Abstract:
Lake Victoria (L. Victoria) is the largest African tropical and freshwater lake, with one of the
highest pollution levels, globally. It is shared among Uganda, Kenya and Tanzania, but it is drained
only by the river Nile, the longest river in Africa. Though environmental studies have been conducted
in the lake, investigations of the heavy metals (HMs) contamination of sediments from fish landing
sites and ports on the Ugandan portion of L. Victoria are limited. In this study, sediments of an urban,
industrial and fish landing site (Port Bell) on L. Victoria, Uganda was investigated to establish its
HMs pollution levels and potential health risks to humans and ecosystems. Sediment samples were
collected in triplicate (n = 9) from three different points of Port Bell, digested and analyzed using
atomic absorption spectrometry for the presence of these HMs: copper (Cu), lead (Pb), cadmium (Cd)
and chromium (Cr). The average daily dose through dermal contact and hazard quotient (HQ) were
calculated to assess the health risk that is associated with dredging works (lake sand mining). Four
geochemical enrichment indices: contamination factor (CF), geo-accumulation index (Igeo), pollution
load index (PLI) and potential ecological risk (PERI) were used to quantify the contamination of
the HMs in the sediments. The results showed that the mean HM content of the samples ranged
from: 6.111 ± 0.01 to 7.111 ± 0.002 mg/kg for Cu; from 40.222 ± 0.003 to 44.212 ± 0.002 mg/kg for
Pb; from 0.352 ± 0.007 to 0.522 ± 0.010 mg/kg for Cr; from 3.002 ± 0.002 to 3.453 ± 0.003 mg/kg
for Cd. Health risk assessments indicated that there are no discernible non-carcinogenic health
risks that could arise from the dredging works that are conducted in the study area as the indices
were all below one. The contamination factors that were obtained suggest that Cd has reached a
state of severe enrichment in the sediments (CF > 6). An assessment using Igeo established that the
sediments were not contaminated with regards to Cu and Cr, but they exhibited low-to-median and
median contamination with respect to Pb and Cd, respectively. Though the pollution load indices
show that the contamination levels raise no serious concerns, the potential ecological risk indices
show that there is considerable pollution of the Port Bell sediments, particularly with regard to Cd
