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351.
The leaves of Robinia pseudo-acacia L. (Fabaceae) were evaluated as a biomonitors of heavy metal contamination in Denizli city, Turkey. Concentrations of Fe, Zn, Pb, Cu, Mn and Cd were determined in washed and unwashed leaves and soils collected from a wide range of sites with different degrees of metal pollution (industry, urban roadside, suburban) and from a rural (control) site by atomic absorption spectrometry. All the elements that measured were found to be at high levels in samples collected at industrial sites, except for lead and copper which were found at high levels in samples collected from urban roadsides that associated with the road traffic. The strong correlation between the degree of contamination and concentrations in all plant leaves assessed display that the leaves of R. pseudo-acacia reflect the environmental changes accurately, and that they seem as an effective biomonitor of environmental quality in areas subjected to industrial and traffic pollutions.  相似文献   
352.
Computer professionals and Carpal Tunnel Syndrome (CTS).   总被引:1,自引:0,他引:1  
Carpal Tunnel Syndrome (CTS) is an important problem among computer professionals. Hence the prevalence of CTS among computer professionals and risk factors were studied. 648 subjects were selected from 4,276 computer professionals from 21 companies by with simple random sampling method. CTS was diagnosed based on clinical features. The prevalence of CTS was found to be 13.1% (95% CI 10.5-15.7%). Subjects with over 8 years of computer work, over 12 hrs of work per day and system administrators were at a higher risk for CTS (OR 3.3, 4.9 and 2.5 respectively). Flexed or extended hand position had higher risk for CTS. Higher risk for CTS was found with higher exposure to computer work. Ergonomic considerations are important in facilitating proper positioning of hand while working with a computer. Further studies on CTS risk factors among computer professionals are essential for planning prevention.  相似文献   
353.
Abstract: Efficient water resource management is one of the most important policy issues facing agriculture in Hawaii in the years ahead. Soil water sensors, multisensor capacitance probes (MCP), have been successfully used for different water management projects. These MCPs monitor water content at multiple depths and at various locations in real-time. The objectives of this study were to determine the effect of water content on field soil bulk density of Wahiawa silty clay tropical soil; measure field saturated hydraulic conductivity of this tropical soil: calibrate MCP system for this soil: and monitor and evaluate real-time soil water content variations under a tomato crop using the calibrated MCP system. Sensor calibration was conducted under laboratory conditions. Soil bulk density at different water contents and saturated hydraulic conductivity were measured on the field. Bulk density increased with increasing water content: there was a 30 percent bulk density increase as a result of 0.25 cm3 cm-3 water content variation. Compared with the manufacturer's calibration, site specific laboratory calibration of MCP gave a more accurate determination of soil water. Field determined saturated hydraulic conductivity was higher than laboratory determined values reported in the literature for the same soil type. Real-time soil water content monitoring within the root zone showed substantial variations due to water input (irrigation and rainfall) and water output (evapotranspiration and deep percolations). However, water content variations were much further reduced in the soil layer below the root zone.  相似文献   
354.
Relation of fish larvae and zooplankton biomass in the Gulf of Aden   总被引:2,自引:0,他引:2  
This study is based on zooplankton samples collected in the upper 50 m by the F.R.V. Manihine in the Gulf of Aden during October–November, 1966 and February–March, 1967. Generally, the displacement volume of zooplankton varied between 20 and 67 ml/m2. Some higher values, up to 100 ml/m2, were also observed. The number of larval fish in positive hauls ranged from 2 to 282 larvae/m2. An inverse relationship between the number of larval fish and the accompanying volume of zooplankton was noted. This relationship is discussed. It is hypothesized that larval mortality due to predation in the Gulf of Aden during the northeast monsoon (November, February and March) was very high.  相似文献   
355.
In order to assess the effects of wood ash application to forests on small mammals, we collected bank voles (Clethrionomys glareolus) and common shrews (Sorex araneus) from a forest area in southern Finland. Part of the sample population was from sites that had been treated with ash 1.5 years earlier, part from untreated control sites. The ash increased the soil pH and gave an average cadmium load in soil of 44 g ha(-1). When comparing treated and control areas, we found slightly but significantly lower Cd concentrations in vole muscle, liver, and kidney from treated plots, whereas the Cd concentrations in shrew tissues were greater in animals from treated plots. In voles we detected an increase in Cd concentrations during the 45-d sampling period in treated and untreated plots. The relative weight of kidneys was greater from the ash-treated areas than untreated areas for both voles and shrews. The difference in Cd concentrations between the voles and shrews could be explained by the different food habits.  相似文献   
356.
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358.
Environmental Science and Pollution Research - Nitrite is present as a noxious contaminant in drinking water and causes oxidative damage in various tissues of humans and animals. It is a well-known...  相似文献   
359.
Spectrophotometry in combination with ionic liquid-based dispersive liquid–liquid microextraction (DLLME) was applied for the extraction and determination of formaldehyde in real samples. The method is based on the reaction of formaldehyde with methyl acetoacetate in the presence of ammonia. The variation in the absorbance of the reaction product was measured at 375?nm. An appropriate mixture of ethanol (disperser solvent) and ionic liquid, 1-hexyl-3-methylimidazoliumhexafluoro-phosphate [C6MIM][PF6] (extraction solvent) was rapidly injected into a water sample containing formaldehyde. After extraction, sedimented phase was analyzed by spectrophotometry. Under the optimum conditions, the calibration graph was linear in the range of 0.1–20?ng?mL?1 with the detection limit of 0.02?ng?mL?1 and limit of quantification of 0.08?ng?mL?1 for formaldehyde. The relative standard deviation (RSD%, n?=?5) for the extraction and determination of 0.8?ng?mL?1 of formaldehyde in the aqueous samples was 2.5%. The results showed that DLLME is a very simple, rapid, sensitive, and efficient analytical method for the determination of trace amounts of formaldehyde in wastewaters and detergents, and suitable results were obtained.  相似文献   
360.
The concentrations of heavy metals such as Cd, Cr, Cu, Mn, Ni, Pb and Zn were investigated in drinking water sources (surface and groundwater) collected from Swat valley, Khyber Pakhtunkhwa, Pakistan. The potential health risks of heavy metals to the local population and their possible source apportionment were also studied. Heavy metal concentrations were analysed using atomic absorption spectrometer and compared with permissible limits set by Pakistan Environmental Protection Agency and World Health Organization. The concentrations of Cd, Cr, Ni and Pb were higher than their respective permissible limits, while Cu, Mn and Zn concentrations were observed within their respective limits. Health risk indicators such as chronic daily intake (CDI) and health risk index (HRI) were calculated for adults and children separately. CDIs and HRIs of heavy metals were found in the order of Cr 〉 Mn 〉 Ni 〉 Zn 〉 Cd 〉 Cu 〉 Pb and Cd 〉 Ni 〉 Mn 〉 Cr 〉 Cu 〉 Pb 〉 Zn, respectively. HRIs of selected heavy metals in the drinking water were less than 1, indicating no health risk to the local people. Multivariate and univariate statistical analyses showed that geologic and anthropogenic activities were the possible sources of water contamination with heavy metals in the study area.  相似文献   
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