SPATIAL VARIATION IN CONCENTRATIONS OF HEAVY-METALS IN MARINE-SEDIMENTS

Spatial variation in the distribution of copper, lead and zinc in sedi ments in Botany Bay, Australia, is described. Sampling was done accord ing to a nested, hierarchical design, and variation was detected at sp atial scales from 10 m to several kilometres. In studies where the des ign of sampling is inadequate, the existence of variation at small spa tial scales will confound comparisons at larger scales. Adequate repli cation at different scales, necessary to avoid confounding, has rarely been done in published studies. Implications of 'patchiness' for envi ronmental sampling and monitoring, and the means of overcoming associa ted problems, are discussed.