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Query: UMLS:C0205700 (ash)
 15,125 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

All eight members of a rural Wisconsin family experienced recurring neurological and medical illness over three years, especially during the winter months. Arsenic, in concentrations of 12 to 87 ppm, was noted in the hair of the mother and father, and analysis of hair and fingernails of all family members demonstrated pathological levels of arsenic. For four years the five-room home had been heated with a small wood stove in which outdoor or marine plywood and wood remnants had been preferentially burned. Stove ashes that contained more than 1,000 ppm of arsenic contaminated the living area, and the ratio of copper, chromium, and arsenic pentoxide in this ash matched the ratio used in the chromium-copper-arsenate-treated wood.
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PMID:Seasonal arsenic exposure from burning chromium-copper-arsenate-treated wood. 670 90

Analytical procedures are described for the determination of arsenic, cadmium, calcium, copper, lead, mercury, selenium, and zinc in animal feed. Mercury is determined by digesting the feed sample in a mixture of concentrated nitric and sulfuric acids with vanadium pentoxide added as an oxidation catalyst, reducing with stannous chloride, and sweeping the elemental mercury into an absorption tube for measurement by atomic absorption (AA) spectrophotometry. Arsenic and selenium are determined simultaneously by digesting the sample with a mixture of concentrated nitric, sulfuric, and perchloric acids; the hydrides of arsenic and selenium, which are formed with the addition of sodium borohydride, are swept into an argon-hydrogen flame for analysis by AA. A low temperature ash is prepared and dissolved in IN HNO3 for the analysis of calcium, copper, and zinc by emission spectroscopy using the inductively coupled argon plasma source; the same solution is used for the determination of cadmium and lead by flameless AA. Animal feed spiked with 3 levels of each of the 8 elements gave recoveries that ranged from 80 to 107%.
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PMID:Analysis of laboratory animal feed for toxic and essential elements by atomic absorption and inductively coupled argon plasma emission spectrometry. 730 50

Little information is available on the relationship between occupational exposure to inorganic arsenic in coal fly ash and urinary excretion of arsenic metabolites. This study ws undertaken in a coal-fired power plant in Slovakia during a routine maintenance outage. Arsenic was measured in the breathing zone of workers during 5 consecutive workdays, and urine samples were obtained for analysis of arsenic metabolites--inorganic arsenic (Asi), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA)--prior to the start of each shift. Results from a small number of cascade impactor air samples indicated that approximately 90% of total particle mass and arsenic was present in particle size fractions >/= 3.5 micron. The 8-hr time-weighted average (TWA) mean arsenic air concentration was 48.3 microg/m3 (range 0.17-375.2) and the mean sum of urinary arsenic (SigmaAs) metabolites was 16.9 microg As/g creatinine (range 2.6-50.8). For an 8-hr TWA of 10 microg/m3 arsenic from coal fly ash, the predicted mean concentration of the SigmaAs urinary metabolites was 13.2 microg As/G creatinine [95% confidence interval (CI), 10.1-16.3). Comparisons with previously published studies of exposure to arsenic trioxide vapors and dusts in copper smelters suggest that bioavailability of arsenic from airborne coal fly ash (as indicated by urinary excretion) is about one-third that seen in smelters and similar settings. Arsenic compound characteristics, matrix composition, and particle size distribution probably play major roles in determining actual uptake of airborne arsenic.
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PMID:Airborne arsenic and urinary excretion of arsenic metabolites during boiler cleaning operations in a Slovak coal-fired power plant. 934 99

A number of recent studies have linked developmental, physiological, and behavioral abnormalities in amphibians to coal combustion wastes (coal ash). Few studies, however, have determined trace element concentrations in amphibians exposed to coal ash. In the current study we compare total body concentrations of 20 trace elements in adult southern toads, Bufo terrestris, inhabiting coal ash settling basins with toads that were not exposed to the combustion wastes (reference). In addition, we document the accumulation of trace elements in toads transplanted from reference sites to field enclosures in an ash settling basin for 7 and 12 weeks. Arsenic, selenium, and vanadium levels were significantly elevated in toads captured at the ash-contaminated site in comparison to toads from the reference site. All three of these elements were also significantly elevated in toads exposed to the contaminated habitat for only 7 weeks. Our study suggests that adult anurans can bioaccumulate particularly high levels of selenium and may be useful bioindicators in agricultural and coal ash-impacted habitats.
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PMID:Elevated trace element concentrations in southern toads, Bufo terrestris, exposed to coal combustion waste. 968 May 25

The concentration of As, Cr and Ni and their speciation (As3+;5+, Cr3+;6+ and Ni0;2+) in milled coal, bottom ash and ash collected by electrostatic precipitator (ESP) from a coal fired-power plant in western Canada were determined using HGAAS, ICP-AES and XANES. The chemical fractionation of these elements was also determined by a sequential leaching procedure, using deionized water, NH4OAC and HCI as extracting agents. The leachate was analyzed by ICP-AES. Arsenic in the milled coal is mostly associated with organic matter, and 67% of this arsenic is removed by ammonium acetate. This element is totally removed from milled coal after extraction with HCI. Arsenic occurs in both the As3+ and the As5+ oxidation states in the milled coal, while virtually all (>90%) of the arsenic in bottom ash and fly ash appears to be in the less toxic arsenate (As5+) form. Both Ni and Cr in the milled coal are extracted by HCI, indicating that water can mobilize Ni and Cr in an acidic environment. The chromium is leached by water from fly ash as a result of the high pH of the water, which is induced during the leaching. Ammonium acetate removes Ni from bottom ash through an ion exchange process. Chromium in milled coal is present entirely as Cr3+, which is an essential human trace nutrient. The Cr speciation in bottom ash is a more accentuated version of the milled coal and consists mostly of the Cr3+ species. Chromium in fly ash is mostly Cr3+, with significant contamination by stainless-steel from the installation itself.
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PMID:Monitoring the species of arsenic, chromium and nickel in milled coal, bottom ash and fly ash from a pulverized coal-fired power plant in western Canada. 1125 1

Small-scale (1 m2) wetland mesocosm experiments were conducted over two consecutive growing seasons to investigate the effects on soil and leachate chemistry of using a recycled coal combustion product as a liner. The coal combustion product used as a liner consisted of flue gas desulfurization (FGD) by-products and fly ash. This paper provides the chemical characteristics of mesocosm soil and leachate after 2 yr of experimentation. Arsenic, Ca, and pH were higher in FGD-lined mesocosm surface soil relative to unlined mesocosms. Aluminum was higher in the soils of unlined mesocosms relative to FGD-lined mesocosms. No significant difference of potentially phytotoxic B was observed between lined and unlined mesocosms in the soil. Higher pH, conductivity, and concentrations of Al, B, Ca, K, and S (SO4-S) were observed in leachate from lined mesocosms compared with unlined controls while Fe, Mg, and Mn were higher in leachate from unlined mesocosms. Concentrations of most elements analyzed in the leachate were below national primary and secondary drinking water standards after 2 yr of experimentation. Initially high pH and soluble salt concentrations measured in the leachate from the lined mesocosms may indicate the reason for early effects noted on the development of wetland vegetation in the mesocosms.
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PMID:Chemical analysis of soil and leachate from experimental wetland mesocosms lined with coal combustion products. 1147 25

A coal-burning power station in the Nitra Valley in central Slovakia annually emitted large quantities of arsenic (up to 200 tonnes) between 1953 and 1989. Since then, pollution-control measures have reduced arsenic emissions to less than 2 tonnes a year. However, the power station was still a source of airborne arsenic pollution. As part of an EU-funded study on exposure to arsenic and cancer risk in central and Eastern Europe we carried out a study of environmental levels of arsenic in the homes and gardens of residents of the district. Garden soil samples (n=210), house dust samples (n=210) and composite house dust samples (n=109) were collected and analysed using inductively coupled plasma atomic absorption spectroscopy (ICP-AES) at Imperial College. The mean arsenic content of coal and ash in samples taken from the plant was 519 microg/g (n=19) and 863 microg/g (n=22), respectively. The geometric mean (GM) arsenic concentration of garden soils was 26 microg/g (range 8.8-139.0 microg/g), for house dust 11.6 microg/g (range 2.1-170 microg/g) and for composite house dust 9.4 microg/g (range 2.3-61.5 microg/g). The correlation between the arsenic levels in soil and in house dust was 0.3 (P<0.01), in soil and composite house dust 0.4 and house dust and composite house dust 0.4 (P<0.01 for both), i.e., were moderate. Arsenic levels in both house dust and soil decreased with distance from the power station. Overall, levels in both fell by half 5 km from the point source. Weak correlations were seen between the total urinary arsenic concentrations and arsenic concentrations in composite house dust.
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PMID:Assessment of environmental arsenic levels in Prievidza district. 1203 14

A preliminary survey of an arsenic contaminated site from an abandoned copper smelting facility and feasibility study of using solidification/stabilization (S/S) process to treat the contaminant waste were undertaken. It was found that the waste, located in the three-flue gas discharge tunnels, contained 2-40% arsenic. The pH of the contaminated waste is extremely low (ranging from 1.8 to 3.6). The X-ray diffraction evidence indicates that the arsenic particles present in the flue gas mainly exist as As(III), or As(2)O(3). The total amount of arsenic contaminated waste is estimated to be 700 ton in the studied area. About 50% of the particle sizes are less than 2 mm. Arsenic is easily extracted from wastes with a variety of leaching solutions. In order to meet the arsenic leaching standard of the toxicity characteristic leaching procedure (TCLP), an extremely high cement dosage is required in the S/S process (cement/waste weight ratio>6). The waste with lower particle size having higher specific surface area exhibits somewhat positive effect on the S/S performance. The use of fly ash from municipal waste incinerators, in conjunction with the reduced amount of cement, is able to meet the TCLP arsenic and lead standards. The use of lime alone could meet the TCLP arsenic standard, but lead leaching concentrations exceeded leaching Pb standard. The results of semi-dynamic leaching tests of some solidified samples indicate higher accumulated arsenic leaching concentrations after only a few leachant renewals.
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PMID:Arsenic contaminated site at an abandoned copper smelter plant: waste characterization and solidification/stabilization treatment. 1312 9

The proper end-of-life management of chromated copper arsenate (CCA)-treated wood, which contains arsenic, copper, and chromium, is a concern to the solid waste management community. Landfills are often the final repository of this waste stream, and the impacts of CCA preservative metals on leachate quality are not well understood. Monofills are a type of landfill designed and operated to dispose a single waste type, such as ash, tires, mining waste, or wood. The feasibility of managing CCA-treated wood in monofills was examined using a simulated landfill (a leaching lysimeter) that contained a mix of new and weathered CCA-treated wood. The liquid to solid ratio (LS) reached in the experiment was 0.63:1. Arsenic, chromium, and copper leached from the lysimeter at average concentrations of 42 mg/L for arsenic, 9.4 mg/L for chromium, and 2.4 mg/L for copper. Complementary batch leaching studies using deionized water were performed on similar CCA-treated wood samples at LS of 5:1 and 10:1. When results from the lysimeter were compared to the batch test results, copper and chromium leachability appeared to be reduced in the lysimeter disposal environment. Of the three metals, arsenic leached to the greatest extent and was found to have the best correlation between the batch and the lysimeter experiments.
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PMID:Leaching of chromated copper arsenate (CCA)-treated wood in a simulated monofill and its potential impacts to landfill leachate. 1640 90

Experiments were conducted to study CCA-treated wood combustion over a range of temperature and oxygen concentrations with a view to understanding the factors affecting energy and metals recovery from waste treated timber. CCA-treated wood was burned in a furnace at temperatures from 400 to 940 degrees C and oxygen concentrations between 5 and 21%. The ash and condensed volatiles were digested for total concentrations of metals and subjected to leaching tests to determine the stabilized concentrations of metals. Arsenic volatilisation increased with increasing furnace temperature whereas the copper and chromium reported mainly to the ash product. The effect of oxygen concentration was weak although it appeared that more arsenic volatilises at higher oxygen concentrations. However, a larger proportion of the arsenic in the ash generated at lower oxygen concentrations is solubilised during leaching tests, with the result that the concentration of stabilized arsenic in the ash is relatively unaffected by oxygen concentration.
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PMID:Deportment and management of metals produced during combustion of CCA-treated timbers. 1660 Apr 91


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