Benthic foraminiferal distributions in polluted marine areas have been investigated over the last three to four decades, and several workers have pointed out that they provide one of the most sensitive and inexpensive markers available for indicating deterioration of marginal marine environments, Most investigations have been carried out in temperate regions, in areas exposed to several pollution sources, However, environments characterized by organic waste contamination (e.g., sewage or paper and pulp mills) have been addressed more frequently than areas exposed to oil, thermal and various other kinds of pollution. Among the most abundant species close to many outfall areas in temperate regions are Elphidium excavatum and/or Eggerella advena (NW Atlantic)/Eggerelloides scabrus (NE Atlantic), The dominant tolerant or opportunistic: species seems to depend on local hydrographical properties rather than type of effluent, Increased abundance, due to increased nutrient concentrations and reduced predation and competition, is often recorded in areas having high organic inputs, Such abundance aureoles may be separated from outfall centers by an area of strongly reduced abundance or, in severe cases, by a dead zone, Characteristic features of proximal areas include decreased diversity and increased dominance of tolerant or opportunistic species compared to distal areas, Whether agglutinated or calcareous forms dominate seems to depend on the local hydrography, acidity of the sediment porewater and whether living, dead or total (living + dead) assemblages are considered. Test deformation in foraminifera is known from the geological record, In modern environments, deformation occurs more frequently in polluted than in non-polluted areas, Whether different kinds of test deformation develop under pollution- versus naturally-induced stress and what kind of stress properties cause deformations have not yet been established. Differential adaptions to the complex, and in many cases unique, hydrographical and physical conditions that characterize estuarine environments often make it difficult to separate natural faunal properties from pollution effects, especially in a temporal context, Consequently, pollution effects on the biota in estuaries can best be evaluated by comparing the natural, pre-pollution assemblages with those of the present day, The presence of empty foraminiferal tests in sediment cores penetrating through contaminated intervals provides this kind of information, but possible diagenetic alterations of the original assemblages must always be considered, The fossil record can also provide a comparative baseline for evaluating to what extent legislation, intending to cause environmental improvements, has had a positive effect.
