Evaluation of Cadmium Contamination in the Sediments of Northern Kaohsiung Harbor, Taiwan

Abstract

The distribution, enrichment, accumulation, and potential ecological risk of Cadmium (Cd) in the surface sediments of northern Kaohsiung Harbor, Taiwan were investigated. Sediment samples from 12 locations of Kaohsiung Harbor were collected and characterized for Cd, aluminum, water content, organic matter, total nitrogen, total phosphorous, total grease, and grain size. Results showed that the Cd concentrations varied from 0.25–2.28 mg/kg with an average of 0.58±0.58 mg/kg. The spatial distribution of Cd reveals that the Cd concentration is relatively high in the river mouth region, and gradually diminishes toward the harbor entrance region. This indicates that upstream industrial and municipal wastewater discharges along the river bank are major sources of Cd pollution. Results from the enrichment factor and geo-accumulation index analyses imply that the sediments collected from the river mouth can be characterized between moderate and severe degree enrichment and between moderate and moderate to strong accumulation of Cd, respectively. Results of potential ecological risk index indicate that the sediment has higher to high ecological potential risk. Therefore, a strategy for effective controlling and managing river upstream pollution needs to be immediately implemented in order to improve the sediment quality and alleviate the ecological risk.