选择淮南矿区典型采煤沉陷积水区作为研究对象,以周边农田土壤作为对比,采用静态培养柱进行了底泥营养盐的释放潜能实验,设定好氧、缺氧两种条件,通过测定在240 h内上覆水中pH、氧化还原电位(ORP)、溶解氧(DO)、NH_4~+、NO_2~-、NO_3~-、PO_4~(3-)和总有机碳(TOC)的浓度值,研究了沉陷积水区底泥及周边土壤中营养盐向上覆水的释放潜能.结果表明,在积水初期,上覆水pH、ORP、DO等对底泥中氮、磷及有机物的富集与释放起着重要的作用,底泥会释放以NH+4为主的无机氮,厌氧条件下氨化作用更强烈,而好氧、厌氧两种条件土壤培养柱中无机氮和总氮均是从上覆水向土壤富集.采煤沉陷积水区底泥向上覆水释磷,而土壤淹水后好氧、厌氧两种条件下均不释放磷.综合来看,积水初期沉陷积水区低水位(2—5 m)条件下的好氧环境有利于上覆水中的有机物、氮、磷元素向底泥富集,内源负荷潜能较低.
A typical subsidence water area was chosen to evaluate its nutrient release potential of sediment during the initial-stage of coal mine subsidence processes in Huainan Coal Mine areas. Sediment samples were collected to conduct simulation experiments for nutrient release in contrast with surrounding soils in agriculture. Water parameters in the overlying water, including pH, ORP, (DO)、NH_4~+、NO_2~-、NO_3~-、PO_4~(3-) and TOC, were monitored during a period of 240 hours. It was found that the parameters of pH, ORP and DO in the overlying water played important roles in controlling the release of nitrogen, phosphorus and organic matters. Sediments released nitrogen in the form of ammonia, especially under anaerobic conditions. On the contrary, sediment enriched nitrogen from the overlying water under both anaerobic and aerobic conditions. Sediments showed phosphorus release potential while inundated soils didn't. During the initial stage in the waters of subsidence processes, low water depth (2--5 m) and intensive mixing aerobic environments would promote concentration of organic matters, nitrogen, phosphorus from overlying water to sediment, resulting in less risk of nutrient internal loading.