Development of Models for Predicting the Predominant Taste and Odor Compounds in Taihu Lake, China

Abstract

Taste and odor (T&O) problems, which have adversely affected the quality of water supplied to millions of residents, have repeatedly occurred in Taihu Lake (e.g., a serious odor accident occurred in 2007). Because these accidents are difficult for water resource managers to forecast in a timely manner, there is an urgent need to develop optimum models to predict these T&O problems. For this purpose, various biotic and abiotic environmental parameters were monitored monthly for one year at 30 sites across Taihu Lake. This is the first investigation of this huge lake to sample T&O compounds at the whole-lake level. Certain phytoplankton taxa were important variables in the models; for instance, the concentrations of the particle-bound 2-methylisoborneol (p-MIB) were correlated with the presence of Oscillatoria, whereas those of the p-β-cyclocitral and p-β-ionone were correlated with Microcystis levels. Abiotic factors such as nitrogen (TN, TDN, NO3-N, and NO2-N), pH, DO, COND, COD and Chl-a also contributed significantly to the T&O predictive models. The dissolved (d) T&O compounds were related to both the algal biomass and to certain abiotic environmental factors, whereas the particle-bound (p) T&O compounds were more strongly related to the algal presence. We also tested the validity of these models using an independent data set that was previously collected from Taihu Lake in 2008. In comparing the concentrations of the T&O compounds observed in 2008 with those concentrations predicted from our models, we found that most of the predicted data points fell within the 90% confidence intervals of the observed values. This result supported the validity of these models in the studied system. These models, basing on easily collected environmental data, will be of practical value to the water resource managers of Taihu Lake for evaluating the probability of T&O accidents.

In situ enclosure experiments on the occurrence, development and decline of black bloom and the dynamics of its associated taste and odor compounds

“…In this study, regression analysis demonstrated that T&O compounds were highly correlated with certain water quality parameters (e.g., TN, pH and S 2− ) in groups M and H, which exhibited black bloom. These strong relationships are also supported by several previous studies (Downing et al, 2010;Qi et al, 2012). In addition, the absolute value of r 2 was generally higher in group H than in group M. These results indirectly suggest that T&O compounds are strongly correlated with black bloom.…”

Autumnal increase in proportion of toxic Microcystis in Lake Taihu depends more on temperature adaptability than on effects of toxigenicity

“…In September, the decline of temperature appeared to trigger a cell death and/or sinking process in the dense Microcystis population, causing a continual decrease in cell density (Qi et al . ). Under this condition, types 6, 9 and 10 arose in the Microcystis population rapidly, replacing type 1 and other summer strains.…”

Habitat-specific differences in adaptation to light in freshwater diatoms

“…During this time, the Hanjiang River flows fast and turbid, and the range of measured discharge was 800 to 8000 m 3 s −1 in 2010 (Yang et al 2012). In Gonghu Bay (Lake Taihu), the average Secchi depth was 117 cm in the spring of 2010 (Qi et al 2012). Diatoms were isolated according to standard phycological methods (Stein and Hellebust 1979).…”

“…meneghiniana is often a dominant species in relatively calm water conditions (Qi et al 2012;Zeng et al 2007) and is considered as a large niche breadth species (Wang et al 2010). S. parvus is found in many temperate lakes at low to modest relative abundance (Sokal 2007).…”