摘要：As a result of climate changes, the occurrence of flood events has been increasing. In order to reveal the characteristics of total dissolved iron (TD Fe) output and its species during different type of flood events, the water was sampled from the Songhua River at Harbin City, during the flood event caused by extreme precipitation associated to Typhoon Bolaven struck northeastern China during 28th-30th August, 2012 and spring flood period in 2013, which was the severest spring flood in decades. Filtration and crossflow ultrafiltration were employed to analyze the chemical speciation of TD Fe. The results showed that the TD Fe concentrations varied between 0.183 and 0.318 mg/L (mean 0.251 mg/L) during the flood event caused by Typhoon and fluctuated from 0.199 to 0.326 mg/L (mean 0.256 mg/L) during the spring flood period, with the output of 32.53 ton/ day and 44.24 ton/day, respectively. The proportion of TD Fe species is in the following order: complexed iron> ionic iron> colloidal iron. Further, the increase of TD Fe output during the flood event can be attributed to iron-rich terrestrial runoff and DOM transported into the river due to the significant positive correlation between TD Fe and DOC. Besides, a significantly negative correlation was observed between TD Fe and NO3--N, indicating that NO3- inhibits Fe(III) reduction cycle. Therefore, flood events can exert significant influence on the out and species of TD Fe in the Songhua River, further affect the transport and cycling of nutrients in the river.
关键词：total dissolved iron; iron species; DOM; flood event; Songhua River
