Mackey A P, Hodgkinson M C
Centre for Biological Population Management, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia.
Environ Pollut. 1995;90(2):181-6. doi: 10.1016/0269-7491(94)00106-n.
Fifty surface sediment samples were collected from 12 transects through a mangrove woodland near the mouth of the Brisbane River, Australia. Samples were analyzed for 10 trace metals; measured concentrations (microg g(-1)) were: Cu 3.1-34.1; Pb 7.7-84.7; Zn 40.8-144.0; Ag nd-2.8; Cr 7.6-116.8; V 16.4-57.9; Mo 7.6-82.6; Ni 2.4-57.6; As nd-13.0; and Cd nd-2.0. Coefficients of variation ranged from 22-153%. Sediments were moderately contaminated, with Mo being enriched by up to thirty times background levels. Spatial variation was considerable, and canonical trend analysis showed concentrations of all metals but Ag and Cr tended to increase downshore, suggesting tidal deposition was important in determining metal concentrations. Silver and Cr concentrations appeared to be a consequence of contamination from landward point sources. An investigation of different random sampling intensities showed the spatial variation required that many samples be taken for a satisfactory assessment of metal burdens. Even so, mean values were not a good indication of the possible environmental effects of the metal contamination. Since metal concentrations increase downshore in inter-tidal environments, a more appropriate sampling strategy would be to take a downshore series of samples normal to the shoreline.
从澳大利亚布里斯班河河口附近的一片红树林林地的12条样带中采集了50个表层沉积物样本。对样本进行了10种痕量金属的分析;测量浓度(微克/克)为:铜3.1 - 34.1;铅7.7 - 84.7;锌40.8 - 144.0;银未检出 - 2.8;铬7.6 - 116.8;钒16.4 - 57.9;钼7.6 - 82.6;镍2.4 - 57.6;砷未检出 - 13.0;镉未检出 - 2.0。变异系数范围为22% - 153%。沉积物受到中度污染,钼的富集程度高达背景水平的30倍。空间变化相当大,典型趋势分析表明,除银和铬外,所有金属的浓度都倾向于向岸下游增加,这表明潮汐沉积在决定金属浓度方面很重要。银和铬的浓度似乎是来自陆源点源污染的结果。对不同随机采样强度的调查表明,空间变化要求采集许多样本才能对金属负荷进行令人满意的评估。即便如此,平均值并不能很好地指示金属污染可能产生的环境影响。由于在潮间带环境中金属浓度向岸下游增加,更合适的采样策略是沿垂直于海岸线的方向采集一系列向岸下游的样本。