A baseline investigation into heavy metal status in the mangrove sediments was conducted in Shenzhen, China where rapid urban development has caused severe environmental contamination. It is found that heavy metal contamination in this mangrove wetland is characterised by the dominant presence of tungsten and cobalt, which is markedly different from the neighbouring Hong Kong and other parts of the world. The vertical variation pattern of these two metals along the sediment profile differed from other heavy metals, suggesting an increasing influx of tungsten and cobalt into the investigated mangrove habitat, as a result of uncontrolled discharge of industrial wastewater from factories that produce or use chemical compounds or alloys containing these two heavy metals. Laboratory simulation experiment indicated that seawater had a stronger capacity to mobilise sediment-borne tungsten and cobalt, as compared to deionised water, diluted acetic, sulfuric and nitric acids.
Authors: Xu S, Lin C, Qiu P, Song Y, Yang W, Xu G, Feng X, Yang Q, Yang X, Niu A. ;Full Source: Marine Pollution Bulletin. 2015 Aug 28. pii: S0025-326X (15)00535-4. doi: 10.1016/j.marpolbul.2015.08.031. [Epub ahead of print] ;