Spatial and temporal variations of heavy metal contamination in sediments of a mangrove swamp in Hong Kong

摘要: Abstract Spatial and temporal variations of heavy metal contamination in sediments a small mangrove stand Hong Kong were examined by laying two transects perpendicular across the shore. Surface sediment samples taken along running landward to seaward at intervals 5 or 10 m during December 1989, March, July September 1990. Total concentrations Cu, Zn, Mn Pb did not show any specific trend each transect, although maximum concentration metals tended occur edge. There was high level variability among locations within transect; for instance, Cu fluctuated from 1 42 μg g−1. Certain sites contained exceptionally levels total metals. as 42, 150, 640 650 g−1, respectively, recorded, implying contaminated sediment. A comparison indicated that Transect B seemed contain higher Zn but lower than those A. Most accumulated extractable with ammonium acetate no detected these extracts. The low, less 10% sediment, appeared decrease samples. For both metals, there significant seasonal fluctuations transects, trends could be identified. These spatial suggest scale representativeness sampling require careful planning, single sample might give satisfactory evaluation ecosystems.