Particle size distribution and characteristics of heavy metals in road-deposited sediments from Beijing Olympic Park
Haiyan Li
,
Anbang Shi
,
Xiaoran Zhang
DOI:10.1016/j.jes.2014.11.014
Received August 04, 2014,Revised November 13, 2014, Accepted , Available online June 08, 2015
Volume 27,2015,Pages 228-237
Due to rapid urbanization and industrialization, heavy metals in road-deposited sediments (RDSs) of parks are emitted into the terrestrial, atmospheric, andwater environment, and have a severe impact on residents' and tourists' health. To identify the distribution and characteristic of heavy metals in RDS and to assess the road environmental quality in Chinese parks, samples were collected from Beijing Olympic Park in the present study. The results indicated that particles with small grain size (<150 μm) were the dominant fraction. The length of dry period was one of the main factors affecting the particle size distribution, as indicated by the variation of size fractionwith the increase of dry days. Theamount of heavymetal (i.e., Cu, Zn, Pb and Cd) content was the largest in particles with small size (<150 μm) among all samples. Specifically, the percentage of Cu, Zn, Pb and Cd in these particleswas 74.7%, 55.5%, 56.6% and 71.3%, respectively. Heavy metals adsorbed in sediments may mainly be contributed by road traffic emissions. The contamination levels of Pb and Cd were higher than Cu and Zn on the basis of the mean heavy metal contents. Specifically, the geoaccumulation index (Igeo) decreased in the order: Cd>Pb>Cu>Zn. This study analyzed the mobility of heavy metals in sediments using partial sequential extractionwith the Tessier procedure. The results revealed that the apparent mobility and potential metal bioavailability of heavy metals in the sediments, based on the exchangeable and carbonate fractions, decreased in the order: Cd>Zn≈Pb>Cu.
