RELEVANCE OF INTERSTINAL HELMINTH PARASITES OF Parachanna Obscura and Sarotherodon Melanotheron ON THE HOST METAL ACCUMULATION IN LEKKI LAGOON, LAGOS, NIGERIA

Abstract

This paper assesses the role of intestinal helminth parasites of Parachanna obscura and Sarotherodon melanotheron on host metal accumulation in Lekki Lagoon, Lagos, Nigeria.  Heavy metal concentrations were determined I water, sediment, intestinal parasites, liver and gill of infected and non-infected individuals of the fishes.  Water sediment, intestinal parasites, the liver and gill were analyzed using Atomic Absorption Spectrophotometer to determine concentrations of iron, cadmium, lead, nickel, zinc and copper.  The parasites of Parachanna obscura, Procamallanus sp and Spirocamallanus sp accumulated less metals compared to their host tissues. Procamallanus sp and Spirocamallanus sp did not accumulate zinc and lead respectively while Procamallanus sp only accumulated more lead than the host organs.  The parasite of Sarotherodon melanotheron, Clinostomum sp, a trematode larva, accumulated more concentration of cadmium and zinc (mg/1), 0.33+0.26, 8.31 +1.83respectivelywhile Procamalanus sp only accumulated more lead than the host organs.  The parasite of Sarotherodon melanotheron, Clinostomum sp, a trematode larva, accumulated more concentration of cadmium and zinc, (mg/1), 0.23+ 0.26, 8.31+ 1.83 respectively compared to the host liver, cadmium (mg/1), 0.01 + zinc(mg/1), 4.92 +1.43. Infected individuals of Parachanna obscura accumulated more metal concentrations in their tissues compared to non-infected ones. This is because their parasites, Procamallanus sp and Spirocamallanus sp have very low bioaccumulation potential for metals such as iron, nickel, cadmium, zinc and copper except lead.  These parasites had similar concentrations of these metals in their tissues as that contained in the water and sediment media.  Infected individuals of Sarotherodon melanotheron accumulated more of iron, nickel, zinc and copper, while the non-infected one accumulated more of cadmium and lead.  Its parasite, Clinostomum sp, accumulated 23 times more cadmium and twice more zinc.  This parasite must have accumulated these metals from its host, reducing the concentration of these metals in the tissues of the infected fishes compared to non-infected present.  Integration of multiple stressors increases accumulation of heavy metals in fish tissues, an indicator of susceptibility as shown in this study.