Water quality of the volcanic crater lake, Lake Barombi Kotto, in Cameroon

Abstract

Cameroon is endowed with many freshwater lakes and rivers but, because of increasing anthropogenic activities, most of these water bodies are gradually being degraded. Lake Barombi Kotto is one of the volcanic crater lakes in Cameroon that serves as a prime source of drinking water for the Barombi Kotto community. The overall objective of the study was to determine the water quality of Lake Barombi Kotto making use of some physico-chemical parameters, Carlson’s Trophic State Index (TSI), Heavy Metal Pollution index (HPI) and some bacteriological parameters. Water samples were collected over two seasons across a longitudinal transect at two depths and subjected to physico-chemical, bacteriological, nutrient, Chlorophyll a and phytoplankton analyses using standard methods. Descriptions, Analyses of Variance, ordinations and correlations were used to analyse resulting data at α = 0.05. Lake Barombi Kotto had a TSI of 93.67 and 87.92 in the dry and rainy season, respectively, indicating it is eutrophic. Of the six heavy metals studied, only the concentration of Fe was above the WHO (2008) drinking water quality limits. The HPI of the lake was 4.17 and 6.19 for the dry and rainy seasons, respectively, well below the critical index limit of 100. This lake is contaminated with faecal coliforms and pathogenic bacteria, such as Salmonella. This study has not only set baseline conditions for additional monitoring, but has exposed key dynamics and significant socio-economic and public health risks to humans.

Keywords: heavy metal pollution, Lake Barombi Kotto, microbiological contamination, Microcystis spp., pollution index, trophic state