Assessment of Heavy Metal Bioaccumulation in Spinach, Jute Mallow and Tomato in Farms Within Kaduna Metropolis, Nigeria

Urban Farm DB summary

Soil and vegetable samples (spinach, jute mallow, and tomato) were collected from farms and gardens across 20 zones within Kaduna, Nigeria, plus two rural control villages about 30 km from the city, and analyzed for heavy metals by Flame Atomic Absorption Spectrophotometer. Pollution Load Index results showed soils in the city farms were moderately enriched with cadmium and chromium and strongly enriched with lead and nickel from anthropogenic sources. Mean soil concentrations of lead and cadmium exceeded WHO/FAO permissive limits for agricultural soil (nickel and chromium did not), while vegetable metal concentrations exceeded the permissive limits for every metal except nickel — a finding flagged as concerning given the toxicity of lead and cadmium in particular, which have no known biological use.