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Cadmium (Cd) accumulation and pollution in arable soils are particularly serious in the lower reaches of the Minjiang River in southwest of China. In this study, the remediation efficiency of Cd contamination in arable soils, the distribution pattern of Cd concentration in crops, and the food safety to humans of three typical cropping systems (S1: maize + sweet potato-Chinese cabbage, S2: maize + ginger-stem mustard, and S3: rice) were investigated and evaluated. After 1-year rotation, the percentage of Cd extracted by crops from the plough soil layer was observed in three system fields with the trend of S1 (2.30 %) > S2 (1.16 %) > S3 (0.21 %) and Cd extraction amount in crops was maximum in sweet potato, then in maize. The same kind of crop had the same pattern of Cd distribution in organs, and the edible parts generally accumulated less Cd amount than the inedible parts. Further, the grain crops were found to possibly be suitable one for using as phytoaccumulators of Cd contamination for farmlands. Direct consumption of these crops from the three systems would pose a high health risk to local inhabitants since it would result in the monthly intake of Cd (247 μg kg body weight) being nearly 10 times higher than the recommended tolerable monthly intake (RTMI) (25 μg kg body weight), resulting mainly from the consumption of vegetables rather than the grains, which would be potentially reduced by these foods being consumed by livestock firstly. [ABSTRACT FROM AUTHOR]

Heavy metal pollution is a major concern of the public due to their threats to the safety of food chains. A 60-day pot experiment was conducted using Macleaya cordata as plant material to investigate the phytoremediation potential and anti-oxidative responses of M. cordata under different Cd stress. Significant growth inhibition phenomenon and toxic symptoms were not detected in the experiment. The high biomass of the plant provided high accumulation capacity for Cd with an average dry weight of 3.6 g. The maximum extraction amount of Cd was 393 μg·plant, suggesting that this species had potential for phytoremediation of Cd-contaminated soil. A slight increase of chlorophyll (CHL) content was observed in Cd10 treatment. The plant was confirmed to have relatively high tolerance to the Cd stress on the basis of tolerance indexes (TI), relative water content, and CHL/CHL ratio. M. cordata could maintain high level of superoxide dismutase (SOD) activity under Cd stress, indicating strong tolerance capacity for reactive oxygen species (ROS) in plant cells. Catalase (CAT) activity show a certain range of decline in the experiment compare to the control. And peroxidase (POD) activity in leaves changed irregularly when compared to the control. The malondialdehyde (MDA) content increased as Cd concentration elevated compared to the control. In addition, as an inedible crop with relatively high economic value, M. cordata have shown the advantage of high biomass and high tolerance under Cd stress, which can provide a new plant resource for sustainable phytoremediation. [ABSTRACT FROM AUTHOR]

In order to evaluate the exposure risk of lead and cadmium in seafood for coastal residents in the coastline of the South China, representative seafood such as sea fish, crustaceans and molluscs were collected and used as research samples in many sampling points. By determining lead and cadmium content in sample using graphite furnace atomic absorption spectrometry, we carried out a safety evaluation of lead and cadmium contamination of seafood by single factor pollution index method. By calculating lead, cadmium intake of the coastal residents eating seafood, their exposure risk of lead, cadmium was assessed. It was found that, firstly, the content of lead and cadmium in mollusks was both higher than sea fish and crustaceans in the same waters. Secondly, the lead and cadmium pollution in seafood near the mouth of Pearl River was the most serious. Thirdly, lead and cadmium intakes of the coastal population eating seafood were at a basic level of security, but there were certain risks on the males less than 17 years old eating molluscs in Shenzhen Bay. [ABSTRACT FROM AUTHOR]

Free metal ion concentrations have been recognized as a better indicator of metal bioavailability in aquatic environments than total dissolved metal concentrations. However, our understanding of the determinants of free ion concentrations, especially in a metal mixture, is limited, due to underexplored techniques for measuring multiple free metal ions simultaneously. In this work, we performed statistical analyses on a large dataset containing repeated measurements of free ion concentrations of Cu, Zn, Pb, Ni, and Cd, the most commonly measured metals in seawater, at five inshore locations in Boston Harbor, previously collected using an in-situ equilibrium-based multi-metal free ion sampler, the ‘Gellyfish’. We examined correlations among these five metals by season, and evaluated effects of 10 biogeochemical variables on free ion concentrations over time and location through multivariate regressions. We also explored potential clustering among the five metals through a principal component analysis. We found significant correlations among metals, with varying patterns over season. Our regression results suggest that instead of dissolved metals, pH, salinity, temperature and rainfall were the most significant determinants of free metal ion concentrations. For example, a one-unit decrease in pH was associated with a 2.2 (Cd) to 99 (Cu) times increase in free ion concentrations. This work is among the first to reveal key contributors to spatiotemporal variations in free ion concentrations, and demonstrated the usefulness of the Gellyfish sampler in routine sampling of free ions within metal mixtures and in generating data for statistical analyses. [ABSTRACT FROM AUTHOR]

The present study aimed to identify urine metabolites in women exposed to high cadmium (Cd) levels. Twenty-one women exposed to environmental Cd and 12 age-matched controls were categorized as high exposure (urine Cd ≥ 15 μg/g creatinine; n = 9) or low exposure (15 μg/g creatinine > urine Cd > 5 μg/g creatinine; n = 12). Low-molecular weight metabolites in urine were analyzed by gas chromatography and mass spectrometry after derivatization. An orthogonal partial least-squares discriminant analysis model was constructed, and metabolites from the dimensional model were selected according to the variable importance in projection (>1). Metabolites differing significantly in abundance between different exposure groups were identified by searching mass spectral databases, and related pathways were analyzed using the Kyoto Encyclopedia of Genes and Genomes. Approximately 110 significantly different metabolites were detected with variable importance in projection > 1, and 48 of them were found to differ markedly in abundance among the 3 groups. Twenty-seven matched with known metabolites, including 22 significantly increased and 5 markedly decreased in the high-exposure group ( p < 0.01). Kyoto Encyclopedia of Genes and Genomes results indicated that carbohydrate, amino acid, bone, and intestinal flora metabolism and the tricarboxylic acid cycle were affected by Cd exposure. The present study identified metabolites that differed in abundance in response to Cd exposure. Further studies may connect these biomarkers to early damage caused by Cd. Environ Toxicol Chem 2016;35:1268-1275. © 2015 SETAC [ABSTRACT FROM AUTHOR]

The rational for the study was to review the literature on the toxicity and corresponding mechanisms associated with lead (Pb), mercury (Hg), cadmium (Cd), and arsenic (As), individually and as mixtures, in the environment. Heavy metals are ubiquitous and generally persist in the environment, enabling them to biomagnify in the food chain. Living systems most often interact with a cocktail of heavy metals in the environment. Heavy metal exposure to biological systems may lead to oxidation stress which may induce DNA damage, protein modification, lipid peroxidation, and others. In this review, the major mechanism associated with toxicities of individual metals was the generation of reactive oxygen species (ROS). Additionally, toxicities were expressed through depletion of glutathione and bonding to sulfhydryl groups of proteins. Interestingly, a metal like Pb becomes toxic to organisms through the depletion of antioxidants while Cd indirectly generates ROS by its ability to replace iron and copper. ROS generated through exposure to arsenic were associated with many modes of action, and heavy metal mixtures were found to have varied effects on organisms. Many models based on concentration addition (CA) and independent action (IA) have been introduced to help predict toxicities and mechanisms associated with metal mixtures. An integrated model which combines CA and IA was further proposed for evaluating toxicities of non-interactive mixtures. In cases where there are molecular interactions, the toxicogenomic approach was used to predict toxicities. The high-throughput toxicogenomics combines studies in genetics, genome-scale expression, cell and tissue expression, metabolite profiling, and bioinformatics. [ABSTRACT FROM AUTHOR]

In this research, the biosorption of cadmium from aqueous solution byCrataegus oxyacantha(CO) stones andPunica granatum(PG) seeds was studied using batch technique. Experiments were conducted on factors, such as initial pH, biosorbent dosage, contact time, and initial concentration of cadmium. The equilibrium adsorption data were modeled according to Langmuir, Freundlich, and Dubinin–Radushkevich (D–R) isotherms. It was proven that D–R isotherm with a correlation coefficient of 0.991 was more precise for demonstrating adsorption capacity of CO compared to other two models. The Freundlich equation withR2value of 0.996 was used to represent PG adsorption data. By increasing the optimum dosage of PG and CO to 20 g/L, the Cd adsorption was increased to more than 93–95%. Adsorption mechanism was defined by pseudo-first- and pseudo-second-order kinetic models, and it was found that it follows a pseudo-second-order kinetic algorithm. The study showed that the PG and CO can be suitable adsorbents with high absorption capacities for removing Cd(II) from solution. [ABSTRACT FROM PUBLISHER]

Background: An Annex XV restriction dossier for cadmium in artists' paints was submitted by an EU member state to the European Chemicals Agency ECHA. By cleaning, used brushes under the tap cadmium can enter the food chain via waste water treatment and subsequent agricultural application of the sewage sludge. It was estimated that 110 kg Cd per year is spread on agricultural land via this exposure route. Other sources of Cd amount to almost 120 tons per year. Results: The mobility of Cd from pigments was studied in a field-like scenario by leaching experiments using soil samples amended with sewage sludge and spiked with Cd pigments in percolation columns. The redox conditions were confirmed to be the decisive factor for the release of Cd. The release of Cd from artists' paints was in most cases 1 % or lower in the experiments performed. Conclusions: Application of sewage sludge containing Cd from artist paints does not increase the amount of Cd leached from this soils. Furthermore, the quantity of Cd from artists' paints calculated in the restriction dossier is negligible compared to other sources of Cd to agricultural soil. Therefore, ECHA did not consider the proposed restriction to be the most appropriate EU wide measure to address the negligible level of risk. [ABSTRACT FROM AUTHOR]

Micellar-enhanced ultrafiltration (MEUF) was applied to remove cadmium ion from wastewater using sodium dodecyl sulfate (SDS) as a micelle in this study. Investigations were carried out on operational parameters such as initial permeate flux, retentate pressure, initial cadmium concentration, pH solution, molecular weight cut-off (MWCO), and molar ratio of cadmium to SDS. Removal efficiency of cadmium increased with increase in retentate pressure, pH solution, and molar ratio of cadmium to SDS and decreased with increase in initial permeate flux. Higher removal efficiency of cadmium was achieved using lower MWCO. In optimized experimental condition, cadmium removal efficiency reached 75% within an hour. With MEUF–ACF hybrid process, removal efficiencies of cadmium and SDS were found to be over 99 and 90%, respectively. Freundlich isotherm equation fitted better with experimental results on adsorption of SDS by ACF than Langmuir isotherm equation. Overall SDS removal efficiency of ACF unit in series was 90%. [ABSTRACT FROM AUTHOR]

Concentrations of total mercury (THg) and total cadmium (TCd) were determined in muscle and liver of ringed seals ( Pusa hispida ) from up to 14 locations across the Canadian Arctic. Location, trophic position (TP) and relative carbon source best predicted the THg and TCd concentrations in ringed seals. THg concentrations in ringed seals were highest in the western Canadian Arctic (Beaufort Sea), whereas TCd was highest in the eastern Canadian Arctic (Hudson Bay and Labrador). A positive relationship between THg and TP and a negative relationship between THg and relative carbon source contributed to the geographical patterns observed and elevated THg levels at certain sites. In contrast, a negative relationship between TCd and TP was found, indicating that high TCd concentrations are related to seals feeding more on invertebrates than fish. Feeding ecology appears to play an important role in THg and TCd levels in ringed seals, with biomagnification driving elevated THg levels and a dependence on low-trophic position prey resulting in high TCd concentrations. The present study shows that both natural geological differences and diet variability among regions explain the spatial patterns for THg and TCd concentrations in ringed seals. [ABSTRACT FROM AUTHOR]

Eggshell waste was successfully used for the removal of heavy metal ions from model solutions. The effect of ball milling on the structure and adsorption ability of eggshell (ES) and its membrane (ESM) was investigated, with the conclusion that milling is benefitial only for the ES. The adsorption experiments showed that the ESM is a selective adsorbent, as the adsorption ability toward different ions decreased in the following order: Ag(I) > Cd(II) > Zn(II). The obtained Q m values for Ag(I) adsorption on the ESM and ES were 52.9 and 55.7 mg g −1 , respectively. The potential industrial application of ES was also demonstrated by successful removal of Ag(I) from the technological waste. [ABSTRACT FROM AUTHOR]

Toxicokinetic – toxicodynamic energy-based models offer new alternatives to the commonly used approaches for the analysis of mixture toxicity data. Based on the Dynamic Energy Budget theory, DEBtox models enable the description of several endpoints over time simultaneously under the same framework. However, such model still has to be faced with experimental data in a multi-contamination context. In this study, the predictive capacities of a DEBtox model to describe the uranium and cadmium joint toxicity over the entire growth and reproduction period of the soil nematode Caenorhabditis elegans was examined. The two reference additivity approaches, Concentration Addition and Response addition, implemented in the DEBtox model were tested. Assuming no interaction between the two toxicants through Response addition, the DEBtox model allowed a rather accurate fit of the U and Cd joint effects on the growth and reproduction of C. elegans : an interaction between the two metals at the toxicokinetic or toxicodynamic level seems thus unlikely or has only minor consequences. Interestingly, this study underlines that even if the compounds of a mixture share the same DEBtox physiological mode of action (in this case a decrease in assimilation), the Response addition approach may provide a better fit of joint toxicity data than the Concentration addition approach. Moreover, the present work highlighted limitations in the model predictions which are related to the simplifications of the DEBtox framework and its adaptations to the physiology of C. elegans and which lead to an overestimation of the U and Cd joint toxicity in some cases. [ABSTRACT FROM AUTHOR]

Since mudsnails are able to avoid contaminated sediment and that the contaminants in sediment are not uniformly distributed, the mudsnail Peringia ulvae was exposed to cadmium (Cd) spiked sediment and assessed for avoidance response in a heterogeneous contamination scenario. Four Cd concentrations were prepared and disposed in patches on dishes, which were divided in 25 fields (six fields for each sediment concentration); 24 organisms were deployed in the central field, with no sediment. Observations were made at 2, 4 and 6 h (corresponding to immediate response), 8, 10 and 12 h (very short term), and 24 h (short term). A trend to avoid contaminated patches was observed in the immediate and very short term. After 24 h exposure, the organisms exposed to the highest level of contamination seemed to have lost the ability to move and avoid contaminated patches. In a contamination scenario in which non- and contaminated sediment patches are heterogeneously distributed, local mudsnail populations can simply rearrange their locality without needing to move to a different habitat. Such less contaminated patches can become donor areas in a future recolonization scenario. [ABSTRACT FROM AUTHOR]

To better understand the fate of metals in the environment, numerous parameters must be studied, such as the soil properties and the different sources of contamination for the organisms. Among bioindicators of soil quality, the garden snail ( Cantareus aspersus) integrates multiple sources (e.g. soil, plant) and routes (e.g. digestive, cutaneous) of contamination. However, the contribution of each source on metal bioavailability and how soil properties influence these contributions have never been studied when considering the dynamic process of bioavailability. Using accumulation kinetics, this study showed that the main assimilation source of Cd was lettuce (68 %), whereas the main source of Pb was the soil (90 %). The plant contribution increased in response to a 2-unit soil pH decrease. Unexpectedly, an increase in the soil contribution to metal assimilation accompanied an increase in the organic matter (OM) content of the soil. For both metals, no significant excretion and influence of source on excretion have been modelled either during exposure or depuration. This study highlights how the contribution of different sources to metal bioavailability changes based on changes in soil parameters, such as pH and OM, and the complexity of the processes that modulate metal bioavailability. [ABSTRACT FROM AUTHOR]

Vermicomposting is an eco-friendly technology, where earthworms are introduced in the waste, inter alia sewage sludge, to cooperate with microorganisms and enhance decomposition of organic matter. The main aims of the present study was to determine the influence of two different earthworm species, Eisenia fetida and Eisenia andrei, on the changes of selected metallic trace elements content in substratum during vermicomposting process using three different sewage sludge mainly differentiated by their metal contents. Final vermicompost has shown a slight reduction in Cd, Cu, Ni, and Pb, while the Zn concentration tends to increase. Accumulation of particular heavy metals in earthworms' bodies was assessed. Both species revealed high tendency to accumulate Cd and Zn, but not Cu, Ni, and Pb, but E. andrei has higher capabilities to accumulate some metals. Riboflavin content, which content varies depending on metal pollution in several earthworms species, was measured supravitaly in extruded coelomocytes. Riboflavin content decreased slightly during the first 6 weeks of exposure and subsequently restored till the end of the 9-week experiment. Selected agronomic parameters have also been measured in the final product (vermicompost) to assess the influence of earthworms on substratum. [ABSTRACT FROM AUTHOR]

A field experiment was established to support the hypothesis that application of different silicon (Si) fertilizers can simultaneously reduce cadmium (Cd) and arsenic (As) concentration in rice grain. The 'semi-finished product of Si-potash fertilizer' treatment at the high application of 9000 kg/ha (NP+S-KSi9000) significantly reduced the As concentration in rice grain by up to 20.1 %, compared with the control. Si fertilization reduces the Cd concentration in rice considerably more than the As concentration. All Si fertilizers apart from sodium metasilicate (NaSiO) exhibited a high ability to reduce Cd concentration in rice grain. The Si-calcium (CaSi) fertilizer is the most effective in the mitigation of Cd concentration in rice grain. The CaSi fertilizer applied at 9000 kg/ha (NPK+CaSi9000) and 900 kg/ha (NPK+CaSi900) reduced the Cd concentration in rice grain about 71.5 and 48.0 %, respectively, while the Si-potash fertilizer at 900 kg/ha (NP+KSi900), the semi-finished product of Si-potash fertilizer at both 900 kg/ha (NP+S-KSi900) and 9000 kg/ha (NP+S-KSi9000), and the rice straw (NPK+RS) treatments reduced the Cd concentration in rice grain about 42, 26.5, 40.7, and 23.1 %, respectively. The results of this investigation demonstrated the potential effects of Si fertilizers in reducing Cd and As concentrations in rice grain. [ABSTRACT FROM AUTHOR]

This study focused on the expression analysis of antioxidant defense genes in Brassica oleracea and in Trifolium repens. Plants were exposed for 3, 10, and 56 days in microcosms to a field-collected suburban soil spiked by low concentrations of cadmium and/or lead. In both species, metal accumulations and expression levels of genes encoding proteins involved and/or related to antioxidant defense systems (glutathione transferases, peroxidases, catalases, metallothioneins) were quantified in leaves in order to better understand the detoxification processes involved following exposure to metals. It appeared that strongest gene expression variations in T. repens were observed when plants are exposed to Cd (metallothionein and ascorbate peroxidase upregulations) whereas strongest variations in B. oleracea were observed in case of Cd/Pb co-exposures (metallothionein, glutathione transferase, and peroxidase upregulations). Results also suggest that there is a benefit to use complementary species in order to better apprehend the biological effects in ecotoxicology. [ABSTRACT FROM AUTHOR]

This work focuses on the exposure of maize plants to nanomolar concentrations of Cd, which is relevant for agricultural soils cropped with food and feed plants. Maize plants were cultivated in nutrient solution at 0.8 or 20 nM Cd during the vegetative growth stages. No significant hormesis or toxic effects of Cd were observed on maize growth, but a decrease in the allocation of Cd to shoots between the 0.8 and 20 nM Cd exposures revealed that the plants already responded to these low concentrations of Cd according to a shoot Cd excluder strategy. The Cd, Cu and Zn concentrations in shoots decreased with time as the result of an early decrease in the root/shoot ratio and of a decrease in the coefficient of allocation to aboveground for Zn and Cd at 20 nM. As a consequence, shoots of young plants were richer in micronutrients Cu and Zn but also in toxic Cd. The rate of delivery of Cd, Cu and Zn from xylem sap was successfully used to predict the time course of concentrations of Cd, Cu and Zn in the shoot. However, it overestimated the actual concentrations of Cd in the shoot, presumably because the reallocation of this trace element from shoots back to roots was not taken into account. [ABSTRACT FROM AUTHOR]

In order to understand the physiological response of oilseed rape ( Brassica napus L.) leaves to cadmium (Cd) stress and exploit the physiological mechanisms involved in Cd tolerance, macro-mineral and chlorophyll concentrations, reactive oxygen species (ROS) accumulation, activities of enzymatic antioxidants, nonenzymatic compounds metabolism, endogenous hormonal changes, and balance in leaves of oilseed rape exposed to 0, 100, or 200 μM CdSO were investigated. The results showed that under Cd exposure, Cd concentrations in the leaves continually increased while macro-minerals and chlorophyll concentrations decreased significantly. Meanwhile, with increased Cd stress, superoxide anion (O) production rate and hydrogen peroxide (HO) concentrations in the leaves increased significantly, which caused malondialdehyde (MDA) accumulation and oxidative stress. For scavenging excess accumulated ROS and alleviating oxidative injury in the leaves, the activity of enzymatic antioxidants, such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), was increased significantly at certain stress levels. However, with increased Cd stress, the antioxidant enzyme activities all showed a trend towards reduction. The nonenzymatic antioxidative compounds, such as proline and total soluble sugars, accumulated continuously with increased Cd stress to play a long-term role in scavenging ROS. In addition, ABA levels also increased continuously with Cd stress while ZR decreased and the ABA/ZR ratio increased, which might also be providing a protective role against Cd toxicity. [ABSTRACT FROM AUTHOR]

The response specificity of three metallothionein ( MT) genes ( CdMT, CuMT and Cd/CuMT) was assessed after long-term exposure (20 days) of Cantareus aspersus eggs to cadmium (Cd) (2 to 6 mg/L) or to the fungicide Bordeaux mixture (BM) (2.5 and 7.5 g/L). MT gene expression measured by quantitative real-time PCR (qRT-PCR) revealed that in the unexposed embryos, the transcript levels of the three MT genes decreased significantly through embryonic development. However, the CdMT gene was strongly upregulated with increasing Cd exposure concentration, whereas the transcript levels of the other two genes increased less pronouncedly, but significantly above an exposure concentration of 4 mg Cd/L. Upon exposure to BM, all three MT genes were significantly upregulated above a BM concentration of 2.5 g/L. It is concluded that long-term Cd exposure in hatched snails induced patterns of MT gene expression that differed from those obtained after short-term exposure (24 h). [ABSTRACT FROM AUTHOR]

The article discusses various papers published in this issue including one by Pauget et al. on metal bioavailability and contamination, one by Cornu et al. on soil-to-plant transfer of cadmium and zinc, and one by Lebrun et al. on soil fungi.

Evidence exists that Cd and certain nutrient elements, such as Fe and Mg, could share similar mechanisms of plant uptake and accumulation. Here we report that Mg and Fe deficiency in mature plants ofSalix viminalis, grown in hydroponic solutions containing 5 µg ml−1of Cd, caused a significant increase in Cd accumulation in roots, stems and leaves. Cd (µg g−1dry weight) was determined following three treatments: 1) Cd treatment in complete nutrient solution; 2) Cd treatment with Fe deficiency; and 3) Cd treatment with Mg deficiency, yielding, respectively: in young leaves (65.3, 76.1, and 92.2), mature leaves (51.5 to 76.3 and 87.1), upper stems (80.6, 116.8, and 130.6) lower stems (67.2, 119, and 102.3), roots (377.1, 744.8, and 442,5). Our results suggest that Cd utilizes the same uptake and transport pathways as Mg and Fe. Evidence exists that Mg and Fe uptake and translocation could be further facilitated by plants as an adaptive response to deficiency of these elements. Such physiological reaction could additionally stimulate Cd accumulation. Although Cd uptake was mostly confined in roots, high Cd content in aerial plant parts (51.5–130.6 µg g−1) indicates that the analysedSalix viminalisgenotype is suitable for phytoextraction. [ABSTRACT FROM AUTHOR]

The potentials ofAdansonia digitataroot powders (ADRP) for adsorption of Pb2+, Cd2+and Cu2+from aqueous solutions was investigated. Physico-chemical analysis of the adsorbent (ADRP) shows that hydroxyl, carbonyl and amino groups were predominant on the surface of the adsorbent. Scanning Electron Microscope (SEM) image revealed its high porosity and irregular pores in the adsorbent while the Energy Dispersive X-ray Spectrum showed the major element with 53.0% Nitrogen, 23.8% carbon, 9.1% calcium, 7.5% potassium and 6.6% magnesium present. The found optimal conditions were: initial concentration of the metal ions = 0.5 mg/L, pH = 5, contact time = 90 min, adsorbent dose = 0.4 g and particle size = 32 µm. Freundlich isotherm showed good fit for the adsorption of Pb2+, Cd2+and Cu2+. Dubinin-Radushkevich isotherm revealed that the adsorption processes were physisorption Cd(II) and Cu(II) but chemisorption with respect to Pb(II) ions. The kinetics and thermodynamic studies showed that Pseudo-second order and chemisorptions provided the best fit to the experimental data of Pb (II) ions only. Batch desorption result show that desorption in the acidic media for the metal ions were more rapid and over 90% of the metal ions were recovered from the biomass. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) contamination in rice in Youxian, Hunan, China is a major environmental health concern. In order to reveal the Cd contamination in rice and paddy soils and the health risks to the population consuming the local rice grain, field surveys were conducted in eight towns in Youxian, China. The Cd contents of paddy soils averaged 0.228–1.91 mg kg −1 , 90% exceeding the allowable limit of 0.3 mg kg −1 stipulated by the China Soil Environmental Quality Standards. Low average pH values (for air dried oxidized soils) ranging from 4.98 to 6.02 in paddy soil were also found. More than seventy percent (39 of 53) of the grain samples exceeded the maximum safe concentration of Cd, 0.2 mg kg −1 on a dry weight basis. Considering the high consumption of local rice (339 g capita −1 DW d −1 ) and Cd levels measured, dietary ingestion of 78% of the sampled rice grains would have adverse health risks because the intake exposure of Cd was greater than the JECFA recommended exposures, 0.8 µg Cd BW kg −1 day −1 or 25 µg Cd BW kg −1 month −1 . [ABSTRACT FROM AUTHOR]

Cadmium is released into the environment in increasing amounts from different natural and anthropogenic activities contaminating the aquatic habitats. Amphibian tadpoles develop in water and hence are likely to be adversely affected by cadmium present in the aquatic environment. We have studied the toxic and genotoxic effects of CdCl 2 on the tadpoles of Rana limnocharis . CdCl 2 in the concentration range between 0.1 and 0.4 mg/L induced significant mortality in R. limnocharis tadpoles in a dose and time dependent manner. The 10-day LC 50 which has more ecological relevance was far less than the 24-h LC 50 . Tadpoles exposed to CdCl 2 metamorphosed at an early age possibly as a survival strategy to move out of the stressful environment. The body weight of the CdCl 2 exposed animals at metamorphosis was lower compared to the control individuals which may affect survival and reproductive fitness in adult life. Besides, the average body length of the metamorphosed individuals in the CdCl 2 exposed group was higher than the control group. CdCl 2 was found to be genotoxic in micronucleus test and comet assay. The ambient concentration of Cd could reach up to 60 μg/L or more. Exposure to 18.5 μg/L of CdCl 2 (1% of 24-h LC 50 ) induced significant increase in DNA strand breaks as compared to the control. The present findings demonstrate that presence of cadmium in the aquatic environment can significantly alter the life history traits and cause DNA damage in amphibians and hence, could contribute towards their population decline. [ABSTRACT FROM AUTHOR]

Co-occurrence of pesticides such as synthetic pyrethroids and metals in aquatic ecosystems raises concerns over their combined ecological effects. Cypermethrin, 1 of the top 5 synthetic pyrethroids in use, has been extensively detected in surface water. Cadmium (Cd) has been recognized as 1 of the most toxic metals and is a common contaminant in the aquatic system. However, little information is available regarding their joint toxicity. In the present study, combined toxicity of cypermethrin and Cd and the underlying mechanisms were investigated. Zebrafish embryos and adults were exposed to the individual contaminant or binary mixtures. Co-exposure to cypermethrin and Cd produced synergistic effects on the occurrence of crooked body, pericardial edema, and noninflation of swim bladder. The addition of Cd significantly potentiated cypermethrin-induced spasms and caused more oxidative stress in zebrafish larvae. Cypermethrin-mediated induction of transcription levels and catalytic activities of cytochrome P450 (CYP) enzyme were significantly down-regulated by Cd in both zebrafish larvae and adults. Chemical analytical data showed that in vitro elimination of cypermethrin by CYP1A1 was inhibited by Cd. The addition of Cd caused an elevation of in vivo cypermethrin residue levels in the mixture-exposed adult zebrafish. These results suggest that the enhanced toxicity of cypermethrin in the presence of Cd results from the inhibitory effects of Cd on CYP-mediated biotransformation of this pesticide. The authors' findings provide a deeper understanding of the mechanistic basis accounting for the joint toxicity of cypermethrin and Cd. Environ Toxicol Chem 2016;35:435-445. © 2015 SETAC [ABSTRACT FROM AUTHOR]

Borago officinalis has successfully been evaluated as a biosorbent for the removal of cadmium and manganese from aqueous solutions in batch and column systems. Maximum biosorption for Cd and Mn ions was obtained at original pH values of the solutions. The temperature-independent and fast biosorption of Cd and Mn onto B. officinalis could be observed. The biosorption data were successfully correlated with the pseudo-second-order kinetic and Langmuir isotherm models. The maximum monolayer biosorption capacities were found to be 40.26 and 20.42 mg g−1 for Cd and Mn, respectively. Column studies were carried out at the optimum flow rate of 1.0 and 0.5 mL min−1 for Cd and Mn, respectively. The highest desorption yield could be achieved using 0.01 M HNO3 as desorbing agent. Fourier transform infrared spectrometry, scanning electron microscopy, transmission electron microscopy, Brunauer, Emmett and Teller analysis and energy dispersive X-ray spectroscopy showed that the biosorption of Cd and Mn onto B. officinalis involved different mechanisms mainly electrostatic interaction, complexation and chemical-ion exchange. As a conclusion, this study indicated that B. officinalis could be an ecofriendly biosorbent and could effectively remove Cd and Mn from aqueous solutions. [ABSTRACT FROM AUTHOR]

In the present study, the effect of contact time, adsorbent dosage, and initial cadmium concentration on the adsorption of Cd(II) ions from aqueous solutions by pre-conditioned phosphogypsum was investigated. The kinetics of adsorption was studied and, pseudo-first-order, pseudo-second-order, and Elovich models were used to fit the experimental data, which was obtained from batch experiments. The kinetic adsorption data fitted well into the second-order kinetic model. Adsorption mechanism was explained with the intraparticle diffusion and Boyd kinetic models. [ABSTRACT FROM PUBLISHER]

Adsorption of Cd by dried biomass of the freshwater mossVesicularia dubyanafrom model solutions under conditions of batch and continuous column systems was studied using γ-spectrometry and109CdCl2as radiotracer. The Cd adsorption by moss biomass was a rapid process and concentration equilibrium was reached within 60 min of exposure. The efficiency of the adsorption process and removal of Cd from the solutions was significantly dependent on the value of pH (2–8), initial concentration of CdCl2(20–320 μM) and changes in Cd speciation induced by the presence of Cl−anions in the solutions. Experimental data of Cd adsorption by designed packed bed column system comprising dried moss biomass at an initial concentration 36 mg/l CdCl2and flow rate 0.80 ml/min of solution in the column were well described by adsorption kinetic models according to the Clark (R2 = 0.981), Thomas (R2 = 0.964) or Yoon–Nelson (R2 = 0.962) and modified dose–response (R2 = 0.954) models. The suitability of the mentioned models was also evaluated on the basis of differences in the values of root mean square errors, residual sum of squares or corrected Akaike’s information criterion. Adsorbed Cd was removed from the dried moss biomass with high efficiency (>92%) by desorption with 0.1 M HCl or EDTA-Na2solutions under batch conditions, whereby the desorption efficiencyDeffdecreased in the order: 0.1 M HCl (93%) ≈ 0.1 M EDTA-Na2(92%) > 0.1 M ZnCl2(85%) > deionized water (20%). The high desorption efficiency in the case of 0.1 M EDTA-Na2was also confirmed under conditions of a continuous column system. [ABSTRACT FROM PUBLISHER]

Dinoflagellate algal blooms (DABs), with Lingulodinium polyedrum as the dominant species, have increased over the past few years in coastal areas off Baja California, Mexico. Vertical and temporal variability of particulate cadmium (Cd p ), dissolved Cd (Cd d ), PO 4 3 − and Cd d /PO 4 3 − were investigated during two intense DABs of L. polyedrum that occurred during the fall of 2011 and 2012 in Todos Santos Bay. Results were then, compared with data gathered in the absence of algal blooms during the autumn of 2013. In both algal blooms, L. polyedrum tended to be concentrated near the surface throughout the duration; however, during DAB 2011 the number of cells was twice as abundant ([10.0 ± 8.0] × 10 5 cells L − 1 ) as in DAB 2012 ([5.0 ± 4.4] × 10 5 cells L − 1 ). During DAB 2011, Cd p increased significantly (up to 1.02 ± 0.99 nmol kg − 1 ) and was positively correlated with the cell abundance of L. polyedrum , suggesting that this dinoflagellate is able to assimilate and concentrate Cd d . Likewise, Cd d (up to 0.71 ± 0.17 nM) increased in the days of highest cell abundance, which could be attributed to uptake and subsequent regeneration of Cd d resulting from the remineralization of organic particulate matter produced during the bloom, as well as with the presence of organic ligands secreted by L. polyedrum that could keep Cd d in solution. During DAB 2011, dissolved Cd d /PO 4 3 − ratios exhibited high vertical and temporal variability in the upper 5 m of the water column, but remained virtually constant near the bottom, suggesting a depth-dependent decoupling between these two dissolved components during the bloom development. Given the observed differences in the vertical and temporal variability of Cd d , Cd p , and PO 4 3 − between these two intense DABs, we propose the existence of an abundance threshold of approximately 10 6 cells L − 1 of L. polyedrum above which Cd and PO 4 3 − significantly increased due to remineralization in coastal waters during the bloom development. [ABSTRACT FROM AUTHOR]

This study was designed to investigate a prevalent brominated flame retardant tetrabromobisphenol A (TBBPA) and four heavy metals of Pb, Cr, As, Cd in dust samples (52 indoor and 52 outdoor) collected from residential houses in an e-waste recycling area in Southeast China. For TBBPA, the mean concentration in indoor dust (3435 ng/g, dw) was higher than that in outdoor dust (1998 ng/g, dw). For heavy metals, the mean concentrations of Pb, Cr, As, Cd were 399, 151, 48.13, and 5.85 mg/kg in indoor dust, respectively, and were 328, 191, 17.59, and 4.07 mg/kg in outdoor dust, respectively. Except for As, concentrations of TBBPA and other metals decreased with the increased distance away from the e-waste recycling center, suggesting significant contribution of e-waste activities. The daily exposure doses of TBBPA ranged from 0.04 to 7.50 ng/kg-bw/day for adults and from 0.31 to 58.54 ng/kg-bw/day for children, representing the highest values reported to date for TBBPA exposure via dust ingestion. Daily exposure doses of Cr, As, and Cd were all below the reference doses. However, daily exposure dose of Pb for children in areas near the e-waste processing center was above the reference dose, posing significant health concern for children in that region. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) contaminated in rice grains is a serious problem because most Asians consume rice on a daily basis. Rice grown in Cd-contaminated soil normally did not have high concentration of Cd. However, soil samples used in this study had high concentrations of Cd. The purpose of this study was to clearly see the effects of biochar and microorganism addition in rice growing in Cd-contaminated soil. The initial Cd concentration in Cd-contaminated soil used in this study was about 650 mg kg. Cadmium concentration in rice plants grown in Cd-contaminated soil with the addition of 1 % ( w/ w) different biochars such as sawdust fly ash (SDFA), bagasse fly ash (BGFA), and rice husk ash (RHA) was investigated. The results showed that SDFA was the best biochar in terms of reducing cadmium accumulation in rice grains when compared to BGFA and RHA under the same conditions. In addition, rice plants grown in Cd-contaminated soil with the addition of various nonpathogenic microorganisms, such as Pseudomonas aeruginosa, Bacillus subtilis, and Beauveria bassiana were also studied. The results showed that the addition of 2 % ( v/ v) microorganisms can reduce Cd accumulation in grains. It was found that grains obtained from Cd-contaminated soil with the addition of P. aeruginosa had the lowest cadmium concentration compared to the ones from soil amended with other strains. This was due to the fact that P. aeruginosa adsorbed more Cd itself into its cells than other strains. The rice plants grown in Cd-contaminated soil with the addition of biochars and microorganisms were also compared. The results showed that adding 2 % ( v/ v) microorganisms seemed to reduce Cd accumulation in rice grains better than adding 1 % ( w/ w) biochars. In addition, the amounts of calcium and magnesium in rice grains and the dry weight of plant in Cd-contaminated soil amended with P. aeruginosa were the highest in comparison to other microorganisms, biochars, and the soil without any amendments (Cd-soil control). It might be possible that microorganisms can cause leaching of Ca, Mg, etc. from contaminated soil and compete with Cd to be uptaken by plants. This would cause the increase in plant dry weight and higher mineral nutrients accumulation in grains. Both biochars and microorganisms are suitable for reducing the amount of Cd in rice grains. The application should depend on farmers, biochars available in nearby areas, etc. Therefore, microorganisms and biochars can be used to solve the problem of cadmium contamination in rice grains. [ABSTRACT FROM AUTHOR]

Pristine chitosan beads were modified with sulfur (S)-containing functional groups to produce thiolated chitosan beads (ETB), thereby increasing S donor ligands and crosslinks. The effect of temperature, heating time, carbon disulfide (CS)/chitosan ratio, and pH on total S content of ETB was examined using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The total S content of ETB increased with increasing CS/chitosan ratio and decreased with decreasing pH and increasing temperature (>60 °C) and heating time (at 60 °C). Spectroscopic analyses revealed the presence of thiol (-SH)/thione, disulfide (-S-S-), and sulfonate groups in ETB. The thiolation mechanism involves decomposition of dithiocarbamate groups, thereby forming thiourea crosslinks and trithiocarbonate, resulting in -SH oxidation to produce -S-S- crosslinks. The partially formed ETB crosslinks contribute to its acid stability and are thermodynamically feasible in adsorbing Cd and Cu. The S-containing functional groups added to chitinous wastes act as sorbents for metal remediation from acidic environments. [ABSTRACT FROM AUTHOR]

To examine the differences in root morphological responses of soybean cultivars with different cadmium (Cd) tolerance and accumulation to Cd stress, the biomass, Cd concentration, and root morphological features of five soybean cultivars were determined under 0, 9, 23, 45, and 90 μM Cd stress via hydroponic experiments. Significantly genotypic differences in Cd tolerance and Cd concentration were observed between five soybean cultivars at four Cd levels. For Cd tolerance, HX3 showed a strong Cd tolerance with tolerance indexes of shoot biomass at 92.49, 76.44, 60.21, and 46.45 % after 18 days at four Cd levels, and others had similar weak tolerance at young seedling. For Cd accumulation, Cd concentration in roots showed far higher than that in shoots. The different accumulation features in roots and shoots among five cultivars were found at four Cd levels. Comparing with the control, the total root length (RL), root surface area (SA), and root volume (RV) of all cultivars were decreased significantly at four Cd levels. Tolerant cultivar HX3 had the largest root system and sensitive cultivar BX10 had the smallest root system at young seedling stage. Correlation analysis indicated that RL, SA, and RV were positively correlated with root biomass and shoot biomass under 9 and 23 μM Cd treatments, but root average diameter (RD) was negatively correlated with shoot biomass and root biomass only under 9 μM Cd treatments, while RL and SA were negatively correlated with root Cd concentration under 23 and 45 μM Cd treatments. The results suggested that root morphological traits were closely related to Cd tolerance at young seedlings under Cd treatments. [ABSTRACT FROM AUTHOR]

A seasonal environmental monitoring program was carried out (winter 2009 to summer 2010) to evaluate the spatial and seasonal cadmium concentrations in the intertidal environments of the Óbidos Lagoon (Portugal). Also, some environmental parameters were monitored at each sampling station. Both the water and the sediment samples were contaminated, although to different degrees. In general, cadmium contamination appears to be mostly focused on the inner areas of the lagoon, namely, in Barrosa's arm, which receives a small tributary contaminated by agro-industrial activities. Only cadmium concentration in sediment showed to be significantly influenced by seasons. Some environmental parameters presented spatial and temporal heterogeneity which influenced, to some extent, cadmium bioavailability. The results of this study allow a better understanding of the environmental quality of this ecosystem regarding cadmium contamination and may assist in the definition of future coastal management measures specifically targeted to trace metal contamination and pollution monitoring. [ABSTRACT FROM AUTHOR]

Mulberry leavesare rich in plant polyphenol and flavonoid. Amounts of hydroxyl and hydroxyl functional groups are distributed on the surface, which can be absorbed with heavy metal ions by complexation and electrostatical processes. However, there are commonly soluable tannic in organisms and it is not suitable to use organisms to remove Cd from waste water. In this study, mulberry leaves were used as the experimental materials and were boiled and modified with 1 mol/L H3PO4 to prepare an adsorbent for cadmium. Results show that the absorption effect of modified mulberry leaves to Cd(Ⅱ) is best when pH is 4.0. When the initial concentration of Cd is 150 mg/L,6 g/L modified mulberry leaves have absorption recovery of 96.58%. The adsorption process of modified mulberry leaves to Cd(Ⅱ) adheres to the pseudo-second order equation. The isothermal adsorption process of cadmium with modified mulberry leaves fits the Langmuir model well. Maximum absorption capacity of Cd(Ⅱ) on the chemically modified mulberry leaf absorbent is 30.58 mg/g, which is higher than that of a previous study. The modified mulberry leaves are easily available, which provides a new method for Cd removal from waste water. [ABSTRACT FROM AUTHOR]

The upper Orava region is located at the North Slovakia, near of potential sources of environmental contamination due by mining of coal, zinc and lead ores. The aim of the study was to evaluate the risk of consumption of wild forest fruit from Upper Orava region from the aspect of cadmium content. Ten sampling points were found by random search. From these points samples of soil, leaves and fruits of wild berries (9 samples of blueberries Vaccinium Myrtillus and 1 sample of strawberries Fragaria Vesca) were collected. In soil samples the active soil reaction (pH/H2O) ranged from 3.53 (strong acidity) to 4.56 (extremly strong acidity), and the determined percentage of humus ranged from 1.66 (low humic soil) to 4.90 (high humic soil). In two soil samples the total content of cadmium determinated in soil extracts by aqua regia exceeded limit 0.70 mg.kg-1 given by the legislation in tne Slovak Republic. In three soil samples the determined content of cadmium mobile forms determined in soil extracts by NH4NO3 exceeded the limit 0.10 mg.kg¹. The content of Cd determined in leaves as well as in fruits was evaluated according to Food Codex of the Slovak Republic. Only in one sample of leaf samples the limit 1.00 mg.kg¹ was exceeded. The other leaf samples are safely when used as an ingredient in tea mixtures. On the other hand even in 7 fruit samples the limit 0.05 mg.kg¹ was exceeded. This fruit can pose a risk for the human organism when is directly consumed as well as may negatively affect the human health when is used as raw materials in the food industry. [ABSTRACT FROM AUTHOR]

The aim of the present study was to determine the effect of chronic cadmium (Cd) action on the germination of spores and gametophyte differentiation in species Athyrium filix-femina (L.) Roth and Dryopteris filix-mas (L.) Schott, on different culture media (Knop solution, soil) for a period of 3 months. Cadmium was used in the following concentrations: C=0 mg Cd ∙ L-1 Knop solution/kg-1 soil, V1=25 mg Cd ∙ L-1 Knop solution/kg-1 soil, V2=50 mg Cd ∙ L-1 Knop solution/kg-1 soil, V3=100 mg Cd ∙ L-1 Knop solution/kg-1 soil, V4=150 mg Cd ∙ L-1 Knop solution/kg-1 soil. The percentage of germinated spores was found to decrease with the increasing Cd concentration in the environment, while germination is delayed in time. Unlike the Knop solution variants, in the soil variants gametophyte development was not significantly affected; for V1-2 soil concentrations the sporophyte appears in Athyrium filix-femina, a stage that was also noted for the Knop solution control, for the same species. In the case of the variants grown on Knop solution, although the spores did germinate and the gametophyte began to differentiate, Cd-induced chronic stress cannot be compensated by the gametophyte, so that the cells lose their membrane integrity, and their survival is compromised. [ABSTRACT FROM AUTHOR]

The synergistic activity between plants and microorganisms may contribute to the implementation of proactive management strategies in the stabilization of contaminated sites, although heavy metals, such as cadmium (Cd), are potentially toxic to them. The aim of this study was to evaluate the degree of tolerance to Cd contamination (supplying twice 40 mg kg of Cd) in poplar cuttings [clone I-214, P. × euramericana (Dode) Guinier] inoculated or not with two concentrations of Serratia marcescens strain (1 × 10 CFU/g and 2 × 10 CFU/g of potting mix). The response of the plant-bacteria system to excess Cd was investigated with special reference to the structural traits of plants and the functional efficiency of bacteria. Bacterial colonization and substrate components were previously assessed in order to define the best solution for formulating the experimental plant growth media. The tested plant-bacteria association, especially when bacteria were provided in double concentration, stimulated specific tolerance mechanisms to Cd through the promotion of the poplar growth. Inoculated plants produced larger leaves and increased stem diameter, while roots grew longer and wider in Cd-treated plants. The effect of bacterial inoculum on plant growth traits and metal partitioning in plant organs was assessed in order to define the potential of this poplar clone to be a suitable candidate for phytostabilization of Cd-contaminated soil. The final effect of the inoculation with bacteria, which alleviated the metal load and Cd phytotoxicity due to their bioaccumulation ability, suggests promising phytostabilization potential of these plant-bacteria associations. [ABSTRACT FROM AUTHOR]

A magnetic-dispersive solid-phase extraction (MDSPE) was used for precocentration of Pb(II) and Cd(II) in milk, yoghurt and water samples. An appropriate amount of suspension containing the magnetic graphene and Triton X-114 was injected rapidly into the aqueous sample by a syringe. Triton X-114 was used to achieve stable suspension of graphene in solution. The structure of the resulting products was confirmed by Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD) spectrometry. The effects of various parameters were studied. A detection limit of 0.16 and 0.50 µg L for Cd(II) and Pb(II) was obtained, respectively. The relative standard deviations (RSDs, n = 10) of 50 µg L of Pb and Cd were 3.3 % and 2.1 %, respectively. The results indicated that the present method can be reliably used for determination of Pb(II) and Cd(II) in dairy products and water samples with good recoveries. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is one of the most toxic heavy metals in aquatic ecosystem which affects fish health and aquaculture. In the present study, we examined the bioaccumulation of Cd in the gonads of tilapia via dissolved and dietary routes. We evaluated the subchronic effects of Cd on the histology of gonads, steroid hormone levels and sex-related gene expressions in tilapia. In addition, we also studied maternal transfer of Cd. Our results indicated that Cd was accumulated significantly in both ovary and testis from both exposure routes. Histopathological analysis showed that Cd induced ovary and testis injuries. Estradiol levels were significantly increased in dissolved Cd exposed female fish. In addition, the Cd exposure displayed different effects on gene expressions in gonads. In females, the estrogen receptor (ERα) was stimulated in dissolved Cd-exposed fish at 70.32 and 143.78 μg/L for 30 days and in fish at 143.78 μg/L for 60 days. Vitellogenin expression was significantly down-regulated in the ovary of dissolved Cd-exposed fish. In testis, GR expression was elevated after 60 days of dissolved Cd and dietary exposure. Furthermore, Cd level was significantly higher in the eggs than that in the fry. Our results demonstrated that both dissolved and dietary Cd exposures affected gonad development by altering steroid hormone levels and sex-related gene expressions in tilapia. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) incorporated into the benthic microfossils has been widely used in reconstructing the past water circulation in the North Atlantic. This requires a major control by conservative mixing over regeneration process on the seawater cadmium distribution in the North Atlantic. Through coupling the recently reported Cd data at depths below 300 m with quantitative water mass analysis along the GA03 transect, we tested two models for cadmium cycling within the North Atlantic: conservative mixing alone and conservative mixing plus regeneration which is termed as regenerative mixing. The results show that the regenerative mixing model reproduces the observations (slope = 0.99 and R2 = 0.97) much better than the conservative mixing model (slope = 0.99 and R2 = 0.88). The regenerative mixing model was applied to estimate the amount of dissolved cadmium regenerated 'within' the North Atlantic. This regionally regenerated cadmium contributes to ~10% and >50% of the total cadmium in the North Atlantic at depths >1000 m and 300-1000 m, respectively, indicating that the microfossil-reconstructed seawater Cd can be attributed to the mixing from the South Atlantic to the North Atlantic with high accuracy for depths below 1000 m, while within 300-1000 m cadmium is more controlled by the regeneration process than the mixing process, complicating the attribution of the microfossil-reconstructed seawater Cd to the changes in water mass geometry within this 300-1000 m depth range. A regionally and vertically constant Cd/PO43− regeneration ratio ~262 pM/µmol/kg was derived from the regenerative mixing model which is comparable with ratios estimated in the recent studies for the North Atlantic. [ABSTRACT FROM AUTHOR]

Low cost, high adsorptivity, fast regeneration and excellent reusability are strongly recommended for a qualified adsorbent used in removing heavy metals from practical wastewater. A sponge-like polysiloxane-graphene oxide (PS-GO) gel adsorbent for removing lead and cadmium from wastewater has been prepared by simple one-step sol-gel method. The maximum sorption capacity of Pb(II) achieves as high as 256 mg/g. PS-GO gel adsorbent exhibits an excellent reusability because of its remarkable mechanical strength and highly efficient desorption/regeneration. In the static treatment process, after five cycles, Pb(II) in actual industrial effluent at 3.225 mg/L could be reduced to below 0.01 mg/L, still holding over 99% removal efficiency. Significantly, in the dynamic treatment process using a fixed-bed column packed with PS-GO gel, the treatment volume of wastewater is as high as 720 bed volume (BV) (8143 mL) for Pb(II) and 480 BV (5429 mL) for Cd(II) with producing only 11.31 mL eluent in each cycle. It should be stressed that the in situ regeneration of PS-GO gel adsorbent in fixed-bed column is operationally feasible and the treatment technology has the advantage of producing “zero” amount of sludge. This work has taken a key step closer to the treatment of actual heavy metals wastewater based on adsorption technology in large scale. [ABSTRACT FROM AUTHOR]

A linkage between Cd speciation in sediments and its bioaccumulation in edible oyster ( Crassostrea sp .) from a tropical estuarine system was established. Bioaccumulation of Cd in edible oyster increased with the increasing lability and dissociation rate constants of Cd-sediment complexes in the bottom sediments. Total Cd concentration in sediment was not a good indicator of Cd-bioavailability. Increasing trace metal competition in sediments increased lability and bioavailability of Cd in the tropical estuarine sediment. Low thermodynamic stability and high bioavailability of Cd in the estuarine sediment were responsible for high bioaccumulation of Cd in edible oysters (3.2–12.2 mg kg − 1 ) even though the total concentration of Cd in the bottom sediment was low (0.17–0.49 mg kg − 1 ). [ABSTRACT FROM AUTHOR]

Key message: Overexpression of the iron transporter NtPIC1 increases iron concentration in shoots and reduces Cd uptake/accumulation in plants, mediating tolerance to cadmium. Abstract: Cadmium (Cd) is toxic to plant cells and causes plants to display a typical iron (Fe) deficiency phenotype. NtPIC1 (Permease In Chloroplast1) is an Fe transporter protein in tobacco, required for Fe homeostasis. Based on preliminary results in transformed Saccharomyces cerevisiae BY4741 cells, which showed that NtPIC1 expression increased Cd tolerance, this study evaluated Cd tolerance in tobacco plants overexpressing NtPIC1 (NtPIC1-OE). We show that these plants have longer roots and higher fresh weights than wild-type (WT) plants after Cd exposure. Under Cd stress, WT plants display more chlorosis, stronger growth inhibition, and lower chlorophyll concentrations than NtPIC1-OE plants. Importantly, NtPIC1-OE plants had higher Fe concentrations in shoots and lower Fe concentrations in roots, and Cd concentrations in NtPIC1-OE plants were significantly lower compared to those in WT plants. Moreover, Fe transport-related genes ( NtPIC1, NtNRAMP1, and NtFER1) were upregulated in NtPIC1-OE plants, while Fe deficiency-related genes ( NtFRO1, NtIRT1, and NtZIP1) that mediate Cd uptake were downregulated. We also found that the activities of several antioxidative enzymes were significantly higher in NtPIC1-OE plants than in WT plants under Cd stress. Overall, our results demonstrate that overexpression of NtPIC1 is an efficient way to increase shoot Fe concentrations and reduce Cd uptake/accumulation in plants. [ABSTRACT FROM AUTHOR]

The threshold value of cadmium (Cd) concentration in grains of barley ( Hordeum vulgare) is the lowest among cereal crops; however, it is poorly understood how Cd accumulation in barley grain is genetically controlled., We investigated genotypic variation in Cd accumulation of different organs in 100 accessions from a subset of the barley core collection using both hydroponic and Cd-contaminated soil culture. We also performed a genome-wide association ( GWA) mapping for Cd accumulation in different organs., A large genotypic variation in the Cd concentration was found in all organs. There was a good correlation between shoot Cd of solution and soil culture, the shoot Cd and grain Cd, but no correlation between the root Cd and grain Cd. GWA mapping detected 9 quantitative trait loci ( QTL) for root Cd, 21 for shoot Cd, 14 for root-to-shoot translocation and 15 for grain Cd. A common QTL for the shoot Cd and root-to-shoot translocation was found at 132.6 cM on chromosome 5H. Two major QTL for grain Cd were identified on chromosome 2H and chromosome 5H., The genetic variation in Cd accumulation and major QTL detected provide useful information helpful for cloning candidate genes for Cd accumulation and breeding low-Cd barley cultivars in future. [ABSTRACT FROM AUTHOR]

Background: Most humans are exposed to environmental contaminants via inhalation. Various toxic inhalants cause lung damage with pathologic changes to the airway system. Lung function decline is an important cause of morbidity and mortality worldwide. Aim: To consider the potential burden of cadmium on pulmonary disease, this study examined the relationship between blood cadmium levels and airflow obstruction in a Korean general population. Subjects and methods: Data from the Korean National Health and Nutrition Examination Surveys from 2008–2011 were used. Male participants were selected who were older than 40 years, who had completed a reliable pulmonary function test and for who measurements of blood cadmium levels were available (n = 1974). The pulmonary function tests were undertaken and airflow obstruction was defined when forced vital capacity/forced expiratory volume in 1 second ratio < 0.7. Results: In an age-adjusted logistic regression model, blood cadmium levels correlated with the risk of obstructive airflow pattern in total participants as well as in smokers or never smokers. Further adjustment for BMI, current occupation and educational level did not attenuate these associations among total participants, smokers and never smokers (OR = 2.53, 95% CI = 1.83–3.50 in total; OR = 2.17, 95% CI = 1.55–3.02 in smokers; OR = 3.71, 95% CI = 1.48–9.33 in never smokers). Conclusions: In conclusion, blood cadmium level was associated with airflow obstruction independently of smoking history and that association was still significant in never smokers. Careful attention is needed for the general population who are potentially exposed to cadmium. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) loading in soil and the environment has been accelerated worldwide due to enhanced industrialization and intensified agricultural production, particularly in the developing countries. Soil Cd pollution, resulting from both anthropogenic and geogenic sources, has posed an increasing challenge to soil quality and food security as well as to human health. Compared with other heavy metals such as copper (Cu) and lead (Pb), Cd demonstrates greater mobility along food chain and in the environment. Cd is harmful to human health and potentially toxic to biota at lower concentrations. Therefore, it is imperative to develop management strategies for control of pollution sources and remediation of contaminated soils. Extensive studies have been conducted in recent years to understand biogeochemical processes of Cd in soils, its cycle in agroecosystems, impacts on soil quality and food security, and the remediation of Cd-contaminated soils. Phytoremediation as an emergent technology has stimulated refreshed interest since it is cost effective and ecofriendly, especially the use of metal hyperaccumulating plants to extract or mine heavy metals from contaminated soils. Progress has been made in the understanding of mechanisms that govern Cd accumulation and detoxification in accumulating plants. This review provides recent progress in soil biogeochemistry and plant physiology of Cd, mechanisms of hyperaccumulation of Cd in plant, remediation strategies including chemical and microbiological enhancement, and optimization of field management practices, in the hope to stimulate more research in the future. [ABSTRACT FROM AUTHOR]