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Environmental Fluid Mechanics - In this paper, the linear stability of sand waves sheared by a turbulent flow is analyzed. The velocity distribution in the streamwise direction is considered to... 相似文献
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PW Kok HY Ong MK Wong WK Au KT Tan WH Phoon CN Ong 《Environmental monitoring and assessment》1997,44(1-3):425-431
Occupational exposure to benzene was measured in two gasoline marketing terminals and five major refineries in Singapore. A total of 280 workers were monitored over two years. This assessment was carried out with two primary objectives: (1) To find out the extent of occupational exposure to benzene in the petroleum industry in Singapore, (2) To identify suitable biomarkers for monitoring of low levels of benzene exposure. The exposure was measured in five different categories of petroleum and petrochemical workers, i.e., truck drivers, despatch assistant, process operators, oil movements operators and laboratory technicians. The results revealed wide variations in exposure, from 0.01 to 13.6 ppm for personal time weighted average (TWA) exposure over the whole workshift. The exposure of truck drivers appeared to be the highest, with geometric mean (GM) of 1.98 ppm (ranged from 0.25 to 13.6 ppm). The average benzene exposure for process operators was relative low with a GM of 0.04 ppm. Lowest benzene exposure was found in the laboratory technicians, with a GM of 0.02 ppm. As cigarette smoking is known to affect metabolism of benzene, data analyses on the relationships with environmental exposure were conducted only on the 190 nonsmokers. The results showed that urinary trans, trans-muconic acid (ttMA), unmetabolized benzene in urine (UBZ) and benzene in blood (BBZ) were better biomarkers for low level benzene exposure as compared to urinary phenolic metabolites in urine, such as hydroquinone, phenol and catechol. 相似文献
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Heavy metal pollution of water resources can be apprehended in East Singhbhum region which is a highly mineralised zone with
extensive mining of copper, uranium and other minerals. Ten groundwater samples were collected from each site and the heavy
metal analysis was done by atomic absorption spectrophotometer. Analysis of the results of the study reveals that the concentration
of iron, manganese, zinc, lead, copper and nickel in groundwater of Bagjata mining area ranged 0.06–5.3 mg l − 1, 0.01–1.3 mg l − 1, 0.02–8.2 mg l − 1, 1.4–28.4 μg l − 1, 0.78–20.0 μg l − 1 and 1.05–20.1 μg l − 1, respectively. In case of Banduhurang mining area, the range was 0.04–2.93 mg l − 1, 0.02–1.1 mg l − 1, 0.01–4.68 mg l − 1, 1.04–33.21 μg l − 1, 1.24–18.7 μg l − 1 and 1.06–14.58 μg l − 1, respectively. The heavy metals were found to be below the drinking water standards (IS:10500 1993) except iron (0.3 mg l − 1) and manganese (0.1 mg l − 1). The hazard quotients of the heavy metals for drinking water were below 1 posing no threat due to intake of water to the
people for both the areas. 相似文献
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Pal Swades Mahato Susanta Giri Biplab Pandey Deep Narayan Joshi Pawan Kumar 《Environment, Development and Sustainability》2021,23(11):15986-16014
Environment, Development and Sustainability - Recorded seasonal variation and uneven distribution of rainfall is one of the major issues to the agrarian society and the domestic water users today.... 相似文献
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