The cosmetics and nutraceutical industries seem obsessed these days with finding uses for natural products
, but they've got nothing on the exhibitors at the International Science and Engineering Fair here in Atlanta
. Two students in the Environmental Management pavilion have found innovative ways to use throwaway products "“ seashells and noxious weeds "“ to solve long-standing problems
Theresa Oei, 14, of Hebron, Connecticut, grew up spending summers at the beach in Stone Harbor, New Jersey. Being the curious sort, she wondered if there was "any use for the shells" she kept tripping over. After all, "they're not being used by nature anymore," and hence are a bit of a freebie resource. She did some research and found that seashells
are composed mostly of calcium carbonate. Further research revealed that calcium carbonate is often used to remove heavy metals from contaminated water. So she wondered if seashells could be used to remove lead from groundwater and effluent. (Text continues after the photo.)
At home, Oei ground up shells into various sizes. She stuck lead fishing sinkers into water to contaminate it, then ran the contaminated water through her seashell filters. She found that small shell particle (about 0.25 millimeters) worked best because they allowed more surface area for the chemical reaction to take place. A high pH level "“ meaning a very alkaline solution -- also enhanced the reaction, because it helped lead bind to the reaction sites.
And enhance the reaction it did. An independent lab calculated that before Oei put the contaminated water through her seashell filters, the lead levels were 8000 parts per billion. After? Undetectable "“ that is, less than 1 part per billion. She's doing further testing to find out the saturation point of seashells, and whether there could be industrial applications. But so far she hasn't been able to do very large experiments: "I don't have capacity at home to use that much lead water!"
Jonathan Suncar, 17, of Uniondale High School in Uniondale, New York, is also using a freebie natural resource (noxious weeds) to solve an environmental problem. His parents like to go to orchards in neighboring Suffolk County, but they kept hearing from farmers about how bad the aphids
were. Killing aphids often involves broad spectrum insecticides. They work, but "They may be causing more harm by killing
everything around the plant including beneficial insects." (Text continues after the photo.)
So Suncar had an idea. Certain species of noxious weeds "“ Bindweed
, Spurge leaves
and Quack grass
"“ all naturally repelled aphids. Could an extract from these weeds be used to naturally deter aphids on other plants? He isolated the extracts and sprayed them on pea plants. The sprayed pea plants themselves grew at the same rate as a control group. Earthworms and lady beetles were unharmed. But 100% of the aphids met their maker.
It's a great result, and many of the farmers Suncar knows have been emailing to find out his progress. "If we can use the chemicals inside weeds to fight aphids, we're getting rid of two problems," he says. First, you can eliminate the use of synthetic insecticides. And second, you don't have to kill the weeds. You can use them.
To achieve these results, Suncar has been working through vacations in Uniondale High School's lab for several years. (How much time have you spent on it? we ask. "How much time haven't I spent on it?" he says). But the experience has got him so interested in research that he's off to the City University of New York this fall for a pre-medical program.
He's also really impressed his science teacher, Paul Lichtman, who came to Atlanta with his charge, and teared up as he discussed the project. "It doesn't get any better, being a teacher and seeing a person like Jon being recognized for his work," he says.
Edited by Christie Nicholson at 05/15/2008 3:30 PM