Environmental Health Risks Due to Anthropogenic Metals in Mtoni Estuary Ecosystem and its Environs, Tanzania

Abstract

Mangrove sediment samples from Kizinga and Mzinga creeks of Mtoni estuary were analysed for metals (Al, Fe, Mn, Cr Ni, Cu, Zn, As, Sr, Cd and Pb) to determine their current levels and their anthropogenic impact in a tropical estuarine environment. Standard sampling techniques were used. Samples were digested using a CEM Microwave Accelerated Reaction System (MARS) and analysis was carried out using a High Resolution Inductively Coupled Plasma Mass Spectrometer (HR-ICP-MS). Sandy particles were dominant, with < 6% of OM in estuary and < 9% in tributaries. Metal levels showed neither distinct depth gradient nor variation between seasons. A clear gradient from upstream of Kizinga and Mzinga rivers to estuarine mouth was observed. Pearson correlation matrix, Principal component analysis (PCA) and Enrichment factors (EF) indicated that most metals in Mtoni estuary probably originated from anthropogenic activities except Sr that was probably derived from natural origin. Levels of anthropogenic pollutants are indicative of human induced environmental change and have repercussions on environmental and human health as well as future status of estuary.