稳定碳同位素技术在北京市公园湖泊沉积物有机质来源分析与评价中的应用

Applying stable carbon isotope techniques to detect different sources of organic matters in lake sediments from Beijing parks

湖泊是陆地水圈的重要组成部分,湖泊沉积物是水体污染物的源和汇,北京湖泊生态环境和环境质量评价越来越受关注。本研究对2012—2013年北京市19个公园湖泊表层沉积物中δ13Corg、C/N值及TOC、TON含量进行分析,探讨了湖泊生产力分布、湖泊营养输入、表层沉积物营养含量以及各沉积物有机质来源。结果表明,湖泊表层沉积物由于存在地域差异,δ13Corg、C/N、TOC、TON含量的差别较大、湖泊生产力与营养水平各不相同;通过有机指数评价法推断,所研究的湖泊中只有3个湖泊较清洁,其他均受到不同程度的有机污染;结合δ13Corg(-27.6‰^-22.1‰)和C/N(8.2~58.1)2个特征值对沉积物进行有机质来源的定性及半定量分析,推断出北京市公园湖泊有机质大多来源为污水有机质,应主要从控制污水输入方面降低湖泊污染风险。

Lake sediment can be a source as well as a sink of water pollutants and, hence, re- presents an important factor in lake ecology. Thus, more and more attention has been paid on the water quality of Beijing park lakes and the chemical characteristics of the sediments. This study detected variations in δ^13Corg, C/N ratios, TOC and TN contents in the sediments from 19 Beijing park lakes collected in 2012 and 2013. The analyses focused on the sources of organic matter, the productivity and the eutrophic status of the lakes. The results showed that the δ^13Corg and C/N values, and TOC and TON concentrations were significantly different among superficial sediments from different lakes, and the productivity and the eutrophic status of the lakes were also different. The sediments of three lakes showed minor contamination, whereas the other lakes were charac- terized by higher degrees of organic pollution. According to the 813Corg values （-27. 6‰ to -22.1 ‰） and C/N ratios （8.2-58.1）, the sedimentary organic matter was mainly derived from sewage. Hence, the pollution of the lakes could be lowered by controlling the discharge of wastewater.