滆湖沉积物理化特征及磷释放模拟

对滆湖表层底泥、柱状层祥和间隙水进行理化分析,模拟不同条件下的沉积物磷释放。结果表明,0~20cm深度范围内,各项理化指标变化较大;大于2cm后差异较小。当提高沉积物-水体系温度、降低氧含量(或Eh),提高pH及施以水动力作用时,可促进沉积物磷释放进程。无菌条件对磷释放有抑制作用。采用实验室模拟和间隙水浓度扩散模型计算得到的磷总释放量分别为10.65t/a和9.40t/a,其中湖面网围区释放量占全湖总量的28.2~35.4%。建议适度控制网围养殖规模,以减少内源磷污染。

Physiochemical characteristics of sediments in Gehu Lake and simulation of its phosphorus release

Surface sediments, columnar layer transect and interstitial water, collected in Gehu Lake during 1992~1993, are physically and chemically analysed, and phosphorus release of the sediments simulated in different conditions. The results show that within the depth of 0~20 cm each physicochemical index changed greater, but over 20 cm its difference was smaller. When the temperature being raised, oxygen concentration (or Eh) reduced, pH increased and hydrodynamic action exerted, the experimental systems were accelerated in the course of phosphorus release across the sediment-water interface, which wast however, restrained in the bacteria-free condition. The amounts of released phosphorus calculated by means of the results of laboratory imitation and model of concentration diffusion in interstitial water are, in the whole lake, 10.65t/a and 9.40 t/a respectively, of which the quantity of phosphorus released from the pen culture district makes up 28.2~35.4 percent. The internal phosphorus pollution of Gehu Lake will be controlled if the pea culture is strengthened in the management and its scale is properly cut down.