Biochemistry of micro-polutants in sediments of Mtoni estuary, Tanzania
type: CreativeWork
description: In order to describe and evaluate the past and current status, and predict the future status of mangrove ecosystem in relation to changing human activities in the coastal areas and its environment in Tanzania, mangrove sediments from the Mtoni estuary were analysed for elemental (C, N) and isotopic (δ13C, δ15N) signatures to establish the role of anthropogenic influence on the contribution of organic carbon and nitrogen in the tropical mangrove sediments. Moreover, metals, PCDD/Fs and dioxin-like PCBs were analysed to describe their current sources and fates in response to anthropogenic and natural changes. Lastly, the study intended to determine and compare the variability in the distribution of potential micro-pollutants in the mangrove sediments of Tanzanian coast. Sandy particles dominated the mangrove sediments, with less than 6% of organic matter (OM) in the estuary and less than 9% in the tributaries. Similarities in the levels of total organic carbon (TOC) and total nitrogen (TN) with depth were observed at all stations, indicating a homogenous, well-mixed top 9- cm sediment layer. A clear gradient of TOC and total nitrogen (TN) levels from the riverine (Kizinga and Mzinga) stations to the estuarine mouth was observed with highest content in most upstream stations and decreasing towards the mouth of the estuary. No clear seasonal trend of C/N ratio was observed except in the confluence region where the ratios were higher in wet than dry season. Wet season δ15N values were lower while δ13C values were higher compared to dry season values for all the stations. Mzinga δ15N values were higher than Kizinga values in both seasons while the opposite was observed for δ 13C, but all were lower than the confluence values. Correlations of the geochemical parameters for both wet and dry seasons suggest that OM in Mtoni sediments originated mainly from sources that are 15N enriched and 13C depleted and are linked to OM degradation processes. Combined elemental and isotop…
abstract: In order to describe and evaluate the past and current status, and predict the future status of mangrove ecosystem in relation to changing human activities in the coastal areas and its environment in Tanzania, mangrove sediments from the Mtoni estuary were analysed for elemental (C, N) and isotopic (δ13C, δ15N) signatures to establish the role of anthropogenic influence on the contribution of organic carbon and nitrogen in the tropical mangrove sediments. Moreover, metals, PCDD/Fs and dioxin-like PCBs were analysed to describe their current sources and fates in response to anthropogenic and natural changes. Lastly, the study intended to determine and compare the variability in the distribution of potential micro-pollutants in the mangrove sediments of Tanzanian coast. Sandy particles dominated the mangrove sediments, with less than 6% of organic matter (OM) in the estuary and less than 9% in the tributaries. Similarities in the levels of total organic carbon (TOC) and total nitrogen (TN) with depth were observed at all stations, indicating a homogenous, well-mixed top 9- cm sediment layer. A clear gradient of TOC and total nitrogen (TN) levels from the riverine (Kizinga and Mzinga) stations to the estuarine mouth was observed with highest content in most upstream stations and decreasing towards the mouth of the estuary. No clear seasonal trend of C/N ratio was observed except in the confluence region where the ratios were higher in wet than dry season. Wet season δ15N values were lower while δ13C values were higher compared to dry season values for all the stations. Mzinga δ15N values were higher than Kizinga values in both seasons while the opposite was observed for δ 13C, but all were lower than the confluence values. Correlations of the geochemical parameters for both wet and dry seasons suggest that OM in Mtoni sediments originated mainly from sources that are 15N enriched and 13C depleted and are linked to OM degradation processes. Combined elemental and isotop…
author: Mihale, M.J.
language: en
keywords: 540 Chemistry & allied sciences
date published: 2013
date modified: 2026-07-24T03:40:41Z
provider: Open University of Tanzania
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Vrije Universiteite Brussel