兰州市排污沟污泥磁性物质来源特征及环境意义

文章通过对兰州市七里河沟、烂泥沟、大沙沟和排洪沟中污泥的低频磁化率、金属元素和粒度的测定,证明低频磁化率可以很好地评价排污沟污泥中重金属的来源特征。兰州市排污沟污泥中磁性矿物主要与还原性环境中的金属硫化物、外源道路和大气中人类活动产生的磁铁矿、磁赤铁矿和赤铁矿及少量顺磁性矿物,以及黄土高原沙尘暴来源的贡献有关;磁性矿物具有多源性和多类型性特征。排污沟污泥中高有机质含量反映了强烈的人类活动,而人为活动输入的磁性物质是兰州市排污沟污泥中磁性矿物的主要来源。

Source Characteristics of Magnetic Mineral of the Mud in Drainage Ditch at Lanzhou and Its Environmental Significance

Based on the low-frequency susceptibility,metal elements and particle of the mud size were analysed in Qilihe Ditch,Lanni Ditch,Dasha Ditch and Paihong Ditch at Lanzhou.It indicates that low-frequency magnetism can evaluate the source characteristics of heavy metal elements of the sludge in the drainage ditch.The magnetic mineral is related to the metal sulfide in the reducing environment,exogenous road and the magnetite,magnetic hematite,hematite and a little of pammagnetic miheral in the atmosphere from human activities,and the sandstorm from the loess plateau of the sludge in drainage ditch at Lanzhou.The characteristic of magnetic mineral has multiple sources and types.The high content of the organic matter reflects the intensive human activities in the drainage ditch.The main source of magnetic minerals is from human activities of the mud in drainage ditch.