Temporal And Spatial Distribution Of Microcystins And Their Relationship With Nutrient Factors In Certain Reservoir Of Hebei Province

Physicochemical parameters were analysied in certain eutrophication reservoir, Hebei Province, and Chla concentration variation was investigated in the reservoir during algal blooms in 2005. The detecting method of microcystin (MC) compounds including pretreatment process and HPLC system factors was optimized by referring domestic and overseas literatures, and a feasible MC analysis method was established. Meanwhile, Year-round spatial distribution and temporal variation of MC compounds were investigated in the reservoir. Besides, the influencing factors about eutrophication water column and the relationship between MCs and nutrient levels were analyzed with SAS8.1 statistic software. The eutrophic level of the reservoir was assessed by TSIM and the results were showed below:1. From 1990, reservoir eutrophication was aggravated gradually year by year, to summer in 2004 the reservoir had been on meso-eutrophic state. In 2005, the reservoir also showed different trophic level every season, mesotrophic in April-June, medi-eutrophic in July-september, and light-eutrophic in October-December.2. Statistic analysis showed, the reservoir eutrophic degree had close relationship with TP, TN, COD_Mn and WT, then secondary PO₄-P and NH4-N. The limited nutrient factors of the reservoir eutrophication was not single, and the eutrophic level was dominated by N and P respectively in different peroids. In April to the first ten days of July, P was the limitation nutrient, while both N and P were limitation nutrients during the last ten days of July to December, 2005.3. The temporal-spatial distribution of MCs demonstrated that MCs concentrations in the reservoir changed significantly with the time changing in 2005. Three kinds of MC concentrations in the reservoir were obviously different at same period and location, and MC-RR concentration was much higher than MC-YR and MC-LR, especially in October and November. During algal blooms, MCs concentrations were not well -proportioned at every location in the reservoir, and the time for appearances, peaks and disappearances of each MC in the reservoir were different.4. Chlα concentration and ACD in water column had the similar changing trend with MCs, while the time for MC peak value occurrence lagged behind that for Chk and ACD.5, From the relationship between MCs concentrations and nutrients level in water, it could be found that these three kinds of MCs correlated positively with TP and NO3-N, and negatively with NH4-N, PO₄-P from April to the first ten days of July, 2005. Then from the last ten days of July to December, MCLR correlated positively with TN,...