Abstract

We investigated the source, contamination level and the potential ecological risk of heavy metals (Al, Cr, Fe, Ni, Cu, Zn, As, Cd and Pb) in the Setiu wetland area, one of the largest natural wetlands on the East Coast of peninsula Malaysia. To do this, we collected surface sediments between 0 and 10 cm depth from 27 locations. These locations covered the major habitat types in the wetland, specifically: Setiu lake, Setiu lagoon, Setiu estuary and Setiu river. Heavy metals were then measured using a closed digestion method which employs high temperatures and strong acids. Analysis of the enrichment factor (EF), Geo-accumulation Index (I_geo) and Contamination Factor (CF) showed a low contamination level of all heavy metals in Setiu wetland besides Cr. In the Setiu lagoon and Setiu river habitats, similar analyses categorised the contamination level of Cr as moderately enriched. Overall, the Pollution Load Index (PLI) classified the Setiu river as un- or moderately polluted. All other habitats were unpolluted by heavy metals. Multivariate analyses suggest that the metals: Al, Mn, Fe, Cu, Zn and Pb originated from the lithogenic process. In contrast, Cr was derived from both lithogenic processes and anthropogenic activities whilst Cd and Ni came from anthropogenic activities into the Setiu wetland ecosystems. Additionally, finer grain size (MS) and higher TOC in the sediments of Setiu lake & Setiu river also facilitated the accumulation of the metal in sediments.

摘要

我们调查了东海岸最大的天然湿地之一塞提乌湿地地区重金属（Al、Cr、Fe、Ni、Cu、Zn、As、Cd 和 Pb）的来源、污染程度和潜在生态风险马来西亚半岛。为此，我们 从 27 个地点收集了 0 到 10 厘米深度的地表沉积物。这些地点涵盖了湿地的主要栖息地类型，特别是：Setiu 湖、Setiu 泻湖、Setiu 河口和 Setiu 河。然后使用采用高温和强酸的封闭消解方法测量重金属。富集因子（EF）分析，地积指数（I _geo) 和污染因子 (CF) 表明，除 Cr 外，Setiu 湿地中所有重金属的污染水平较低。在 Setiu 泻湖和 Setiu 河栖息地，类似的分析将 Cr 的污染水平归类为中度富集。总体而言，污染负荷指数 (PLI) 将 Setiu 河分类为未受污染或中度污染。所有其他栖息地均未受到重金属污染。多变量分析表明，金属：Al、Mn、Fe、Cu、Zn 和 Pb 起源于成岩过程。相比之下，Cr 来自岩石形成过程和人为活动，而 Cd 和 Ni 来自人为活动进入 Setiu 湿地生态系统。此外，Setiu 湖和 Setiu 河沉积物中更细的粒度 (MS) 和更高的 TOC 也促进了金属在沉积物中的积累。