长荡湖表层沉积物中营养盐空间分布与污染特征

通过对长荡湖不同湖区表层沉积物中营养盐及含水率的测定,结合统计分析手段,探讨其空间分布与污染特征。结果表明:长荡湖表层沉积物中TN、TP的质量比、TOC含量及含水率变化范围分别为3.47~10.80 g/kg、0.57~1.83 g/kg、0.66%~4.21%和41.71%~75.78%,其均值分别为6.86 g/kg、1.19 g/kg、1.73%和60.48%,且均呈湖周高、湖心低的空间分布特征;TN、TP和含水率之间呈显著线性相关,TOC与TN、TP和含水率之间无显著相关性;长荡湖表层沉积物中TN、TP及TOC富集系数分别在0.7~2.0、0.6~2.0和0.4~2.5内变化,其平均值分别为1.3、1.3、1.0;污染指数分别在6.3~19.6、1.0~3.1和0.7~4.2内变化,其平均值分别为12.5、2.0和1.7;长荡湖表层沉积物的氮素水平处于重度污染状态,且磷、有机碳均已受到一定程度的污染。

Spatial distribution and contamination characteristics of nutrients in surface sediment of Changdang Lake

By determining the nutrient and water contents in surface sediment in different region of Changdang Lake, combined with statistical analysis method, the spatial distribution and pollution characteristics were discussed. The results showed that the concentration of nutrient ranged from 3. 47 to 10. 80 g/kg for TN, from 0. 57 to 1. 83 g/kg for TP, from 0. 66% to 4. 21% for TOC, from 41. 71% to 75. 78% for water, with an average of 6. 86 g/kg, 1. 19 g/kg, 1. 73% and 60. 48%, respectively, which all had spatial distribution of high content in surrounding and low in central in the lake. A significant linear correlation was observed among total nitrogen, total phosphorus and water content, while there was not significant correlation among total organic carbon and total nitrogen, total phosphorus and water content. The enrichment coefficients varied from 0. 7 to 2. 0 for total nitrogen, from 0. 6 to 2. 0 for total phosphorus and from 0. 4 to 2. 5 for total organic carbon, with an average of 1. 3, 1. 3, 1. 0, respectively. And that pollution index varied from 6. 3 to 19. 6 for total nitrogen, from 1. 0 to 3. 1 for total phosphorus and from 0. 7 to 4. 2 for total organic carbon, with the average of 12. 5, 2. 0 and 1. 7, respectively, indicating that nitrogen level was in heavily polluted state and Changdang Lake was under a certain level of pollution of phosphorus, organic carbon in the surface sediment.