南襄盆地浅层地下水质量影响因子解析

Impact factors of shallow groundwater quality in the Nanyang-Xiangyang basin

在现场调查和地下水样品检测分析的基础上,采用单指标评价和综合评价相结合的方法对南襄盆地浅层地下水质量进行评价:Ⅱ至Ⅲ类占26.27%,Ⅳ类占43.22%,Ⅴ类占30.51%;南襄盆地地下水质量受地质营力作用的原生指标和人类活动的次生指标共同影响,人类生活生产、采油采矿活动是影响该地区地下水质量的主要因素。通过"单指标超Ⅲ类水贡献率"和"人类活动影响度"的计算,来识别影响地下水质量的主要因素。单指标超Ⅲ类水贡献率最大的为硝酸盐,达56.32%,其次为总硬度、铁、锰等指标。南襄盆地浅层地下水人类活动影响度为54.87%,主要影响指标为"三氮"。

This study is based on the field investigation and analysis of groundwater samples. It used single-index evaluation and comprehensive evaluation methods to evaluate the groundwater quality of the Nanyang-Xiangyang basin：The Ⅱ-Ⅲ type shallow groundwater accounted for 26.27 % in the Nanyang-Xiangyang basin; the Ⅳ type shallow groundwater accounted for 43.22 %, and the V type shallow groundwater accounted for 30.51 %. The primary indices affected by geological forces and the secondary indices affected by human activities jointly influenced the groundwater quality of Nanyang-Xiangyang basin. Human living and production,oil extraction,and mining activities were the main factors affecting the quality of groundwater in the area. In this study, the main factors influencing the quality of groundwater were identified through the calculation of ＂single index＇s contribution rate to Ⅵ-Ⅴ type groundwater＂ and ＂human activities influence degree＂. The single index with the largest contribution rate to Ⅵ Ⅴ type groundwater was nitrate,which contributed 56.32 %. It was followed by total hardness, iron, and manganese. The human activities influence degree to the shallow groundwater in Nanyang-Xiangyang basin was 54.87 %, and the main impact index was the ＂three nitrogens＂.