ABSTRACT

A mathematical model was developed describing the influence of toxicants upon aquatic ecosystems. Computer simulations were conducted to find an optimal size for experimental systems in ecotoxicological studies, and to assess possibilities of extrapolating data obtained in a small scale laboratory system to natural water bodies. Large size systems are more relevant to study the effects of a toxicant at low nutrient levels, but the effect is still seen in small systems. At high nutrient levels systems of all sizes become equally sensitive to the toxic influence. Taking into account the greater cost of larger experimental units, small systems may be preferable. When working with a lipophilic toxicant, it should be borne in mind that the real toxicant effect on a large natural system may be much greater than the effect observed on a small experimental system.