State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
Environ Pollut. 2021 Nov 1;288:117683. doi: 10.1016/j.envpol.2021.117683. Epub 2021 Jul 3.
Reservoirs are an important type of drinking water source for megacities, while lots of reservoirs are threatened by odor problems during certain seasons. The influencing factors of odor compounds in reservoirs are still unclear. During August 2019, a nationwide survey investigating the distribution of odor compounds in reservoirs used as drinking water sources was conducted on seven reservoirs. 2-methylisoborneol (2-MIB) and geosmin were detected in almost every reservoir, and some odor compound concentrations even exceeded the odor threshold concentration. The average concentration of 2-MIB was 2.68 ng/L, and geosmin was 3.63 ng/L. The average chlorophyll a concentration was 8.25 μg/L. The dominant genera of phytoplankton in these reservoirs belonged to cyanobacteria and diatom. Statistical analysis showed that odor compound concentration was significantly related to the chlorophyll a concentration and indicated that the odor compounds mainly came from phytoplankton. The concentration of odor compounds in the euphotic zone was significantly related to phytoplankton species and biomass. Therefore, the odor compound concentrations in the subsurface chlorophyll maxima layer was generally higher than in the surface layer. However, the odor compounds in the hypolimnion layer were related to the density current. This research suggests that both phytoplankton proliferation events and heavy storm events are important risk factors increasing odor compounds in reservoirs. Control of algal bloom, in-situ profile monitoring system and depth-adjustable pumping system will greatly reduce the risk of odor problems in reservoirs using as water supplies for large cities.
水库是特大城市的重要饮用水源，但许多水库在某些季节会受到异味问题的威胁。水库中异味化合物的影响因素尚不清楚。2019 年 8 月，对全国七个用作饮用水源的水库进行了一项全国性调查，调查了水库中异味化合物的分布情况。几乎每个水库都检测到了 2-甲基异莰醇（2-MIB）和土臭素，有些异味化合物浓度甚至超过了异味阈值浓度。2-MIB 的平均浓度为 2.68ng/L，土臭素为 3.63ng/L。平均叶绿素 a 浓度为 8.25μg/L。这些水库中浮游植物的优势属属于蓝藻和硅藻。统计分析表明，异味化合物浓度与叶绿素 a 浓度显著相关，表明异味化合物主要来自浮游植物。真光层中异味化合物的浓度与浮游植物的种类和生物量显著相关。因此，次表层叶绿素最大值层中的异味化合物浓度通常高于表层。然而，表底层中的异味化合物与密度流有关。这项研究表明，浮游植物大量繁殖事件和强风暴事件都是增加水库中异味化合物的重要风险因素。控制藻类大量繁殖、原位剖面监测系统和深度可调式抽水泵系统将极大地降低作为大城市供水水源的水库发生异味问题的风险。
