Sunflowers can help remove certain pollutants from soil and water.

The common sunflower, Helianthus annuus, has the ability to absorb contaminants through its roots. 

This process is known as Phytoremediation, in which plants help draw pollutants out of the environment.

As the plant grows, some contaminants move through its vascular system and accumulate in the stems, leaves, or roots. These may include heavy metals such as lead or cadmium, as well as radioactive elements like cesium or strontium.

Once the plants have absorbed these substances, they are harvested and removed from the site. The contaminated plant material is then treated as hazardous waste. In some cases it is incinerated in controlled facilities, while radioactive material may be stored in secure disposal sites.

Sunflowers were planted in remediation experiments after the Chernobyl disaster and later following the Fukushima Daiichi nuclear disaster as scientists explored ways plants might help reduce contamination.

The pollutants themselves are not destroyed. Instead, they become concentrated inside the plants, which can then be safely removed and managed.

In some landscapes, a field of sunflowers marks the beginning of environmental cleanup.