涟江上游表层岩溶泉水污染源解析

为明确涟江上游表层岩溶泉水化学污染特征及其污染来源,选取区域内7个地表饮用泉作为研究对象.测定泉水水温(T)、电导率(EC)、溶解氧(DO)、pH、总氮(TN)、总磷(TP)、氨氮(NH4-N)、硝氮(NO₃-N)、高锰酸盐指数(COD)并研究其与泉眼半径200、500、1000 m范围内耕地、住宅用地及交通用地面积的相关性.研究结果表明,依据地表水环境质量标准(GB3838-02)等水质标准,涟江上游7个表层岩溶泉水TN均超标,耕地周围的泉水TP、NH₄-N、NO₃-N也超过标准值,表明该区域表层岩溶泉水总体高N而局部高P的污染特征.主成分分析表明农业活动对泉水TN、TP、NH₄-N、NO₃-N及COD含量产生了一定的影响.泉眼半径200 m范围内耕地面积与TP、NH₄-N显著正相关,表明小范围内农业活动是泉水N、P污染的主要源头;500 m范围内EC与住宅用地面积显著正相关,表明较大规模人类聚居可能造成泉水离子成分偏复杂.从保护地表饮用泉的角度出发,建议泉眼半径200 m内减少农业活动强度及频率,泉眼半径500 m内控制人口密度及日常生活排污量.

Analysis on pollution sources of epikarst spring water in the upper reaches of Lianjiang River

In order to clarify the hydrochemical characteristics and pollution sources of epikarst spring water in the upper reaches of the Lianjiang River,seven epikarst springs in the area were selected as research objects.The water temperature(T),electrical conductivity(EC),dissolved oxygen(DO),pH,total nitrogen(TN),total phosphorus(TP),ammonia nitrogen(NH₄-N),nitrate nitrogen(NO₃-N),and permanganate index(COD)were measured.The correlation between hydrochemical parameters and area of cultivated land,residential land,and transportation land within the radius of 200,500 and 1000 m was studied.The results showed that:(1)The water TN of 7 epikarst springs,the levels of TP,NH₄-N,and NO₃-N in water samples collected from epikarst spring in cultivated land exceeded the Surface Water Quality Standards of People's Republic of China(GB 3838-02),indicated that the epikarst spring water was mainly characterized by overall high N and locally high P in in the upper reaches of the Lianjiang river.(2)Principal Component Analysis(PCA)indicated that agricultural activities had an impact on TN,TP,NH₄-N,NO₃-N and COD of epikarst spring water.(3)The area of cultivated land within a radius of 200 m had a significant positive correlation with TP and NH₄-N,suggesting that agricultural activities were the main source of N and P of spring water.Within a radius of 500 m,the area of the residential land had a significantly positive correlation with EC,which showed that human settlement caused complex ion components in epikarst spring water.From the perspective of protecting drinking springs,it was recommended to reduce the intensity and frequency of agricultural activities within a radius of 200 m,and control population density and daily sewage discharge within 500 m.