Effect of manganese and iron at a neutral and acidic pH on the hematology of the banded tilapia (Tilapia sparrmanii).

Abstract

The pollution of natural water bodies is a common phenomenon in developing countries. Increases in population densities lead to increased mining and industrial activities in the area. With the establishment of gold and coal mines in South Africa, several industrial zones were created to support the mining industry. Many of these industries consist of heavy metal processing factories. Over the years pollution from the mines has led to acidification of the streams and lakes in the Transvaal. It was also found that high concentrations of heavy metals occurred in the water, sediments, plants and fish tissue in the affected water systems. Of all the heavy metals, iron and manganese were found in the highest concentrations. In order to determine the subtle, non-lethal effects induced by sublethal concentrations of heavy metals on the physiology of fish, it is necessary to monitor certain clinical parameters. The use of hematological methods as indicators of sublethal stress can supply valuable information concerning the physiological reactions of fish in a changing environment. The reason for this is the close association between the circulatory system of the fish and the external environment. The objective of the present paper was to evaluate the effects of manganese andmore » iron at a neutral and acidic pH on the hematology of Tilapia sparrmanii. 19 refs., 2 figs.« less