Abstract: Heavy metal pollution assessment has been successfully applied to studies on river,lake,ocean,and soil environments,but not too much on marshes,especially on time sequence of heavy metal pollution.Sediment can be considered the sink and end-result area for the heavy metals imported into water.Here a case study was reported of the Xianghai marsh at downstream of an inland river—Huolin River.High resolution analysis of the samples gathered from profiles in the marsh was performed with the aid of radionuclide timing and heavy metal pollution assessment,and based on normalization of heavy metals to aluminum in sediment in the typical profiles,heavy metal pollution and enrichment levels and time sequence were analyzed and compared using the methods of comparison between upper and lower layers,sediment enrichment factor(K_SEF),index of geoaccumulation(I_geo).The results showed that within the upper layer of the profiles,significant enrichment of heavy metals was observed up to the level of pollution,indicating that the disturbance of the wetlands downstreams caused by human activities in the upper and middle reaches of Huolin River has been intensifying in recent 20 years.

Key words: sediment, heavy metal, pollution assessment, marsh wetland