Sediment Composition across different Land uses as an Environmental Quality Indicator in the Catchment of Tropical man-made Reservoirs

Abstract

his study evaluates anthropogenic enrichment of reservoir bottom sediments by trace
elements and nutrients to indicate the environmental quality of tropical reservoirs with
differing surrounding land uses - commercial and institutional. We assess the toxic level of
sampled sediment in determining the degree of pollution, and its potential effects on human
health and the aquatic ecosystem. The trace elements and nutrients of bottom sediments were
obtained from reservoirs using standard methods at seven different stations. The ecotoxicological analysis of trace elements and nutrients in sediment samples suggests a high
toxic level due to the presence of Cd, Pb, and Cu. An Analysis of Variance (ANOVA) test
shows a significant difference in the concentration of trace elements and nutrients across the
sampled stations; F (7, 48) = 207.032, p < .05. The Wilcoxon W. test conducted indicates
that there is no significant difference between the examined reservoirs in ecological toxic risk
conditions, Ws = 50, z = −0.319, p>0.05. The results of various environmental indices
suggest poorer environmental quality in the commercial catchment area compared with the
institutional one. This study shows that anthropogenic activities have a significant impact on
the composition of reservoir bottom sediments – and thus sediment composition could serve
as an indicator of the impact of land-use changes and corresponding environmental quality
within reservoir catchments, especially in tropical developing economies where multiyear
environmental monitoring data is sparse.