Seasonal occurrence and species specificity of fishy and musty odor in Huajiang Reservoir in winter, China

Abstract

This paper describes the results of measurements from one year period on the existence of fishy and musty odor in drinking water at low temperatures (1–2°C) in Baotou, China, using an open-loop stripping analysis (OLSA) systems and Gas chromatography spectrometry (GC). The main results show that it is micro-contaminated water body of the raw water in Huajiang Reservoir. The average phytoplankton abundance was 2.06×107L−1, Cyanobacteria counts were at 2.0×106L−1 and the dominate family of the algae are Chlorophyta, Cryptophyta, and Bacillariophyta. Experimental results indicated that under the ice whose thickness was 0.55m, the photosynthetically active radiation (PAR) of the surface varied from 70 to 636Wm−2 from November to March of next year. The average surface PAR was 114.8Wm−2, and the lowest value was 70.57Wm−2 (in December) and the average bottom PAR was 19.04Wm−2, and the lowest value was 3.84Wm−2 (in December). The surface PAR, bottom PAR, eutrophic conditions in ice-covered Huajiang reservoir satisfied the growth and MIB/geosmin production of Cyanobacteria algae in winter. The 2-methyl-isoborneol (MIB) concentration ranged from 29ngL−1 to 102ngL−1. The concentration of trans-1,10-dimethyl-trans-9-decalol (geosmin) ranges from 20ngL−1 to 65ngL−1 and it is 2 to 5 times of the odor threshold concentrations (OTC). The correlations between MIB/geosmin and nitrogen are 0.63–0.37. Eutrophication is the most important factor influencing synthesis of taste and odors, but not temperature. Using bypassing pipe pumping Yellow River water directly to the Water treatment plant (WTP) is an efficient way about T&O compounds׳ control in drinking water of Baotou city in winter.