"That's a very real possibility," said Hatcher, "one that certainly deserves further investigation. There is enough reason to believe that the natural environment may be able to stop the action of pollutants very readily by such a process."
Hatcher and Zang fed a rare isotope of nitrogen to algae in the laboratory, and then exposed protein extracts of the algae to a sample of humic acid from peat that Hatcher gathered in the Florida Everglades.
They used this particular isotope, nitrogen-15, because it is highly visible in nuclear magnetic resonance (NMR) data. The more common isotope of nitrogen in the air and soil is nitrogen-14, Hatcher explained, but nitrogen-15 was an appropriate substitute because plants can absorb it in the same way.
An NMR scan of the humic acid revealed that it had trapped the nitrogen-15 enriched proteins.
To test Hatcher's idea that the humic acid had stored the nitrogen-15 enriched proteins within tough molecular shells, he and Zang treated the humic acid with a strong acid -- hydrochloric acid.