Health and ecological risk assessment of heavy metals in water and sediments within a data scarce urban catchment in Tanzania – A case of Ngerengere River, Morogoro Municipality
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Date
2024-05-03
Journal Title
Journal ISSN
Volume Title
Publisher
MEDCRAVE
Abstract
Low-, middle- and high-income countries, exhibit indications of risks associated with water
quality. The study investigated heavy metal concentrations in surface water and sediments
within the Urban catchment of the Ngerengere River in the Morogoro Municipality of
Tanzania, an Urban Catchment Area (UCA) with limited available data mainly because of
inadequate monitoring and reporting capabilities. Analysis of health and ecological risks
associated with heavy metal pollution was also carried out using health risk assessments
models, pollution indices, and multivariate analysis techniques. Between the dry and wet
seasons of 2023, water and sediment samples from (13) sampling stations strategically
established along the Ngerengere river and its tributaries were analyzed for six heavy
metals (Pb, Cr, Ni, Cd, Cu and Zn) using the Atomic Absorption Spectrophotometer Model
Perking Elmer 850 Graphite Furnace and Perking Elmer AS 800 Auto-sampler coupled
with a computer interface for operational, displaying and reading the results. The calculated
degree of water contamination (Cd) values in river water in both dry and wet seasons ranged
from 0 to 6.803 indicating low and high degrees of contamination respectively. Heavy
metal concentration in sediment decreases in the order of Zn>Ni>Cr>Cu>Cd>Pb. The non-
cancer risk index (HI) via ingestion and dermal pathways in dry and wet seasons for both
children and adult groups was <1 hence no non-cancer risk, However, cumulative dermal
and ingestion exposure in both children and adults indicated potential cancer risk in dry
and wet season. The analysis of ecological risks associated with heavy metal enrichment in
the sediment indicated high enrichment of sediments with Cd, Ni and Zn. Conclusively, in
wet months, risk indices tend to be low, while in dry months, they typically remain high
Description
Research Article, PP. 72-87
Keywords
Heavy metal, Sediment, Health risk, Ecological risk, Ngerengere river, Tributaries
Citation
10.15406/mojes.2024.09.00309