The depth distribution of total Al, Fe, Mn, Zn, Cu, Cd, Pb, Ca, Mg, POC, and nitrogen were determined in sediment cores from a series of stations in the Tudor, Makupa and Gazi creeks of the Kenyan coast of the Indian ocean. The results indicates varying distributional profiles in the three creeks. Makupa creek shows the highest levels for the trace elements (Zn, Cu, Pb, andCd) analysed among the three creeks and this was attributed to increased recent anthropogenic loading in the creek. The concentration of trace metals increase towards the open sea in Tudor creek. Factor analysis of the correlation matrices suggests continental crustal source for Fe, Cu and Mg in Tudor and Makupa creeks while in Gazi creek it suggests crustal source for all the elements except Pb which was attributed to atmospheric input. Enrichment factors relative to the average crustal composition are defined and computed for all the cores. Large variations of crustal enrichments were observed for Tudor and Makupa creeks for trace metals. The high enrichments relative to the crust for the trace metals was attributed to recent anthropogenic loadings of the creeks. Pb was enriched in all the three creeks and its source was mainly attributed to atmospheric Pb input. The nature of POM in the sediments was assessed and it was found out that most of it was a contribution from the mangrove litter deposition in Tudor and Gazi creeks. |
