Harmful Elements in Estuarine and Coastal Systems

Estuaries and coastal zones are dynamic transitional systems which provide many economic and ecological benefits to humans, but also are an ideal habitat for other organisms as well. These areas are becoming contaminated by various anthropogenic activities due to a quick economic growth and urbanization. This chapter explores the sources, chemical speciation, sediment accumulation and removal mechanisms of the harmful elements in estuarine and coastal seawaters. It also describes the effects of toxic elements on aquatic flora and fauna. Finally, the toxic element pollution of the Venice Lagoon, a transitional water body located in the northeastern part of Italy, is discussed as a case study, by presenting the procedures adopted to measure the extent of the pollution, the impacts on organisms and the restoration activities

Behaviour of dredged mud after stabilization with different additives

Mechanical stabilization methods for improving chemical stability of contaminated dredged material used for upland disposal are presented. Assessments of long term environmental consequences involving effects on heavy metal immobilization, TOC, COD, BOD, anion release, gas production and -composition after addition of lime, calcium carbonate, cement, coal fly ash and gypsum to fine grained Hamburg harbour sediments have been studied. Best results are attained with CaCO3 dure to insitu pH conditions and sufficient buffer capacity, which is of prime importance for metal immobilization and gas production