三峡库区澎溪河营养盐时空变化特征及富营养化评价

Temporal and Spatial Variations of Nutrients and Eutrophication Assessment of Pengxi River of Three Gorges Reservoir

为考察三峡库区澎溪河营养盐的时空分布特征及营养状态,于2013~2014年对澎溪河不同断面透明度、高锰酸盐指数以及总氮、氨氮、总磷、叶绿素a的含量进行取样调查,对营养盐的时空变化特征进行分析,结合相关性分析,利用单因子法和综合营养状态指数法评价水体营养盐结构和营养状态。结果发现,澎溪河营养盐具有明显的季节差异性和空间分布差异性。相关性分析表明澎溪河上游河段叶绿素a含量与透明度、高锰酸盐指数、总氮含量、总磷含量的线性相关性不显著,而中段高阳渡口叶绿素a含量与总磷含量呈极显著正相关。单因子法评价结果显示,澎溪河水质为Ⅱ~Ⅲ类。水体综合营养状态指标范围为56~135,处于富营养至重度富营养化状态之间;春季3~5月及秋季10月,部分断面富营养化状态极高。

In order to investigate the temporal and spatial variations of nutrients and eutrophication status of Pengxi River, a tributary of the Three Gorges Reservoir, the samples from different cross sections were collected during 2013 and 2014. Transparency, permanganate index, total nitrogen, ammonia, total phosphorus, and chlorophyll a were determined. The nutrient structure and eutrophication of water were also assessed by the means of correlation analysis, single - factor and cintegrated nutrition state index evaluation method. The results showed that transparency, permanganate index, total nitrogen, ammonia, total phosphorus and chlorophyll a have obvious seasonal variation and spatial differentiation in Pengxi River. Correlation analysis showed that at upper reaches of Pengxi River, chlorophyll a does not have significant correlation with transparency, total nitrogen, total phosphorus, and permanganate index. However, at Gao Yang cross section in the middle of Pengxi River, chlorophyll a has a significant positive correlation with total phosphorus. The result of single - factor evaluation indicated water quality was Class Ⅱ to Ⅲin Pengxi River. Cintegrated nutrition state index of Pengxi River ranged from 56 to 135, which was in the state of eutrophic to severe eutrophic. Eutrophication in some sections is extremely high at March to May and October.