Tuesday, April 28, 2009

Lettuce, the Lead Vacuum

Lead is a soft metallic element that has long been popular in human history due to its easy malleability and low melting point. However, the relationship between humanity and lead is far from perfect. When inhaled or ingested, lead causes some serious health problems in humans. People most vulnerable are children, pregnant women, and women who are breastfeeding.

So What Does Lettuce Have to do With Lead?
Lead is a naturally occurring element that can be found all over. However, when concentrations of lead rise above natural levels, contamination has occurred. Lead contamination is mostly from lead paint used in old homes and automobile emissions. When chips from old paint, dust created by sanding or sawing wood painted with lead paint, or an excess amount of pollution is around, lead particles can settle in the soil. Have your soil tested if you think it may have a high concentration of lead.

This lead can then find its way into your body through consumption. If your garden soil has a lead problem, the highest risk of getting lead poisoning is through consuming the soil itself. Care must be taken with children (I have a nephew who absolutely loved to eat dirt as a baby, luckily he lives were the risk of lead or other human pollutants is extremely low) and if you are consuming food harvested from that soil, carefully wash it off.

Some of the lead can also be absorbed directly into the plants. Research suggests that if this is the case, the lead does not accumulate in the fruits of plants but in the leafy and rooty parts. If you want to grow a root or leafy vegetable, like carrots or lettuce, and think your soil may have a high concentration of lead, try growing lettuce. Grow a crop or two of lettuce, letting the plants get as large as they will, then dispose of the plants. If there was any lead in the soil that could have been absorbed by plants, those crops of lettuce would have sucked some of it out.

Another strategy you can use is to limit the absorption of lead by maintaining a soil pH above 6.5. Add lime to raise the pH.

If you think your soil is extremely contaminated by lead, dig it out and replace it with new top soil.

If you live near a major highway or other source of pollution, try surrounding your garden with hedges, shrubs, and trees. These plants will help filter out the lead particles in the air.

1 comment:

Desert Survivor said...

I had no idea lettuce was a good lead vaccuum. Thanks for enriching my life.