东平湖沉积物有效磷空间分布特征及其环境意义研究

Spatial Distribution Characteristics of Available Phosphorus and Environmental Significance of Sediments in Dongping Lake

通过磷形态分级提取法方法,分析了东平湖沉积物有效磷的空间分布特征及其形态组成并探讨了沉积物有效磷的环境影响。结果表明,东平湖表层沉积物有效磷的含量范围为1.61~20.90 mg·kg_(-1),占总磷含量的0.32%~2.57%,参与沉积物-水界面磷循环进而影响上覆水体磷浓度的能力较弱;表层沉积物各形态有效磷平均含量表现为Al-P(5.11 mg·kg_(-1))>Ex-P(1.23 mg·kg_(-1))>Fe-P(0.86 mg·kg_(-1)),其中Al-P是主要的潜在磷源。沉积物有效磷含量在水平上表现为在老湖码头北部近湖区、腊山码头和大汶河入湖口附近区域相对较高,受人为污染较重;在垂直上表现为除个别采样点外,沉积物有效磷含量在2~4 cm变化较大,而在深度10 cm以下较为稳定。东平湖沉积物内源磷负荷相对较低,但是由于该湖易发生水力扰动,沉积物中有效磷的潜在释放风险增加,需要对其进行控制。

The spatial distribution characteristics of available phosphorus(Ex-P, Al-P, Fe-P) in Dongping Lake sediments were analyzed by the method of phosphorus morphological grading extraction, and discussed the environmental impact on this basis. The results showed that the available phosphorus content in the surface sediments of Dongping Lake ranged from 1.61~20.90 mg·kg_(-1), accounting for 0.32 %~2.57 % of the total phosphorus content. The ability to part in the phosphorus circulation at the sediments water interface and thus affect the magnetic concentration of the over water was weak. The average available phosphorus content in the surface sediments of lake was shown as Al-P(5.11 mg·kg_(-1))>Ex-P(1.23 mg·kg_(-1))>Fe-P(0.86 mg·kg_(-1)), and Al-P was the main potential phosphorus source. The level of available phosphorus in sediments was relatively high in the area near the Laohu Wharf, Lashan Wharf and the Lake entrance of Dawen River.The vertical expression was that, except for individual sampling point, the available phosphorus content of the sediments varies greatly from 2 to 4 cm, and was relatively stable under 10 cm. The endogenous phosphorus load in the sediments of Dongping Lake was relatively low, but since the hydraulic disturbance of Dongping Lake was easy to occur, the potential release risk of available phosphorus in the sediments increased.