M. Dassenakis et al., TRACE-METALS IN SEDIMENTS OF A MEDITERRANEAN ESTUARY AFFECTED BY HUMAN ACTIVITIES (ACHELOOS RIVER ESTUARY, GREECE), Science of the total environment, 168(1), 1995, pp. 19-31
Trace metals were studied in the sediments of the ecologically, econom
ically and scientifically important estuary of the Acheloos river, in
western Greece. Human activities (dams, agriculture, traffic, etc.) in
fluence the estuarine system of Acheloos and in combination with the h
ydrological, mineralogical and morphological characteristics of the es
tuary affect the chemical behaviour and the distribution patterns of t
race metals in its sediments. The large scale disturbance of the syste
m is imminent in the near future as it is planned to divert similar to
50% of the river water. A study of the distribution patterns of trace
metals revealed that in the estuary there are zones with different me
tal levels. The concentrations of most metals (Al, Fe, Cu, Ni, Zn) are
elevated in three of these zones (upstream, sill, seawards). A differ
ent behaviour was observed for Mn due to its association with carbonat
es that were observed in significant concentrations throughout the est
uarine zone. A sequential extraction procedure, applied to the sedimen
ts, indicated low percentages of easily exchangeable metals, increased
mobility of Cu and Zn and increased association of Ni, Cr and Fe with
the aluminosilicate lattice. Although the river is not considered to
be heavily polluted, some metals have shown an enrichment in the surfa
ce sediments as a result of general anthropogenic activities not deriv
ed from point sources.