Heavy metals contamination in soils and selected edible parts of free-range local chicken

A study was carried out to determine the levels of heavy metals [(arsenic (As), mercury (Hg), cadmium (Cd) and lead (Pb)] contamination in soils and edible parts of free-range local chicken (liver, muscle tissues and abdominal fat) collected randomly in three locations viz Tabata, Kigogo and Vingunguti located in Dar es Salaam city, Tanzania. Concentration of Pb in soils ranged from 5.304 to 7.529, Cd from 0.046 to 0.055, Hg from 0.034 to 0.060 and As from 0.239 to 0.329 ppm, respectively. Lead concentration in soils differed significantly (P ≤ 0.05) between locations. Differences in soil concentration of As, Hg and Cd between locations were not significant (P > 0.05). Heavy metal concentration in chicken parts differed significantly between locations (P ≤ 0.05). High lead concentration in chicken parts was registered in samples collected at Tabata than at Kigogo and Vingunguti. As and Cd concentration in soil and that in liver and Pb concentration in soil and that in muscle tissues were positive and significant correlated [(P ≤ 0.001) and (P ≤ 0.05)], respectively. Negative significant (P ≤ 0.05) correlation was observed between Hg concentration in soils and that in liver and between As concentration in soils and Hg concentration in muscle tissues. Results have shown that heavy metals contaminated in soils may find route into different tissues and organs parts of free-range local chicken; a health concern, hence, calls for safe disposal of industrial and domestic potential sources of heavy metal contamination in soils.