Levels of aluminium, arsenic, cadmium, chromium, copper, iron, mercury, manganese, nickel, lead and zinc in tap water, groundwater-fed protected spring and bottled water were determined. The cancer and non-cancer risks associated with ingestion of heavy metals (HM) were also assessed for both children and adults. Forty seven water samples obtained from five divisions of Kampala city were analyzed using atomic absorption spectrophotometry. Cancer and non-cancer risks were determined using incremental lifetime cancer risk (ILCR) and non-carcinogenic hazard quotient (HQ), respectively. Lead content was higher than permissible limits (PL) according to East African Standard, World Health Organization, European Union and United States Environmental Protection Agency (USEPA). Arsenic showed minor exceedances above guideline values in tap water and groundwater-fed protected spring, whereas mercury, manganese and nickel were higher than PL. Levels of aluminium, cadmium, chromium, copper, iron, and zinc were below the PL. The lifetime risk of developing cancer through the oral route was greater than the USEPA acceptable level for both children and adults, revealing that exposure to HM in drinking water posed an unacceptable potential cancer risk. Arsenic contributed ca. 90% of the ILCR in tap water and groundwater-fed protected spring. The combined non-cancer risk of the HM expressed as hazard index (HI) was greater than one, with values for children being higher than those for adults. Lead contribution towards HI was in all cases above 90%. These results demonstrate the presence of alarming non-cancer risks for children.

Tea (Camellia sinensis (L.) Kuntze) is among the most widely consumed non-alcoholic beverages. It is a rich source of essential dietary elements mainly potassium and manganese. Tea may also contain toxic metals such as cadmium and lead which pose a threat to human health because of their toxicity. Twenty samples of commercial black tea in Kampala city were randomly obtained and analysed for potassium, sodium, aluminium, arsenic, cadmium, chromium, copper, iron, mercury, manganese, nickel, lead and zinc using Atomic Absorption Spectrophotometry. Human health risks due to exposure to toxic elements from daily consumption of tea were determined using incremental lifetime cancer risk and non-cancer hazard quotient. Metal contents of black tea sold in Kampala were below international regulatory limits. The estimated daily intake of the elements in two grams of black tea was below the recommended values. Hazard quotient and hazard index were within acceptable range. Total cancer risk levels for all the teas were also within United States Environmental Protection Agency (USEPA) acceptable range. Daily consumption of one cup containing two grams of black tea over a lifetime will promote consumer overall health and wellbeing.

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Purpose The aim of this paper is to investigate fat content and fatty acid profile of cultivated (Pleurotus ostreatus) and wild edible mushrooms (Amanita spp and Termitomyces microcarpus). Design/methodology/approach Pleurotus ostreatus was grown in soil and on cotton seed husks in mushroom growing rooms at Busitema University, Uganda. T. microcarpus and Amanita spp were collected from the wild. Freshly harvested mushrooms were dried at 60°C for 48 h in a hot air oven. Oil was extracted using a Clevenger apparatus. Fatty acid analysis was done using gas chromatography with flame ionization detection. Findings Fat content ranged between 0.24 and 5.23 per cent. Variation was noted between P. ostreatus grown in soil and on cotton seed husks (p = 0.0090). Similarly, Amanita spp and T. microcarpus had differing fat contents (p = 0.0098). Polyunsaturated fatty acids (PUFA) predominated over saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA). Linoleic acid (LA) was the most abundant fatty acid (FA) (30.91 to 54.35 per cent). It varied between Amanita spp and T. microcarpus (p = 0.0001) but not between substrates (p = 0.1891). Ratios of PUFA/SFA, MUFA/SFA and PUFA/MUFA were within the desirable ranges. Omega-6 FA/ω-3 FA ratio was higher than that recommended for a healthy diet. However, the low amount of fat in mushrooms suppresses the negative effects of a high ω-6 FA/ω-3 FA ratio. Originality/value Information on FA profile of cultivated and wild edible mushrooms will provide a basis for commercial exploitation of the cultivated mushrooms. This work showed that P. ostreatus, Amanita spp and T. microcarpus are healthy foods with regard to the low fat content and high amounts of LA.