Asparagus ploidy distribution related to climates adaptation in Iran

Environment, Development and Sustainability - Asparagus basic chromosome number is 2n?=?2x?=?20. The high rate of polyploidy in wild asparagus has been found in natural...     

Assessment of Metal Contamination in Doñana National Park (Spain) using Crayfish (Procamburus Clarkii)

Water quality assessment in the Aznalcollar area was attempted using multivariate methods based on heavy metal concentrations in red swamp crayfish (Procamburus clarkii). Trace levels of four heavy metals, copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb), were detected in crayfish from eleven different stations. Principal component analysis (PCA) highlighted a gradient of contamination between the sampling stations. Cluster analysis (CA) distinguished three groups of stations. Discriminant analysis also differentiated three groups. The group centroids of the first discriminant function were used to devise an index that varies according to the source of the crayfish. These standardized values are proposed for use as a water quality index. The ability of this index to successfully predict environmental quality was proved with random samples.     

Risk assessment of particulate matter by considering time-activity-pattern and major microenvironments for preschool children living in Seoul,South Korea

Environmental Science and Pollution Research - Preschool children aged 3–6 years are vulnerable to exposed to particulate matter (“PM10” and “PM2.5”). It is required...     

Volcanic mercury in Pinus canariensis

Mercury (Hg) is a toxic element that is emitted to the atmosphere by both human activities and natural processes. Volcanic emissions are considered a natural source of mercury in the environment. In some cases, tree ring records taken close to volcanoes and their relation to volcanic activity over time are contradictory. In 1949, the Hoyo Negro volcano (La Palma-Canary Islands) produced significant pyroclastic flows that damaged the nearby stand of Pinus canariensis. Recently, 60 years after the eruption, we assessed mercury concentrations in the stem of a pine which survived volcano formation, located at a distance of 50 m from the crater. We show that Hg content in a wound caused by pyroclastic impacts (22.3 μg kg^?1) is an order of magnitude higher than the Hg concentrations measured in the xylem before and after the eruption (2.3 μg kg^?1). Thus, mercury emissions originating from the eruption remained only as a mark—in pyroclastic wounds—and can be considered a sporadic and very high mercury input that did not affect the overall Hg input in the xylem. In addition, mercury contents recorded in the phloem (9.5 μg kg^?1) and bark (6.0 μg kg^?1) suggest that mercury shifts towards non-living tissues of the pine, an aspect that can be related to detoxification in volcanism-adapted species.     

Effect of anaerobic digestion on the high rate of nitritation, treating piggery wastewater

Laboratory reactors were operated by using piggery wastewater and the effluent of anaerobic digester from piggery wastewater plants to study the effect of anaerobic digestion on nitritation rate.     

Ambient air monitoring of PCDD/Fs and co-PCBs in Gyeonggi-do, Korea

We started the monitoring for PCDD/Fs in ambient air and soil in August 2001, and co-PCBs in January 2002. Decreasing of PCDD/Fs and co-PCBs levels in ambient air were observed. The higher PCDD/Fs levels were found in winter and lower in autumn. We found that the industrial incinerators influenced the PCDD/Fs levels in ambient air. In the 2,3,7,8-substituted PCDD/Fs concentration profiles, the three major congeners occupied 67% of the total mass. In case of co-PCBs, PCB#118, #105 and #77 were observed as the main congeners. Five cluster groups discriminated by ratio of four components, O(8)CDD, 1,2,3,4,6,7,8-H(7)CDD, 1,2,3,4,6,7,8-H(7)CDF and O(8)CDF, were obtained from HCA (hierarchical cluster analysis).     

Partitioning of hydrogen peroxide between the gas and liquid phases in the presence of surfactant

Gas-liquid phase partitioning is a key physical property that can predict the environmental fate of a compound between two phases. Several environmental factors have been known to affect the gas-liquid phase partitioning. We investigated the influence of surfactant on the gas-liquid phase partitioning of hydrogen peroxide (H(2)O(2)). The surfactant used was ammonium perfluorooctanoate (APFO). H(2)O(2) solution containing the surfactant was equilibrated in a closed system and gas phase H(2)O(2) concentration was measured by the peroxyoxalate chemiluminescence (PO-CL) method. Gas phase H(2)O(2) concentrations remained constant below the critical micelle concentration (CMC) and increased linearly with surfactant concentration above the CMC, which indicated that surfactant micelles influenced the gas-liquid phase partitioning of H(2)O(2). This result showed that H(2)O(2)-micelle interactions are less favorable than H(2)O(2)-H(2)O interactions. Surfactant monomers did not affect the gas-liquid phase partitioning of H(2)O(2) due to the absence of micelles. Solvent (methanol) effect was also investigated and showed that gas phase H(2)O(2) concentrations increased with the addition of solvent. This indicated the unfavorable interaction of H(2)O(2) with hydrophobic medium compared to hydrophilic one. It is consistent with the result that H(2)O(2)-micelles has a weaker interaction than H(2)O(2)-water because surfactant micelles are hydrocarbon-like organic phase rather than aqueous phase.     

Performance of an electrochemical COD (chemical oxygen demand) sensor with an electrode-surface grinding unit

An electrochemical COD (chemical oxygen demand) sensor using an electrode-surface grinding unit was investigated. The electrolyzing (oxidizing) action of copper on an organic species was used as the basis of the COD measuring sensor. Using a simple three-electrode cell and a surface grinding unit, the organic species is activated by the catalytic action of copper and oxidized at a working electrode, poised at a positive potential. When synthetic wastewater was fed into the system, the measured Coulombic yields were found to be dependent on the COD of the synthetic wastewater. A linear correlation between the Coulombic yields and the COD of the synthetic wastewater was established (10-1000 mg L(-1)) when the electrode-surface grinding procedure was activated briefly at 8 h intervals. When various kinds of wastewater samples obtained from various sewage treatment plants were measured, linear correlations (r(2)> or = 0.92) between the measured EOD (electrochemical oxygen demand) value and COD of the samples were observed. At a practical wastewater treatment plant, the measurement system was successfully operated with high accuracy and good stability over 3 months. These experimental results show that the application of the measurement system would be a rapid and practical method for the determination of COD in water industries.     

Removal of gaseous elemental mercury by dielectric barrier discharge

The removal of elemental mercury (Hg(0)) with the reactive species produced from dielectric barrier discharge (DBD) was studied. The effects of the operating parameters, such as the applied voltage, residence time, initial concentration and co-existence of other pollutants, were investigated. The removal of Hg(0) was significantly promoted by an increase in the applied voltage of the DBD reactor system. The presence of NO gas decreased the Hg(0) removal efficiency within the range of input powers tested compared to the case of Hg(0)-only due to the competition for ozone between Hg(0) and NO gas in the DBD reactor.