GENOTOXIC EFFECTS OF MERCURY AND ZINC ON ACANTHAMOEBA SP, A FREE –LIVING AMOEBA FROM SETIU WETLANDS WATER: A LABORATORY STUDY

Heavy metals are stable in the environment and cannot be degraded or destroyed so they tend to build up in the atmosphere, soils, sediments and water. Excessive levels of metals in our environment will contribute pollution and pose a risk to humans and other living things, including Acanthamoeba. Acanthamoeba spp are free-living amoebae that are in abundance, especially in the aquatic environment. Their role as mainly a bacterial consumer indicates their importance in the food-web cycle of the ecosystem. Previous studies showed that heavy metals, like cadmium, lead, mercury and zinc, inhibited the growth of Acanthamoeba spp. Therefore, the objectives of the present study were to examine further the effects of mercury and zinc on Acanthamoeba sp, an amoeba isolated from water in Setiu Wetlands, by looking at the level of DNA damage in the amoeba cells. The amoebae were exposed to five different concentrations of the metals for 72h before the cytotoxic and genotoxic effects on the amoebae were observed. The IC50 values of mercury and zinc against the amoeba obtained in this study were 1.10 ppm and 39.00 ppm, respectively. The DNA damage with various score levels in Acanthamoeba cells by different concentrations of mercury and zinc treatment are presented and discussed.