T119 Sources, Transport, and Fate of Trace and Toxic Elements in the Environment (Posters)

Monday, 19 October 2009
9:00 AM - 6:00 PM
Hall A

LEVELS AND SOURCES OF POTENTIAL HARMFUL ELEMENTS IN SOILS AND SEDIMENTS IN THE CHANGJIANG RIVER DELTA REGION

Paper number: T119-20
Program: Technical Sessions
Time: 9:00 AM – 6:00 PM

Authors

Abstract

Introduction

Potential harmful elements (PHEs) in soils and sediments are particulary toxic for living organisms. It is important to recognize the distribution and enrichment of PHEs in urbanization areas for the ecological risk evaluation.

Study area

The studied areas are located in the Changjiang River Delta Region, one of fast urbanization areas in China. Three areas are divided in this research, including urban area, mixed area and agricluture area. Nanjing was choiced as the urban area which comprise the industry, transportation, commerce and living facilities. Yixing-Wujin in the western Thaihu Lake was researched as mixed area, where the urbanization is accelerating. Huzhou-Anji was regarded as agricultural area, where the traditional agriculture is dominant.

Results and Discussion

Soil and sediment samples were collected in these areas.An enrichment factor(EF) was calculated to characterize the polluted levels of PHEs in soils and sediments by Al normalizing. Results show PHEs in sediments are much enriched than in soils. EFs in the urban area are higher than those in the mixed area and the agricultural area. But they are diverse in the mixed area and the agricultural area.

The assemblies of high risk elements(HRE) in soil and sediment are Cr-As-Hg and Cd-Pb-As-Cr in urban area. In the mixed area, Cr-As-Hg and Pb-Cr-As-Cd-Zn are HREs in soils and sediments. The agricultural area shows that Cr-Cd-Hg-As and Cd-Cr-As are dominant HREs in soils and sediments.

Primary component analysis of PHEs and major elements reveal sources of PHEs. PHEs in the city are correlated with structure and industrial wastewater. PHEs in agricultural area mainly originate from fertilizer and erosion. The mixed area shows diverse sources for PHEs. Sediments contain different PHEs in levels and assembly comparing with soils.

Conclusions

Cr and As are high rick elements in the whole study area. The enrichment of PHEs in each area is associated with the sources.