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The feasibility of the bioremediation of cadmium (Cd) using microalgal-biochar immobilized complex (MBIC) was investigated. Major operating parameters (e.g., pH, biosorbent dosage, initial Cd(II) concentration and microalgal-biochar ratio) were varied to compare the treatability of viable algae ( Chlorella sp.), biochar and MBIC. The biosorption isotherms obtained by using algae or biochar were found to have satisfactory Langmuir predictions, while the best fitting adsorption isotherm model for MBIC was the Sips model. The maximum Cd(II) adsorption capacity of MBIC with a Chlorella sp.: biochar ratio of 2:3 (217.41 mg g −1 ) was higher than that of Chlorella sp. (169.92 mg g −1 ) or biochar (95.82 mg g −1 ) alone. The pseudo-second-order model fitted the biosorption process of MBIC well ( R 2 > 0.999). Moreover, zeta potential, SEM and FTIR studies revealed that electrostatic attraction, ion exchange and surface complexation were the main mechanisms responsible for Cd removal when using MBIC. [ABSTRACT FROM AUTHOR]

Cadmium is a major environmental toxicant that is released into the atmosphere, water and soil in the form of cadmium oxide, cadmium chloride, or cadmium sulfide via industrial activities, such as the manufacturing of batteries and pigments, metal smelting and refining and municipal waste incineration. In the present study, we investigated the effects of cadmium exposure on sperm quality parameters, fertilization capacity and early embryonic development. Our study showed that in vitro incubation of human or mouse sperms with cadmium for a long time (up to 24 hours) could significantly decreased sperm motility in a concentration- and time-dependent manner. Exposure to cadmium in the environment for a short term (30 min) did not affect sperm motility but significantly reduced in vitro fertilization rate. We also evaluated the effects of cadmium at concentrations of 0.625 μg/ml, and 1.25 μg/ml on early embryonic development in vitro and observed that the blastocyst formation rate dramatically decreased with increasing cadmium concentration. This finding emphasizes the hazardous effects of cadmium on sperm quality as well as on natural embryo development and raises greater concerns regarding cadmium pollution. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) pollution is a worldwide environmental problem which heavily threatens human health and food security. Sorghum, as one of the most promising energy crop, has been considered to be the source of high-quality feedstock for ethanol fuel. Ninety-six sorghum genotypes were investigated under hydroponic conditions to compare their capabilities of Cd-tolerance, accumulation and translocation for their potential in remediation of Cd contamination. Different genotypes varied largely in the tolerance to Cd stress with tolerance indexes ranked from 0.107 to 0.933. Great difference was also found in Cd uptake and accumulation with concentrations ranging from 19.0 to 202.4 mg/kg in shoots and 277.0–898.3 mg/kg in roots. The total amounts of Cd ranked from 6.1 to 25.8 μg per plant and the highest translocation factor was over 4 times higher than the lowest one. The correlation analysis demonstrated that Cd concentration in shoot reflected the ability of Cd translocation and tolerance of sorghum, and the path coefficient analysis indicated that root biomass could be taken as a biomarker to evaluate Cd extraction ability of sorghum. The results in this study can facilitate the restoring of Cd contaminated areas by sorghum. [ABSTRACT FROM AUTHOR]

Adult female and male, and final instar nymph of Anisops sardeus (Heteroptera: Notonectidae) were exposed to graded concentrations of cadmium in 96 h static-with-renewal acute toxicity tests, which were conducted in dry (March) and wet (May–June) seasons. The 96 h LC 50 values for instar V nymph, adult female and male were found to be 0.9, 0.59 and 0.51 mg L −1 Cd, respectively, in wet season, while these were 26.7 and 20.2 mg L −1 Cd for adult female and male, respectively, in dry season. Adult males were most sensitive to Cd, followed by females in both seasons, while highest tolerance in wet season was observed in instar V nymph. There was a steep decline in LC 50 values from 24 to 96 h in wet season. Besides mortality at higher concentrations of Cd, sublethal effects in terms of reduced ‘velocity magnitude’ (swimming speed) and mostly increased ‘rotation angle’ (turning angle) could be discerned at concentrations as low as 0.03 mg L −1 . The swimming pattern of Cd-exposed nymph and adults were also affected. Based on the bioaccumulation factor (BAF) values, A. sardeus could be designated as a macroconcentrator of Cd (BAF > 2), with highest Cd accumulation in instar V nymph, followed by that in female, and with lowest Cd accumulation in male. [ABSTRACT FROM AUTHOR]

Detailed knowledge of the processes that metals undergo during dry weather periods whilst deposited on urban surfaces and their environmental significance is essential to predict the potential influence of metals on stormwater quality in order to develop appropriate stormwater pollution mitigation measures. However, very limited research has been undertaken in this area. Accordingly, this study investigated the geochemical phase and particle size relationships of seven metals which are commonly associated with urban road dust, using sequential extraction in order to assess their mobility characteristics. Metals in the sequentially extracted fractions of exchangeable, reducible, oxidisable and residual were found to follow a similar trend for different land uses even though they had variable accumulation loads. The high affinity of Cd and Zn for exchangeable reactions in both, bulk and size-fractionated solid samples confirmed their high mobility, while the significant enrichment of Ni and Cr in the stable residual fraction indicated a low risk of mobility. The study results also confirmed the availability of Cu, Pb and Mn in both, stable and mobile fractions. The fine fraction of solids (<150 μm) and antecedent dry days can be highlighted as important parameters when determining the fate of metals associated with urban road dust. The outcomes from this study are expected to contribute to the development of effective stormwater pollution mitigation strategies by taking into consideration the metal-particulate relationships. [ABSTRACT FROM AUTHOR]

Paenibacillus ferrarius CY1T (= KCTC 33419T = CCTCC AB2013369T) is a Gram-positive, aerobic, endospore-forming, motile and rod-shaped bacterium isolated from iron mineral soil. This bacterium reduces sulfate (SO42-) to S2-, which reacts with Cd(II) to generate precipitated CdS. It also reduces the toxic chromate [Cr(VI)] and selenite [Se(VI)] to the less bioavailable chromite [Cr(III)] and selenium (Se0), respectively. Thus, strain CY1T has the potential to bioremediate Cd, Cr and Se contamination, which is the main reason for the interest in sequencing its genome. Here we describe the features of strain CY1T, together with the draft genome sequence and its annotation. The 9,184,169 bp long genome exhibits a G + C content of 45.6%, 7909 protein-coding genes and 81 RNA genes. Nine putative Se(IV)-reducing genes, five putative Cr(VI) reductase and nine putative sulfate-reducing genes were identified in the genome. [ABSTRACT FROM AUTHOR]

A comprehensive and detailed investigation of cadmium (Cd) pollution in surface riverine sediments of the Haihe Basin in north China was carried out. Total Cd concentrations in these sediments ranged from 0.153 to 22.1 mg/kg, exceeding the soil background value at all sampling sites. The mean Cd concentration of the bioavailable fraction was 0.557 mg/kg, accounting on average for 51.58% of the total Cd. A mean value of the Cd enrichment factor of 11.6 suggested that Cd has accumulated in most riverine sediments, resulting in a high degree of anthropogenic pollution. In fact, there were high levels of Cd pollution in the riverine sediments throughout the Haihe Basin, yielding geo-accumulation index values for Cd from 0.071 to 7.25. According to the potential ecological risk index, risk assessment code, and consensus-based sediment quality guidelines, Cd was a serious pollutant in this ecosystem. Because it occurred as a high proportion in the exchangeable/acid soluble fraction (21.21% on average), it may also have biological toxicity. Our findings indicated that it is important to consider Cd in control strategies for managing riverine sediment pollution in the Haihe Basin. [ABSTRACT FROM AUTHOR]

Different pollutants induce distinct toxic responses in earthworms ( Eisenia fetida ). Here, we used proteomics techniques to compare the responses of E. fetida to exposure to the 10% lethal concentration (14d-LC 10 ) of benzo[ a ]pyrene (BaP) or cadmium (Cd) in natural red soil (China). BaP exposure markedly induced the expression of oxidation-reduction proteins, whereas Cd exposure mainly induced the expression of proteins involved in transcription- and translation-related processes. Furthermore, calmodulin-binding proteins were differentially expressed upon exposure to different pollutants. The calcium (Ca 2 + )-binding cytoskeletal element myosin was down-regulated upon BaP treatment, whereas the Ca 2 + -binding cytoskeletal element tropomyosin-1 was up-regulated upon Cd treatment. Some proteins exhibited opposite responses to the two pollutants. For instance, catalase (CAT) and heat shock protein 70 were up-regulated upon BaP treatment and down-regulated upon Cd treatment. A significant ( p < 0.05, one-way ANOVA with least-significant difference (LSD) test) increase in the level of reactive oxygen species (ROS) and CAT activity further showed that BaP mainly induces oxidative stress. Real-time PCR analysis showed that mRNA expression often did not correlate well with protein expression in earthworms subjected to Cd or BaP treatment. In addition, the expression of the gene encoding the protein metallothionein, which was not detected in the protein analysis, was induced upon Cd treatment, but slightly reduced upon BaP treatment. Therefore, BaP and Cd have distinct effects on the protein profile of E. Fetida with BaP markedly inducing ROS activity, and Cd mainly triggering genotoxicity. Capsule summary Distinct patterns of protein expression are induced in earthworms upon exposure to different pollutants; BaP markedly induces high levels of ROS, while Cd resultes in genotoxicity. [ABSTRACT FROM AUTHOR]

The present study characterized the chronic effect of binary-metal mixtures of cadmium (Cd) and zinc (Zn) on Daphnia magna. The titration design was chosen to characterize the 21-d chronic effects of the binary-metal mixtures on survival, growth, reproduction, and metal accumulation in D. magna. Using this design, increasing concentrations of Zn (10, 20, 40, 80, 120, 160, and 200 μg/L) were titrated against a constant concentration of 1.5 μg/L Cd. The results demonstrated that Cd was highly toxic to D. magna. In a mixture with Cd and Zn, sublethal concentrations of 10 and 20 μg/L Zn were insufficient to protect D. magna from chronic Cd toxicity, whereas mixtures containing 40, 80, and 120 μg/L Zn provided strong protective effects to D. magna at all endpoints and resulted in less-than-additive effects. At higher Zn concentrations, such as 160 and 200 μg/L, Zn appeared to contribute to the toxicity. The less-than-additive effects observed in the Cd-Zn mixture can be explained by the decrease in body Cd concentration when the Zn concentration was increased in the exposure media. Embryos analyzed for morphological alterations in the Cd-Zn mixtures demonstrated severe developmental defects. The effect of Cd on undeveloped embryos while both Zn and Cd are present in the organisms raises a question of whether the competitive binding mechanism of Zn and Cd is still happening at the cellular level in the organisms. The results of the present study are useful for development of the biotic ligand model and environmental quality guidelines for metal mixtures. Environ Toxicol Chem 2017;36:2739-2749. © 2017 SETAC [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is one of the most common pollutants in the environment and it is known to cause a range of tissue damages and apoptosis in invertebrates. In this study, we investigated the effect of Cd on the hepatopancreas of the crab Eriocheir sinensis , a commercially and ecologically important species of crustacean. The crabs were first exposed to water containing different concentrations of Cd 2+ (0, 0.63, 1.26, 2.52, 5.04 and 10.07 mg/L) for 6 days. Typical morphological characteristics and physiological changes of apoptosis were then observed using various methods, including AO/EB double fluorescence staining, transmission electron microscopy and DNA fragmentation analysis. The results showed that Cd 2+ induced cell damage and apoptosis in a concentration-dependent manner. Transmission electron microscopy revealed the presence of cellular swelling and necrosis with reduced number of microvilli on the cell surface and damages to individual organelles. The mitochondria became swollen and vacuolated. The rough endoplasmic reticulum (Rer) was expanded, with membrane rupture and many different sizes of vesicles, suggesting the destruction of protein-synthesizing structures in the hepatopancreatic cells. The activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidases (GPx) initially increased and subsequently decreased with increasing Cd 2+ concentrations. This was accompanied by increases in malondialdehyde (MDA) and H 2 O 2 contents, which led to membrane lipid peroxidation. Crabs exposed to Cd 2+ also displayed significant increases in caspase-3, −8, and −9 activities compared to control crabs. Cadmium induced the production and accumulation of ROS in the hepatopancreas, which resulted in oxidative damage and abnormal metabolism. Taken together, the results indicated that Cd 2+ could induce oxidative damage as well caspase-dependent apoptosis in E. sinensis hepatopancreas. [ABSTRACT FROM AUTHOR]

Liquid phase microextraction (LPME) has been widely used in extraction and preconcentration systems as an excellent alternative to conventional liquid phase extraction. In this work, a critical review is presented on liquid phase microextraction techniques used in the determination of cadmium in environmental samples. LPME techniques are classified into three main groups: single-drop liquid phase microextraction (SDME), hollow fiber liquid phase microextraction (HF-LPME), and dispersive liquid-liquid microextraction (DLLME). Methods involving these liquid phase microextraction techniques are described, addressing advantages and disadvantages, samples, figures of merit, and trends. [ABSTRACT FROM AUTHOR]

Pollution by heavy metals presents an environmental concern, and their toxicity threats soil, water, animals and human health. Phytoremediation can be used as a solution to remediate contaminated soils. The aim of this study was to identify native plants collected from tailings: material of Pb-Zn mine sites of Fedj Lahdoum and Jebel Ressas (two abandoned mines located, respectively, in the northwest of Tunisia and in the south of Tunis City). The tolerance of plant to heavy metals (lead, zinc and cadmium) is evaluated. Soil samples were collected and analyzed for Pb, Zn and Cd concentration. The total soil Pb, Zn and Cd are, respectively, reached 6132 mg kg, 11,052 mg kg and it doesn't exceed 479 mg kg for Cd. The highest content of Zn in plants was detected in shoots of Rumex bucephalophorus (1048 mg kg), and the highest Pb concentration was detected in roots of Chrysopogon zizanioides (381 mg kg), while for Cd Silene colorata it accumulated the highest content in roots (51 mg kg). From all plants, only 12 have a translocation factor for Pb which is higher than one. Among all plants, only 17 have a translocation factor that is higher than one for Zn, while for Cd only 13 plants indicate TF > 1. As for the biological absorption coefficient, all samples indicate a rate which is lower than one. These plants can be primarily hyper accumulators and useful in remediation of lead- and zinc-contaminated soils after further biochemistry researches in mechanism of accumulation and translocation of heavy metals in plants. [ABSTRACT FROM AUTHOR]

The generation of electricity has been identified as one of the main pollutant activities, and some studies have established an increment of heavy metals in soil in the areas surrounding these plants. The aim of this study was to evaluate the soil concentrations of heavy metals in the zone surrounding a thermoelectric power in Mexico. Thirty-two top soil samples (0-5 cm) were collected; additionally, four depth profiles (1 m) were investigated. Median concentrations for chromium, vanadium, nickel, mercury, and cadmium were 47, 47, 73, 0.02, and 0.01 mg/kg, respectively. Higher Cr, Ni, and V concentrations were observed in the soil depth profiles located closer to the plant in comparison with the concentrations found in the soil depth profile located further away from the plant; these results may indicate a possible accumulation of these metals. The geoaccumulation index results indicated that most of the sites were in the classifications of unpolluted and unpolluted to moderately polluted (classes 1 and 2). The statistical results showed that downwind of the plant in relation to the prevailing winds, there was a strong correlation between soil concentrations of chromium, copper, nickel, and vanadium. Based on the results of this study, it can be concluded that the use of fuel oil at the thermoelectric plant contributed to the accumulation of vanadium and nickel in the soil of the surrounding areas, as well as chromium and copper. [ABSTRACT FROM AUTHOR]

Environmental pollution tends to reduce the quality of water sources around the world. Thus, there is a clear need for strategic assessments of conditions that negatively affect river basins. The São João River basin is located in a strategic conservation area due to the abounding water resources and biodiversity, but is strongly affected by anthropic activity. In this study, eight metals were evaluated (Cu, Mn, Fe, Zn, Cr, Co, Cd and Pb) in sediment and water from ten different points in the São João water basin. The São João basin pollution was evaluated through the geoaccumulation index (Igeo), ecological risk potential (ERP) and degree of pollution (Dp). The most toxic metals found in sediments were Cr (3.1-10.7), Cd (2.1-5.5) and Pb (5.0-28.1) in µg g. In the water samples, the most toxic metals were Cr (3.7-33.2), Cd (6.3-14.2) and Pb (5.0-57.5) in µg L. The Igeo presented indices between 2 and 3 in 80% of the samples, indicating significant pollution in the sediment. In 40% of the points sampled, the ERP values indicated severe risk for the ecosystem. In 30% of the water samples, the Dp values were over 40, indicating the highest pollution level. The results reveal that the use of land and water in the São João water basin without proper care might represent considerably high ecological and sanitary risk. [ABSTRACT FROM AUTHOR]

A green tunable dispersive liquid-liquid micro extraction (TDLLME) technique was established for the simultaneous enrichment of lead (Pb) and cadmium (Cd) from different lakes water before analysis by flame atomic absorption spectrometry (FAAS). A solvent known as tunable polarity solvent (TPS), mixture of 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) and 1-decanol, has been employed as extractant in aqueous medium. In first step this mixture can be made polar by slowly bubbling the antisolvent trigger (CO 2 ) through the solution, which makes a monophasic solution. During this step hydrophobic complexes of the metals with 8-hydroxy quinoline (8-HQ) were extracted by TPS. Then the mixture was switched back to hydrophobic one by heating and/or bubbling nitrogen, turning the mixture into two phases again. In second phase the metals were leached out from the complexes entrapped in TPS, by treating with a solution of nitric acid and exposing the mixture to CO 2 , which switched the mixture into single phase. Then N 2 purging and/or heating again turned the mixture into two phases. The acidic aqueous phase containing the metals was introduced to FAAS for analysis, whereas TPS was recycled for next experiment. Different parameters, affecting the efficiency the technique, were optimized by multivariate approach. The method was applied to certified reference material of water and to a real sample spiked with standards of known concentration, to confirm its validity and accuracy. LOD obtained for Pb and Cd were 0.560 and 0.056 μg L − 1 respectively. The developed method was applied successfully to the real water samples of two lakes of Sindh, Pakistan. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) pollution in food chains pose a potential health risk for humans. Sulfur (S) is a significant macronutrient that plays a significant role in the regulation of plant responses to diverse biotic and abiotic stresses. However, no information is currently available about the impact of S application on ascorbate-glutathione metabolism (ASA-GSH cycle) of Pakchoi plants under Cd stress. The two previously identified genotypes, namely, Aikangqing (a Cd-tolerant cultivar) and Qibaoqing (a Cd-sensitive cultivar), were utilized to investigate the role of S to mitigate Cd toxicity in Pakchoi plants under different Cd regimes. Results showed that Cd stress inhibited plant growth and induced oxidative stress. Exogenous application of S significantly increased the tolerance of Pakchoi seedlings suffering from Cd stress. This effect was demonstrated by increased growth parameters; stimulated activities of the antioxidant enzymes and upregulated genes involved in the ASA-GSH cycle and S assimilation; and by the enhanced ASA, GSH, phytochelatins, and nonprotein thiol production. This study shows that applying S nutrition can mitigate Cd toxicity in Pakchoi plants which has the potential in assisting the development of breeding strategies aimed at limiting Cd phytoaccumulation and decreasing Cd hazards in the food chain. [ABSTRACT FROM AUTHOR]

The aim of the work was to evaluate the usefulness of the in vitro multiplication of Biscutella laevigata calamine ecotype for in situ reclamation of post-flotation wastes polluted with Pb and Cd. The experiment was conducted on three steps: (i) plant shoots’ production under in vitro condition, (ii) establishment of the material in greenhouse experiment, and finally (iii) field cultivation directly on the mining-waste heap of Olkusz Ore-Bearing Region, Poland. This region is known to be one of the most chemically-degraded area in central Europe. The laboratory-set in vitro analysis enabled to obtain the high-quality plant shoots, which multiply the most effectively (with growth tolerance index 130–150%) on medium containing 5.0 μM CdCl 2 and 0.5 mM Pb(NO 3 ) 2 . These plants were used for the next two ex vitro experiments. Several biometric and physiological analysis ( i.e . of photosystem II activity F v /F m and PI, photosynthetic pigment contents) were done to indicate plant physiological status during these experiments. The main novelty of the work was to prove that in vitro -multiplied shoots of B. laevigata - the representative of native flora from Olkusz Ore-Bearing Region - can be successfully implemented in situ for the restoration of these degraded area. Moreover, the addition of sewage sludge as a source of organic compounds significantly improved plants’ growth and development what is especially important due to the lack of other legal solutions for the management of the sewage sludge in some countries. [ABSTRACT FROM AUTHOR]

The aim of this study was to estimate the benchmark dose (BMD) as the threshold limit level of the cadmium (Cd) concentration in rice for itai-itai disease and/or suspected disease; it was based on the data that previously evaluated the association for such diseases with the Cd concentration in rice by using a logistic regression model. From 1971 to 1976, a total of 2446 rice samples were analyzed across the 88 hamlets in the Jinzu river basin. The mean Cd concentration in rice in each hamlet was used as the index of external Cd exposure of the entire population of the hamlet. We employed the incidence of itai-itai disease and/or suspected disease obtained from the available 55 hamlets. As the threshold, the lower limit of the BMD (BMDL) of the Cd concentration in rice for itai-itai disease and/or suspected disease was estimated using a logistic model, setting the benchmark response at 1% or 2%. The estimated BMDLs of the Cd concentration in rice for itai-itai disease and/or suspected disease were 0.62-0.76 and 0.27-0.56 mg kg−1 in men and women, respectively. The lowest BMDL was 0.27 mg kg−1 in women. In the present study, the threshold limit level of the Cd concentration in rice for itai-itai disease, which is the most severe form of chronic Cd poisoning, was estimated for the first time. This result provides important information about the worldwide standard for the Cd concentration in rice. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the influence of chemical leaching on permeability and Cd removal from fine-grained polluted soils. Column leaching experiments were conducted using two types of soils (i.e., artificially Cd-polluted loam and historically polluted silty loam). Chemical agents of CaCl, FeCl, citric acid, EDTA, rhamnolipid, and deionized water were used to leach Cd from the soils. Results showed that organic agents reduced permeability of both soils, and FeCl reduced permeability of loam soil, compared with inorganic agents and deionized water. Entrapment and deposition of colloids generated from the organic agents and FeCl treatments reduced the soil permeability. The peak Cd effluence from the artificially polluted loam columns was retarded. For the artificially polluted soils treated with EDTA and the historically polluted soils with FeCl, Cd precipitates were observed at the bottom after chemical leaching. When Cd was associated with large colloid particles, the reduction of soil permeability caused Cd accumulation in deeper soil. In addition, the slow process of disintegration of soil clay during chemical leaching might result in the retardation of peak Cd effluence. These results suggest the need for caution when using chemical-leaching agents for Cd removal in fine-grained soils. [ABSTRACT FROM AUTHOR]

Sewage sludge is an important class of bioresources whose energy content could be exploited using pyrolysis technology. However, some harmful trace elements in sewage sludge can escape easily to the gas phase during pyrolysis, increasing the potential of carcinogenic material emissions to the atmosphere. This study investigates emission characteristics of arsenic, cadmium and lead under different pyrolysis conditions for three different sewage sludge samples. The increased temperature (within 723–1123 K) significantly promoted the cadmium and lead emissions, but its influence on arsenic emission was not pronounced. The releasing rate order of the three trace elements is volatile arsenic compounds > cadmium > lead in the beginning of pyrolysis. Fast heating rates promoted the emission of trace elements for the sludge containing the highest amount of ash, but exhibited an opposite effect for other studied samples. Overall, the high ash sludge released the least trace elements almost under all reaction conditions. [ABSTRACT FROM AUTHOR]

A large amount of Cu-Cd zinc plant residues (CZPR) are produced from the hydrometallurgical zinc plant operations. Since these residues contain substantial amount of heavy metals including Cd, Zn and Cu, therefore, they are considered as hazardous wastes. In order to realize decontamination treatment and efficient extraction of the valuable metals from the CZPR, a comprehensive recovery process using sulfuric acid as the leaching reagent and air as the oxidizing reagent has been proposed. The effect of temperature, sulfuric acid concentration, particle size, solid/liquid ratio and stirring speed on the cadmium extraction efficiency was investigated. The leaching kinetics of cadmium was also studied. It was concluded that the cadmium leaching process was controlled by the solid film diffusion process. Moreover, the order of the reaction rate constant versus H 2 SO 4 concentration, particle size, solid/liquid ratio and stirring speed was calculated. The XRD and SEM-EDS analysis results showed that the main phases of the secondary sulfuric acid leaching residues were lead sulfate and calcium sulfate. [ABSTRACT FROM AUTHOR]

In this research, a novel activated biomass was prepared from Caryota urens based on sulphuric acid treatment (surface-modified Caryota urens seeds, SMCUS) followed by ultrasonication (ultrasonic-assisted Caryota urens seeds, UACUS). The prepared material was effectively applied to treat a cadmium-contaminated water system. The novel synthesized material was analyzed by scanning electron microscopic (SEM) and Fourier transform infrared (FTIR) spectroscopic analyses. Adsorption experiments were conducted to check the adsorption-influencing parameters, including contact time, initial cadmium concentration, temperature, and system pH. Adsorption isotherm and kinetics for cadmium removal by adsorbents were studied systematically. Adsorption equilibrium data were explained by three, four, and five parameter isotherm models at different temperatures. The kinetics for cadmium adsorption was explained by pseudo-first-, and pseudo-second-order models and also by Elovich models at different temperatures. The Langmuir adsorption capacity of UACUS was calculated as 183.4 mg=g. Cadmium adsorption by adsorbents has been well described in the literature and by pseudo-first-order models. Cadmium adsorption was decreased with increased temperature (30-60°C). This confirms that the present adsorption system is exothermic in nature. Thermodynamic factors include ΔG°, ΔH°, and ΔS° < 0, showed that cadmium adsorption is spontaneous, exothermic, and enthalpy driven, respectively. The decrease in ΔG° values with the increase in temperature from 30 to 60°C states that more adsorption sites exist at lower temperature. [ABSTRACT FROM AUTHOR]

Eulimnogammarus cyaneus and Eulimnogammarus verrucosus, closely related amphipod species endemic to Lake Baikal, differ with respect to body size (10- to 50-fold lower fresh weights of E. cyaneus) and cellular stress response (CSR) capacity, potentially causing species-related differences in uptake, internal sequestration, and toxic sensitivity to waterborne cadmium (Cd). We found that, compared to E. verrucosus, Cd uptake rates, related to a given exposure concentration, were higher, and lethal concentrations (50%; LC50) were 2.3-fold lower in E. cyaneus (4 weeks exposure; 6 °C). Upon exposures to species-specific subacutely toxic Cd concentrations (nominal LC1; E. cyaneus: 18 nM (2.0 µg L-1); E. verrucosus: 115 nM (12.9 µg L-1); 4 weeks exposure; 6 °C), Cd amounts in metal sensitive tissue fractions (MSF), in relation to fresh weight, were similar in both species (E. cyaneus: 0.25 ± 0.06 µg g-1; E. verrucosus: 0.26 ± 0.07 µg g-1), whereas relative Cd amounts in the biologically detoxified heat stable protein fraction were 35% higher in E. cyaneus. Despite different potencies in detoxifying Cd, body size appears to mainly explain species-related differences in Cd uptake and sensitivities. When exposed to Cd at LC1 over 4 weeks, only E. verrucosus continuously showed 15-36% reduced oxygen consumption rates indicating metabolic depression and pointing to particular sensitivity of E. verrucosus to persisting low-level toxicant pressure. [ABSTRACT FROM AUTHOR]

The concentrations of four metals (copper, cadmium, zinc and lead) were quantified in blue crabs ( Callinectes sapidus) tissues collected in January, April, June and September at two stations in Mersin Bay, northeastern Mediterranean Sea, using ICP-MS. The metal concentrations in crabs from the two stations differed significantly. The hepatopancreas was the major organ accumulating metals, followed by gill and muscle tissues. Except for lead, the highest concentrations of metals were measured in the hepatopancreas. The hepatopancreas had higher concentrations of all heavy metals (Cu 321.1 ± 4.30; Zn 182.2 ± 3.40; Cd 48.2 ± 2.00) compared to gill (Cu 90.2 ± 1.35; Zn 104.3 ± 2.30; Cd 22.3 ± 3.40) and muscle (Cu 19.1 ± 1.10; Zn 55.1 ± 3.25; Cd 2.5 ± 0.20). Among the metals analyzed, Cu, Zn and Pb were the most abundant in the different tissues while Cd was the least abundant in C. sapidus. Seasonality in the levels of the four metals was determined.The highest concentrations of all metals were observed in the June (Zn 55.1 ± 3.25; Cu 19.1 ± 1.10; Cd 2.5 ± 0.20; Pb 5.1 ± 0.18) compared to all other months (Zn 34.1 ± 3.23; Cu 11.1 ± 1.15; Cd 0.9 ± 0.20; Pb 3.1 ± 0.21). [ABSTRACT FROM AUTHOR]

The study aimed to assess whether cadmium administered via ingestion to Steatoda grossa cobweb spiders (Theridiidae) affects the energy content and selected structural properties of the produced hunting webs. Cadmium content in webs was assessed with AAS and SEM X-ray microanalysis, while the diameters of silk fibers were estimated with SEM. The energy content of samples was measured in an oxygen micro-bomb calorimeter. Females and males showed different reactions to cadmium supplied through food. In comparison to females, males displayed higher metal concentrations in their bodies and hunting webs, however their calorific values and structural features were not significantly changed. Cadmium-treated females spun webs with smaller single-strand diameters and more frequent multi-stranded threads and invested 47% less energy in web production than the control individuals. It cannot be excluded that such a reduction in energy expenditure for web building in females resulted from energetically costly detoxifying reactions triggered in response to direct and indirect effects of cadmium toxicity. [ABSTRACT FROM AUTHOR]

This study was designed to identify in the pearl oyster Pinctada margaritifera , used as a bio-accumulator, molecular biomarkers for the presence of heavy metals in the lagoon environment. Pearl oysters were exposed to 2 concentrations (1 and 10 μg L − 1 ) of cadmium (Cd) and chromium (Cr) compared to a control. Twelve target genes encoding proteins potentially involved in the response to heavy metal contamination with antioxidant, detoxification or apoptosis activities were selected. P. margaritifera accumulated Cd but not Cr, and mortality was related to the amount of Cd accumulated in tissues. In response to Cd-Cr contamination, metallothionein (MT) was significantly up-regulated by Cd-Cr at both concentrations, while 7 others (SOD, CAT, GPX, GSTO, GSTM, CASP, MDR) were down-regulated. Based on the development of these molecular tools, we propose that the pearl oyster, P. margaritifera , could be used as a sentinel species for heavy metal contamination in the lagoons of tropical ecosystems. [ABSTRACT FROM AUTHOR]

Surface-deposited sediment in urban area is an essential environmental medium for assessing heavy metal contamination. A total of 10 sampling trips were conducted to collect road-deposited and roof-deposited sediments for the comparison of nickel (Ni), copper (Cu), cadmium (Cd), lead (Pb), zinc (Zn), and chromium (Cr) contamination characteristics. Results indicated that roof sediment appeared to have a finer size distribution than road sediments. Roof sediment indicated higher metal concentration and lower surface loading than road sediment. The impact of particle size on heavy metal contamination was quantified by using the developed pioneering term of finer particle effect factor; it differed according to surface types and grain size fraction. Particles in individual grain size fraction showed different contribution to the surface loading for bulk sediments. No consistent trend was found for the grain size fraction loading along with grain size for the studied heavy metals for road sediments. In contrast, an asymmetric 'W' trend was observed for the roof sediments, and it had the following results: Fraction of <63 and 250-500 μm showed higher loading, while fraction of 90-125 and >850 μm indicated the smaller loading. Findings above facilitated the appropriate management practice selection for the treatment of surface-deposited sediments. [ABSTRACT FROM AUTHOR]

There is an increasing demand for the development of brick kiln area in Iran, which emits a considerable amount of pollutants to environment. The present study aimed to investigate the extent of soil contamination by heavy metals around the brick kiln area in Aran-o-Bidgol City. The correlation coefficients, analysis of variance, principal component analysis, cluster analysis, soil contamination indices and interpolation technique were utilized to investigate the soil contamination and pinpoint the possible sources of contamination. The results showed the average concentration of all heavy metals were greater than background values and soils were contaminated by heavy metals to some extent. Results also indicated that copper, nickel and zinc had simultaneously emanated from anthropogenic including agricultural activities and urban emissions while the sources of cadmium and lead could mostly be attributed to different anthropogenic activities including brick kilns and related transportation. The distribution maps revealed that the brick kiln emissions had only affected the concentrations of cadmium and lead to some degree. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is a non-essential trace element that is toxic to humans. Previous studies of Cd in the environment have primarily focused on pollution resulted from anthropogenic sources, but little is known on naturally occurring sources of Cd. This paper aims to review the geochemical distribution of geogenic Cd and associated environmental risk. The source, accumulation, mobility, transportation, and health risk of Cd are discussed in a geo-environmental perspective, with an emphasis on black shale soils. Cadmium generally occurs in sulfides in black shale, and is easily released when exposed to oxygen and water. Leaching of these rocks tends to elevate Cd concentrations in aquatic systems, and may pose the potential to produce acid rock drainage (ARD) as well. Weathering of Cd-rich rocks also elevates soil Cd concentrations, and influence the geochemical species of Cd. Crops grown in these soils tend to accumulate higher Cd and threaten the food safety. Local inhabitant exposed to high geogenic Cd via food chains may experience Cd-related health risk. High Cd concentrations are observed in urine, and renal damage is also detected in Cd naturally enriched area based on low molecular weight proteins in urine. Overall, the findings in literature have provided with insights for potential health risk of Cd in areas with high Cd geochemical background levels, particular for the black shale exposed areas, more attentions should be paid on the geogenic Cd pollution, and suitable strategies of remediation and geo-environmental management for geogenic Cd pollution need further research. [ABSTRACT FROM AUTHOR]

We synthesized fluorescent Cd nanoclusters (CdNCs) through a protein-directed method, and the synthesis method was utilized for a homogeneous, ultrasensitive, and selective detection of cadmium ion (Cd 2+ ). CdNCs were synthesized using a modified protein-directed method for developing a rapid Cd 2+ detection system. For rapid Cd 2+ detection, the reaction time was reduced by optimizing the reaction conditions such as temperature, reducing agent concentration, and protein concentration. The synthesized CdNCs had ca . 2 nm diameter and showed strong fluorescence at 485 nm under 365 nm UV light. The fluorescence of the CdNCs increased with increasing Cd 2+ concentrations, and the limit of detection in deionized water was 15.68 fM. This method enables the detection of Cd 2+ through the Cd concentration-dependent formation of fluorescent CdNCs in tap, fountain, and pond water samples with detection limits of 0.75, 7.65, and 48.2 fM, respectively. The sensitivity and specificity of our method are comparable to those of several existing methods for Cd 2+ detection. Furthermore, the system enables the homogeneous detection of Cd 2+ without separation and washing, thereby broadening its application in analytical chemistry. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) accumulation in rice and its subsequent transfer to food chain is a major environmental issue worldwide. Understanding of Cd transport processes and its management aiming to reduce Cd uptake and accumulation in rice may help to improve rice growth and grain quality. Moreover, a thorough understanding of the factors influencing Cd accumulation will be helpful to derive efficient strategies to minimize Cd in rice. In this article, we reviewed Cd transport mechanisms in rice, the factors affecting Cd uptake (including physicochemical characters of soil and ecophysiological features of rice) and discussed efficient measures to immobilize Cd in soil and reduce Cd uptake by rice (including agronomic practices, bioremediation and molecular biology techniques). These findings will contribute to ensuring food safety, and reducing Cd risk on human beings. [ABSTRACT FROM AUTHOR]

As an emerging contaminant, 1-H-benzotriazole (1H-BTR) has been detected in the engineered and natural aquatic environments, which usually coexists with heavy metals and causes combined pollution. In the present study, wild-type and transgenic zebrafish Danio rerio were used to explore the acute toxicity as well as the single and joint hepatotoxicity of cadmium (Cd) and 1H-BTR. Although the acute toxicity of 1H-BTR to zebrafish was low, increased expression of liver-specific fatty acid binding protein was observed in transgenic zebrafish when the embryos were exposed to 5.0 μM of 1H-BTR for 30 days. Besides, co-exposure to 1H-BTR not only reduced the acute toxic effects induced by Cd, but also alleviated the Cd-induced liver atrophy in transgenic fish. Correspondingly, effects of combined exposure to 1H-BTR on the Cd-induced expressions of several signal pathway-related genes and superoxide dismutase and glutathione-s-transferase proteins were studied. Based on the determination of Cd bioaccumulation in fish and the complexing stability constant (ß) of Cd-BTR complex in solution, the detoxification mechanism of co-existing 1H-BTR on Cd to the zebrafish was discussed. [ABSTRACT FROM AUTHOR]

Ecotoxicology provides data to inform environmental management. Many testing protocols do not consider offspring fitness and toxicant sensitivity. Cadmium (Cd) is a well-studied and ubiquitous toxicant but little is known about the effects on offspring of exposed parents (transgenerational effects). This study had three objectives: to identify endpoints related to offspring performance; to determine whether parental effects would manifest as a change in Cd tolerance in offspring and how parental exposure duration influenced the manifestation of parental effects. Adult snails were exposed to Cd 0, 25, 50, 100, 200 and 400 μg Cd/L for eight weeks. There were effects on adult endpoints (e.g., growth, reproduction) but only at the highest concentrations (>100 μg/L). Alternatively, we observed significant transgenerational effects at all Cd concentrations. Surprisingly, we found increased Cd tolerance in hatchlings from all parental Cd exposure concentrations even though eggs and hatchlings were in Cd-free conditions for 6 weeks. Explicit consideration of offspring performance adds value to current toxicity testing protocols. Parental exposure duration has important implications for offspring effects and that contaminant concentrations that are not directly toxic to parents can cause transgenerational changes in resistance that have significant implications for toxicity testing and adaptive responses. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the relationships between environmental exposure to metals/metalloids and semen quality, sperm apoptosis and DNA integrity using the metal/metalloids levels in seminal plasma as biomarkers. We determined 18 metals/metalloids in seminal plasma using an inductively coupled plasma-mass spectrometry among 746 men recruited from a reproductive medicine center. Associations of these metals/metalloids with semen quality (n = 746), sperm apoptosis (n = 331) and DNA integrity (n = 404) were evaluated using multivariate linear and logistic regression models. After accounting for multiple comparisons and confounders, seminal plasma arsenic (As) quartiles were negatively associated with progressive and total sperm motility using multivariable linear regression analysis, which were in accordance with the trends for increased odds ratios (ORs) for below-reference semen quality parameters in the logistic models. We also found inverse correlations between cadmium (Cd) quartiles and progressive and total sperm motility, whereas positive correlations between zinc (Zn) quartiles and sperm concentration, between copper (Cu) and As quartiles and the percentage of tail DNA, between As and selenium (Se) quartiles and tail extent and tail distributed moment, and between tin (Sn) categories and the percentage of necrotic spermatozoa (all Ptrend<0.05). These relationships remained after the simultaneous consideration of various elements. Our results indicate that environmental exposure to As, Cd, Cu, Se and Sn may impair male reproductive health, whereas Zn may be beneficial to sperm concentration. [ABSTRACT FROM AUTHOR]

Filamentous plastic litter collected from two beaches in south west England has been characterized by FTIR and XRF. The majority of samples were constructed of polyethylene and consisted of twisted or braided strands of a variety of colours that appeared to be derived from commercial fishing nets. A number of different elements were detected among the samples but, from an environmental perspective, the regular occurrence of Cr and Pb and the occasional or isolated occurrence of Br, Cd and Se were of greatest concern. The highest total concentrations of Br (2420 μg g-1), Cd (1460 μg g-1), Cr (909 μg g-1), Pb (3770 μg g-1) and Se (240 μg g-1) were always encountered among orange samples and are attributed to the presence of lead chromates and cadmium sulphoselenide as colourants and to brominated compounds as flame retardants. Element bioaccessibility was evaluated by ICP-MS following an acidic extraction test that mimics the digestive tract of seabirds, with maximum values after a seven-day incubation period and relative to respective total concentrations of 0.2-0.4% for Cd, Cr and Pb and about 7% for Br. In addition to the well-documented impacts on wildlife through entrapment, filamentous plastic waste may act as a significant source of hazardous chemicals into the marine foodchain through ingestion. [ABSTRACT FROM AUTHOR]

Wastewater reclamation and reuse represent a feasible solution to meet the growing demand for safe water. An environmentally sustainable technology such as phytoremediation is targeted for the reclamation of polluted waters. To this end, the capability of different plant species to tolerate and accumulate pollutants has to be investigated. In this work, eucalypt plants were studied by analysing biometric, physiological, and biochemical parameters related to cadmium (Cd) tolerance and accumulation in two clones (“Velino ex 7” and “Viglio ex 358”) of Eucalyptus camaldulensis Dehnh. × E. globulus subsp. bicostata (Maiden, Blakely & J.Simm.) J.B. Kirkp exposed to 50 μM CdSO4 under hydroponics for three weeks. The results indicated that both eucalypt clones have a valuable tolerance to cadmium, expressed as the tolerance index (Ti). Biometric investigations showed that, regardless of the clone, the metal exposure affected most parameters related to biomass allocation and leaf growth. On the contrary, significant differences were found between the clones with respect to the chlorophyll content and the Chl a to Chl b ratio. These findings were also confirmed from the analysis of chlorophyll fluorescence transient (OJIP) using the JIP test. Cadmium accumulation occurred in both clones and in particular in the roots, with a poor amount of metal reaching the aerial parts, and the Velino clone showed the highest Cd accumulation. The metal uptake ratio and the phytoextraction efficiency highlight a good Cd phytoremoval ability, especially for the Velino clone. The results are discussed taking into account that, in wastewater phytoremediation systems, root biomass can be completely harvested allowing for the removal of the absorbed metal. Finally, the notable tolerance to submersion and the large environmental adaptability of eucalypt suggest that this plant species represents an interesting candidate for the phytoremediation of Cd-polluted wastewaters. [ABSTRACT FROM AUTHOR]

A hydroponic experiment was conducted to investigate the effects of an endophytic bacterium SaMR12 on Sedum alfredii Hance metal ion accumulation, chlorophyll concentration, and the expression of three metal transporter families, zinc-regulated transporters, iron-regulated transporter-like protein (ZIP); natural resistance-associated macrophage protein; and heavy metal ATPase (HMA) at different Cd treatment levels. The results showed that at relatively low Cd conditions (≤25 μM), SaMR12 demonstrated a 19.5-27.5% increase in Fe, a 46.7-90.7% increase in Zn, and a 7.9-43.7% increase in Cu content in the shoot and elevated expression of SaIRT1, SaZIP3, SaHMA2, and SaNramp3 in the shoot and SaZIP1, SaHMA2, SaNramp1, and SaNramp3 in the root. At high Cd conditions (100 and 400 μM), SaMR12 demonstrated a 16.4-18.5% increase in leaf chlorophyll concentration, a 18.9-23.2% increase in Fe, and a 15.4-17.5% increase in Mg content in the shoot and elevated expression of SaZIP3, SaNramp6, SaHMA2, and SaHMA3 in the shoot and SaZIP3, SaNarmp1, SaNarmp3, and SaNarmp6 in the root. These results indicated that SaMR12 can elevate essential metal ion uptake and regulate the expression of transport genes to promote plant growth and enhance Cd tolerance and uptake to improve Cd accumulation up to 118-130%. [ABSTRACT FROM AUTHOR]

In this study, functionalized diatomite was prepared by grafting of 3-mercaptopropyltrimethoxysilane (MPTMS) to diatomite (MPTMS-diatomite). The diatomite with thermal treatment from 100 to 700°C was functionalized by MPTMS under dry and humid conditions. The obtained MPTMS-diatomite was characterized by X-ray diffraction (XRD), thermal gravity-differential scanning calorimeter (TG-DSC), and Fourier transformation infrared (FT-IR). The results showed that an increase in treatment temperature seems to reduce the loading of MPTMS onto diatomite. The humidity of diatomite was favorable for the grafting of functional groups on the surface. The possible mechanisms of MPTMS loading to diatomite (MPTMS-diatomite) were also proposed. The performance of a carbon paste electrode (CPE) modified with MPTMS-diatomite in the simultaneous determination of Cd(II) and Pb(II) ions was addressed. [ABSTRACT FROM AUTHOR]

The article focuses on use of electrochemical reactor with stainless steel concentric tubes electrode for removal of cadmium from waste water, and talks of cathodic reaction, mass transfer control, and electrolyte flow rate.

The article focuses on sorption of cadmium ion using lignocellulose biomass from leaves of camphor tree, and talks of X–ray photoelectron spectroscopy (XPS), Langmuir and Freundlich isotherms, and waste water treatment.

In this study, the endophytic fungal community associated with Solanum nigrum was isolated and characterized for cadmium (Cd) tolerance and host plant growth modulation under Cd contamination for the first time. In total, 42 culturable endophytic fungal isolates representing various morphotypes were isolated, among which 14 different genera of the fungal phylum Ascomycota were identified based on the analysis of the internal transcribed spacer (ITS) region of the rRNA gene. Among the identified genera, Colletotrichum (18%) represented the dominant genus followed by Alternaria (14%), and Fusarium (14%). The majority of the endophytic isolates were sensitive to a lower concentration (0.5 mM) of Cd. However, Glomerella truncata PDL-1, and Phomopsis fukushii PDL-10 showed the highest tolerance to a concentration gradient of Cd (0.5⿿2 mM). Owing to the levels of Cd tolerance detected, in order to simulate a tripartite plant-microbe-metal interaction, S. nigrum plants were inoculated with PDL-1 and PDL-10 under Cd spiking of 0, 5, 15, and 25 mg kg ⿿1 . The results indicated that PDL-10 inoculated plants had significantly higher Cd content in shoots as well as in roots than observed in the PDL-1 inoculated plants. Additionally, irrespective of Cd stress, PDL-1 and PDL-10 inoculation significantly improved plant growth attributes such as shoot and root length, chlorophyll content, and fresh and dry shoot/root weight as compared to those of non-inoculated control plants. The results of this study highlight the possible role of fungal endophytes harbored inside S. nigrum , which has the potential to improve the efficiency of phytoremediation or phytostabilization in the cleanup of Cd-contaminated soil. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is regarded as one of the most toxic environmental pollutants. A better understanding of the growth response, uptake, and translocation of Cd in barnyard grass (Echinochloa crus-galli) would be helpful for evaluating the role of this grass species as a potential candidate to be used for phytoremediation. The studied plants were grown in treated soils with increasing doses of Cd (0, 0.3, 0.6, 0.9, and 1.5 mg·kg-1). The results showed that Cd contents in plant tissues were found to increase with increasing doses of Cd. The pattern of Cd accumulation in different parts of the plant were found as: root>aboveground part > seed. Translocation factor (TF) values were found to be less than 1, and translocation from root to aboveground part was found to be higher as compared to that of aboveground part to seed. There was no significant difference on the aboveground part fresh weight (FW) and tiller number per plant under different concentrations of Cd stress. The root FW and the lengths of roots and shoots were significantly decreased in response to Cd treatments at low concentrations. However, the 1.5 mg·kg-1 Cd application didn't affect significant changes on the root and shoot length than that of the control. A high concentration of cadmium supply could promote chlorophyll content. SOD showed a similar trend to POD in Cd-exposed plants, with an increase at lower concentrations and a decrease at higher concentrations. [ABSTRACT FROM AUTHOR]

Kaolinite was utilized as in-furnace sorbent to control submicron lead (Pb) and cadmium (Cd) emissions during waste incineration in a fluidized bed furnace. The secondary combustion chamber temperature ranged from 850 to 1000 °C. The metal capture was investigated for aspects of chemical reaction, physical conglutination and control performance of submicron metal emission. Pb reacted with kaolinite and caused conglutination of nanoscale metal particles at a lower temperature than Cd. Emission control of submicron Pb was far more effective than that of submicron Cd, particularly below 950 °C. For both Pb and Cd, there was capture limitation and an increase of kaolinite fraction above 3% could not further reduce the submicron metal emission. According to toxicity factors (5 Pb = 1 Cd) and the leaching fraction of submicron particles, the comprehensive performance of kaolinite was evaluated and numerous contradictory results were obtained. [ABSTRACT FROM AUTHOR]

With its unique structure, graphene exhibits a number of outstanding mechanical, optical, and electronic properties, thus promising several potential applications. In the current work, graphene sheets were prepared from graphite and surface-modified via an acid treatment. The synthesized material physicochemical properties were assessed using X-ray diffraction, nitrogen adsorption and BET analysis, transmission electron microscopy, and Raman as well as X-ray photoelectron spectroscopy techniques. The ability of the surface-modified graphene in the adsorptive elimination of Pb(II) and Cd(II) cations from aqueous solutions was investigated batchwise under numerous experimental conditions. A pseudo-second order kinetic model described adequately the adsorption kinetic profiles. The adsorption isotherms were compared to the Langmuir and Freundlich models. It was found that for both heavy metal cations, adsorption isotherms were reasonably described by Langmuir model equation. Maximum adsorption capacities reached 0.946 and 1.779 mmol ion/g for Pb(II) and Cd(II), respectively. [ABSTRACT FROM AUTHOR]

Poly (acrylic acid) modified activated carbon nanocomposite (PAA-AC) was synthesized. The structure and morphology of this nanocomposite were characterized by FTIR, SEM, TEM, XRD and Zeta potential. The adsorption of some heavy metal ions on PAA-AC was studied. The characterization results indicated that PAA-AC was a novel and ear-like nanosheet material with the thickness of about 40 nm and the diameter of about 300 nm. The adsorption results exhibited that the introduction of carboxyl groups into activated carbon evidently increased the uptake for heavy metal ions and the nanocomposite had maximum uptake for Cd(II). Various variables affecting adsorption of PAA-AC for Cd(II) were systematically explored. The maximum capacity and equilibrium time for adsorption of Cd(II) by PAA-AC were 473.2 mg g −1 and 15 min. Moreover, the removal of Cd(II) for real electroplating wastewater by PAA-AC could reach 98.5%. These meant that the removal of Cd(II) by PAA-AC was highly efficient and fast. The sorption kinetics and isotherm fitted well with the pseudo-second-order model and Langmuir model, respectively. The adsorption mainly was a chemical process by chelation. Thermodynamic studies revealed that the adsorption was a spontaneous and endothermic process. The results revealed that PAA-AC could be considered as a potential candidate for Cd(II) removal. [ABSTRACT FROM AUTHOR]

Heavy metal contamination due to natural and anthropogenic sources is a global environmental threat which can produce harmful effects on human health when they are taken up in amounts that cannot be processed by the organism. Technologies involving microbial cells for metal removal and recovery may provide an alternative to conventional methods. In the present study, three cadmium resistant bacteria were isolated from soil collected from industrial area of Faridabad, Haryana, India. Screening of the bacterial isolates for metal resistance against Cd2+, Ni2+, Hg2+, Cu+2 and Pb2+ was done by determining the minimal inhibitory concentration ranging from 10ppm to 250ppm. Moreover these isolates showed a significant ability to remove 70 to 78% of cadmium. These isolates were identified as Bacillus sp.263ZY1 (MA5), Bacterium YC-LK-LKJ45 (MB5) and Bacillus subtilis strain DHXJ07(MC5) on the basis of 16S r-RNA gene sequencing. The ability of these microbes to tolerate high concentration of a range of heavy metals provides a scope of use of these bacterial strains for bioremediation of heavy metal from industrial effluent. [ABSTRACT FROM AUTHOR]

Traditional duckweed toxicity tests only measure plant growth inhibition as an endpoint, with limited effects-based data. The present study aimed to investigate whether Fourier-transform infrared (FTIR) spectroscopy could enhance the duckweed ( Lemna minor L.) toxicity test. Four chemicals (Cu, Cd, atrazine, and acetochlor) and 4 metal-containing industrial wastewater samples were tested. After exposure of duckweed to the chemicals, standard toxicity endpoints (frond number and chlorophyll content) were determined; the fronds were also interrogated using FTIR spectroscopy under optimized test conditions. Biochemical alterations associated with each treatment were assessed and further analyzed by multivariate analysis. The results showed that comparable x% of effective concentration (EC x) values could be achieved based on FTIR spectroscopy in comparison with those based on traditional toxicity endpoints. Biochemical alterations associated with different doses of toxicant were mainly attributed to lipid, protein, nucleic acid, and carbohydrate structural changes, which helped to explain toxic mechanisms. With the help of multivariate analysis, separation of clusters related to different exposure doses could be achieved. The present study is the first to show successful application of FTIR spectroscopy in standard duckweed toxicity tests with biochemical alterations as new endpoints. Environ Toxicol Chem 2017;36:346-353. © 2016 SETAC [ABSTRACT FROM AUTHOR]

Crustaceans found in metal-contaminated regions are able to survive, and the authors investigated the physiological mechanisms involved by comparing populations from contaminated and noncontaminated areas. The objective of the present study was to measure the cellular transport of a nonessential metal (cadmium [Cd]) in gills and hepatopancreas of Ucides cordatus, together with cell membrane fluidity, metallothionein levels, and lipid peroxidation. The 2 populations compared were from a polluted and a nonpolluted mangrove area of São Paulo State, Brazil. The authors found, for the first time, larger Cd transport in gills and hepatopancreatic cells from crabs living in polluted mangrove areas. The cells also had lower plasma membrane fluidity, increased lipid peroxidation and less metallothionein compared to those from nonpolluted regions. The authors also found larger amounts of Cd in intracellular organelles of gills, but not in the hepatopancreas, from crabs in polluted regions. Therefore, in polluted areas, these animals showed higher Cd transport and lower plasma membrane fluidity and storage of Cd intracellularly in gill cells, whereas hepatopancreatic cells used metallothionein as their main line of defense. The findings suggest that crabs from polluted areas can accumulate Cd more easily than crabs from nonpolluted areas, probably because of an impairment of the regulatory mechanisms of cell membrane transport. Environ Toxicol Chem 2017;36:361-371. © 2016 SETAC [ABSTRACT FROM AUTHOR]

The soil-living mite Oppia nitens Koch has recently been proposed as a promising test species for the ecotoxicological risk assessment of contaminated boreal soils. Adding oribatid mites to the assemblage of test species for soil is highly desirable given the enormous diversity and ecological significance of these microarthropods. The authors aimed at revealing how toxicity, lethal body concentration, and bioaccumulation of cadmium (Cd) changed over a period of 7 wk when mites were exposed to Cd-spiked natural soils. The estimated median lethal concentration (LC50) values showed a gradual decrease with time, but a steady state was not reached within 7 wk. Estimates for lethal body concentration varied from 44 μg Cd/g to 91 μg Cd/g dry body weight, with a tendency to increase with time. The estimated 50% effective concentration (EC50) for effects on reproduction after 7-wk exposure was 345 μg Cd/g dry soil. Accumulation of Cd in mites was extremely variable but overall showed a nonsaturating increase. A simple 1-compartment toxicokinetic model did not describe the data well. The analysis suggests that O. nitens has a storage-detoxification strategy that is not at equilibrium under chronic exposure. Considering the tiny body size of the animal, it is remarkable that long exposure times are necessary to reveal chronic toxicity. The use of oribatids provides a clear added value to soil risk assessment but trades off with exposure length. Environ Toxicol Chem 2017;36:408-413. © 2016 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Humin is the component of humic substances that is recalcitrant to extraction by either strong bases or strong acids, which contains a variety of functional groups that may combine with heavy metal ions. The present study employed humin as an adsorbent to investigate the efficacy of a remediation strategy under the effects of humin-enhanced electrokinetics. Because the cations gravitate toward cathode and anions are transferred to anode, humin was placed in close proximity to the cathode in the form of a package. The humin was taken out after the experiments to determine whether a target pollutant (cadmium) might be completely removed from soil. Acetic acid-sodium acetate was selected as the electrolyte for these experiments, which was circulated between the two electrode chambers via a peristaltic pump, in order to control the pH of the soil. The results indicated that when the remediation duration was extended to 240 h, the removal of acid extractable Cd(II) could be up to 43.86% efficiency, and the adsorption of the heavy metal within the humin was 86.15 mg/kg. Further, the recycling of the electrolyte exhibited a good control of the pH of the soil. When comparing the pH of the soil with the circulating electrolyte during remediation, in contrast to when it was not being recycled, the pH of the soil at the anode increased from 3.89 to 5.63, whereas the soil at the cathode decreased from 8.06 to 7.10. This indicated that the electrolyte recycling had the capacity to stabilize the pH of the soil. [ABSTRACT FROM AUTHOR]