Responses to lead in the freshwater isopods Asellus Aquaticus and A. Meridianus

There is now an increasing awareness of the deterioration of the environment caused by human activities and much research and debate has centred on this subject in recent years. Current and Increasing concern is focused on the release of heavy metals into the environment. In aquatic environments, the concentrations of heavy metals are generally very low, although higher natural concentrations occur in rivers and estuaries which are associated with outcropping metalliferous lodes. As a result, the concentrations of heavy metals in natural waters can easily increase to levels that aquatic organisms have not previously encountered. The introduction of metals by industrial effluents and domestic sewage (Holdgate 1979) and aerial fallout (Peyton et aI. 1976) to aquatic environments can cause heavy metal loads to rise far above natural levels, with subsequent effects on the ecology of the area concerned. In view of this, it was decided to concentrate on the heavy metal lead, in the investigations, because of its potential role as an environmental pollutant caused by its release into the environment. The freshwater isopods, AselIus aquaticus and A. meridianus were used in the study and experiments concerned with the effects of acute lethal and sub lethal concentrations of lead on various aspects of the physiology of the two species were carried out.