粉煤灰充填复垦地理化特性与重金属分布特征研究--以淮南洛河电厂粉煤灰复垦地为例

Study on Distribution Character of Physical and Chemical Properties and Heavy Metals in Reclaimed Land Filled with Fly Ash:A Case Study of Reclaimed Land of Luohe Power Plant in Huainan City

本文以淮南上窑储灰场中的粉煤灰充填复垦地为研究对象,选择粉煤灰复垦地与灰场周边非复垦区对照地块进行布点采样,在复垦地中分六层[H1(0～20cm)、H2(20～40cm)、H3(40～60cm)、H4(60～80cm)、H5(80～100cm)、H6(100～120cm)]分别采集土壤、粉煤灰样品并进行监测,对照地块按照同样方法采样监测,分析复垦地土壤理化性质和重金属的分布特征。研究结果显示,随着采样深度的增加,复垦地pH值从8.21到8.49呈递增的空间分布特征,各采样层pH值均高于对照地块;随着采样深度的增加,复垦地的含水量呈增加的空间分布特征,对照地块的含水量则是先增加后减少,粉煤灰基质具有良好的保水性能;养分含量在不同层位存在较大差异,粉煤灰复垦地速效氮、速效钾含量从H1至H6层呈现减少后增加的空间分布特征,在H3层处达到最小值16.23mg·kg-1、158.97mg·kg-1,复垦地各层位的速效氮含量均低于对照地块、速效钾含量均高于对照地块;复垦地与对照地块的速效磷含量均呈现先减少后增加再减少的空间分布特征,最大有效磷含量分别为10.01mg·kg-1、11.91mg·kg-1。对比土壤养分分级标准,复垦地土壤中速效氮、速效磷含量均处于缺乏水平,应增施磷肥、氮肥或有机肥以增加土壤养分。粉煤灰复垦地表层土壤和粉煤灰中的Cu、Cr、Pb、Zn、Cd、Ni等元素中Cr、Pb、Zn含量均低于淮南土壤背景值和中国土壤背景值,其中粉煤灰层中各重金属元素均处于土壤环境质量标准的二级范围内,其余各层位重金属元素除Cd均处于土壤环境质量标准的一级范围内;土壤中各重金属元素含量除Zn外均低于粉煤灰中的含量,且粉煤灰层中重金属有向表土迁移的趋势。

For researching the distribution character of physical and chemical properties and heavy metals in reclaimed land,the fly ash re-claimed land in Shangyao fly ash ponds of Huainan City are choosed as research field.The fly ash reclaimed land and normal farmland（as compared farmland block） nearby the reclaimed land are choosed to take samples.During sampling,each sampling block are separated as 6 horizons [H1（0～20 cm） 、H2（20～40 cm） 、H3（40～60cm） 、H4（60～80 cm） 、H5（80～100 cm） 、H6（100～120 cm） ] to collect samples for analysing physical and chemical properties and heavy metals contents.The result shows that pH values of reclamied land are increased from 8.21 to 8.49 with the sampling depth increasing,at same horizon,the pH value of reclaimed land is higher than normal farmland.The mois-ture contents are increased with the samping depth increasing in reclamied land,but moisture contents of normal land are increased at top horizons then decreased at bottom horizons.Nutrient contents are different at different sampling horizons,available nitrogen and available potassium contents of reclamation land are decreased at top horizons then increased at bottom horizons,and minimum value are 16.23 mg·kg-1 and 158.97 mg·kg-1 at H3 horizon respectively in reclaimed land,the available nitrogen content is lower than normal land at each same sam-pling horizon,but available potassium content is higher than normal land at each same sampling horzion.The available phosphorus contents in reclaimed land and normanl farmland are decreased at top horizons then increased at middle horizons then decreased again at bottom hori-zons,the maximum content are 10.01 mg·kg-1 and 11.91 mg·kg-1 respectively.Compared with soil nutrient national standard,the available nitrogen and available phosphorus contents in reclaimed land are belongs to insufficiency level,the phosphatic fertilizer and nitrogenous fer-tilizer or organic fertilizer can be used to add the soil nutrient.the analysed result shows that the contents of Cr,Pb,Zn in topsoil and flyash are lower than Huainan soil background value and Chinese soil background values,the contents of Cd,Cu,Cr,Pb,Zn,Ni in fly ash are be-longs the second level criterion of national soil quality standard,the contens of Cu,Cr,Pb,Zn,Ni in cover soil are belongs the first level crite-rion of national soil quality standard,all analysed heavy metal contents in cover soil are lowed than heavy metal contents in fly ash except Zn,and heavy metals are migrated from fly ash to coversoil.