Spatial Variation of Soil Lead in an Urban Community Garden: Implications for Risk‐Based Sampling

Urban Farm DB summary

This study examined small-scale spatial variability of soil lead within a 15 × 30 m urban community garden plot on two adjacent residential lots in Detroit, Michigan, analyzing 80 samples for total, fine-fraction, and bioaccessible lead. Concentrations varied at 1–10 m scales with a hot spot exceeding 400 ppm, and Monte Carlo simulations showed that increasing sample numbers reduces the chance of missing hot spots while compositing reduces overestimation of the mean. The authors suggest US EPA sampling objectives and guidelines should be reconsidered for reclaimed city lots where soil lead is nonuniform.