Why are sunflowers planted in nuclear affected areas?

Sunflowers are what environmental scientists call hyper-accumulators, which are plants that have the ability to absorb high concentrations of toxic materials in their tissues. Fields of sunflowers have been planted near the sites of the Chernobyl and Fukushima nuclear power plant meltdowns, to help remove radiation in the soil.

While most plants simply absorb nutrients from the soil, sunflowers take it a step further. Sunflowers are quick growers that require plenty of nutrients, many of which are just as effective even if they’re isotopes leftover from radioactive activity. While it seems peculiar, and even a bit impossible, a sunflower does not discriminate between radioactive and otherwise – oftentimes the radioactive isotope mimics the naturally-occurring nutrient. Sunflowers then pull the isotope out of the soil and into their stems and leaves, effectively cleaning the soil.

Scientists first investigated the use of this technique after the devastation of Chernobyl in the 1990s. Much to their surprise, sunflowers were extremely effective in cleaning water sources. However, the sunflowers were less effective for soil-cleaning, as the radioactive elements had a longer time to become fixed to minerals in the dirt.