Much research has already been done using the sunflower and its ability to absorb heavy metals, but I could not find any studies on the remediation of perchlorate with this plant. Because I have a rudimentary understanding of chemistry and plant processes, I had to work from the ground up.
Although it is a modern city, LA has had its issues with water supply and filtration. Drinking water has been deemed unsafe in several locations, even recently. In 2010, the San Fernando Valley went through a water crisis, as deadly chemicals including perchlorate prevented water from being ingested. Perchlorate affects the thyroid and inhibits iodine absorption. In heavy concentrations, it can affect cognition and growth. The cleanup required $850 million, and the city lost another $100 million in imported water costs. Water is just too valuable to waste, and the city agreed, and heavily invests in a water recycling program, that of which usually involves chlorine and ozone.
I needed to find a growing method that solely lets the flowers intake my toxins and minerals. The answer: hydroponics. Hydroponics is the science of growing plants in water, without soil. It is
There are a variety of perchlorates to experiment with, as multiple elements bond with ClO4-. I choose to use sodium perchlorate, due to its solubility in water and lower health risks; it still has the chemical formula I need, NaClO4. Amounts in drinking wells have spiked at 820 ppm, but I'm using 500 ppm level as a baseline, as that is the lowest amount I can measure with my equipment.
Finally, I have been lead to consider what to do with the actual sunflowers themselves. Plants usually absorb water and other materials through roots. Osmosis allows water to pass the cell membrane, and active transport lets other materials, including the possible perchlorates, through. Research findings show that some materials make it into the organism and remain there. Irma Reyes, of the Huntington Botanical Gardens, has stated that these plants, "Hyperaccumulators, can incorporate the chemicals from the soil into the plant structure." There is also fear on how chemicals might make their way up into the food chain. However, some other sources have said that the sunflowers metabolize certain materials, allowing materials to be used and harvested from them (Prasad,2006). I have revised my experiment to include analysis of the plant tissue after it has remediated, to see if it removed toxins or simply held them in their cells.