Heavy metal contamination in urban agriculture: evidence from Nairobi

Urban Farm DB summary

A study that randomly sampled leafy greens from farms across Nairobi, Kenya, and measured lead, cadmium and mercury. Mean concentrations were 0.68 ppm lead, 0.09 ppm cadmium and 0.11 ppm mercury; plots closer to roads had higher lead and plots near industrial sites had higher mercury. Leafy greens alone pushed 71% of adults and 69% of children above safe lead exposure limits, and 52% of adults above the mercury limit. Comparison greens sourced from outside Nairobi were similarly contaminated, so the authors do not treat contamination as unique to urban farming and instead call for systematic food surveillance in low- and middle-income countries.