DEVELOPMENT OF SEDIMENT-QUALITY CRITERIA - A PROPOSAL FROM EXPERIMENTAL FIELD STUDIES OF THE EFFECTS OF COPPER ON BENTHIC ORGANISMS

Very few of the numerous studies of the effects of copper on animals l iving in marine sediments have involved manipulative field-experiments . Such experiments provide greater realism than laboratory-based studi es in terms of environmental variability or complexity, but the otherw ise confounding effects of this variation can be removed by random all ocation of treatments to experimental units. We describe an experiment in sandy sediments in Botany Bay, NSW, Australia, in which concentrat ions of copper in the sediments were manipulated using blocks of plast er impregnated with copper sulphate. Replicate copper-enhanced and con trol treatments were randomly allocated to experimental units. Thus, a ny differences among treatments in the patterns of change in their fau nas can be unambiguously ascribed to the copper treatment, The use of manipulative field-experiments is discussed in the context of the deve lopment of sediment-quality criteria.