JUDY WOODRUFF: Next, the enormous challenges of trying to clean up radiation contamination from the nuclear accident in Fukushima, Japan. Sunday marked the first anniversary of the earthquake, tsunami and subsequent meltdowns.
NewsHour science correspondent Miles O'Brien returned to the region for a series of stories.
Here's his second report.
MILES O'BRIEN: It was a lonely, sad ride home for Kimeo and Yoko Matsuzaki. I joined them as they returned for a quick visit to gather some belongings and check up on the place.
We are in the town of Namie, Japan, five miles from the Fukushima Daiichi nuclear power plant. Radiation contamination here was 35 millisieverts a year. Twenty millisieverts is the allowable limit for radiation workers. And only one millisievert a year is considered acceptable for average citizens.
Nearly a year after they had to hastily abandon it, their home is showing the signs of damage from the earthquake and neglect.
Kimeo is the 30th generation of Matsuzakis to grow rice on this land. A Buddhist statue in his shrine room dates back to the 15th century, 500 years, one family, one place, until now. And seeing it is understanding they will not be coming home.
"I expected a better situation," she told me. "I expected, if we fixed it, we could return and live in it. I thought so when we left, but, looking at this, no way. We were living a happy life. That memory came back to me. Sorry. Thinking that we will retrieve the happy days, I'm so sad. Sorry."
The Matsuzakis' home is too close to the plant and too contaminated to consider a cleanup.
But farther away, where the radiation readings are a little lower, there is a lot of work under way to fight the fallout. Kunihiro Yushida is doing his part to try to make things right, volunteering his time to clean up yards and school playgrounds in the city of Minamisoma, 12 miles north of the Fukushima Daiichi plant.
But as I watched him work, I quickly realized the dimensions of the dilemma. At this home outside the mandatory evacuation zone, he has scraped off the top layer of soil and bagged it all up. But since there is no government-designated dumping ground, he trucked the hot soil bags a few miles away to an apartment building owned by a friend and left them there.
"It's illegal, but I keep them in an empty space," he told me. "When the government sets up interim dumping sites, I will move them there right away."
And back at the home, while the soil may now be safe for kids to play, the driveway is still dangerously contaminated with cesium. The only solution, grind off the top layer of concrete. Kunihiro Yushida believes this neighborhood should be officially evacuated so that residents can be compensated.
"The government is just delaying the inevitable, in my eyes," he said. "Instead, the government should honestly acknowledge that decontamination is unrealistic, apologize and evacuate citizens as soon as possible."
The mayor of Minamisoma, Katsunobu Sakurai, is conflicted on this issue.
Is it possible that this cleanup can't be done?
"It's impossible," he said. "Only a few parts of the area may be decontaminated. It is better than doing nothing, so it should be done anyway."
In the city of Onami, about 40 miles from the Fukushima Daiichi nuclear plant, they are embracing that philosophy, putting a lot of time, effort and money to clean up some once-fertile rice farms now heavily contaminated with cesium fallout. Rice grown here has been banned from the market.
Yasuyoshi Onami, also a 30th-generation rice farmer, believes he will be the last.
"I have no choice but to give up farming, given the current situation," he said.
An army of workers is here trying to put the rice growers back in business. They have scraped off the top layer of soil, bagged it and removed it, carefully leveled the fields, and then checked and recorded the radiation readings. But this model project may be fundamentally flawed. The mountains that rim this valley are covered with a contaminated cedar forest.
Worker Yuichi Ito told me what happens after the cleanup.
YUICHI ITO, cleanup worker: A few days later, the radiation -- it's cesium. Cesium -- cesium is very familiar to the soil, so the dust in the soil will fly from the mountain and come here.
MILES O'BRIEN: It comes right back down.
YUICHI ITO: Yes. Yes. Yes. Yes.
MILES O'BRIEN: The cedar forest will remain a persistent source of cesium contamination spread by the pine needles and cones and pollen. Consider the so-called Red Forest near Chernobyl, so named because radiation from the meltdown there in 1986 killed large swathe of trees.
I walked through it with physicist Gennadi Milinevsky of the University of Kiev a year ago, and it remains highly contaminated to this day.
The ground is just hot, isn't it? It is hot.
GENNADI MILINEVSKY, University of Kiev: Yes.
MILES O'BRIEN: So this used to be pine trees as far as you can see.
GENNADI MILINEVSKY: Yes.
MILES O'BRIEN: And the cesium came through here after the explosion. And that's -- and to this day is. . .
GENNADI MILINEVSKY: Yes, still over there.
MILES O'BRIEN: Are there animals that can live here or not?
GENNADI MILINEVSKY: No, no.
MILES O'BRIEN: No animals here?
GENNADI MILINEVSKY: Not really, yes.
TIMOTHY MOUSSEAU, University of South Carolina: All right, shall we get some -- some pine needles?
MILES O'BRIEN: Milinevsky's colleagues, scientists Tim Mousseau and Andres Moller, have studied the impact of Chernobyl on flora and fauna for more than a decade. They're here now in Fukushima gathering samples of various trees and plants.
ANDRES MOLLER, University of Paris-Sud: The greenness of the vegetation tells something about the stages of the plants and the plant community. The more green it is, the more healthy the vegetation is.
TIMOTHY MOUSSEAU: And, of course, you know, the plant community is the foundation, the basis of the -- everything else that goes on in the community. It's what the insects feed on. It's what some of the birds feed on, where they live. And so what happens to the plant community can have a dramatic impact on the rest of the ecosystem.
MILES O'BRIEN: Scientists suggest the Japanese engage in a form of fallout triage.
John Boice is a professor of medicine at Vanderbilt University.
JOHN BOICE, Professor of Medicine, Vanderbilt University: They have developed three zones, though, for the Japanese authorities, zones less than 20 millisieverts, 20 to 50 and 50 above. And the areas that are 50 and above, there will be no repopulation.
In the other areas below 20 millisieverts, you will be allowed to return. The 20 to the 50, that is where they will be working on to see how low they can get the levels, and if they can get below 20 millisieverts.
MILES O'BRIEN: For now, the tidy, tiny, temporary housing for evacuees is looking more and more like a permanent fixture.
People like Katsuhiko Nakagawa, who lost his wife, son and mother in the tsunami, told me, "My village fell apart. We hoped we could do collective relocation, but it's not realistic."
MILES O'BRIEN: There is no way to sweep away the mess or bury the sense of loss here one year after everything seemed to change. It is a long road home, to be sure.
GWEN IFILL: In his next story, Miles examines food safety in Japan after the disaster.
On our website, you can watch his first report about the long-term risks of radiation exposure.