漳泽水库主要入库河流氮、磷营养盐特征

以2006—2007年的漳泽水库3条入库河流(南漳河、石子河、绛河)的水文、水质调查数据为依据,研究了漳泽水库入库河流的主要水文变化特征、氮磷营养盐浓度及其通量的逐月动态。3条入库河流水体流速缓慢,水温适宜,年平均值在12.5℃～15.1℃。3—5月水温回升较快,夏季水温高,光照充足,易发生水华。3条入库河流中总氮含量年平均值在1.75～8.90mg·mL-1,总磷含量平均值在0.005～3.760mg·mL-1,氮磷营养盐浓度总体偏高,其中石子河贡献了48.3%的总氮和77.3%的总磷。溶解态无机氮(DIN)是氮的主要存在形式,而其中又以硝酸盐氮(NO3--N)为主,平均占到DIN的60%以上。氮磷通量季节性变化规律不明显,且月均波动较为平缓。点源污染是氮磷进入南漳河、石子河的主要途径,而绛河的氮主要来自面源污染。从保护漳泽水库的角度考虑,应重点控制南漳河和石子河的点源污染。

Flux dynamics of nitrogen and phosphorus in major input rivers of Zhangze Reservoir

Based on the investigation data of the hydrology and water quality of three input rivers(Nanzhang,Shizi and Jianghe)of Zhangze Reservoir in 2006-2007,this paper studied the main hydrological characteristics and the nitrogen and phosphorus concentrations and their monthly flux dynamics in the rivers.The flow speeds of the three rivers were slow,and the water temperature was suitable,with an annual mean value 12.5 ℃-15.1 ℃.The water temperature increased rapidly from March to May,and became higher in summer.Accompanying with adequate sunlight,the higher water temperature in summer induced the occurrence of algal bloom.The yearly average concentrations of total nitrogen and phosphorus in the three rivers were 1.75-8.90 mg·L~(-1) and 0.005-3.760 mg·L~(-1),respectively,being relatively higher in general.Shizi River contributed 48.3% of the total nitrogen and 77.3% of the total phosphorus to the Zhangze Reservoir.Dissolved inorganic nitrogen was the major form of total nitrogen,which was dominated by nitrate nitrogen(NO_3~--N),accounting for 60% or more.The nitrogen and phosphorus fluxes had no obvious seasonal variation,and their monthly fluctuations were also gentle.Point pollution was the main source of the nitrogen and phosphorus in Nanzhang and Shizi rivers,while the nitrogen in Jianghe River was mainly come from non-point pollution.To protect the Zhangze Reservoir,it would be critical to control the point source pollution of Nanzhang and Shizi rivers.