ABSTRACT
Aquatic sediments are a mixture of different organic and inorganic matter. The organic matter consists of micro-organisms, the remains of macrophytes and other large-sized organisms, and detritus from decaying material. The inorganic matter consists of mineral grains, small rock particles, clay minerals, precipitates and coatings. Sediments may contain a great variety of contaminants reflecting the industrial, agricultural and municipal discharges of the drainage area. Some sediments have naturally occurring concentrations of various substances, for instance metals from the “parent” rock, which may or may not pose risks to aquatic organisms and human health, depending on bio-availability.
