Fukushima municipal workers Wednesday planted some 10,000 sunflower seeds in a 6,000-sq.-meter field identified as a radioactive hot spot, in the hope the plants will help cleanse the area of contamination.

Radiation measuring 4.43 microsieverts per hour was recorded last month at the field in the Oguraji district in the city of Fukushima, making the area off-limits to neighborhood residents.

The radiation likely came from the Fukushima No. 1 nuclear power plant. One-time exposure to radiation of 100 millisieverts is believed to increase the risk of death by cancer by 0.5 percent.

Research suggests that sunflowers can remove some radioactive materials from contaminated soil.

About 30 workers wearing protective masks to guard against inhaling radioactive materials planted the seeds in the field about 1 km from the prefectural office.

Some of the workers temporarily stopped working because it was hard to breathe through the tightly sealed protective masks.

Two to three seeds were planted every 50 cm in straight lines.

"This is a place where lots of people get together to see cherry blossoms in spring. We'd like to bring people back here by lowering the radiation level," said Yoshiaki Takagi, a city official in charge of the project.