Jia Binyang, Tang Ya, Yang Bo, Huang Jen-How
Chengdu Academy of Environmental Sciences, Environmental Protection Building, No.8 Fanglin Road, Chengdu, Sichuan, 610072, People's Republic of China.
Department of Environment, College of Architecture and Environment, Sichuan University, No 24, South Section One, First Ring Road, Chengdu, Sichuan, 610065, People's Republic of China.
Environ Monit Assess. 2017 Jan;189(1):16. doi: 10.1007/s10661-016-5727-z. Epub 2016 Dec 14.
Phosphorus (P) fractionations in the surface sediment of Sancha Lake in China's southwestern Sichuan Province were examined to assess the potential P release at the water-sediment interface and to understand its seasonal (2009-2010) and historical dynamics (1989-2010) in the surface water. Elevated P concentrations were detected in the sediment at main reservoir inflow, south canal of the Dujiangyan irrigation network, and intensive cage fish farming area, accounting for 32 and 40% of current total P discharges. The highest total P concentration (11,200 μg P g) was observed in the upper sediment below intensive fish farming area with a specific enrichment of HCl-P (51% of total P) mainly from fish feeds and feces. These sediments had larger MgCl-P pools with higher diffusive P fluxes (0.43-0.47 mg m d) from surface sediment than those from other areas (0.25-0.42 mg m d). The general small proportion of MgCl-P (5.7-10%) and low diffusive P fluxes from surface sediment (<0.02% of sediment P storage (0-1 cm)) indicate low mobility and slow release of P from sediments. The sediment as an internal P source led to a 3-4-year lag for P concentration decrease in the surface water after restriction of anthropogenic P discharges since 2005. Thus, the peak P concentration in April and September could be explained as a combined effect of supplementing internal loading via reductive processes in sediments and seasonal water vertical circulation in the early spring and fall. Policy played a crucial role in reducing P inputs to the lake.
对中国西南部四川省三岔湖表层沉积物中的磷（P）进行了分级，以评估水 - 沉积物界面处潜在的磷释放，并了解其在地表水的季节性（2009 - 2010年）和历史动态（1989 - 2010年）。在主要水库入水口、都江堰灌溉网络南干渠以及集约化网箱养鱼区的沉积物中检测到磷浓度升高，占当前总磷排放量的32%和40%。在集约化养鱼区下方的上层沉积物中观察到最高的总磷浓度（11200μg P g），其中HCl - P的特定富集量（占总磷的51%）主要来自鱼饲料和粪便。这些沉积物具有较大的MgCl - P库，其表层沉积物的扩散磷通量（0.43 - 0.47mg m d）高于其他区域（0.25 - 0.42mg m d）。MgCl - P的总体比例较小（5.7 - 10%）以及表层沉积物的低扩散磷通量（<沉积物磷储量（0 - 1cm）的0.02%）表明沉积物中磷的迁移性低且释放缓慢。自2005年限制人为磷排放以来，沉积物作为内部磷源导致地表水磷浓度下降出现3 - 4年的滞后。因此，4月和9月的磷浓度峰值可以解释为沉积物中还原过程补充内部负荷以及早春和秋季季节性水体垂直循环的综合作用。政策在减少湖泊磷输入方面发挥了关键作用。
