Pollution Status, Source Apportionment, Ecological and Human Health Risks of Potentially (Eco)toxic Element-Laden Dusts from Urban Roads, Highways and Pedestrian Bridges in Uganda
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Date
2021
Journal Title
Journal ISSN
Volume Title
Publisher
Cham: Springer International Publishing
Abstract
The occurrence of potentially (eco)toxic elements (PTEs) in street, indoor and roadside
dusts have been associated with potential human health risks. For the first time, the pollution levels of
PTEs—copper (Cu), nickel (Ni), manganese (Mn), zinc (Zn), lead (Pb), cadmium (Cd) and chromium
(Cr)—were investigated in 24 dust samples from eight selected sampling sites on urban roads, highways
and pedestrian bridges constructed over River Manafwa, a flood-prone river in Eastern Uganda.
Concentration of PTEs in the sample digests were quantified by atomic absorption spectrometry.
Multivariate geostatistical (Pearson’s Correlation, Principal Components and Hierarchical Cluster)
analyses were used to apportion sources of the contaminants. Contamination, ecological and human
health assessment indices and models were employed to establish any potential risks the elements
could pose to the environment and humans. The study revealed that there is severe PTE pollution of
dusts from roads, highways and pedestrian bridges in Eastern Uganda when compared with their
crustal averages, except for Cu, Ni and Cr. The mean concentrations (mg kg1) of Cu (11.4–23.2), Ni
(0.20–23.20), Mn (465.0–2630.0), Zn (26.8–199.0), Pb (185.0–244.0), Cd (0.178–1.994) and Cr (5.40–56.60)
were highest in samples obtained near high-traffic areas. Source apportionment studies suggested
that Cu, Ni, Mn and Cr are from combustion processes and vehicular traffic, whereas Pb, Zn and Cd
came from traffic and geogenic contributions. Assessment using the pollution load index indicated
that only dust from Zikoye–Bushika road, the junction of Zikoye–Bushika and Bududa–Manafwa
roads and Manafwa town were substantially polluted as the indices were greater than 1. Further
assessment of pollution degree of the dust samples using index of geo-accumulation revealed that the
dusts were practically uncontaminated to medium-to-strongly contaminated. Health risk assessment
showed that there are non-carcinogenic health risks that could emanate from direct ingestion of PTEs
in dusts by children. This study therefore opens the lead for investigation of the contamination levels
and the health risks of PTEs in dusts from industrial areas as well as busy Ugandan cities such as
Kampala, Jinja, Mbarara and Gulu.
Description
Keywords
Toxic metals, Particulate matter, Pedestrian bridges, Highways, Cancer risk, Target hazard quotient
Citation
Opolot, M.; Omara, T.; Adaku, C.; Ntambi, E. Pollution Status, Source Apportionment, Ecological and Human Health Risks of Potentially (Eco)toxic Element-Laden Dusts from Urban Roads, Highways and Pedestrian Bridges in Uganda. Pollutants 2023, 3, 74–88. https://doi.org/10.3390/ pollutants3010007