Heavy metal contamination in mangrove habitats of Singapore
Heavy metal contamination in mangrove habitats of Singapore
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DOI：
10.1016/j.marpolbul.2005.09.008
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发表时间：
2005-12-01
影响因子：
5.8
通讯作者：
Obbard, JP
中科院分区：
文献类型：
--
作者：
Cuong, DT;Bayen, S;Obbard, JP
红树林是多种海洋动物的重要生态栖息地，也是多种候鸟的越冬地，但由于直接开发和干扰，红树林在东南亚处于高度濒危状态。在新加坡，1820年红树林约占陆地总面积的13%，但现在覆盖率不到5%（Ng和Sivasothi，1999年）。红树林受到环境污染物的威胁，特别是与各种人类活动有关的重金属，包括航运，疏浚和城市废水排放。据报道，澳大利亚、香港和巴西等许多国家的红树林沉积物中积累了重金属（Harbison，1986年; Tam和Wong，1995年a，B，1996年; Lacerda等人，1991;马查多等人，2002 a，B）。虽然已经对新加坡沿海海洋沉积物中的重金属水平进行了调查（Goh和Chou，1997年; Wood等人，1997; Nayar等人，2004年），本地红树林生境的重金属数据不足。本研究的目的是：（一）确定新加坡代表性红树林生境中的重金属水平;（二）比较新加坡和马来西亚之间的陆地连接堤道两侧的两个红树林生境之间的水平;以及（三）根据其他国家报告的类似数据评估污染情况。这项研究的数据是有用的，我们了解污染物的命运和影响的红树林系统，以及在新加坡的保护剩余的红树林栖息地。2004年4月，在为期一周的时间内，在新加坡的两个红树林地点，即双溪毛禄和双溪哈提卜峰苏采集了样本（图1）。这些地点位于柔佛海峡中新加坡和马来西亚之间的陆地连接堤道的两侧。这条堤道是新加坡北方海岸周围海洋流体动力学的物理屏障，那里的海水不会穿过堤道进行交换。色葡萄布洛红树林在1989年被宣布为自然保护区之前，过去一直被用作对虾养殖场。S. Khatib Bongsu不是受保护的网站。红树林样品包括海洋表面微层（SML）和次表层水、沉积物和生物群。砷，镉，铬，铜，镍，铅和锌的水平进行了测量，在所有的样品（除了砷在沉积物和铬在生物群）。两个地下海水（深度40厘米，2升）和SML样品（2升）收集在S。Buloh和S. Khatib Bongsu红树林。使用玻璃板法收集SML样品（Harvey和Burzell，1972; Carlson，1982和Zhang等人，2003年）。将玻璃板（30· 30·0.5cm）垂直浸入水面，并以约5- 6cm/s的速度取出。使用橡胶刀片将玻璃板两侧上的附着水擦除到样品瓶中，然后用收集的水彻底冲洗。通过将每次平板浸渍收集的体积除以平板的表面积来确定收集的SML的厚度。在本研究中，SML的采样厚度约为40-60 μm。的定义和
Mangroves represent a critical ecological habitat to a diverse range of marine fauna and serve as a wintering site for a wide variety of migratory birds, but are highly endangered in Southeast Asia due to direct exploitation and disturbance. In Singapore, mangroves comprised around 13% of the total land area in 1820, but coverage is now less than 5%(Ng and Sivasothi, 1999). Mangroves are at risk from environmental pollutants, especially heavy metals that are associated with a diverse range of anthropogenic activities including shipping, dredging, and urban wastewater discharges. The accumulation of heavy metals in mangrove sediments has been reported for a number of countries including Australia, Hong Kong and Brazil (Harbison, 1986; Tam and Wong, 1995a, b, 1996; Lacerda et al., 1991; Machado et al., 2002a, b). Although there have been investigations on the levels of heavy metals in the coastal marine sediments of Singapore (Goh and Chou, 1997; Wood et al., 1997; Nayar et al., 2004), heavy metal data for local mangrove habitats are lacking. The objectives of this study were:(i) to determine the levels of heavy metals in representative mangrove habitats of Singapore;(ii) to compare levels between two mangrove habitats that are on opposite sides of a land-linked causeway between Singapore and Malaysia; and (iii) to evaluate contamination in the context of similar data reported from other countries. The data from this study is of use with respect to our understanding of the fate and impact of pollutants in mangrove systems, as well as the conservation of remaining mangrove habitats in Singapore. Samples were collected within a one-week period in April 2004 at two mangrove sites in Singapore ie Sungei Buloh and Sungei Khatib Bongsu (Fig. 1). These sites are located on opposite sides of a land-linked causeway between Singapore and Malaysia in the Straits of Johore. The causeway represents a physical barrier to marine hydrodynamics around SingaporeÕs northern coast, where there is no exchange of seawater across the causeway. The S. Buloh mangrove has been used in the past as a site for prawn aquaculture before being declared a protected nature reserve in 1989. S. Khatib Bongsu is not a protected site. Mangrove samples included the sea surface microlayer (SML) and subsurface water, sediments and biota. Levels of As, Cd, Cr, Cu, Ni, Pb and Zn were measured in all samples (except for As in sediments and Cr in biota). Two subsurface seawater (depth 40 cm, 2 l) and SML samples (2 l) were collected at the S. Buloh and S. Khatib Bongsu mangroves, respectively. SML samples were collected using the glass plate method (Harvey and Burzell, 1972; Carlson, 1982 and Zhang et al., 2003). A glass plate (30· 30· 0.5 cm) was dipped vertically through the water surface and withdrawn at a speed of about 5–6 cm/s. The attached water on both sides of the glass plate was wiped off into a sample bottle using a rubber blade, and then thoroughly rinsed with the water being collected. The thickness of the SML collected was determined by division of the volume collected with each plate dip by the surface area of the plate. In this study, the sampling thickness of the SML was around 40–60 μm. The definition and