Hazardous bauxite red mud and ferrous slag management to produce sustainable construction materials

Journal of Material Cycles and Waste Management - This paper reports the development and characterization of new ceramics from hazardous bauxite red mud (50...     

Psychological consequences of prenatal diagnosis in a case of familial Angelman Syndrome

Angelman Syndrome (AS), characterized by mental retardation, absence of speech, seizures and motor dysfunction, is caused by genetic defects leading to loss of expression of the maternal copy of the chromosome 15q11–13 imprinted region. Most cases are sporadic, being caused by de novo deletion of maternal chromosome 15q11–13 (75%) or by paternal uniparental disomy (3–4%). Familial cases can occur, due to mutations in the UBE3A gene or in the imprinting center. We describe the case of a pregnant woman having two nephews with AS caused by a UBE3A mutation; lack of communication within the family led the woman to be completely unaware of the risk of disease recurrence until 15 weeks of gestation. UBE3A genetic testing revealed she carried the familial mutation 892–893delCT. Prenatal diagnosis was performed on amniotic fluid and demonstrated that the fetus had inherited the mutation. The unexpected diagnosis and the subsequent termination of the pregnancy caused the woman to undergo acute psychological distress showing relevant psychopathological symptoms. Nevertheless, at 2-year follow-up, adverse consequences were minimized, and the couple was planning a new pregnancy. Factors affecting the psychological outcome of abortion and the role of psychological support in reducing the risk of long-term unfavorable consequences are discussed. Copyright © 2006 John Wiley & Sons, Ltd.     

SOIL ZINC CONTAMINATION FROM CORROSION OF GALVANIZED STRUCTURES

The present work relates to galvanized structures with several years of time life subjected to atmospheric corrosion, like galvanized high tension steel pylons. The mass and fate of zinc released is evaluated both via empirical and experimental procedures. The corrosion rate determination requested atmospheric condition characterization, especially for SO 2 concentration and experimental activities focused on soil sampling around pylons. The soil zinc content, total and exchangeable, is determinates by different analytical procedures. The zinc diffusion in environment and the zinc extension under the top soil is evaluated using 1-dimensional mathematical model for miscible species in porous soil.     

Assessing health risk from benzene pollution in an urban area

A health hazard, specifically the leukaemia risk, is evaluatedfrom different sources of benzene exposure with relation to apopulation living in an urban area of Italy. The population exposure is calculated for a reference year by sexand lyfestyle, with respect to smokers and non smokers. Potentialhealth risk is therefore quantified by means of mathematicalmodels and the relative significance of the different sources is described. The results of the analysis are useful for the identification ofappropriate risk reduction strategies to minimize exposure, inparticular when resulting from lifestyle and personal activities.     

The effects of anthropogenic particulate emissions on roadway dust and Nerium oleander leaves in Messina (Sicily, Italy)

Complementary studies on the inorganic chemical composition of Nerium oleander leaves collected in the town of Messina (Sicily, Italy) and seven grain-size fractions of local roadway dust have been carried out. Data and maps are presented to show that the particulate matter present in the air of Messina contains trace elements significantly in excess with respect to the average continental earth crust. The anomalies follow the outline of the urban area, the highest concentrations of trace elements being observed where traffic density is highest. Chemical and isotopic analyses of both road dust and Nerium oleander leaves indicate that Pb contamination still characterizes roads with heavy traffic. In addition to Pb, other metals such as Pt, Pd, Sb, Au, Br, Zn, Cu, Mo, and Cd are significantly enriched in roadway dust, indicating their common anthropogenic origin, especially from traffic. SEM/EDS study of some roadway dust particles has shown the presence of gypsum probably of secondary origin, mixed particles formed by coagulation or gas-to-particle conversion, and porous spherical particles apparently emanating from combustion processes.     

Optimum Dose Of Lime And Fly Ash For Treatment Of Hexavalent Chromium–Contaminated Soil

The presence of hexavalent chromium, Cr(VI), in soil is an environmental concern due to its effect on human health. The concern arises from the leaching and the seepage of Cr(VI) from soil to groundwater. In this paper, a stabilization technology to prevent this problem was simulated on an artificial soil contaminated with hexavalent chromium. The process is a physico-chemical treatment in which the toxic pollutant is physically entrapped within a solid matrix formed by the pozzolanic reactions of lime and fly ash to reduce its leachability and, therefore, its toxicity. This paper presents the optimum ratio of fly ash and lime in order to stabilize artificial soils contaminated with 0.4 wt.% of Cr (VI) in a brief term process. The degree of chromium released from the soil was evaluated using a modified Toxicity Characteristic Leaching Procedure (TCLP) by US Environmental Protection Agency (EPA). Overall, experimental results showed reduced leachability of total and hexavalent chromium from soils treated with both fly ash and quicklime, and that leachability reduction was more effective with increasing amount of fly ash and quicklime. Stabilization percentages between 97.3% and 99.7% of the initial chromium content were achieved, with Cr(VI) concentration in the TCLP leachates below the US EPA limit for chromium of 5 mg/l. Adequate treatment was obtained after 1 day of curing with just 25% fly ash and 10% quicklime.     

Air quality biomonitoring through pollen viability of Fabaceae

In this study, pollen viability and germination of three plant species, Cercis siliquastrum L., Robinia pseudoacacia L., and Spartium junceum L., belonging to the Fabaceae family, was evaluated in sites with different intensity of road traffic, constantly monitored with continuous analysers for air pollutants (carbon monoxide (CO), sulphur dioxide (SO₂), and nitrogen dioxide (NO₂)) by the Municipality of Catania. Two sites, in which road traffic was absent, were selected, too. The percentages of viable pollen by 2,3,5-trypheniltetrazolium chloride (TTC) test ranged from 59.0 to 90.2 % in C. siliquastrum, from 61.5 to 83.5 % in S. junceum and from 67.5 to 84.3 % in R. pseudoacacia. The percentages of germination varied from 41.0 to 72.7 % in C. siliquastrum, from 42.0 to 64.7 % in S. junceum and from 38.3 to 66.3 % in R. pseudoacacia. The highest percentages of viable pollens were found in no-road traffic stations by either TTC or germination tests, while the lowest values were detected in a site characterised by heavy road traffic. In the monitored period (2007–2009), pollen viability, germinability and tube length of C. siliquastrum resulted in a significant negative correlation to CO, SO₂ and NO₂, whereas data from TTC and germination tests on S. junceum and R. pseudoacacia pollens were not well correlated to air pollutants. The results showed that pollen viability, germination and tube growth in C. siliquastrum were affected by air pollution. S. junceum and R. pseudoacacia were not very influenced by air pollutants, suggesting a different pollen sensitivity of these species.     

海上注聚井渗氮油管腐蚀失效原因

渤海S油田A2井渗氮防腐油管在注聚过程中发现多处腐蚀穿孔,为避免换管柱后再次发生腐蚀失效,通过腐蚀形貌观察、腐蚀产物分析、腐蚀介质分析对A2井油管腐蚀失效原因进行了研究。认为A2井油管部分渗氮层脱落,形成了电化学腐蚀的阳极,这是造成局部腐蚀的根本原因。注入水中存在较高含量的氯离子和硫酸盐还原菌,加剧了腐蚀进程,造成油管腐蚀穿孔,形成了以FeCO_3为主的腐蚀产物。建议加强渗氮油管质量管控,防止入井前渗氮层脱落,同时在注入水中加入杀菌剂减少细菌对腐蚀的影响,并在井下安装牺牲阳极短节预防腐蚀。     

Sinterability study of ceramic bodies made from a mixture of mineral coal bottom ash and soda-lime glass cullet.

The aim of this study was to investigate the sinterability to improve the technical properties of ceramic bodies made from coal bottom ash and soda-lime glass cullet. Different mixtures of bottom ash and glass cullet were formulated. The amount of bottom ash was 100, 70, 50 and 30 wt.%. The particle size distribution was the same for all formulations. The mixture containing 50 wt.% bottom ash also had its particle size distribution changed. Samples were formed by dry pressing and then fired at 950, 1050 and 1150 degrees C. Samples were evaluated for linear shrinkage, water absorption, flexural mechanical resistance, scanning electronic microscopy, pyroplastic deformation and thermodilatometric analysis. The higher firing temperature led to a decrease in water absorption and increased linear shrinkage, mechanical resistance and pyroplastic deformation. This effect was also observed for addition of glass up to 50 wt.%. The effect of smaller particles of bottom ash was more significant for linear shrinkage and mechanical resistance of ceramic bodies fired at 1150 degrees C. The use of a finer powder contributed to increase these properties. The influence of finer particles on water absorption and mechanical resistance of ceramic bodies fired at 950 and 1050 degrees C was not significant.