Urban chook keepers may be feeling a little wary after learning that a recent University of Newcastle study found high levels of lead in home-grown backyard eggs.
I stopped eating eggs from my urban chooks a few years ago when I discovered lead contamination in our backyard.
Lead exposure is particularly risky for young children and pregnant women, so I was furious when I realised that I had been unknowingly gardening in lead-contaminated soil during my daughter's pregnancy and that she had been playing in a lead-contaminated garden.
Why hadn't anyone told me of the risk? Education material regarding the risk of lead exposure when renovating old houses is everywhere - yet I'd never heard of the risk of lead in urban soil.
I've since learnt that soil in older densely populated urban areas is likely to be contaminated with lead and other heavy metals from a range of sources including lead-based paint dust and lead petrol fumes.
Thankfully, it is possible to garden safely and grow your own food in lead-contaminated urban areas.
Nine steps for lead-safe urban gardening:
2. Cover all areas of bare soil with grass, gravel, or thick mulch. We covered our daughter's play area in weed mat and then a thick layer of gravel.
3. Ensure chooks don't have access to contaminated bare soil, for example by laying pavers in their pen or housing in a chicken tractor over raised garden beds containing uncontaminated soil. Ensure they always have access to uncontaminated soil for dust bathing, even if it's just a large pot of soil in the corner of their pen. Restrict free ranging to areas where they can't access contaminated soil.
4. Locate food gardens away from painted buildings that were constructed during and prior to the 1970s, as they are likely painted in lead-based paint.
5. In areas where you can't easily create a barrier between old and new uncontaminated soil, favour fruits rather than root vegetables or leafy greens as research has found little accumulation of lead in fruits in comparison to leaves, roots and stems.
6. Maintain soil pH around 6.5 by adding lime if needed. Lead is relatively unavailable at or above this level.
7. Add loads of organic matter to your soil. Organic compounds bind lead and make it less available to the plant. I'm assuming this is why our blood lead levels came back normal - despite eating veges and eggs from our backyard prior to learning of the contamination.
8. Clean produce thoroughly.
9. Consider wearing gloves and wash hands immediately after gardening and before eating.
[Originally published in my column LESS IS MORE in the The Newcastle Herald Weekender Magazine 16th March 2013]