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1.
Optimal ranges of variables for an effective adsorption of lead(II) by the agricultural waste pomelo (Citrus grandis) peels using Doehlert designs.
Yu, XL, He, Y
Scientific reports. 2018;(1):729
Abstract
The capacity of pomelo peels' adsorption on lead(II) from aqueous solutions without modifications was investigated and confirmed. Four variables in this study, pH, temperature, time and initial concentration of lead(II), significantly affected the adsorption rate of pomelo peels. The prediction model and optimal ranges of optimized variables were given by Doehlert designs, which made the selection of variables rapid, flexible and effortless to obtain an adsorption rate reaching 99.9% and 20 mg/L for initial lead(II) concentration, 3 for pH, 50 °C for temperature and 210 min for time was a choice. The higher correlation coefficient as well as the more consistent value of experimental equilibrium adsorption capacity of the pseudo-first-order model suggested it bore a better prediction of the adsorption kinetics than the pseudo-second-order model. Langmuir model indicated the adsorption mechanism of pomelo peels was monolayer sorption with the help of both physical adsorption and chemical bonding, which were demonstrated by scanning electron microscopy and Fourier transform-infrared, respectively. The ability of pomelo peels to adsorb lead(II) from aqueous solutions was not interfered with the presence of calcium(II), magnesium(II), copper(II) and zinc(II). Pomelo peels had the potential to be utilized in the simultaneous adsorption of toxic heavy metal ions.
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2.
Ultrasonic seed treatment improved physiological and yield traits of rice under lead toxicity.
Rao, G, Ashraf, U, Huang, S, Cheng, S, Abrar, M, Mo, Z, Pan, S, Tang, X
Environmental science and pollution research international. 2018;(33):33637-33644
Abstract
Lead (Pb) is a highly toxic metal that damages normal plant metabolism and often results in reduced crop growth and yield. To measure whether or not ultrasonic seed (US) treatment alleviates Pb stress in rice, the seeds of two rice cultivars, i.e., Guangyan1 and Huahang31, were exposed to 30 min of ultrasonic vibration and then the seedlings were transplanted to Pb-contaminated soil. Results revealed that the Pb contents in roots, stems, leaves, panicles (at heading), and brown rice (at maturity) were lower in US treatment than control (CK; without US treatment); the trend for accumulation of Pb in different plant parts was recorded as: root ˃ stems ˃ leaves ˃ panicles ˃ brown rice in both rice cultivars. Overall, the Pb contents in the brown rice of Huahang31 were higher than those in Guangyan1. Moreover, the contents of proline and soluble protein as well as the activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) were significantly higher while the malondialdehyde (MDA) contents were significantly reduced in US treatment compared to CK. The effective panicle number, seed set percentage, grains per panicle, 1000-grain weight, and grain yield were increased by 8.9%, 5.3%, 6.8%, 4.4%, and 26.6% in Guangyan1 and 3.2%, 5.7%, 5.7%, 5.0%, and 24.2% in Huahang31, respectively in US treatment compared to CK. Hence, seed treatment with ultrasonic waves could improve rice performance and reduce brown rice Pb accumulation under Pb-polluted soils.
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3.
Formation of a lead-insoluble phase, pyromorphite, by hydroxyapatite during lead migration through the water-unsaturated soils of different lead mobilities.
Ogawa, S, Sato, T, Katoh, M
Environmental science and pollution research international. 2018;(8):7662-7671
Abstract
This study combined the original unsaturated-column-percolation test with X-ray diffraction (XRD) analysis to understand how lead is transformed into lead-insoluble phase and immobilized by hydroxyapatite during lead migration in the water-unsaturated soil of different lead mobilities. The amounts of lead migrated from the soils without hydroxyapatite ranged from 4 to 46%, depending on the lead mobilities of soils. On the other hand, those of soils with hydroxyapatite were greatly suppressed by > 95% as compared with those without hydroxyapatite. The XRD analysis showed that the amounts of lead transformed into pyromorphite were compatible with those of lead migrated from the soil irrespective of the different lead mobilities. To the best of our knowledge, this study provides the first experimental evidence that lead migration can induce lead to transform into pyromorphite in the water-unsaturated soil. In addition, this study quantitatively demonstrates that the amount of lead migrated is almost equal to that of lead formed into pyromorphite. Thus, it was found that even if soluble lead remains after the application of immobilization material, it would be immobilized by the material during the lead migration as long as adequate material is applied to the soil.
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4.
Concentrations of arsenic and lead in rice (Oryza sativa L.) in Iran: A systematic review and carcinogenic risk assessment.
Fakhri, Y, Bjørklund, G, Bandpei, AM, Chirumbolo, S, Keramati, H, Hosseini Pouya, R, Asadi, A, Amanidaz, N, Sarafraz, M, Sheikhmohammad, A, et al
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association. 2018;:267-277
Abstract
Exposure to heavy metals such as arsenic (As), lead (Pb), and cadmium (Cd) in either the short or the long term can cause cancers in humans. Dietary intake and consumption of rice (Oryza sativa L.) is increasing in Iran, and several studies on the concentration of heavy metals in rice have been carried out in this country in recent years. In this perspective, the main objective of the present study was to investigate, even via a meta-analysis of the existing literature, the presence of As and Pb in rice from many geographical areas in Iran, as well as to estimate the carcinogenic risk of these heavy metals in rice consumers. The results of the present ten years-spanning systematic review indicate that 21 reports, collecting a total of 2088 samples, were performed between 2008 and October 2017. The minimum and maximum concentration of As was observed in the Golestan area (0.01 ± 0.01 mg/kg d.w) and the Gillan region (3 mg/kg d.w); and Pb in the Shahrekord (0.07 ± 0.02 mg/kg d.w) and Mazandaran (35 mg/kg d.w). The meta-analysis of data showed that pooled concentration of As in the rice was 0.04 (95%CI: 0.02-0.06 mg/kg d.w), which resulted lower than the National Standard (NS) limits. However, the pooled concentration of Pb in the rice was 0.38 (95%CI: 0.25-0.5 mg/kg d.w), i.e., higher than NS limits. The heterogeneity was significant between As (I2 = 63%, P value = .003) and Pb (I2 = 96%, P value < .001) studies. The carcinogenic risk assessment showed that minimum and maximum incremental lifetime cancer risk (ILCR) of As was in the 45-54 (4.53 × 10-2) and 15-24 (5.50 × 10-2) year age groups consumers; and Pb, 45-54 (2.442 × 10-3) and 15-24 (2.96 × 10-3), respectively. The overall carcinogenesis risk of As (4.864 × 10-2) was 18.5 times higher than Pb (2.623 × 10-3). All age groups consumers of rice content of As and Pb are at considerable carcinogenesis risk (ILCR > 10-3). Therefore a decreased level of heavy metals in rice cultivation should be encouraged and performed in next planning.
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5.
Suspended cells of metallicolous and nonmetallicolous Viola species tolerate, accumulate and detoxify zinc and lead.
Sychta, K, Słomka, A, Suski, S, Fiedor, E, Gregoraszczuk, E, Kuta, E
Plant physiology and biochemistry : PPB. 2018;:666-674
Abstract
We studied the zinc and lead accumulation and tolerance level of suspended cells of four Viola species with different metallophyte statuses: Viola lutea ssp. westfalica (obligate metallophyte), V. tricolor (facultative metallophyte), V. arvensis (accidental metallophyte) and V. uliginosa (nonmetallophyte), in order to determine the correlation between cell and plant tolerance. Cells of all studied species/genotypes were tolerant to metal concentrations applied to the medium for 24, 48 and 72 h, more for zinc than for lead, as estimated by cell viability using the alamarBlue assay. Viable cells of each analyzed species/genotype accumulated zinc and particularly lead in very high amounts after treatment with 2000 μM for 72 h (1500-4500 mg kg-1, 24 000-32 000 mg kg-1, respectively), determined by atomic absorption spectrometry. The bioaccumulation factor values confirmed the cells' hyperaccumulation strategy. The cell-activated detoxification mechanism, consisting in deposition of metals in the cell wall and vacuoles, as shown by transmission electron microscopy with X-ray microanalysis, allows the cells to survive despite the high level of metal accumulation. These results indicate innate high tolerance to zinc and lead in violets with different metallophyte statuses and also in the nonmetallophyte, suggesting that evolutionarily developed hypertolerance may occurs in this group as a whole.
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6.
Effect of Residential Lead-Hazard Interventions on Childhood Blood Lead Concentrations and Neurobehavioral Outcomes: A Randomized Clinical Trial.
Braun, JM, Hornung, R, Chen, A, Dietrich, KN, Jacobs, DE, Jones, R, Khoury, JC, Liddy-Hicks, S, Morgan, S, Vanderbeek, SB, et al
JAMA pediatrics. 2018;(10):934-942
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Abstract
IMPORTANCE Childhood lead exposure is associated with neurobehavioral deficits. The effect of a residential lead hazard intervention on blood lead concentrations and neurobehavioral development remains unknown. OBJECTIVE To determine whether a comprehensive residential lead-exposure reduction intervention completed during pregnancy could decrease residential dust lead loadings, prevent elevated blood lead concentrations, and improve childhood neurobehavioral outcomes. DESIGN, SETTING, AND PARTICIPANTS This longitudinal, community-based randomized clinical trial of pregnant women and their children, the Health Outcomes and Measures of the Environment (HOME) Study, was conducted between March 1, 2003, and January 31, 2006. Pregnant women attending 1 of 9 prenatal care clinics affiliated with 3 hospitals in the Cincinnati, Ohio, metropolitan area were recruited. Of the 1263 eligible women, 468 (37.0%) agreed to participate and 355 women (75.8%) were randomized in this intention-to-treat analysis. Participants were randomly assigned to receive 1 of 2 interventions designed to reduce residential lead or injury hazards. Follow-up on children took place at 1, 2, 3, 4, 5, and 8 years of age. Data analysis was performed from September 2, 2017, to May 6, 2018. MAIN OUTCOMES AND MEASURES Residential dust lead loadings were measured at baseline and when children were 1 and 2 years of age. At 1, 2, 3, 4, 5, and 8 years of age, the children's blood lead concentrations as well as behavior, cognition, and executive functions were assessed. RESULTS Of the 355 women randomized, 174 (49.0%) were assigned to the intervention group (mean [SD] age at delivery, 30.1 (5.5) years; 119 [68.3%] self-identified as non-Hispanic white) and 181 (50.9%) to the control group (mean [SD] age at delivery, 29.2 [5.7] years; 123 [67.9%] self-identified as non-Hispanic white). The intervention reduced the dust lead loadings for the floor (24%; 95% CI, -43% to 1%), windowsill (40%; 95% CI, -60% to -11%), and window trough (47%; 95% CI, -68% to -10%) surfaces. The intervention did not statistically significantly reduce childhood blood lead concentrations (-6%; 95% CI, -17% to 6%; P = .29). Neurobehavioral test scores were not statistically different between children in the intervention group than those in the control group except for a reduction in anxiety scores in the intervention group (β = -1.6; 95% CI, -3.2 to -0.1; P = .04). CONCLUSIONS AND RELEVANCE Residential lead exposures, as well as blood lead concentrations in non-Hispanic black children, were reduced through a comprehensive lead-hazard intervention without elevating the lead body burden. However, this decrease did not result in substantive neurobehavioral improvements in children. TRIAL REGISTRATION ClinicalTrials.gov identifier: NCT00129324.
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The Effect of a Short-Term Exposure to Lead on the Levels of Essential Metal Ions, Selected Proteins Related to Them, and Oxidative Stress Parameters in Humans.
Dobrakowski, M, Boroń, M, Birkner, E, Kasperczyk, A, Chwalińska, E, Lisowska, G, Kasperczyk, S
Oxidative medicine and cellular longevity. 2017;:8763793
Abstract
The present study was designed to explore the possible influence of subacute exposure to lead on the levels of selected essential metals, selected proteins related to them, and oxidative stress parameters in occupationally exposed workers. The study population included 36 males occupationally exposed to lead for 36 to 44 days. Their blood lead level at the beginning of the study was 10.7 ± 7.67 μg/dl and increased to the level of 49.1 ± 14.1 μg/dl at the end of the study. The levels of calcium, magnesium, and zinc increased significantly after lead exposure compared to baseline by 3%, 3%, and 8%, respectively, while the level of copper decreased significantly by 7%. The malondialdehyde (MDA) level and the activities of catalase (CAT) and superoxide dismutase (SOD) did not change due to lead exposure. However, the level of lipid hydroperoxides (LPH) in serum increased significantly by 46%, while the level of erythrocyte lipofuscin (LPS) decreased by 13%. The serum levels of essential metals are modified by a short-term exposure to lead in occupationally exposed workers. A short-term exposure to lead induces oxidative stress associated with elevated levels of LPH but not MDA.
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Mesophyll cell ultrastructure of wheat leaves etiolated by lead and selenium.
Semenova, GA, Fomina, IR, Kosobryukhov, AA, Lyubimov, VY, Nadezhkina, ES, Balakhnina, TI
Journal of plant physiology. 2017;:37-44
Abstract
The ultrastructure of mesophyll cells was studied in leaves of the Triticum aestivum L. cv. "Trizo" seedlings after two weeks of growth on soil contaminated by Pb and/or Se. The soil treatments: control; (Pb1) 50mgkg-1; (Pb2) 100mgkg-1; (Se1) 0.4mgkg-1; (Se2) 0.8mgkg-1; (Pb1+Se1); (Pb1+Se2); (P2+Se1); and (Pb2+Se2) were used. Light and other conditions were optimal for plant growth. The (Se1)-plants showed enhanced growth and biomass production; (Pb1+Se1)-plants did not lag behind the controls, though O2 evolution decreased; chlorophyll content did not differ statistically in these treatments. Other treatments led to statistically significant growth suppression, chlorophyll content reduction, inhibition of photosynthesis, stress development tested by H2O2 and leaf etiolation at the end of 14-days experiment. The tops of etiolated leaves remained green, while the main leaf parts were visually white. Plastids in mesophyll cells of etiolated parts of leaves were mainly represented by etioplasts and an insignificant amount of degraded chloroplasts. Other cellular organelles remained intact in most mesophyll cells of the plants, except (Pb2+Se2)-plants. Ruptured tonoplast and etioplast envelope, swelled cytoplasm and mitochondria, and electron transparent matrix of gialoplasm were observed in the mesophyll cells at (Pb2+Se2)-treatment, that caused maximal inhibition of plant growth. The results indicate that Pb and Se effects on growth of wheat leaves are likely to target meristem in which the development of proplastids to chloroplasts under the light is determined by chlorophyll biosynthesis. Antagonistic effect of low concentration of Se and Pb in combination may retard etiolation process.
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Ascorbic acid protects Coccomyxa subellipsoidea against metal toxicity through modulation of ROS/NO balance and metal uptake.
Kováčik, J, Rotková, G, Bujdoš, M, Babula, P, Peterková, V, Matúš, P
Journal of hazardous materials. 2017;:200-207
Abstract
Impact of exogenous ascorbic acid (AsA, 100μM) on acute metal toxicity (Pb and Hg, 24h of exposure to 100μM) in unicellular green alga Coccomyxa subellipsoidea was studied. Hg (often extensively) depleted amount of pigments, potassium, soluble proteins, endogenous AsA, non-protein thiols and nitric oxide signal but elevated ROS signal and activities of catalase and superoxide dismutase. Responses to Pb application (if any) were less visible with ROS signal being slightly elevated and amount of non-protein thiols being slightly reduced. Exogenous AsA considerably improved mainly Hg-induced damage at the level of oxidative stress and physiological parameters and evoked an increase in nitric oxide signal. Maximum amount of total Hg was almost 4-fold higher than that of Pb (36.5 vs. 9.73mg/g DW) and AsA depleted both total and intracellular accumulation. At the level of ascorbate-related proteins, exogenous AsA suppressed metal-induced expression and activity of MDHAR and APX but not of DHAR, which may indicate a role of DHAR in algal stress tolerance. Our data suggest that given Coccomyxa species is suitable candidate for remediation of Hg or Pb and that ascorbic acid effectively ameliorates metal-induced toxicity without side effects.
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Biosorption of lead ions from aqueous effluents by rapeseed biomass.
Morosanu, I, Teodosiu, C, Paduraru, C, Ibanescu, D, Tofan, L
New biotechnology. 2017;(Pt A):110-124
Abstract
Lead, as well as other heavy metals, is regarded as priority pollutant due to its non-biodegradability, toxicity and persistence in the environment. In this study, rapeseed biomass was used in the biosorption of Pb(II) ions in batch and dynamic conditions, as well as with tests for industrial wastewater. The influence of initial concentration (5-250mg/L), pH and contact time (0.5-6h) was investigated. The kinetic data modeling resulted in good correlations with the pseudo-second order and intraparticle diffusion models. The maximum sorption capacities of Pb(II) were 18.35, 21.29 and 22.7mg/L at 4, 20 and 50°C, respectively. Thermodynamic parameters indicated the spontaneity and endothermic nature of lead biosorption on rapeseed biomass. The biosorption mechanism involves both physical and chemical interactions. The breakthrough curves at 50 and 100mg/L were determined and evaluated under dynamic conditions. The breakthrough time lowered with increasing the influent Pb(II) concentration. The experimental data obtained from fixed-bed column tests were well fitted by Thomas and Yoon-Nelson models. The calculated sorption capacities were in good agreement with the uptake capacity of Langmuir model. The applicability of rapeseed to be used as a sorbent for Pb(II) ions from real wastewater was tested, and Pb(II) removal efficiency of 94.47% was obtained.