福鼎市桐江溪卤乙酸分布特征及潮汐影响分析

Distribution characteristics and tidal effects of haloacetic acids in Tongjiang River, Fuding City

为了掌握福鼎市桐江溪卤乙酸(HAAs)的含量、时空分布规律及其来源,对水体中HAAs化合物进行取样调查。根据桐江溪水文情势及沿岸特点设置10个取样点,于2017年12月及2018年7月按照涨潮、退潮情况分别对水样进行采集,检测HAAs分布情况,同时将卤乙酸(HAAs)与水质特性、涨退潮进行了相关性分析。研究发现,HAAs是普遍存在于桐江溪中的污染物质。其中,一氯乙酸(MCAA)、二氯乙酸(DCAA)、三氯乙酸(TCAA)、一溴乙酸(MBAA)、二溴乙酸(DBAA)等5种卤乙酸(HAA5)质量浓度为0.44~3.39μg/L;一氯乙酸(MCAA)、二氯乙酸(DCAA)、三氯乙酸(TCAA)、一溴乙酸(MBAA)、二溴乙酸(DBAA)、三溴乙酸(TBAA)、一溴一氯乙酸(BCAA)、一溴二氯乙酸(BDCAA)、二溴一氯乙酸(CBDAA)等9种卤乙酸(HAA9)质量浓度为0.83~56.15μg/L。桐江溪中HAAs主要为DCAA,TCAA,TBAA3种,其中DCAA为制药厂及医院排水导致,主要分布在下游;TCAA主要来源于河段上游的农业生产活动;TBAA为上游沸石矿尾矿库受雨水冲刷而流入的Br-所生成,主要分布于河流中下段。相关性分析结果表明,温度与HAA5,HAA9质量浓度呈现正相关,pH值与HAA5,HAA9质量浓度呈现负相关;TCAA质量浓度于相同季节不同潮汐及不同季节相同潮汐时均呈现上游高于下游的现象,其他HAAs均不因涨潮、退潮的差异造成质量浓度分布的变化。掌握桐江溪HAAs的含量、时空分布规律及来源,探讨其与水质的相关性,对于净水工艺选择、水厂出水HAAs含量的溯源分析、水体环境风险评估以及研究水生生物体内HAAs的累积效应等有重要意义。

In order to understand the content, temporal and spatial distribution and source of haloacetic acids (HAAs)inTongjiang River of Fuding City, the HAAs compounds in water were sampled and investigated. According to the hydrological situation and coastal characteristics of Tongjiang River, 10 sampling points were set up. In December 2017 and July 2018, water samples were collected according to the situation of high and low tide, and the distribution of HAAs was detected. At the same time, the correlation between HAAs and water quality characteristics, high and low tide was analyzed. It is found that HAAs are ubiquitous pollutants in Tongjiang River. There are five haloacetic acids (HAA5): monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), monobromoacetic acid (MBAA) and dibromoacetic acid (DBAA) Acids, with concentrations of 0.44~3.39 μg/L. Nine haloacetic acids(HAA9) include: MCAA,DCAA,TCAA,MBAA,DBAA,tribromoacetic acid (TBAA), bromoacetic acid (BCAA), bromochloroacetic acid (BDCAA), and chlorodibromoacetic acid (CBDAA), with concentrations of 0.83~56.15 μg/L. The HAAs in Tongjiang River are mainly DCAA, TCAA and TBAA, among which DCAA is caused by the drainage of pharmaceutical factories and hospitals and mainly distributes in the lower reaches;TCAA mainly comes from agricultural production activities in the upper reaches of the river;TBAA is generated by bromide ioninflow from the upstream zeolite tailings reservoir washed by rainwater and mainly distributes in the middle and lower reaches of the river. The results of correlation analysis show that temperature is positively correlated with HAA5 and HAA9 concentration, pH is negatively correlated with HAA5 and HAA9 concentration, TCAA is higher in upstream and downstream in the same season, different tides and different seasons, and other HAAs do not change in concentration distribution due to the difference of high and low tide. To grasp the content, temporal and spatial distribution and source of HAAs in Tongjiang River and to explore its correlation with water quality are of great significance for water purification process selection, traceability analysis of HAAs content in effluent of waterworks, water environmental risk assessment and Research on accumulation effect of HAAs in aquatic organisms.