人为扰动情形下城郊溪流沉积物磷形态及污染特征分析

Phosphorus Speciation and Pollution Characteristics of Suburban Stream Sediments under Anthropogenic Disturbance

为揭示巢湖流域某一城郊溪流表层沉积物磷素赋存形态及变化特征,于2019年3~8月采集了该溪流表层沉积物样品,通过现场测定上覆水及沉积物基本理化性质,并应用SMT和三步提取法对表层沉积物磷形态的测定.结果表明,该城郊溪流总磷污染浓度241.94 mg·kg^(-1)~924.81 mg·kg^(-1),其中情形2超过安全级(600 mg·kg^(-1))的标准.从季节来看,总磷浓度春季高于夏季;从各情形来看,各磷形态均在情形2条件下达到最高,且情形3含量低于情形1,表明人为扰动给溪流底质污染带来严重影响.总磷污染评价表明该溪流水体沉积物潜在环境风险不高,但表现出受人为扰动变化显著的特征.

To reveal the occurrence and variation characteristics of phosphorus in layered sediments of a suburban stream in the Chaohu Lake basin,the surface sediment samples of the stream were collected from March to August 2019.The basic physical and chemical properties of overlying water and sediments were obtained through an on the spot measurement,and the phosphorus form of surface sediments was determined by applying SMT and three-step extraction method.The results show that the total phosphorus pollution concentration in urban streams is 241.94~924.81 mg·kg^(-1),among which the concentration of Condition 2 exceeds the safety level standard(600 mg·kg^(-1)).Examined in terms of seasons,it is found that the total phosphorus concentration is higher in spring than in summer.In view of all cases,all phosphorus forms reach their maximum under Condition 2,and the content of phosphorus in Condition 3 is lower than that of Condition 1,which indicates the serious pollution caused by anthropogenic disturbance to the bottom sediments of the stream.The total phosphorus pollution assessment demonstrates the low potential environmental risks of the sediments in this stream,but it can be significantly affected by the anthropogenic disturbance.