粒径和底床地形对沉积物中有机磷释放的影响

发布时间：2018-12-18 17:23

【摘要】：主要研究了2种沉积物粒径(35μm和130μm)及底床微地形对沉积物中内源溶解性有机磷释放的影响。选取某浅水湖泊沉积物为研究对象,对其人工污染溶解性有机磷R%用室内循环直流水槽顶盖驱动流模拟风生流,考察静态和风生流作用下不同粒径沉积物及底床微地形对溶解性有机磷释放的影响。实验结果表明:在20 cm·s~(-1)及38 cm·s~(-1)2种驱动流速条件下35μm粒径沉积物实验组中沉积物有机磷释放速率均大于130μm实验组。对于35μm粒径沉积物实验组在20 cm·s~(-1)驱动水流扰动下,沉积物有机磷的平衡释放量为0.44 mg·L~(-1),在38 cm·s~(-1)驱动水流扰动下为0.49 mg·L~(-1);对于130μm粒径沉积物实验组在20 cm·s~(-1),和38 cm·s~(-1)2种扰动下的沉积物有机磷平衡释放量分R%为0.29 mg·L~(-1)、0.30 mg·L~(-1);驱动流速的提高促使达到平衡状态时的释放量提高小粒径沉积物提高驱动流速更利于平衡释放量的提高且高驱动流速缩短达到释放平衡所需的时间。在底床微地形(对地形的描述采用:y=O.1sin2πx)实验中发现,静态条件下波峰处上覆水有机磷浓度首先逐渐降低至0.18 mg·L~(-1),其后升高至0.40 mg·L~(-1)并达到平衡而波谷处则不断上升至极大值0.87 mg·L~(-1)其后下降至0.77 mg·L~(-1)并达到平衡;而在20 cm·s~(-1)的驱动水流扰动下,波峰波谷处上覆水有机磷浓度变化较为_致均逐渐增长至极大值0.39 mg·L~(-1)和0.45 mg·L~(-1)后达到平衡状态。此外,在静态和动态条件下,波谷处上覆水中有机磷含量始终高于波峰处。
[Abstract]:The effects of two sediment diameters (35 渭 m and 130 渭 m) and the microtopography of the bottom bed on the release of endogenous dissolved organic phosphorus from sediments were studied. In this paper, a shallow lake sediment was selected as the research object, and its artificially polluted dissolved organic phosphorus (R%) was simulated by the roof driving flow of indoor circulating direct current flume. The effects of sediment size and microtopography on the release of dissolved organic phosphorus under static and wind-induced flow were investigated. The results showed that the release rate of organic phosphorus in the sediment of 35 渭 m sediment was higher than that in the experimental group at 20 cm s ~ (-1) and 38 cm s ~ (-1). For the experimental group with 35 渭 m diameter sediment, the equilibrium release of organic phosphorus was 0.44 mg L ~ (-1) under 20 cm s ~ (-1) driven flow disturbance. Under 38 cm s ~ (-1) driven flow disturbance, it is 0.49 mg L ~ (-1); For the 130m diameter sediment experiment group, the organic phosphorus equilibrium release of the sediment under 20 cm s ~ (-1) and 38 cm s ~ (-1) disturbance was 0.29 mg L ~ (-1), 0.30 mg L ~ (-1); The higher the driving velocity, the higher the release at equilibrium state. The higher the driving velocity of sediment is, the better the release rate is, and the shorter the time to reach the release equilibrium is. In the experiment of bottom bed microtopography (y=O.1sin2 蟺 x), it was found that the concentration of organic phosphorus at the top of the wave peak decreased gradually to 0.18 mg L ~ (-1) under static condition. Then it increased to 0.40 mg L ~ (-1) and reached equilibrium, while the trough continued to rise to a maximum of 0.87 mg L ~ (-1) and then decreased to 0.77 mg L ~ (-1) and reached equilibrium. However, under the driving water disturbance of 20 cm s ~ (-1), the concentration of organic phosphorus in the overlying water increases to the maximum of 0.39 mg L ~ (-1) and 0.45 mg L ~ (-1), and reaches equilibrium state after the change of the concentration of organic phosphorus in the overlying water at the peak and trough of the wave gradually increases to a maximum of 0.39 mg L ~ (-1) and 0.45 mg L ~ (-1). In addition, under static and dynamic conditions, the content of organic phosphorus in the overlying water at the trough is always higher than that at the peak.
【作者单位】：长沙理工大学水沙科学与水灾害防治湖南省重点实验室;
【基金】：国家自然科学基金资助项目(51309032,51408068,51479215,51308069)
【分类号】：X524

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