Parametrization of groundwater quality of the Quaternary aquifer in N’Djamena (Chad), Lake Chad Basin: application of numerical and multivariate analyses

The urban groundwater of the Quaternary aquifer of the Lake Chad basin in N’Djamena has been subject to many hydrochemical studies. However, the results are often not presented in a way that enables water quality managers to make an appropriate decisions, which restrict development and poverty reduction efforts. The objective of the present study was to contribute the improved management of the local groundwater resources. A total of 85 groundwater samples were interpreted using hydrochemical techniques associated with integrated numerical indices and multivariate statistical analysis. The hydrochemical results coupled with the relative residence time of water have shown that the chemical composition of these waters is linked to geogenic and anthropogenic factors and to their proximity to the Chari-Logone rivers. These investigations showed that the groundwater quality in N’Djamena is characterized by a high spatial variability. This study also assessed the suitability of groundwater for user needs and identified areas which are more/less favorable for a specific use. The evaluation of water quality and its suitability for human consumption is also a problem of optimizing data acquisition strategy, and this study used the correlation between water quality index (WQI) and electrical conductivity (EC) to orientate future data acquisition strategies. This parametrization can assist the decision makers and water management professionals in evaluating groundwater availability and setting up a robust water quality management plan in areas with similar hydrogeological and climatic conditions.

     

水稻新材料耐淹涝能力的比较研究

以“禾稗”ＤＮＡ导入后代及受体、供体为试验材料，应用地上部干重和根系干重的相对受害率（ＲＤ／％），叶片的电导率（ｋ）和膜脂过氧化物的产物丙二醛（ＭＤＡ）的增加量几个生长、生理指标，在苗期模拟没顶淹水处理２、４、６ｄ，比较研究了“禾稗”ＤＮＡ导入后代与供体、受体耐淹涝能力。结果显示：在淹涝胁迫下，“９４Ｄ－０５”、“９４Ｄ－３４”的干重ＲＤ／％分别小于它们的受 “科长早３号”和“圭６３０”，达到或接