| dc.description.abstract | Heavy metals retained in sediments pose a threat to aquatic ecosystem and society. Knowledge of the status and sustainability of lake sediment in areas undergoing rapid economic development is scarce, and yet it is required in order to
achieve the United Nations Sustainable Development goals. We investigated heavy metal concentration in Lake Naivasha
sediments using enrichment factor, geoaccumulation index, pollution load index (PLI), risk index (RI) and multivariate
statistics to determine metal accumulation, distribution and the lake’s pollution status. Sediments sampling followed a
grid approach, and seven heavy metals: Co, Cr, Cu, Mn, Pb, Zn and Fe, were analyzed in total; concentrations were determined using portable X-ray fuorescence. The distribution maps were interpolated in a GIS platform, and the toxicity risk
of sediments was determined. The concentrations of elements in the sediments are in the following decreasing order:
Fe>Mn>Zn>Cu>Cr>Co>Pb. High concentration of heavy metals is found in the southern shoreline and east of the
lake due to shoreline discharge and agricultural efuents drained into the lake and shoreline transgression. Pb and Zn
are of anthropogenic origin, while Cu and Mn originate from both natural and anthropogenic sources and Fe and Co are
from natural sources. In addition, the mean toxicity decreases in the order: Cu>Fe>Co>Pb>Zn>Mn>Cr. The PLI values
were above one (>1), indicating progressive deterioration of the sediment quality. Though the overall ecological risk of
the lake is low to moderate (RI 36.73–60.51), hotspots of pollution should be marked for intervention. This assessment
also helps to fll the knowledge gap required to formulate the right policies in implementing sustainable development
goals in similar lakes | en_US |
