STUDIES ON THE DIURNAL VARIATION OF THE ODOROUS COMPOUNDS AND CORRELATED FACTORS IN LAKE DALIANHUA, WUHAN

Located in the Park Lianhuahu, Hanyang District, Wuhan, Lake Dalianhua mainly serves as a public recreation landscape and covers an area of about 64000m2. In recent years, the great damage to the scenic value and economic revenue of Lianhuahu Park have been caused by the frequent outbreak of cyanobacterial bloom and thereby the diffusion of strong off-flavour in the lake. In the paper, the diurnal variation of environmental parameters, algae and odorous compounds in LakeDalianhua were investigated. TheMicrocystis was found to be a dominant genus in the lake. The trend of the diurnal variation of biomass of the total algae is the same as that of the dominant algae. Three odorous compounds 2-Methylisoborneol, B-Cyclocitral and B-Ionone in the lake were identified by using aGC-MS. The diurnal highest concentration of soluble 2-Methylisoborneol, B-Cyclocitral and BIonone reached 69.1ng/L, 32.6ng/L and 453.9ng/L, respectively. Compared the above concentrations with their odor threshold concentrations, it could be concluded that 2-Methylisoborneol and B-Ionone weremainly responsible for the strong off -flavours in the lake. Aaveragely, particulate 2-Methylisoborneol, B-Cyclocitral and B-Ionone accounted for 70.9%, 74.4% and 81.4% of its total content, respectively, showing that these particulate odorous compoundswere themajor components among the odorous components in the lake. All the soluble, particulate and total B-Cyclocitral correlated significantly with the biomass of total algae andMicrocystis, particulateB-Cyclocitral and B-Ionone correlated significantly with the biomass of total algae and light intensity, and particulate 2-MIB had a significant correlation with the biomass ofAnabaena.