Legacy of Lead Paint Use and Its Impact on Soil Contamination at a California University Campus.

Lead toxicity can lead to adverse health effects in humans by inhibiting muscle, bone, cognitive, and nervous system development. The use of lead paint before it was outlawed in 1978 poses a potential hazard to humans through exposure to lead sinks, such as soil. This study was conducted to assess the risk associated with lead in soil near buildings built primarily before 1978 on the California Polytechnic State University, San Luis Obispo (Cal Poly) campus. The type of lead extraction method used (total lead via USEPA 3050B and bioaccessible lead via Mehlich 3), depth of soil sample (0-5 cm and 10-15 cm), and age of buildings from which soil was sampled were all factors that influenced soil lead concentrations. There was a significant positive (R² = 0.86; α < 0.01) linear relationship between total and bioaccessible lead concentrations where total lead levels were approximately twice those of bioaccessible lead levels. Surface lead concentrations (average: 46.63 ppm) were higher than subsurface lead concentrations (average: 29.97 ppm) for the majority of samples. The highest concentrations of lead in soil occurred near buildings built before 1965, and the highest concentration of soil lead (261.52 ppm) for the entire study was found in the subsoil near a building constructed in 1927, which was the oldest of the buildings from which soil was sampled. Soil lead concentrations for all sites sampled fell below the US EPA’s soil screening level of 400 ppm, which suggests that lead in Cal Poly’s soils does not pose a human health hazard.