江西省余江县水体营养状况分析

用营养状态指数法(TSI)对江西省红壤区余江县东塘、五湖、仙塘三个水库的水质状况进行综合评价，结果表明三个水体的水质状况均呈富营养态。在此基础上对三个水库的10项主要水化学指标进行主成分分析，表明亚硝态氮和氨氮对第一主成分的贡献最大，COD为第二主成分的主要贡献者；而且三个水库的水质受水中有机物含量的影响最大，这一结果与当地的农业结构密切相关。

STUDIES ON TROPHIC STATES OF WATERS IN YUJIANG COUNTY,JIANGXI PROVINCE

By means of trophic state index (TSI) and its modificator (TSIm) in which algal chlorophyll a (Chla), water transparency (Sd) and total phosphorus (TP) are used as evaluation factors, the continuous numerical classification for the trophic states of three waterbodies (Dongtang, Wuhu and Xiantang reservoirs) of 1998 and 1999 in Yujiang county, Jiangxi province were obtained. The results indicated that all the three reservoirs were in the state of eutrophication. The values of TSI and TSIm of Dongtang reservoir were 69 and 70 respectively, which means that the trophic state of this reservoir was highly eutrophicated and was the worst among the three reservoirs. Although Wuhu reseroirs got the lowest values of TSI and TSIm, they also reached 60 respectively. Thereafter principal component analysis (PCA) was carried out to explore which factors (including K ++Na +?PO 4-P?TP?NO 2-N?NO 3-N?NH 4-N?TN?SiO 2?pH?COD) were specially responsible to the water qualities of these waterbodies. The results showed that NH 4-N was the most important factor to the first principal component, which weighted 0.986, and NO 2-N was the second weighted one with the corresponding value of 0.909, so it can be inferred that nitrogen was the main contributor to the first principal component. With the loading of 0.837, COD dominated the second principal component. Studies on the data of September of 1999 showed that COD acted as the most important role in the water trophic state of three reservoirs. Corresponding analysis suggested that it was local agricultural system that resulted in superfluous organic fertilizers, which had been poured in these reservoirs and eutrophicated the waters. This result could be important to local agriculture and reservoir managements.