Hatje V, Rae K, Birch G F
Environmental Geology Group, School of Geosciences, University of Sydney, NSW 2006, Australia.
J Environ Monit. 2001 Feb;3(2):251-6. doi: 10.1039/b008457n.
The temporal variation in the concentrations of particulate trace metals (Cu, Pb and Zn) and total suspended solids (TSS) was examined in three rivers that drain into the Port Jackson estuary, Australia, using a nested, hierarchical sampling design. Sampling was conducted between March and June 1999, under low flow conditions. The sampling design incorporated four temporal scales (hours, days, weeks and months). It was considered that hours, days, weeks and months were representative of such time scales and could be analyzed as random, nested sources of variation in an analysis of variance (ANOVA). Significant variation was found at temporal scales ranging from hours, within the same day, to months. The amount and scales of variation differed between particulate trace metals and TSS concentrations and between rivers. In many cases, differences between small-scale were as important as differences between months. The results suggest that higher anthropogenic influences cause higher variability at small temporal scale. Results indicate the need for nested sampling designs to be incorporated into studies of temporal variation in order to unconfound small-scale temporal variation. The conclusions of this study are likely to be applicable to other water quality variables and pollutants.
采用嵌套分层抽样设计，对流入澳大利亚杰克逊港河口的三条河流中的颗粒态痕量金属（铜、铅和锌）及总悬浮固体（TSS）浓度的时间变化进行了研究。采样于1999年3月至6月在低流量条件下进行。采样设计包含四个时间尺度（小时、天、周和月）。认为小时、天、周和月代表了此类时间尺度，并且在方差分析（ANOVA）中可作为随机嵌套的变异源进行分析。在从同一天内的小时到月的时间尺度上均发现了显著变异。颗粒态痕量金属和TSS浓度之间以及不同河流之间的变异量和尺度有所不同。在许多情况下，小尺度之间的差异与月份之间的差异同样重要。结果表明，较高的人为影响在小时间尺度上导致更高的变异性。结果表明，有必要将嵌套抽样设计纳入时间变化研究中，以区分小尺度时间变化。本研究的结论可能适用于其他水质变量和污染物。
