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281.
4-Nonylphenol, a degradation intermediate of commercial surfactant and known endocrine disruptor, has been frequently detected at levels up to several thousand microgl(-1) in surface waters and up to several hundred mgkg(-1) (dry weight) in soil and sediment samples. Large quantities of 4-NP can be quickly sorbed by the organic rich solid phase during wastewater treatment and are concentrated in biosolids, a possible major source for 4-NP in the environment. Microbial transformation in culture studies followed different mechanisms for different 4-NP isomers, which have different estrogenic activity. Composting is a process of solid matrix transformation where biological activity is enhanced by process control. This approach has been used successfully in remediation of contaminated soils and sludges. In this study, the transformation kinetics of 4-NP and its isomers were characterized during biosolids composting. Five distinctive 4-NP isomer groups with structures relative to alpha- and beta-carbons of the alkyl chain were identified in biosolids. Composting biosolids mixed with wood shaving at a dry weight percentage ratio of 43:57 (C:N ratio of 65:1) removed 80% of the total 4-NP within two weeks. At this biosolids/wood shaving ratio (B:WS), the transformation of total 4-NP and its isomers followed second-order kinetic. Higher B:WS ratios yielded significantly slower 4-NP transformation which followed first-order kinetic. Isomers with alpha-methyl-alpha-propyl structure transformed significantly slower than those with less branched tertiary alpha-carbon and those with secondary alpha-carbon, suggesting isomer-specific degradation of 4-NP during biosolids composting. 相似文献
282.
Mahesh Kumar Sahu Ashim Das Gupta 《Journal of the American Water Resources Association》2001,37(3):675-684
ABSTRACT: Operation of a storage‐based reservoir modifies the downstream flow usually to a value higher than that of natural flow in dry season. This could be important for irrigation, water supply, or power production as it is like an additional downstream benefit without any additional investment. This study addresses the operation of two proposed reservoirs and the downstream flow augmentation at an irrigation project located at the outlet of the Gandaki River basin in Nepal. The optimal operating policies of the reservoirs were determined using a Stochastic Dynamic Programming (SDP) model considering the maximization of power production. The modified flows downstream of the reservoirs were simulated by a simulation model using the optimal operating policy (for power maximization) and a synthetic long‐term inflow series. Comparing the existing flow (flow in river without reservoir operation) and the modified flow (flow after reservoir operation) at the irrigation project, the additional amount of flow was calculated. The reliability analysis indicated that the supply of irrigation could be increased by 25 to 100 percent of the existing supply over the dry season (January to April) with a reliability of more than 80 percent. 相似文献
283.
284.
S. M. Das 《Environmental management》1979,3(5):385-386
Conclusions In addition to this natural water-holding capacity of completely forested mountains, development for conservation of water should insure man-made mountain water storage systems, consisting of tanks, ponds, small dams and reservoirs, and artificial lakes at varying altitudes in the Himalayas. An elaborate system of canals would be needed to carry clean water for drinking and cultivation. Alternatively, adjacent highland lakes may be linked up by canals provided with wiers and sluice gates, to carry water to all levels. 相似文献
285.
A study of ground water contamination by arsenic in the residential area of Behala, Calcutta due to industrial pollution 总被引:1,自引:0,他引:1
Due to the discharge of industrial effluent after production of the insecticide Paris-Green [Copper acetoarsenite Cu(CH(3)COO)(2).3Cu(AsO(2))(2)] by a local factory at the P. N. Mitra Lane, Behala, ground water has become contaminated with arsenic. More than seven thousand people were using this arsenic contaminated tube-well water for drinking and house-hold purposes. Many people of the area were hospitalised and symptoms of arsenic toxicity were visible amongst a large number of the population. Analytical study reveals that soil around the area of effluent dumping point, which is at the middle of the locality, contains a very high concentration of arsenic and copper. For the last 20 years this factory had been producing 20 tons of Paris-Green per year and had been dumping its effluent in that area. It seems, the effluent treatment for arsenic removal was not adequate and finally arsenic percolated to the underground aquifers. Consequently, arsenic concentration in the ground water is very high. Both arsenite and arsenate are present in ground water. An alternate source of water other than the ground water is immediately necessary for the people of P. N. Mitra Lane. 相似文献
286.
A.J. James Joep Verhagen Christine van Wijk Reema Nanavaty Mita Parikh & Mihir Bhatt 《Natural resources forum》2002,26(3):205-217
When water supply improvements are coupled with opportunity to create income through micro–enterprises, time released from water collection is converted into income earned. This brings several benefits: reduced drudgery, higher household income, and, consequently, greater women's empowerment through changing gender relations within the household. This article documents the performance of one such scheme in Banaskantha District in the state of Gujarat in India, one of poorest districts in the state and the country. Here, due to the efforts of the Self–Employed Women's Association (SEWA), an Indian NGO, poor women are reaping the social and economic benefits of a government–run regional piped water supply scheme, a project funded by Dutch bilateral aid, focusing on women's development. If government policy–makers took the cue and formulated programmes and schemes that combined these two aspects, viz., actions that release time for rural women from daily chores (e.g., collecting water, fuel wood and fodder)and opportunities for sustainable micro–enterprises to convert time saved into income, this could become a reliable route out of rural poverty into gender–sensitive sustainable development. 相似文献
287.
Mukesh Singh Avijit Das Debashree Singh Pratiti Maiti Md. Shabbir Anangsha Das 《Environmental Chemistry Letters》2014,12(2):321-327
Water pollution is a major environmental problem worldwide. In particular, shipyards are contaminating waters with iron, lead and copper filings, paints, petrochemical products and solvents. There are only a few reports on the genotoxicity of shipyard contaminants. Here, we study genotoxic effects of surface water from five sites of Hooghly River in West Bengal, India, along the banks of which many shipbuilding and scrap industries are located. Genotoxicity was measured by the detection of micronuclei in Allium cepa and other chromosomal aberrations, as well as damage to genomic DNA of calf thymus. Results show that A. cepa roots treated with contaminated water induced morphological distortions, formation of micronuclei and various types of chromosomal aberrations. The mitotic index was lower than 50 % in the treated samples. The breakage of calf thymus DNA was time-dependent with acute damage of 100 % for overnight incubation as evidenced by agarose gel electrophoresis. We conclude that the workers of local shipbuilding and scrap industries, the residents of nearby areas and the aquatic biodiversity are vulnerable to contaminated waters. 相似文献
288.
The impact of universalistic versus particularistic criteria on academic hiring has been receiving growing attention in recent years. Yet, most studies conducted on hiring norms in academy and management academy have ignored the impact of social capital, particularly structural social capital, a particularistic attribute, on occupational outcomes. This could lead to a partial if not misleading view of the sociology of hiring in management academy. We utilize a novel approach, focusing on academic departments' structural social capital in the form of network centrality (based on cumulative PhD exchange networks), and explore how this type of centrality impacts job seekers' occupational prestige for new academic jobs in management departments and early career quality publications. We find that although merit‐based criteria such as publications matter somewhat, academic network centrality explains significant variance in obtaining prestigious jobs. Paradoxically, we find that academic network centrality does not explain early career publications. We discuss the implications of our findings for management science. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
289.
Mandal Reema Das Anirban Sudheer A. K. Kumar Sanjeev Verma Sangeeta Gaddam Mahesh Deshpande R. D. 《Environmental geochemistry and health》2021,43(10):4043-4059
Environmental Geochemistry and Health - Fluoride contamination in groundwaters of a rural region in semi-arid Western India has been studied using combination of geochemical-and-isotopic... 相似文献
290.
Dimethoate, a moderately toxic insecticide, has a wide range of agricultural and domestic applications. Like other organophosphates, dimethoate has anticholinesterase activity. Fish are non-target organisms, inadvertently exposed to pesticides and their metabolic products. The present study includes short-term (96 h) and long-term (36 d) effects of dimethoate exposure on some serum electrolytes Ca2+, Mg2+, and Pi in the freshwater air-breathing catfish Heteropneustes fossilis. The concentration of dimethoate for short-term exposure was 2.24 mg L?1 (75% of 96 h LC50) and for long-term exposure 0.75 mg L?1 (25% of 96 h LC50). The study includes the recovery pattern in serum electrolytes after placing the fish in pesticide-free water. Fish show hypocalcemia, hypermagnesemia, and hyperphosphatemia after short-term and long-term exposure to dimethoate. When placed in pesticide-free water, these electrolytes exhibit recovery towards normalization, indicating significant (p < 0.05) recovery. 相似文献