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Flood control and drainage projects in Bangladesh are intended to give protection from main river floods, flash floods in the east and northeast of the country, and saline intrusion in the lower delta and to improve drainage in order to avoid crop damage. While in some cases such projects have had positive results, in many others their benefits have fallen well below expectations. One of the major reasons for the poor performance of projects is embankment failure, brought about by poor planning, design, construction, operation and maintenance. Recommended measures to improve the efficiency of projects include the involvement of local people in the planning and operation of projects, better training of management staff and the allocation of adequate funds for maintenance. 相似文献
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OLFA TEBOURBI MOHAMMED RIDHA DRISS MOHSEN SAKLY KHÉMAIS BEN RHOUMA 《Journal of environmental science and health. Part. B》2013,48(2):167-176
The bioconcentration and distribution pattern of p,p′-DDT 1,1,1-1trichloro-2,2-bis(2-chlorophenyl-4-chlorophenyl)-ethane] and its main metabolites (p,p′-DDD [1,1-dichloro-2,2-bis (4-chlorophenyl) ethane] and p,p′-DDE [1,1-dichloro-2,2-bis (4-chlorophenyl) in adipose tissue, liver, brain, kidney, thymus, and testis were examined in young rats after 10 days of intraperitoneal injection of 50 and 100 mg of p,p′-DDT/kg of body weight. Analyses were performed by high-resolution gas chromatography. p,p′-DDT was found to be accumulated in a dose-dependent manner with the highest concentration in adipose tissue. However, in brain, the accumulation of pesticide was low and remained unchanged at the higher dose. This difference may relate to the protective role of the blood-brain barrier, which limits the access of the xenobiotic in the cerebral compartment, and to the differential tissue lipid composition. Although tissues concentration of p,p′-DDE and p,p′-DDD correlated positively to total p,p′-DDT levels, the active role in detoxification of pollutants may explain why p,p′-DDD is more abundant in liver than in the rest of organs. On the contrary, in brain, the concentration of p,p′-DDE is higher than that of p,p′-DDD, suggesting that the metabolism of the parent insecticide proceeds via more than one pathway. 相似文献
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