中国干旱内陆流域水体N、P负荷特征与动态变化——以黑河流域为例

N AND P LOADING FEATURES AND DYNAMICAL CHANGES IN ARID INLAND WATER BODIES OF NORTHWEST CHINA

以黑河流域中游地区为研究区域 ,通过 11年在不同河流断面的长期监测和区域内各类水体如地下水、泉水、水库和河流的空间选点取样分析 ,研究了干旱内陆流域水体N、P等植物营养元素的负荷与时空分布及动态变化特征。浅层地下水与河水中NO3 N含量普遍较高 ,含量超过 1.1mg/L ,大部分平原水库水中NH4 N含量超过 0 .3mg/L ;河水与浅层地下水TP、NH4 N与NO3 N含量均呈现沿流域从出山口至下游的显著递增变化 ,同时还具有明显的随时间递增趋势 ,其中NH4 N含量在河流出山口及下游断面平均年增加幅度分别为 0 .11mg/L和 0 .114mg/L ;流域水体N、P含量的季节变化明显 ,黑河流域春季及春夏之交的枯水期大部分河段NH4 N、NO3 N和TP等要素含量为全年最高并出现水质超标污染。控制干旱内陆流域水域尤其是枯水期的N、P污染 。

This study was undertaken to investigate the loadi ng features, temporal-spatial distribution and dynamical changes of plant nutrient element s N and P in arid inland water bodies including ground water, spring water, rese rvoir and river in the midstream area of the Heihe river basin through river section monitoring and sample analyses at selected sites over the past 11 years. NO 3-N con tents in shallow ground water and river water were commonly higher than 1.1 mg/L; NH 4-N contents in most of plain reservoirs exceeded 0.3 mg/L; TP, NH 4-N and NO 3-N contents showed a significant increase tendency from the mountain valle y mouth to the downstream area of the river basin. Further more, they also tended to increase significantly with time, of which NH 4-N contents in the river water at t he mountain valley mouth and the lower reach on an average annually increased 0.11 mg/L and 0.114 mg/L respectively. N and P contents in the basin's water bodi es also exhibited obvious seasonal change, during the low water period from late spring to early summer, TP, NH 4-N and NO 3-N contents in a large part of t he river section reached a peak values of a year or even exceeded polluted water quality level. The control of N and P pollution especially in water period should be viewed as a key content for the protection of water resources in the arid inland river basin.