Assessing the level of lead in maize bran used to make animal feeds in Kalisizo Sub County, Kyotera District

Abstract

Maize bran, a by-product of maize milling, is widely used as a feed ingredient for livestock in Uganda due to its affordability and nutritional value. However, concerns have emerged over its contamination by heavy metals, especially lead (Pb), which poses health risks to animals and humans through the food chain. The World Health Organization (WHO) and Food and Agriculture Organization (FAO) set the permissible limit for lead in cereals at 0.2 mg/kg. There is limited local data on the presence and variability of lead in animal feeds, particularly in rural Ugandan settings like Kalisizo Sub-County, Kyotera District. Objective: To assess the level of lead contamination in maize bran used for animal feeds in Kalisizo Sub-County, Kyotera District. A cross-sectional study design was employed. A total of 20 maize bran samples were collected from milling sites across seven wards in Kalisizo Sub-County. Samples were prepared using standard drying, ashing, and acid digestion techniques. Lead concentrations were measured using Flame Atomic Absorption Spectrophotometry (AAS). Data was statistically analysed using SPSS, with comparisons made to WHO/FAO permissible limits and inter-ward differences assessed using ANOVA and Bonferroni post hoc tests. The mean lead concentration across all samples was 0.15 mg/kg, ranging from 0.06 to 0.23 mg/kg. Sixteen out of 20 samples (80%) were within the WHO/FAO permissible limit. However, 4 samples (20%), primarily from Kyango and Kalisizo Town, met or slightly exceeded the 0.2 mg/kg threshold. Statistically significant differences (p < 0.001) were observed in lead concentrations between wards, with higher contamination in more urbanized areas (Kyango, Kalisizo Town) and lower levels in rural wards (Miti, Kikungwe, Kakoma). While overall lead concentrations in maize bran from Kalisizo SubCounty are within safe limits, specific urban and peri-urban wards show contamination at or above the permissible threshold. These localized risks highlight the need for targeted monitoring and regulatory oversight to prevent lead exposure through the food chain.