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41.
This study was to report and describe the formation of Ca oxalate crystals and to explore whether there is any correlation between their abundant formation and the ability of plant to uptake and accumulate high levels of toxic metals. Soil-grown Corchorus olitorius L. (Tiliaceae) seedlings were further grown in water culture in the presence of Cd, Pb, Cu, or Al (0–10 g/ml) for 20 days. Light and electron microscopic examinations revealed a large number of intracellular prismatic-shaped Ca oxalate crystals in both leaf and callus cells. Crystals were formed in the vacuole, a single large crystal being formed per cell. The crystal-containing cells differed in size and shape from crystal-free cells, they were rich in organelles, membranes, and vesicles and have dense cytoplasm, enlarged nucleus and modified starch-lacking plastids with few grana. These cells look highly active. Corchorus plants treated with Cd, Pb, Cu, and Al accumulated these metals to the levels several times higher than untreated plants. The contents of Pb, Cd, Al, and Cu in leaf tissues of plants grown in the presence of 5 g/ml of these metals were 10, 20, 25, and 40 times higher, respectively, than those in plants grown on media devoid of them. X-ray microanalysis of Ca oxalate crystals in leaves from plants exposed to 5 g/ml Cd, Pb, Al, or Cu indicated the incorporation only of Al into these crystals. Results of this paper suggest a possible contribution for Ca oxalate-crystal formation in sequestering and tolerance of at least some toxic metals. 相似文献
42.
Heavy metal concentrations in the breast milk of Saudi women 总被引:1,自引:0,他引:1
Lead, cadmium, and mercury concentrations were determined in breast milk of Saudi lactating mothers from Riyadh and Al-Ehssa
regions in Saudi Arabia who were not occupationally exposed. The mean levels for cadmium, lead, and mercury were 1.732 μg/L,
31.671 μg/L, and 3.100 μg/L, respectively. In contrast to mercury, mothers living in the Al-Ehssa region had significantly
higher cadmium and lead concentrations in their breast milk than those in the Riyadh region. The estimated weekly intakes
of cadmium, lead, and mercury of breast-fed infants in this study were in some cases higher than the Provisional Tolerance
Weekly Intake (PTWI) recommended by FAO/WHO, which pose a threat to their health. This necessitates the urgent need to undertake
a comprehensive study to determine the sources of exposure to these heavy metals. Breast-feeding is of great benefical value
for the infant’s development; therefore, efforts should be made to prevent its contamination with environmental pollutants. 相似文献
43.
Gregory Engel Todd M. O'Hara Tamara Cardona‐Marek John Heidrich Mukesh K. Chalise Randall Kyes Lisa Jones‐Engel 《American journal of physical anthropology》2010,142(3):453-460
Macaques are similar to humans both physiologically and behaviorally. In South and Southeast Asia they are also synanthropic, ecologically associated with humans. Synanthropy with humans raises the possibility that macaques come into contact with anthropogenic toxicants, such as lead and mercury, and might be appropriate sentinels for human exposures to certain toxic materials. We measured lead (Pb) and mercury (Hg) levels and characterized the stable isotopic compositions of δ15N and δ13C in hair from three groups of free‐ranging macaques at the Swoyambhu temple in Kathmandhu, Nepal, an urban population that has abundant contact with humans. Hair lead levels were significantly higher among young macaques and differed among the three groups of macaques that were sampled. Hair Hg levels were low. No statistical association was found between stable isotopic compositions (δ15N and δ13C) and Pb and Hg levels. Our data did not find evidence that lead levels were associated with diet. We conclude that, in this population of macaques, behavioral and/or physiologic factors may play a significant role in determining exposure to lead. Chemical analysis of hair is a promising, noninvasive technique for determining exposure to toxic elements in free‐ranging nonhuman primates. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc. 相似文献
44.
Anetor JI Ajose OA Adebiyi JA Akingbola TS Iyanda AA Ebesunu MO Babalola OO Aadeniyi FA 《Biological trace element research》2007,116(1):43-51
The relationship between blood lead (Pb) and serum levels of calcium and of neural nutrients such as thiamine and magnesium (Mg) has been determined in a Nigerian population that is occupationally exposed to Pb. Forty-seven male Pb workers were recruited as test subjects and 25 males unexposed to Pb served as controls. The test subjects were classified into three groups, based on severity of exposure to Pb. Blood lead (BPb) and the serum levels of Mg, thiamine, and calcium were determined in both test subjects and controls. The mean blood Pb level was not significantly higher in Pb workers. In contrast, Mg and thiamine levels were significantly decreased (p<0.05; p<0.01, respectively). However, the calcium level was not significantly lower in test subjects than in controls. Also, there was a significant negative correlation between serum thiamine and blood Pb levels (r=-0.50; p<0.01). Furthermore, there was a significant negative correlation between serum calcium and BPb levels (r=-0.41; p<0.01). This study has shown that relatively low BPb levels can enhance Pb absorption and also potentiate Pb neurotoxicity in the presence of decreased serum thiamine and Mg levels. 相似文献
45.
One hundred sixty-four adult male volunteers (29 controls [Group 1] and 135 combi drivers) enrolled in the study. The combi
drivers were divided into three groups as nonusers of either Maras powder or cigarette (Group 2), smokers (Group 3), and users of Maras powder (Group 4). Blood lead levels (BLLs) were analyzed by
atomic absorption spectrophotometer. BLL was detected as 2.8 ± 2.3 μg/dL in Group 1 (n = 29); however, it was 3.5 ± 1.6 μg/dL in Group 2 (n = 33), 3.8 ± 2.4 μg/dL in Group 3 (n = 62), and 3.9 ± 2.4 μg/dL in Group 4 (n = 40). BLL in Group 1 was found significantly lower than other groups (p < 0.05). The use of cigarette or Maras powder by the drivers did not give rise to a marked difference on the BLLs (p > 0.05). BLL of (combi) drivers was detected to be significantly higher than nondrivers; however, it was still under the
hazardous level of 10 μg/dL announced by WHO. Although there are publications reporting that usage of tobacco increases the
level of lead in blood, both smoking and use of Maras powder did not affect BLL markedly in our study.
Poster presented (the abstract section published in Congress Book) at the 7th Congress of Turkish Family Physicians, 23–26
May 2006, Cesme-IZMIR, Turkey. 相似文献
46.
Masaru Shibata Takayuki Konno Ryo Akaike Yong Xu Renfang Shen Jian Feng Ma 《Plant and Soil》2007,290(1-2):201-208
EDTA-assisted phytoextraction of lead (Pb) has been developed, but concerns have arisen due to the possibility of leaching
of both Pb and EDTA to ground water caused by uncontrolled release. We developed five types of controlled-release EDTA (polymer-coated
EDTA) by coating the EDTA with a polyolefin polymer. A test of the release rate showed that the duration for the release of
75% of total EDTA ranged from 3 to 210 days. A pot experiment was conducted to compare the effect of these polymer-coated
EDTA and non-coated EDTA on the concentrations of Pb and EDTA in soil solution, and Pb accumulation in sorghum (Sorghum bicolor L. cv. EARLY SUMAC) in a Pb-contaminated soil. One of the polymer-coated EDTAs, C-EDTA-4, with a release period of 80 days
proved to be the best in decreasing Pb and EDTA concentrations in soil solution, and increasing Pb accumulation in sorghum
shoots compared to the direct application of EDTA. Our results suggest that polymer-coated EDTA has a potential for phytoextraction
of Pb with a reduced environmental risk. 相似文献
47.
48.
R. M. Flores-Rangel P. F. Rodríguez-Espinosa J. A. Montes de Oca-Valero V. Mugica-Alvarez M. E. Ortiz-Romero-Vargas M. Navarrete-Lopez 《人类与生态风险评估》2007,13(6):1359-1372
With the aim to know possible risks to the population, Cd, Co, Cr, Cu, Mn, Ni, Pb, and Tl were determined for the first time in airborne samples of particulate matter in an urban zone in Tampico, México, during the winter of 2003. The 24-hour PM10 samples were collected every 6 days on quartz-filters by using a high volume sampler and analyzed by Inductively Coupled Plasma Optical Emission Spectrometer. Standard reference material was used to verify metal recovery. The maximum PM10 and lead concentrations were 12.05 and 0.040 μ g/m3, respectively, not exceeding Méxican standard values. The greatest metal concentration was that of manganese with 0.90 μ g/m3, followed by Cu and Ni with 0.17 and 0.012 μ g/m3, respectively. Agglomerates, well-defined particles, and heavy metals (e.g., Mn and Cu) were found in PM10 using Scanning Electron Microscopy and Energy Dispersive Spectroscopy. Meteorological conditions associated with the sampling period showed that Pb and Ni are being continuously emitted, and that Mn, Cu, and Co could come from one industry located to the WSW of the region. All of these concentrations do not constitute a potential risk to human health, although it is necessary to continue studying the high concentrations of Mn and Cu in longer sampling periods. 相似文献
49.
Omotayo Sarafadeen Amuda Olumuyiwa Idowu Ojo Theresa Ibibia Edewor 《Bioremediation Journal》2007,11(4):183-194
The shell of the seed of Chrysophyllum albidum carbon was used to adsorb lead (Pb) from aqueous solution, the sorption process with respect to its equilibria and kinetics as well as the effects of pH, contact time, adsorbent mass, adsorbate concentration, and particle size on adsorption were also studied. The most effective pH range was found to be between 4.5 and 5 for the sorption of the metal ion. The first-order rate equation by Lagergren was tested on the kinetic data and the adsorption process followed first-order rate kinetics. Isotherm data were analyzed for possible agreement with the Langmuir and Freundlich adsorption isotherms; the Freundlich and Langmuir models for dynamics of metal ion uptake proposed in this work fitted the experimental data reasonably well. However, equilibrium sorption data were better represented by Langmuir model than Freundlich. The adsorption capacity calculated from Langmuir isotherm was 72.1 mg Pb (II) g- 1 at initial pH of 5.0 at 30°C for the particle size of 1.00 to 1.25 mm with the use of 2.0 g/100 ml adsorbent mass. The structural features of the adsorbent were characterized by Fourier transform infrared (FTIR) spectrometry; the presence of hydroxyl, carbonyl, amide, and phosphate groups confirms the potential mechanism adsorption of the adsorbent. This readily available adsorbent is efficient in the uptake of Pb (II) ion in aqueous solution, thus, it could be an excellent alternative for the removal of heavy metals and organic matter from water and wastewater. 相似文献
50.
The effects of pectin from the eelgrass Zostera marina on toxic liver injury induced by enteral administration of lead acetate are examined in experiments on rats. The results show that pectin helps to rapidly reduce lead concentration in liver, to decrease lipid peroxidation, and to normalize the levels of total cholesterol and triglycerides in blood serum and liver. 相似文献