In our recent study we found that 40 percent of 203 Sydney homes we sampled contain lead in garden soil above the Australian health guideline of 300 milligrams per kilogram (mg/kg).
This presents a hazard because soil lead can adhere to or get absorbed into edible plants. An additional pathway of exposure occurs when contaminated soil dust enters homes and is accidentally ingested. Lead is a potent neurotoxin that affects childhood development.
Urban agriculture and VegeSafe
Urban agriculture is becoming more popular across Australia. Almost half (48%) of all households in metropolitan areas are now growing some form of edible produce.
Most lead contamination is a result of the historical use of lead petrol and lead-based paint (now phased out) and previous industrial emissions. Scientists and regulators are well aware of these legacy issues, but the general public remains underinformed about the potential risks.
To help urban gardeners assess contamination risks associated with their garden soils, we started the community science initiative VegeSafe in 2013. This program offers free soil metal screening to participants.
Each participant receives a formal report on their soil metal results and advice about what to do next if soils contain elevated concentrations of metals. We have provided 5,500 free soil metal tests to over 1,300 homes and community gardens (Australia-wide), the largest program and study of its kind in Australia.