SEDIMENT QUALITY OBJECTIVES AND CRITERIA DEVELOPMENT IN GERMANY

New objectives regarding the improvement of water quality as well as p roblems with the resuspension and land deposition of dredged materials require a standardized assessment of sediment quality. Numerical appr oaches are based on the accumulation, pore water concentrations, solid /liquid partition and elution properties of contaminants; these non-bi ological schemes can be extended and completed by additional biologica l criteria. Specific biological approaches have been combined with che mical surveys (for example Sediment Quality Triad). In Germany, numeri cal criteria are based on the background approach. Biological criteria approaches include bioassays on sediment, porewater and elutriates; r ecent developments are directed towards microbial solid phase bioassay s. Special emphasis is placed on the characteristics of the mineral an d organic solid substrate, in particular, buffer capacity against pH-d epression; these components should be classified on the basis of the c arbonate and sulfide inventories.