WHAT COULD WE UNDERSTAND BETTER? Ongoing environmental monitoring to identify potentially toxic and elevated trace metal concentrations in foods could be improved. Further, given the high levels of metals relative to existing health-based guidelines, quantitative risk assessments of neuro-toxic and other health outcomes among children should be undertaken. The treatment of exposure to mixtures of compounds should be further investigated as should methods for concurrently quantifying both the risks and benefits of given exposures. This would better inform ranking or weighing of risks and benefits across the entire farm-totable spectrum. Further studies are needed, especially into the accumulation of parasite eggs in the environment (such that repeated watering could result in increasing exposure). Also, the factors that lead to penetration of pathogens into vegetable tissues need further study, along with follow-up studies to the work of Amoah et al. on the relative effectiveness of feasible alternatives for treatment of surface-contaminated vegetables. Regarding Kampala farmers’ and consumers’ perceptions of poor taste of cocoyams under certain growing conditions in the wetlands, these should be investigated through further agronomic research. REFERENCES Amoah P, Dreschel P, Abaidoo RC & Klutse A 2007, ‘Effectiveness of common and improved sanitary washing methods in selected cities of West Africa for the reduction of coliform bacteria and helminth eggs on vegetables’, Tropical Medicine and International Health, vol.12 suppl.2, pp. 39-49.
BIOLOGICAL HAZARDS ASSOCIATED WITH VEGETABLES GROWN ON UNTREATED SEWAGE-WATERED HEALTHY HORTICULTURE SOILS IN KAMPALA IN CITIES
173 EDITORS’ COMMENTARY CHAPTER I X
Biological Contaminants: a. Sewage water is hazardous to health. Direct contact with contaminated water presents a health risk to farmers and to children accompanying them, and protective clothing needs to be worn, especially boots. Children should not be allowed to play with sewage water; b. Crops normally processed by cooking, heating or drying before human consumption (grains, yams, oilseeds, sugar beet) are recommended for growing in contaminated areas; c. Fears of pathogenic contamination of cocoyams – a popular staple in Kampala – are misplaced as any biological contamination would be killed by prolonged cooking; d. Growing crops that may be eaten raw, like tomatoes, lettuce, cabbages and onions, should be avoided in sewage-watered areas; e. Avoid contaminating food with pathogenic microorganisms: do not use dirty water to “refresh” market produce, but use only water from a clean source that is safe for drinking; f. Cooking vegetables grown using dirty water destroys most bacteria and the majority of parasite larvae, making them relatively safe to eat; and g. Produce can also be treated by blanching or disinfection with bleach or chlorine tablets to reduce bacterial loads.