Trend analysis and cause diagnosis of eutrophication in Lake Huanggai in the middle reaches of Yangtze River

为评估黄盖湖富营养状况和变化趋势并诊断主要成因,以2015~2021年环境监测站点水质数据和2021年秋季的4次全湖加密监测数据为基础,采用综合营养状态指数(TLI(Σ))评价了黄盖湖富营养化程度及变化趋势,使用污染指数法评价了黄盖湖表层沉积物污染程度,基于沉积物与水体间氮磷的相关关系和入湖河流水质状况,初步推断了黄盖湖富营养化的主要原因。结果表明,2015-2021年黄盖湖TLI(Σ)依次为44.14、45.91、42.39、49.79、49.01、49.62和52.77,呈逐年升高的趋势,由中营养状态转变为轻度富营养状态,夏、秋季富营养化程度高于冬、春季;TLI(SD)、TLI(TN)和TLI(TP)贡献率分别为28%、18%和16%,营养盐浓度增加和透明度降低是黄盖湖水体富营养化的主要驱动因子。沉积物TP和TN平均含量分别为791和2691 mg/kg,为重度污染,有较高的释放风险。表层沉积物与表层水体之间TN相关性较弱,TP相关性较强,但受风速、水深等因素影响较大,湖面风速较高时浅水区域表层沉积物中P更容易释放至上覆水。入湖河流的外源输入以及风浪作用下沉积物再悬浮导致的营养盐浓度升高、透明度下降是近几年黄盖湖水体富营养化的主要驱动因子,建议通过河口湿地修复、水生植被修复等措施减缓黄盖湖水体富营养化趋势。;In order to evaluate the state and temporal variations of eutrophication in Lake Huanggai diagnose main causes changes, comprehensive trophic index was used level variance tendency water body, pollution method degree surface sediments. The correlations between concentration nitrogen phosphorus sediments were analyzed. Based on water, quality river entering into lake, preliminarily inferred. All analyses above based data environmental monitoring stations from 2015 2021 four times intensive whole lake autumn 2021. results showed that 2021, TLI(Σ) scores 44.14, 45.91, 42.39, 49.79, 49.01, 49.62 52.77, respectively, which a trend increase year by year. changed moderate mild, higher summer than winter spring. contribution rates TLI (SD), (TN) (TP) 28%, 18% 16%, respectively. nutrient decrease transparency driving factors Huanggai. average concentrations TP TN 791 mg/kg 2691 mg/kg, indicating heavy high release risk. correlation weak, while strong. However, it greatly affected other factors, such as wind speed depth, etc. When over high, P shallow area easy overlying water. recent years caused inflow rivers re-suspension under action winds waves. It is suggested measures estuarine wetland restoration aquatic vegetation should be taken slow down