Microbial and chemical contamination of water, sediment and soil in the Nakivubo wetland area in Kampala, Uganda

Abstract

The reuse of domestic and industrial wastewater in urban settings of the developing world may harm the health of people through direct contact or via contaminated urban agricultural products and drinking water. We assessed chemical and microbial pollutants in 23 sentinel sites along the wastewater and faecal sludge management and reuse chain of Kampala, Uganda. Water samples were examined for bacteria (thermotolerant coliforms (TTCs), Escherichia coli and Salmonella spp.) and helminth eggs. Physico-chemical parameters were determined. Water, sediment and soil samples and edible plants (yams and sugar cane) were tested for heavy metals. Water samples derived from the Nakivubo wetland showed mean concentrations of TTCs of 2.9 × 105 colony-forming units (CFU)/100 mL. Mean E. coli was 9.9 × 104 CFU/100 mL. Hookworm eggs were found in 13.5 % of the water samples. Mean concentrations of iron (Fe), copper (Cu) and cadmium (Cd) were 21.5, 3.3 and 0.14 mg/L, respectively. In soil samples, we found a mean lead (Pb) concentration of 132.7 mg/L. In yams, concentrations of Cd, chromium (Cr) and Pb were 4.4, 4.0 and 0.2 mg/L, while the respective concentrations in sugar cane were 8.4, 4.3 and 0.2 mg/L. TTCs and E. coli in the water, Pb in soil, and Cd, Cr and Pb in the plants were above national thresholds. We conclude that there is considerable environmental pollution in the Nakivubo wetland and the Lake Victoria ecosystem in Kampala. Our findings have important public health implications, and we suggest that a system of sentinel surveillance is being implemented that, in turn, can guide adequate responses.

Antimicrobial resistance of Escherichia coli found in intestinal tract of Oreochromis niloticus

“…antibiotics are those commonly used for treatment of various ailments in humans, thus strongly supporting the theories of introduction into the aquatic ecosystems from human associated sources. Studies along the Nakivubo channel in Uganda revealed presence of antibiotic residues in sediments, water and soil (Owino, 2014;Fuhrimann et al, 2015) with very low levels of gentamicin and ceftriaxolne which we also found were effective in this study.…”

Egg genotyping reveals the possibility of patent Ancylostoma caninum infection in human intestine

“…It has also to be considered that the potential uptake of animals A. caninum eggs does not necessarily mean that relevant amounts of animals faeces need to be taken up, since eggs may have been attached to food. In fact, many studies report the presence of hookworm eggs in food 43,44 and also in water 45 . However, this a very low probability since twelve A. caninum eggs were found in the respective patient.…”

Microbial contamination along the main open wastewater and storm water channel of Hanoi, Vietnam, and potential health risks for urban farmers

“…Such a system ideally includes both microbial and chemical indicators and is coupled to a pre-defined response for the event that parameter values are above set limits. Such an early warning system would not only allow to recognise trends and seasonal variability of specific health hazards but also enhance a more proactive protection of urban farming communities and consumers of their produce (WHO, 2006;Fuhrimann et al, 2015).…”