乌梁素海沉积物中全磷的分布特征

开展了浅水草型湖泊乌梁素海沉积物中TP(全磷)的分布特征研究。结果表明,乌梁素海表层沉积物中TP含量在0.37~0.99 g/kg之间变化,平均值为0.75 g/kg;水平分布上,TP含量呈现从湖区四周向湖心递减的变化趋势,大部分湖区已具有生态毒性效应,并对湖区底栖生物群落和生态环境构成了较大威胁;垂向上,尽管沉积物中TP含量有所波动,但0~10 cm的表层沉积物中TP含量均随深度增加而递减,揭示了近年来人类活动的加剧对乌梁素海沉积物中磷累积的重大影响;实验得出了粉砂、粘土粒级>极细砂粒级>细砂粒级>中砂以上粒级的TP含量序列,各粒级对TP的吸附贡献率由吸附能力和质量百分比共同控制;磷的沉积对乌梁素海富营养化进程有深远影响。

Distribution of Total Phosphorus in Sediments of Wuliangsuhai Lake

Based on analysis of total phosphorus, horizontal and vertical characteristics of sediments in Wuliangsuhai Lake are discussed. The results indicate that the content of total phosphorus in surface sediments ranges from 0.37 to 0.99 g·kg-1, with mean content of 0.75 g·kg-1. The horizontal distribution of TP had decreasing trend from bank to center and the content of TP in surface sediment of most the lake districts had certain ecological toxic effects. The vertical distribution of TP in the sediment core is various, which indicate that effluents from human activity influence TP contents. The sequence of TP contents is silt, clay＞very fine sand ＞fine sand＞medium sand, TP enriched in the sediments with grains smaller than 63 micron in diameter. The adsorption contribution rates of TP are under the control of adsorbability and mass percenage. Sediment internal load would be a dominant factor controlling water quality when external load was reduced or cut off in Wuliangsuhai Lake.