摘要:
在线高分辨率示踪技术以其精度高、成本低的特点在岩溶地下水文系统研究方面得到较为广泛的应用。重庆市黔江区鱼泉坎岩溶泉的污染问题导致蓬东乡、五里乡及其周边3000居民饮水困难,为了确定水源地主要的污染源,选取荧光素钠、天来宝2种示踪剂,应用在线高分辨率示踪技术确定了重庆某畜禽养殖有限公司的化粪池与鱼泉坎泉之间存在水力联系。两种示踪剂的回收率均较低,分别为:荧光素钠3.51%,天来宝2.56%,且两回收曲线存在一定差别,可能与天来宝的水溶性较荧光素钠低有关。基于荧光素钠初现时间和首个峰值出现时间计算的地下水最大流速与平均流速分别为27.09 m/h、22.32 m/h,反映鱼泉坎岩溶孔隙、裂隙较小,化粪池污染渗漏缓慢、运移时间长。示踪剂质量浓度历时曲线表现为多峰型,推断化粪池至鱼泉坎泉段至少存在4条较大的径流通道,表明示踪段表层岩溶泉裂隙发育的相对均匀性。欲恢复鱼泉坎泉的水质,须对该养殖场进行防渗处理或勒令关闭。
Abstract:
The high-resolution online tracer is widely employed in hydrogeology field due to its characteristics of high precision and low cost.The pollution of the Yuquankan karst spring has caused at least 3 000 local people lack of adequate healthy drinking water.In order to find out the position of the pollution sources,the high-resolution online tracer technique was applied in the survey with fluorescein sodium and tinopal as the tracers.The results show that there is a hydraulic connection between the septic tank of a livestock breeding corporation in Chongqing and the Yuquankan karst spring.The recycle proportion of fluorescein sodium is 3.51%,2.56% for Tinopal.The breakthrough curves of both tracers show certain differences.This phe-nomenon may be caused by lower solubility of fluorescein sodium compaired with Tinopal.The maximum flow velocity and mean velocity of the ground water,calculated by fluorescein sodium’s first showing time and first peak appearing time,are 27.09 m/h,22 and 32 m/h respectively,which suggests small pores and fractures and slow percolation of pollution in the Yuquankan karst spring area.The breakthrough curves are of “multi-peak type”,so at least four groundwater channels are supposed to exist between the septic tank of the livestock breeding corporation and the Yuquankan karst spring,which reflects the uniformity of fracture development of the epikarst spring.In order to recover the quality of the Yuquankan spring water,the live-stock breeding corporation must take action to prevent the leakage or be shut down as soon as possible.
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