泄洪对典型有机污染物迁移转化行为的影响--以丹江口水库为例

The influence of flood discharge on the migration and transformation of typical organic pollutants:A case study on the Danjiangkou Reservoir

随着高坝水库的建设,大坝泄洪雾化对生态环境的影响已得到较多研究,而泄洪雾化对污染物迁移转化行为的影响尚未引起关注.本研究于2019年对丹江口大坝泄洪期间坝前和坝下多个断面进行了采样调查,分析了水体中16种多环芳烃(PAHs)和6种邻苯二甲酸酯(PAEs)的浓度.发现泄洪后坝下水体中检测出的8种PAHs和5种PAEs浓度相比于坝前总体上均呈现沿程降低趋势,与坝前断面相比,PAHs在坝下1、5和10 km处的浓度下降比例范围分别为8.1%~100%、26.2%~100%和36.7%~100%,均值为34.6%、64.8%和75.7%;对应的PAEs浓度下降比例范围分别为0.9%~38.7%、33.7%~71.8%和61.1%~87.5%,均值为21.5%、47.0%和71.3%.基于野外观测结果,从理论上推测分析了大坝泄洪雾化影响坝下水体PAHs和PAEs迁移转化的途径和作用机制,包括污染物的化学氧化、光降解和吸附等.本研究对于开展泄洪雾化条件下水体中污染物迁移转化行为研究具有借鉴意义.

With the construction of high dam and large reservoirs,there have been many studies on the impact of flood discharge atomization on the ecological environment,but the impact of flood discharge atomization on pollutant migration and transformation behavior has not attracted attention.In this paper,water samples in multiple sections in front of and below the dam during the flood discharge of the Danjiangkou reservoir in 2019 were collected,the concentrations of 16 polycyclic aromatic hydrocarbons(PAHs)and 6 phthalate acid esters(PAEs)in the water samples were analyzed.It was found that the concentrations of 8 PAHs and 5 PAEs detected in the water below the dam after the flood discharge showed a decreasing trend along the river compared to the section in front of the dam.By comparing the concentration of the section in front of the dam,the concentration reduction ratio of PAHs at 1 km,5 km and 10 km below the dam was 8.1%-100%,26.2%-100%and 36.7%-100%,respectively;and the mean values was 34.6%,64.8%and 75.7%;the concentration reduction ratio of PAEs was 0.9%-38.7%,33.7%-71.8%,61.1%-87.5%,respectively;and the average value was 21.5%,47.0%and 71.3%.Based on the field observation results,the possible migration and transformation pathways and mechanisms of PAHs and PAEs in Danjiangkou Reservoir by dam flood discharge were analyzed.Photodegradation,chemical oxidation,and adsorption of pollutants were considered as the main mechanisms.This study has implications for researching the migration and transformation behaviors of pollutants in water bodies under flood discharge fogging conditions.