浊度对地下水示踪试验的影响

Effect of Turbidity on Groundwater Tracer Tests

地下水示踪试验是揭示岩溶地下水系统地下水流向、运动特征以及含水介质类型的有效方法之一。根据西南岩溶地区多个不同试验场进行的多组地下水示踪试验结果发现,浊度会影响地下水中示踪剂的浓度监测结果的精度,是影响野外示踪试验结果准确性和成功率的重要因素。通过详细地对比分析浊度及浓度历时曲线,探究浊度对不同类型示踪剂浓度监测结果的影响规律及其原因。研究表明,荧光素钠浓度对浊度变化基本无响应,荧光增白剂浓度仅在几个浊度突变处有轻微波动,而罗丹明浓度对浊度变化较为敏感。罗丹明浓度对地下水浊度的响应规律具体表现为①罗丹明浓度的突变率与浊度的突变率近似呈开口向下的二次函数关系;②当浊度突变率<1.7时,罗丹明浓度的突变率随着浊度突变率的增大而增大。

Groundwater tracer test is one of the effective methods to reveal the flow direction,movement characteristics and the types of water-bearing media in karst groundwater system.According to the results of several groups of groundwater tracer tests conducted in different test sites in karst area of southwest China,it is found that turbidity affects the accuracy of the tracer concentration monitoring results in groundwater,and is an important factor affecting the accuracy and success rate of field tracer test results.By detailed comparative analysis of the turbidity and concentration chronological curve,the influence of turbidity on the concentration monitoring results of different types of tracers and its reasons are explored.This study show that the concentration of fluorescein sodium hardly responds to changes in turbidity,and the concentration of fluorescent whitening agent only fluctuats slightly at several turbidity mutations,while the concentration of rhodamine is sensitive to the change of turbidity.The response characteristics of rhodamine concentration to groundwater turbidity is as follows:①The relationship between the mutation rate of rhodamine concentration and that of turbidity is approximately a quadratic function with opening down;②When the turbidity mutation rate is less than 1.7,the mutation rate of rhodamine concentration increases with the increase of turbidity mutation rate.