【摘要】 汉江是长江的最大支流,全长1532km,年径流总量为591亿m3,流域面积15.1万km2。汉江既是湖北省主要航道之一,又是沿岸居民生活用水和工业用水的重要水源。早在70年代,汉江的水质一直符合地面水II级标准,但自90年代以来,汉江的水质逐年下降,并分别于1992年和1998年的初春先后两次发生硅藻大量繁殖,水色发褐并伴有异味。本文在调查汉江中、下游江段藻类现状的基础上,对硅藻猛增并出现水华征兆的成因进行了分析,结果显示,在汉江中、下游的纳污江段及河湾处,水质污染问题十分严峻,其中汉江下游江段的水质比中游江段的差,武汉江段的水质最差。水体中丰富的氮磷养分是硅藻大量繁殖的主要因素。控制高浓度污水排入汉江是防治藻类过量繁殖和保护汉江水质免遭进一步破坏的关键。更多还原

【Abstract】 Hanjiang River, the laggest tributary of the Yangtze River,is a very important water source with manifold functions. The river has a length of 1 532 km, an annual discharge of 591×10\+8 m\+3 and a basin area (at average water level) of 151×10\+3 km\+2. The water quality of the river was in accord with the water quality standard for the grade II drinking water during the 1970s. However, it is declining recently. The concentration of nutrient and the pollutant source in the watershed increased year after year at the inception of the 1990s. Water blooms of \%Cyclotella\% have occurred twice during the period. The authors made a preliminary study on the characteristics of the phytoplankton in the middle and lower reaches of the Hanjiang River. The results clearly demonstrated that the water quality deteriorated heavily at the investigated reaches of the river, especially at the Wuhan section. It is proved that one of the major reasons for the occurrence of water blooms is the large amount of nutrients draining into the water body. To prohibit the discharge of wastewater with high nitrogen and phosphorus concentration into the river is the key measure for limiting the overgrowth of phytoplankton and for protecting the water quality of the river from further detereoration.更多还原