摘要
基于2016年太湖16条主要河道及对应湖体的水质逐月监测数据,深入探讨了太湖流域不同分区河道的外源营养盐输入对湖体水质影响及其季节变化.结果发现:(1)太湖流域河道总氮(TN)、溶解性总氮(DTN)、总磷(TP)和溶解性总磷(DTP)的月平均浓度均高于对应湖体,主要入流区河道与临近湖体的营养盐浓度呈现显著正相关,表明外源补给对湖体营养盐浓度产生巨大影响;(2)无论是河道还是湖体的营养盐浓度,均呈现明显的季节变化,且峰值产生月份不同:河道平均TN最高值出现在3月,为4.82 mg·L-1,平均TP最高值出现在12月,为0.218 mg·L-1;湖体TN、TP峰值均出现在蓝藻水华暴发期间(7月),分别为4.13 mg·L-1和0.255 mg·L-1;(3)极端降水过程短期内能明显降低河道营养盐浓度,但会引起湖体营养盐外源负荷的明显增高,不利于湖体富营养化控制.本研究表明,对于空间异质性较高的大型浅水湖泊,流域河道入湖污染对湖体营养盐时空格局具有重要的塑造作用,而湖体的污染物自净能力、蓝藻水华物质的空间堆积及风浪引发的底泥再悬浮作用等也都对湖体营养盐浓度、时空格局产生重要影响.
The seasonal and spatial variation of external nutrient loading from rivers and their impact on lake water quality were analyzed in Lake Taihu,China,using the monthly monitoring data from 16 major inflow/outflow rivers and 32 observation sites in the lake. The results showed：（1） The average monthly values of total nitrogen（TN）,dissolved total nitrogen（DTN）,total phosphorus（TP）,and dissolved total phosphorus（DTP） in rivers were all higher than the corresponding areas in the lake. Significant positive correlations were found between nutrient concentrations in the inflow rivers and the corresponding areas in the lake,indicating the pronounced impact of external loading on lake water.（2） Remarkable seasonal variations of nutrient concentration were found both in the rivers and in the lake. The highest TN and TP concentrations in inflow rivers were 4. 82 mg·L^-1（March） and 0. 218 mg·L^-1（December）,while the highest TN and TP concentrations in the lake were 4. 13 mg·L^-1 and 0. 255 mg·L^-1 in July.（3） Extreme rainfall events could decrease the nutrient concentration in the rivers in the short-term,but finally would increase the external loading of nutrients,and indicated disadvantages for the restoration of Lake Taihu. Our study concluded that inflow pollution showed an obvious＂shaping effect＂on the seasonal and spatial distribution of water quality indicators in large and shallow lakes. Additionally,the selfpurification ability of lakes,wind-induced accumulation and migration of algae,as well as the sediment resuspension under the prevailing winds in different seasons,all have vital effects on nutrient concentrations and their spatial-temporal variations.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2018年第3期1102-1112,共11页
Environmental Science
基金
国家自然科学基金项目(41501532,41573076,41671494)
国际科技合作与交流专项(2015DFG91980)
中国科学院前沿科学重点研究项目(QYZDJ-SSWDQC008)
关键词
太湖
营养盐
外源负荷
时空分异
蓝藻水华
水动力作用
Lake Taihu
nutrients
external loading
spatial-temporal variation
algal blooms
hydrodynamics
