as also exposure to certain environmental factors are known to affect the fertility status in human beings. The aim of this study was to evaluate the role of OS and lifestyle and environmental factors affecting IVF outcome.Methods:A total of 253 couples were included, and biological samples such as blood, follicular fluid (FF), cumulus cells and semen were collected. Relevant biochemical parameters and metals namely lead (Pb), cadmium (Cd), copper (Cu) and zinc (Zn) were determined in the biological samples. β-human chorionic gonadotropin levels ≥100 IU/l were considered to predict viable pregnancy on the 15th day of embryo transfer (ET).Results:The mean body mass index (BMI) was significantly lower in females with positive IVF outcome compared to those with negative outcome. Couples residing in the residential area showed more percentage of positive IVF outcomes as compared to couples residing in industrial/agricultural area. FF Zn level was significantly higher (P<0.001) among the females’ participants who have undergone ET as compared to those who have not undergone ET. FF MDA and serum Cu levels were significantly higher (P<0.05) in the female participants with negative IVF outcome as compared to positive IVF outcome. Logistic regression revealed that maternal BMI (P=0.034) and FF MDA level (P=0.047) were significantly associated with the IVF outcome.Interpretation & conclusions:The success rate of IVF was about 31.8 per cent, and BMI was significantly lower in females with positive outcome. The higher levels of MDA in FF and SP might have a negative impact on IVF outcome, higher Zn level in SP, FF and serum might have a positive role in embryo transfer as well as IVF outcome. The role of stress management and nutrition supplementation during the IVF treatment may be explored.

Potentially Toxic Metals in Soil and Dominant Plants from Tonglushan Cu-Fe Deposit, Central China.

Twenty-one soil samples and two dominant plant species (Elsholtzia splendens and Imperata cylindrical) were collected in Tonglushan Cu-Fe deposit, central China. Chemical analysis results showed that the soil contained low-level nutrients and high concentrations of potentially toxic metals. The geoaccumulation index results indicated that the study area was polluted by Cu-Zn-Cd-Pb. The levels of Cu in plant species were highest, followed by Zn, Pb, and Cd. The highest levels of Zn (261mg kg-1), Cd (6.33mg kg-1) and Pb (12.6mg kg-1) were found in the leaf of Elsholtzia splendens and the highest concentration of Cu (1158mg kg-1) was found in the root of Imperata cylindrica. Potentially toxic metals uptake and accumulation abilities were investigated by the bioconcentration factor and translocation factor, respectively. The results suggested that the Elsholtzia splendens may be a suitable candidate for Cd clean up using phytoextraction.

Phenolic metabolism and related heavy metal tolerance mechanism in Kandelia Obovata under Cd and Zn stress

In the present study, a set of pot culture experiments was conducted to reveal how the metabolism process of phenolic compounds was affected by cadmium (Cd) and zinc (Zn) and to further uncover heavy metal tolerance mechanisms in Kandelia obovata. After 60d of treatment, the biomass and chlorophyll a content in the leaves were suppressed, but total phenolic compounds in roots and leaves were improved by the increasing gradient of Cd or Zn concentrations; Total phenolic compounds significantly increased by 3.6–44.6% in the roots, and by 0.4–126.6% in the leaves. At the meantime, the activity of Shikimate dehydrogenase (SKDH), cinnamyl alcohol dehydrogenase (CAD), and polyphenol oxidase (PPO) in the roots increased by 11.2–307.6%, 12.4–175.4% and − 2.7–392.8%, and the results were 3.4–69.5%, 1.7–40.0%, 16.0–99.7% in the leaves. Higher toxicity of Cd than Zn, as well as slight alleviating effect of 100 mg kg−1 Zn on 2.5 mg kg−1 Cd were found. Additionally, a significantly positive correlation coefficients for relationship between phenolic metabolism related enzyme activity and Cd/Zn contamination levels was found, and leaf SKDH, leaf CAD, and leaf PPO activities were moderately correlated with leaf Cd (r = 0.39, r = 0.43, and r = 0.57, respectively) and leaf Zn (r = 0.44, r = 0.41, r = 0.19, respectively) content, which indicate that Cd and Zn play a previously unrecognized but major role in phenolic compounds synthesis, transport, and metabolism in K. obovata. The results also provided evidence that the application of high levels of Cd and Zn was accompanied by three phenolic metabolism pathways participating in heavy metal tolerance process.

A possible etiological factor in obesity: element status in blood and tooth of overweight versus normal-weight children

ABSTRACTWe aimed to assess element status in whole blood and tooth dentin and identify their correlations in overweight or obese children without additional metabolic risk factors. In a case-control study, 40 overweight and 80 normal weight children aged 6–10 years were enrolled. Samples of blood and tooth were collected. While all studied elements were similar in groups in univariate analysis, after adjustment for confounding factors, tooth Mn levels were lower and blood Zn levels were higher in the overweight/obese group (p = 0.049 and p = 0.032, respectively). A significant correlation in blood and tooth dentin levels of Sr and Zn was detected in both groups. In both biological substances, the concentrations of elements did not differ significantly in overweight children without metabolic comorbidities compared to healthy children of normal weight. Presence of low Mn levels in tooth dentin and high Zn levels in blood samples should be explored in further studies.

Metal/metalloid levels in urine and seminal plasma in relation to computer-aided sperm analysis motion parameters

BackgroundExposure to high levels of metals/metalloids may impair semen quality. Computer-aided sperm analysis (CASA) can be used for kinematic analysis of spermatozoa, which provides additional insights into sperm motion characteristics. ObjectiveTo explore the associations of urinary and seminal plasma metal/metalloid concentrations with CASA motion parameters and assess the degree of correspondence between the two sample types. MethodsEighteen metals/metalloids in seminal plasma and repeated urine samples were determined among 746 men recruited from a reproductive center. We assessed their associations with 6 CASA motion parameters [i.e., straight-line velocity (VSL), curvilinear velocity (VCL), average path velocity (VAP), linearity (LIN), straightness (STR) and amplitude head displacement (ALH)] using multivariable linear regression models. ResultsWe found significantly inverse dose-dependent relationships between seminal plasma arsenic (As) and VSL, VCL and VAP, between seminal plasma selenium (Se) and VSL and VAP, between seminal plasma zinc (Zn) and STR and LIN, and between seminal plasma manganese (Mn) and LIN in single-metal models [all false discovery rate (FDR) adjusted P for trend < 0.05]. These dose-response relationships remained statistically significant based on multiple-metal models and restricted cubic spline functions. Metal/metalloid concentrations in urine poorly predicted the same-day seminal plasma concentrations [coefficient of determination (R2) < 0.15]. We didn't find any significant associations between urinary metal/metalloid concentrations and the CASA motion parameters. ConclusionExposure to high levels of As, Se, Mn and Zn may impair sperm motion capacity. Concentrations of metals/metalloids in spot urine samples cannot accurately predict same-day seminal plasma exposure levels.

The lagged effects of environmentally relevant zinc on non-specific immunity in zebrafish

Responses to zinc (Zn) during exposure have well studied but the effects after the exposure are commonly neglected. In the study, non-specific immune response to zinc in blood and spleen of zebrafish was evaluated after exposure. At first, fish were subjected to 0 (control) and 200 μg/L zinc (Zn) for 6 weeks. Specific growth rate, survival rate, blood albumin level, and the activities of Cu/Zn-SOD and iNOS were not significantly changed by Zn exposure. Conversely, Zn increased the levels of globulin and hemoglobin, CAT activity, and mRNA levels of nrf2, sod1, cat, hsf1, hsp70, p65, il-6, il-1β, tnf-α and inos. In the second experiment, zebrafish were transferred to a recovery period for 4 and 8 days. The increased activities of Cu/Zn-SOD and CAT and the up-regulated mRNA levels of nrf2, cat, p65, tnf-α, and inos still were observed. In the third experiment, zebrafish from 4 d post-exposure were re-exposed to the high levels of Zn and cadmium (Cd) (600, 1200 μg/L Zn; 100, 200 μg/L Cd) for 4 days. 100 μg/L Cd caused a higher survival rate in the Zn-exposed fish than the control, suggesting Zn pre-exposure might develop the tolerance to Zn and Cd. Although transcriptional levels of sod1, hsf1, hsf2, hsp70, il-6 and il-1β and activity levels of iNOS recovered to the control levels at 4 and 8 d post-exposure, differences in magnitude of responsiveness were observed between normal fish and Zn-exposed fish. Overall, Zn acclimation persisted when fish recovered, which provides a new perspective about Zn toxicology.

Serum copper and zinc levels and the risk of oral cancer: A new insight based on large-scale case-control study.

Limited evidence exists on the roles of serum copper (Cu) and zinc (Zn) in oral cancer risk. We aimed to preliminarily explore the association between serum Cu and Zn levels and oral cancer risk with relatively large-scale samples. Serum Cu and Zn levels of 344 oral cancer patients and 1,122 matched healthy controls in this case-control study were measured by inductively coupled plasma mass spectrometry (ICP-MS). Restricted cubic spline revealed the U-shaped relationship between serum Cu or Zn levels and the risk of oral cancer. Serum deficient or elevated levels of Cu were significantly associated with the risk of oral cancer: The ORs were 1.38 (95% CI: 1.01-1.89) and 2.82 (95% CI: 1.60-4.98), respectively. The positive association of serum low or high levels of Zn with oral cancer risk was also observed: The ORs were 2.72 (95% CI: 1.60-4.62) and 12.41 (95% CI: 9.09-16.93), respectively. Additionally, there were multiplicative interactions between the aforementioned trace elements and smoking. This preliminary study suggests that both serum excess and deficient levels of Cu or Zn were significant correlation with oral cancer risk, which may provide a new insight on the roles of serum Cu and Zn in oral cancer.

Heavy metals in slag affect inorganic N dynamics and soil bacterial community structure and function

Heavy metal contamination of soil in the vicinity of mining sites is a serious environmental problem around the world when mining residue (slag) is dispersed as dust. We conducted an incubation experiment to investigate the effect of a slag containing high levels of Pb and Zn (62.2 and 33.6 g kg−1 slag as PbO and ZnO, respectively, sampled from a site formerly used as a lead and zinc mine) on the nitrogen cycle when mixed with soil (0–0.048 g slag g−1 soil). The nitrogen cycle provides many life supporting-functions. To assess the quality of the soil in terms of the nitrogen cycle we focused on the dynamics of nitrate and ammonium, and bacterial community structure and functions within the soil. After two weeks of pre-incubation, 15N-labeled urea (500 mg N kg−1) was added to the soil. Changes in soil pH, the concentration and 15N ratio of nitrate (NO3−-N) and ammonium, and bacterial relative abundance and community structure were measured. Results indicated that increasing the ratio of slag to soil had a stronger negative effect on nitrification than ammonification, as suggested by slower nitrate accumulation rates as the slag:soil ratio increased. In the treatment with the highest amount of slag, the concentration of NO3−-N was 50% of that in the controls at the end of the incubation. Regarding the bacterial community, Firmicutes had a positive and Planctomycetes a negative correlation with increasing slag concentration. Bacterial community functional analysis showed the proportion of bacterial DNA sequences related to nitrogen metabolism was depressed with increasing slag, from 0.68 to 0.65. We concluded that the slag impacted the soil bacterial community structure, and consequently influenced nitrogen dynamics. This study could form the basis of further investigation into the resistance of the nitrogen cycle to contamination in relation to soil bacterial community.

Spatial Distribution of Cadmium and Zinc in Soils of Northern North Dakota

Core Ideas Soil Cd and Zn were strongly correlated and characterized by generally similar spatial distribution. Agricultural soils on the Pembina Escarpment and Red River Valley had naturally high total and DTPA‐extractable Cd and Zn. Many soils of the Pembina Escarpment and Red River Valley had naturally high organic C and CEC. Parent materials of high clay content were derived from shale‐enriched glacial till or colluvium, alluvium, and lacustrine deposits. Distribution of Cd and Zn followed the distribution of parent materials and soil CEC, organic carbon, and texture. Cadmium and zinc are trace elements with many geochemical similarities, but Cd is non‐essential and potentially toxic to humans and animals, whereas Zn is an essential micronutrient. Understanding the distribution and availability of these elements in soils is necessary for managing their availability to plants and the accumulation of Cd in edible crops, such as durum wheat. We studied the distribution of Cd and Zn in agricultural soils across the 18 counties of northern North Dakota because this region produces the majority of durum wheat grown in the United States, and many varieties of durum tend to accumulate undesirable levels of Cd in grain. Surface and subsurface soils were sampled and analyzed for concentrations of total and DTPA‐extractable Cd and Zn, pH, organic carbon (OC), and cation exchange capacity (CEC). Soil parent materials were classified based on information in the Soil Survey Geographic database for North Dakota. The spatial dependencies of the concentrations of Cd and Zn, and their (Cd/Zn) were investigated by modeling spatial variograms, and the results used for kriging or co‐kriging to prepare maps of the distribution of these characteristics across northern North Dakota. The distribution of Cd and Zn in these glaciated soils of northern North Dakota appears to be determined largely by the distribution of soil parent materials and by the soil properties CEC, OC, and soil texture. Relatively high levels of Cd and Zn were found in soils derived naturally from clayey shale‐enriched till, colluvium, and lacustrine deposits near the Pembina Escarpment or in the Red River Valley.

Spatial variation of heavy metal contamination in the riparian sediments after two-year flow regulation in the Three Gorges Reservoir, China

Regular impoundment of the Three Gorges Reservoir (TGR) with intensified human activities in the watershed imparts a significant effect on the environmental changes in the riparian zone. In this study, six heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in the riparian sediments of the entire TGR mainstream were investigated in 2014 and 2016 to identify their contamination and risk characteristics and decipher the main factors for the variation of the metal contamination. The results showed that the concentrations of the heavy metals in the sediments did not vary significantly between 2014 and 2016, and their contamination degrees decreased in the order of Cd> > Cu ≈ Zn > Pb > Cr ≈ Ni in 2014 and Cd> > Zn > Cu ≈ Pb > Cr ≈ Ni in 2016. The potential eco-risk of Cd was extremely high in the two years, while the eco-risk of other metals was very low. The sediments showed a moderate to high contamination level, a high potential eco-risk but a low toxic risk to aquatic biota in the two years. Spatially, the contamination and risk levels of heavy metals were relatively higher in the downstream TGR region in 2014 except for the sites close to the urban areas but in the upper-middle TGR region in 2016. Increasing anthropogenic influence contributed to the high contamination and risk levels of Cd, Cu, Pb and Zn in the upper-middle region in 2016. The results indicated that the Cd contamination in the riparian sediments of the TGR was still a vital environmental issue, and the decreased sediment inputs from the upstream major tributaries, the periodic and anti-seasonal flow regulation, local geomorphological characteristics and anthropogenic activities determined the contamination distribution of heavy metals in the riparian sediments.

Solvent strength and biopolymer blending effects on physicochemical properties of zein-chitosan-polyvinyl alcohol composite films

The aim of this research was to optimise and develop edible films made from zein (ZN), chitosan (CS), poly(vinyl alcohol) (PVOH) and poly(ethylene glycol) (PEG400) using Box Behnken Design (BBD). Four factors viz. ZN:CS ratio (w/w) (1:3, 1:1, 3:1), PVOH wt.% (in dry film) (0, 0.25, and 0.5), PEG400 wt% (0.13, 0.21, 0.31) and ethanol (40–80% v/v in water), were investigated. The effects on tensile strength (TS), Young's modulus of elasticity (EM), elongation at break (%EAB), water vapour permeability (WVP), solubility in water (Ws), and optical properties were evaluated. The films were further characterised using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), x-ray diffraction (XRD) and swelling behaviour. SEM micrographs showed that high levels of ZN and PEG400 resulted in rough surfaces with major film defects, but these were minimised at high levels of CS or PVOH. XRD analysis indicated potential interactions through hydrogen bonding between the polar groups of ZN and hydroxyl moieties of PVOH and CS. Stress-strain curves showed that ZN and CS composite films possessed high TS but were brittle. Incorporation of PVOH increased the ductility of the composite films. Optimum films were obtained using ZN/CS/PVOH/PEG400 ratio of 0.35/0.29/0.13/0.23 (wt.%) and 60% ethanol, giving dry state properties of TS, EM, and EAB as 24.21 MPa, 356.62 MPa and 84.23%. respectively. This study demonstrated the influence of critical interactions between solvent features (polarity) and interfacial properties of ZN, CS, PVOH and PEG400. The observed crosslinking behaviour suggested the effectiveness of blending technique in improving the compatibility of biopolymers and overall functionality of edible films.

Insects as sources of iron and zinc in human nutrition.

Dietary deficiencies in Fe and Zn are globally widespread, causing serious health problems such as anaemia, poor pregnancy outcomes, increased risk of morbidity and mortality, stunted growth and impaired physical and cognitive development. Edible insects, of which a diversity of over 2000 species is available, are dietary components for about 2 billion individuals and are a valuable source of animal protein. In the present paper, we review the available information on Fe and Zn in edible insects and their potential as a source of these micronutrients for the rapidly growing human population. The levels of Fe and Zn present in eleven edible insect species that are mass-reared and six species that are collected from nature are similar to or higher than in other animal-based food sources. High protein levels in edible insect species are associated with high Fe and Zn levels. Fe and Zn levels are significantly positively correlated. Biochemically, Fe and Zn in insects occur predominantly in non-haem forms, bound to the proteins ferritin, transferrin and other transport and storage proteins. Knowledge gaps exist for bioavailability in the human alimentary tract, the effect of anti-nutritional factors in other dietary components such as grains on Fe and Zn absorption and the effect of food preparation methods. We conclude that edible insects present unique opportunities for improving the micronutrient status of both resource-poor and Western populations.

Competitive inhibition of cobalt uptake by zinc and manganese in a pacificProchlorococcusstrain: Insights into metal homeostasis in a streamlined oligotrophic cyanobacterium

AbstractIn order to satisfy metabolic requirements for growth, marine cyanobacteria such asProchlorococcusmust acquire cobalt from seawater and synthesize cobalamin cofactors. Through a series of experiments withProchlorococcusstrain MIT 9215 under cobalt limiting conditions, the mechanism ofProchlorococcus' cobalt uptake was investigated. Due to low quotas,ProchlorococcusMIT 9215 can maintain growth at extremely slow rates of cobalt uptake, circa 1 atom per cell per hour. Cobalt quotas were linearly related to the concentration of inorganic cobalt species, Co′, indicating that the metal binding sites on the transporter are strongly unsaturated with respect to cobalt. When limited by cobalt,Prochlorococcusgrowth rates decreased at high levels of both Zn and Mn, suggesting that both metals compete with cobalt for the same transporter. This effect was not observed under a wide range of Fe, Cu, and Ni concentrations, although the onset of exponential growth was delayed at high Ni. These observations agree with prior characterizations of the periplasmic manganese binding protein MntC, which is probably the main pathway for inorganic cobalt uptake and the locus for Mn and Zn competitive inhibition. The toxicity of zinc toward cobalt limitedProchlorococcusMIT 9215 contrasts with the observation of cobalt‐zinc substitution in eukaryotic phytoplankton and is expected to occur at environmentally relevant concentrations of free zinc and cobalt ions. Thus, the ecological success ofProchlorococcusin the modern ocean may depend on access to cobalt complexed by strong organic ligands that are not subject to competitive inhibition by other metals.

Copper and zinc sources and levels of zinc inclusion influence growth performance, tissue trace mineral content, and carcass yield of broiler chickens.

ABSTRACTA 35-d experiment was conducted in broilers to study the effect of supplementation of sulfate or hydroxychloride forms of Zn and Cu at 2 supplemental Zn levels on growth performance, meat yield, and tissue levels of Zn. On day 0, 900 male Ross 308 broiler chicks (45 ± 1.10 g) were allocated to 4 treatments in a randomized complete block design and 2 × 2 factorial arrangement of treatments. The factors were 2 sources (sulfate or hydroxychloride) of Zn and Cu and 2 levels (low or high) of Zn. The Zn sources were zinc sulfate monohydrate (ZSM) or hydroxychloride Zn. Copper sources were copper (II) sulfate pentahydrate or hydroxychloride Cu. Each of the 4 treatments had 15 replicates and 15 birds per replicate. Birds were weighed on days 0, 21, and 35 for growth performance. On day 35, left tibia bone, liver, and blood were collected from 4 randomly selected birds per pen. In addition, 7 birds per pen were used for carcass evaluation. There was no significant source × level interaction on any of the growth performance response. Broiler chickens receiving hydroxychloride Zn and Cu had greater (P < 0.05) gain: feed, whereas broiler chickens receiving lower Zn level had greater (P < 0.01) weight gain. There was no source × level interaction on meat yield. Broiler chickens receiving hydroxychloride Zn and Cu had greater (P < 0.05) % breast yield than those receiving sulfate Zn and Cu. Higher level of Zn, irrespective of source, produced greater (P < 0.01) tibia and plasma Zn levels, whereas liver Cu was greater (P < 0.05) in broiler chickens receiving hydroxychloride Zn and Cu. It was concluded that hydroxychloride Zn and Cu were more efficacious than sulfate Zn and Cu in promoting growth performance and enhancing meat yield in the current study.

Remediation of Heavy Metal Contamination in Paddy Soils through Soil Leaching Combined with Biosorption

Soil contamination and associated pollution plays a detrimental role in the sustainable development of agriculture. In this paper, a novel approach, soil washing combined with biosorption, to remove heavy metal from paddy soil, which contaminated by high levels of Cd, Pb, Cu, Cr and Zn, was evaluated in laboratory-scale batch based on environmental and efficient analysis. The mixture of 3M HCl and 0.2M EDTA solution was used as the leaching agent. Collagen fiber modification persimmon tannin (PTCF) and chitosan functionalization persimmon tannin (PTCS) were used as the biosorbents. The beaker and enlarge experimental results showed that PTCF, PTCS, mixture of PTCF and PTCS can effectively remove five metal ions from leaching liquid of contaminated soil. For the prepared Grade III soil which is critical conditions for the growth of plants (Environmental Quality Standard for Soils/GB 15618-1995), the metal removal efficiency was achieved at 53.36%, 44.89%, 37.73%, 7.60% and 6.02% for Cd, Pb, Cu, Cr and Zn at 10% mixture PTCF and PTCS adsorbent (1:1), respectively. All the results proved that the feasibility of the soil washing combined with biosorption remediation has great potential in the treatment of heavy metal pollution.

Cadmium reduces zinc uptake but enhances its translocation in the cadmium-accumulator, Carpobrotus rossii, without affecting speciation

Interactions between Cd and Zn occur in soils and plants but are inconsistent. This study examined how Cd/Zn interactions influence the growth of Carpobrotus rossii (Haw.) and the accumulation of Cd and Zn in plants. Plants were grown in nutrient solutions containing 5–100 μM Zn and 0, 5 or 15 μM Cd. Plant growth and tissue concentrations were measured, and the speciation of Zn within the plant tissues determined using synchrotron-based X-ray absorption spectroscopy. There was an additive negative interaction between Cd and Zn on root growth. Only the highest level of Zn (100 μM) decreased Cd concentrations in root and shoot tissues (by 40–64%), whilst 100 μM Zn enhanced Cd translocation at 5 μM Cd but decreased it at 15 μM Cd. In contrast, both 5 and 15 μM Cd decreased Zn concentrations in root and shoot tissues but increased Zn translocation by 30–90%. This interaction was not associated with changes in Zn speciation within the plants, with most Zn associated with oxalate (48–87%). The presence of Zn and Cd resulted in an additive negative effect on root growth, but an antagonistic pattern in their accumulation in shoots of C. rossii.

Potentially toxic elements to maize in agricultural soils-microbial approach of rhizospheric and bulk soils and phytoaccumulation.

Maize fields near Mae Tao Creek in Pha Te Village, Tak Province, Thailand are contaminated with Zn, Cd, and Pb. This research studied the interaction between levels of the metals contaminating the soil and maize development, heavy metal accumulation in the seeds, and the soil bacterial community structure. Our field experiment was carried out in five plots with metal contents that gradually decreased from a high level near the creek to a lower level further into the land: Zn 380-4883mgkg-1, Cd 6-85mgkg-1, and Pb 34-154mgkg-1. Cultivation and isolation on nutrient agar (NA) was utilized to study the culturable bacterial community, and polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) was utilized for the unculturable bacterial communities. All statistical analyses clearly indicated that rainfall and irrigation were the main factors affecting total Zn concentration and bioavailable Zn, Cd, and Pb in the field. The variation in the contents of the heavy metals was weakly correlated with the culturable bacterial community indices (Shannon-Wiener, evenness and richness), but the contents resulted in a difference in the overall diversity of the bacteria in the soil. The richness, numbers of culturable rhizobacteria, and maize growth stage significantly affected the amount of Zn and Cd that accumulated in the roots. In addition, maize accumulated a high level of Zn in the seeds, while the low contents of Cd and Pb in the seeds were below our limit of detection. The results obtained could be informative for the management of maize cultivation in the area.

Copper and zinc levels in soil, water, wheat, and hair of inhabitants of three areas of the Orenburg region, Russia

The objective of the present study was to assess the level of zinc and copper in soil, water, wheat and hair of inhabitants of the western, central, and eastern areas of the Orenburg region. A total of 525 water, soil, and wheat samples, as well as 420 hair samples were assessed using atomic absorption spectrometry (water, soil, wheat) and inductively-coupled plasma mass spectrometry (hair). The highest levels of Zn and Cu in water (4.9(4.2–5.1) and 1.0(0.9–1.1) mg/l), soil (23.8(20.7–27.0) and 2.6(1.9–3.1) mg/kg), and wheat (24.7(20.5–31.0) and 4.8(4.2–5.5) mg/kg) were observed in the eastern area (p < 0.001). Hair zinc levels in inhabitants of the western (184(165–198) µg/g) and eastern (224(211–253) µg/g) areas of the region exceeded the respective values from the central area by 32% and 61% (p < 0.001). In turn, hair Cu levels in the central (16.4(14.3–17.8) µg/g) and eastern (17.9(16.4–19.0) µg/g) areas exceeded the values from the western area by 10% and 20%, respectively. Correlation analysis demonstrated that hair Zn levels were positively correlated with water and soil content, whereas wheat Zn levels were associated with soil and water content. For copper significant direct correlation was observed only between soil and water Cu content. In multiple regression models, only water zinc level was significantly associated with hair Zn content, although the general model accounted for 55% of variability of hair Zn content. Higher zinc and copper exposure in the eastern area is presumably associated with higher activity of metal-processing industry.

English

Soybean germplasms were assessed for bioavailable zinc (Zn) and iron (Fe), vitamin A and crude protein using standard methods. Thirty soybean germplasms were investigated. Results were analysed using analysis of variance (ANOVA) and showed statistically significant differences in their Zn, Fe and vitamin A concentrations, as well as in crude protein content (P &lt; 0.05). The Zn content ranged from 5.74 &plusmn; 0.04 to 18.15 &plusmn; 0.05 mg/100 g. TGX 1987-62F had the highest amount of Zn (18.15 &plusmn; 0.05 mg/100 g), while TGX 1485-1D had the least Zn concentration (5.74 &plusmn; 0.04 mg/100 g). The concentration of the Fe ranged from 6.65 &plusmn; 0.05 to 11.58 &plusmn; 0.05 mg/100 g with TGX 1987-62F showing the highest (11.58 &plusmn; 0.05 mg/100 g) and TGX 1987-10F the least (6.65 &plusmn; 0.04 mg/100 g) Fe concentrations. Investigation of the vitamin A content showed that TGX 1951-4F had the highest (8.83 &plusmn; 0.03 mg/L), while TGX 1989-53F had the least (2.48 &plusmn; 0.01 mg/L) vitamin A levels. Crude protein content ranged from 35.40 &plusmn; 0.09 to 57.92 &plusmn; 0.02%. TGX 1989-11F (57.92 &plusmn; 0.02%) showed the highest crude protein content, while TGX 1990-55F showed the least crude protein content (35.40 &plusmn; 0.09%). The germplasm TGX 1987-62F consistently showed high levels of crude protein, Zn and Fe concentrations, but moderate levels of vitamin A, whereas TGX 1989-11F and TGX 1951-4F had the highest levels of crude protein and vitamin A, respectively. No direct correlation with earlier observed genetic and morphological variabilities were observed in terms of bioavailable Fe and Zn, vitamin A and crude protein levels in these soybean germplasms. These genotypes can be widely used in the food industry for the commercial production of high quality protein diet for both human and animal consumption, and can be recommended as good sources of the micronutrients Fe, Zn and vitamin A. &nbsp; Key words: Soybean, diversity, micronutrients, crude protein, iron, zinc, vitamin A. &nbsp

Heavy metal pollution caused by small-scale metal ore mining activities: A case study from a polymetallic mine in South China

Although metal ore mining activities are well known as an important source of heavy metals, soil pollution caused by small-scale mining activities has long been overlooked. This study investigated the pollution of surface soils in an area surrounding a recently abandoned small-scale polymetallic mining district in Guangdong province of south China. A total of 13 tailing samples, 145 surface soil samples, and 29 water samples were collected, and the concentrations of major heavy metals, including Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Pb, and Se, were determined. The results show that the tailings contained high levels of heavy metals, with Cu, Zn, As, Cd, and Pb occurring in the ranges of 739–4.15 × 103, 1.81 × 103–5.00 × 103, 118–1.26 × 103, 8.14–57.7, and 1.23 × 103–6.99 × 103 mg/kg, respectively. Heavy metals also occurred at high concentrations in the mine drainages (15.4–17.9 mg/L for Cu, 21.1–29.3 mg/L for Zn, 0.553–0.770 mg/L for Cd, and 1.17–2.57 mg/L for Pb), particularly those with pH below 3. The mean contents of Cu, Zn, As, Cd, and Pb in the surface soils of local farmlands were up to 7 times higher than the corresponding background values, and results of multivariate statistical analysis clearly indicate that Cu, Zn, Cd, and Pb were largely contributed by the mining activities. The surface soils from farmlands surrounding the mining district were moderately to seriously polluted, while the potential ecological risk of heavy metal pollution was extremely high. It was estimated that the input fluxes from the mining district to the surrounding farmlands were approximately 17.1, 59.2, 0.311, and 93.8 kg/ha/yr for Cu, Zn, Cd, and Pb, respectively, which probably occurred through transport of fine tailings by wind and runoff, and mine drainage as well. These findings indicate the significant need for proper containment of the mine tailings at small-scale metal ore mines.