Two of my students won 1st place in the Western Ct. State Fair. They competed against over 60 other projects in this part of our state. They one 1st place in juniors Bio.
Their title was "Get the Lead Out!- Can plants be used to extract or absorb
lead from soil?"
They took soil samples from heavy traffic areas that might have lots of lead
in the soil from years of leaded gasoline use (highways, exit ramps, major
roads and gas stations) and used a lead testing kit for soil to pick the
most contaminated sample. They planted seeds from brassica, beans, and dill
to see if they could detect any lead in the plants after 2 weeks or if they
could see a decrease in the lead they had planted the seeds in. They then
tried to quantitate this by using an assay they found with lettuce seeds
where you grow the seeds in Petri dishes with a plant or soil extract and
look at the growth of the lettuce seedling roots. Apparently leaf lettuce
seeds are very sensitive to lead contaminants and will not grow well.
They didn't see any positive results from the lead test kits or lettuce seed
bioassay, so it either wasn't sensitive enough, the plants didn't grow
enough, they were the wrong kind of seeds, or you needed more plants per
pot. One article they found suggested that mustard weed should have worked.
Anyway, they followed the whole thing through with appropriate controls, and
they were very thorough and understood it all, so it was a great learning
experience for them. They came up with the idea based on the folks that had
tried to clean up the mercury/arsenic in the soil in Danbury by planting
genetically engineered cottonwood trees.
These two students were sisters of two winners using the plants 3 years ago!