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231.
232.
In the present study total 21 forest stands on different aspects and locations (Hill base, mid slope and ridge top) on the
slope were studied to assess the importance of these two parameters in supporting species regeneration and biodiversity in
a mixed broadleaved forest between 380 and 850 m elevation in the Kumauau Himalayan region. A total of 36 tree species were
recorded in the forest. In all aspects the tree, sapling and shrub richness was higher at hill base stands in comparison to
mid slope and ridge top stand. Maximum tree richness (average across all aspects) was 9.7 and shrub richness was 9.3. Higher
richness at hill base may be attributed to more soil moisture and deeper soils which accumulate the hill base where the slope
steepness declines. The tree richness was higher in the northern aspect whereas southern aspect was more suitable for the
shrub species. From the present study it becomes evident that the base of the hills can support higher biodiversity and are
instrumental in supporting regeneration of several tree and shrub species in sal mixed broadleaved forest. 相似文献
233.
234.
Pasha Q Malik SA Iqbal J Shaheen N Shah MH 《Environmental monitoring and assessment》2008,147(1-3):377-388
The scalp hair samples of benign tumour patients (n = 77) and normal donors (n = 86) were analysed for selected trace metal contents using atomic absorption spectrophotometry. In the scalp hair of benign tumour patients, highest average levels were found for Ca (1,401 microg/g), followed by Na (476.9 microg/g), Mg (441.6 microg/g), Zn (438.3 microg/g), K (119.2 microg/g) and Fe (96.38 microg/g) while in comparison, the maximum mean levels in the scalp hair of normal donors were shown by Ca (556.5 microg/g), followed by Zn (154.2 microg/g), Mg (153.4 microg/g), Na (97.45 microg/g) and Fe (81.68 microg/g). Almost all metal levels revealed higher dispersion and asymmetry in the scalp hair of benign tumour patients compared with the normal donors. The average concentrations of Ca, Cd, Co, K, Mg, Mn, Na, Ni, Pb, Sb, Sr and Zn were significantly higher in the hair of benign tumour patients compared with the normal donors. Significant gender-based differences were also observed in the scalp hair metal contents of benign tumour patients. Strong positive correlations were found between Cd-Cr (0.547) and Cd-Co (0.507) in the hair of benign tumour patients whereas Ca-Mg, Mg-Sr, Co-Cd, Cr-Cd, Li-Cr, Li-Co, Li-Cd, Na-Cd, Na-Co and Na-Li exhibited strong relationships (r > 0.50) in the hair of normal donors. Cluster analysis (CA) and principal component analysis (PCA) were used for the source identification and apportionment of scalp hair trace metals in the two donor groups. The scalp hair of benign tumour patients and normal donors revealed six and five main clusters of trace metals, respectively. PCA extracted seven principal components of trace metals in the scalp hair of benign tumour patients while six principal components were observed in the case of normal donors. The study evidenced significantly different patterns of metal distribution in the hair of benign tumour patients in comparison with normal donors. 相似文献
235.
Statistical source identification of metals in groundwater exposed to industrial contamination 总被引:1,自引:0,他引:1
Tariq SR Shah MH Shaheen N Jaffar M Khalique A 《Environmental monitoring and assessment》2008,138(1-3):159-165
Levels of selected metals Na, Ca, Mg, K, Fe, Mn, Cr, Co, Ni, Cd, Pb and Mn were estimated by flame atomic absorption spectrophotometry
in groundwater samples from Kasur, a significant industrial city of Pakistan. Salient mean concentration levels were recorded
for: Na (211 mg/l), Ca (187 mg/l), Mg (122 mg/l), K (87.7 mg/l), Fe (2.57 mg/l) and Cr (2.12 mg/l). Overall, the decreasing
metal concentration order was: Na > Ca > Mg > K > Fe > Cr > Zn > Co > Pb > Mn > Ni > Cd. Significantly positive correlations
were found between Na–Cr (r = 0.553), Na–Mn (r = 0.543), Mg–Fe (r = 0.519), Mg–Cr (r = 0.535), Pb–K (r = 0.506) and Pb–Ni (r = 0.611). Principal Component Analysis and Cluster Analysis identified tannery effluents as the main source of metal contamination
of the groundwater. The present metal data showed that Cr, Pb and Fe levels were several times higher than those recommended
for water quality by WHO, US-EPA, EU and Japan. The elevated levels of Cr, recorded as 21–42 fold higher compared with the
recommended quality values, were believed to originate from the tanning industry of Kasur. 相似文献
236.
237.
Massive land system changes impact water quality of the Jhelum River in Kashmir Himalaya 总被引:1,自引:0,他引:1
238.
Sabitha Sakkir Junid N Shah Pritpal Soorae Mohamed Al Mehairbi Shaikha Al Dhaheri 《Journal of Coastal Conservation》2017,21(1):189-195
Data on flora and vegetation of 14 off-shore islands representing different habitat types were studied for investigating floristic composition, vegetation types and correlation with their habitats and ecosystem. The results demonstrate considerable plant distribution and diversity among the islands within the limited spectrum of species; encompassing a total of 47 species, belonging to 43 genera under 24 families. The most representative families were Amaranthaceae (9 species), Fabaceae (4 species), Poaceae (4 species) and Asteraceae and Aizoaceae (3 species each). Fourteen families are represented by only one species. The mangrove species, Avicennia marina, occurs throughout the coast of Abu Dhabi in discontinuous patches and in different water salinities. The studies also seek to underline that dominant species that constitutes the flora of Abu Dhabi are salt tolerant in nature. Compared to other Arabian Peninsula ecosystems, UAE perhaps has a higher coastal: mainland area ratio, which has contributed to a natural dominance of salt tolerant species among the community. The studies show 40% similarity among islands with respect to the species diversity. The floristic composition of the off-shore islands also indicates a need to consider these sites as protected sites. 相似文献
239.
Brian Freeman Bahram Gharabaghi Mohammad Munshed Shah Faisal Meshal Abdullah 《Journal of the Air & Waste Management Association (1995)》2017,67(5):565-581
This study presents a new method that incorporates modern air dispersion models allowing local terrain and land–sea breeze effects to be considered along with political and natural boundaries for more accurate mapping of air quality zones (AQZs) for coastal urban centers. This method uses local coastal wind patterns and key urban air pollution sources in each zone to more accurately calculate air pollutant concentration statistics. The new approach distributes virtual air pollution sources within each small grid cell of an area of interest and analyzes a puff dispersion model for a full year’s worth of 1-hr prognostic weather data. The difference of wind patterns in coastal and inland areas creates significantly different skewness (S) and kurtosis (K) statistics for the annually averaged pollutant concentrations at ground level receptor points for each grid cell. Plotting the S-K data highlights grouping of sources predominantly impacted by coastal winds versus inland winds. The application of the new method is demonstrated through a case study for the nation of Kuwait by developing new AQZs to support local air management programs. The zone boundaries established by the S-K method were validated by comparing MM5 and WRF prognostic meteorological weather data used in the air dispersion modeling, a support vector machine classifier was trained to compare results with the graphical classification method, and final zones were compared with data collected from Earth observation satellites to confirm locations of high-exposure-risk areas. The resulting AQZs are more accurate and support efficient management strategies for air quality compliance targets effected by local coastal microclimates.
Implications: A novel method to determine air quality zones in coastal urban areas is introduced using skewness (S) and kurtosis (K) statistics calculated from grid concentrations results of air dispersion models. The method identifies land–sea breeze effects that can be used to manage local air quality in areas of similar microclimates. 相似文献
240.
Atta Rasool Tangfu Xiao Abida Farooqi Muhammad Shafeeque Yizhang Liu Muhammad Aqeel Kamran Ioannis A. Katsoyiannis Syed Ali Musstjab Akber Shah Eqani 《Environmental geochemistry and health》2017,39(4):847-863
In the present study, the tube well water quality and the associated health risks, emphasizing on arsenic contamination, were investigated in rural and urban samples from Tehsil Mailsi located in Punjab, Pakistan. Arsenic concentrations (μg/L) were ranged from 12 to 448.5 and which exceeded the WHO recommended limit (10 μg/L) in all cases. The calculated average daily dose (3.3 × 10?0.4 to 1.2 × 10?0.2 mg/kg day) and hazard quotient (1.1–40) reflected the potential health risk to local population due to tube well water consumption as drinking purpose. Sodium percent (Na%), sodium absorption ratio, residual sodium carbonate, Kelly’s index and magnesium absorption ratio were also determined to assess the suitability of tube well water for irrigation purpose. The resulting piper plot revealed the Na–Ca–HCO3 type water chemistry of the area and generally alkaline environment. The spatial distribution of arsenic in the tube well waters pinpoints the significant contribution of anthropogenic activities to arsenic pollution. Nevertheless, different statistical tools, including principal component analysis, hierarchical cluster analysis and correlation matrices, revealed the contribution of both natural and anthropogenic activities and alkaline type of aquifers toward the high level of arsenic contamination. 相似文献