At this early stage in the unfolding nuclear crisis in Japan, there are too many unknowns to assess whether the region's plants, animals and fish will pay a lasting price.
The Fukushima Daiichi nuclear power station is leaking radiation after suffering damage in the earthquake and tsunami that devastated the country's northeast coast.
The radiation levels are low so far. If the situation does not worsen, the environmental effects will likely be limited, said Kelly Classic, a radiation physicist with the Health Physics Society in the United States.
Still, Dr. Classic suspects some ground contamination has already occurred because radioactive particles have been detected on people's clothing.
"Right now, based on what they are finding on people, it's not much," she said. "People would be able to go back and inhabit the area."
At the moment, Japan's focus is on containing the radiation leak and protecting people from exposure. Down the line, Dr. Classic expects mapping of radiation plumes will be done by air.
Simon Fraser University associate professor Krzysztof Starosta, who specializes in nuclear science, said it's encouraging that radiation levels dropped after spiking Tuesday. He expects there will be some ground contamination, but noted the degree of impact will depend on how much radiation is eventually released and its composition.
"There are some radioactive substances that are very short lived," he said.
However, the ecological fallout from the world's worst nuclear accident at Chernobyl a quarter century ago is still unfolding. A 30-kilometre zone around the site remains uninhabitable.
Nearly 25 years ago, a cloud of radioactive strontium, cesium and plutonium drifted from Chernobyl and affected mainly Ukraine and Belarus, but also parts of Russia and Europe.
Estimates on the number of direct and indirect deaths as a result of the disaster vary widely, while a picture of the ecological toll is just beginning to emerge.
"We're just starting to learn things in Chernobyl, like bird brain size is smaller," said Shawn-Patrick Stensil of Greenpeace Canada. "It takes time to see the longer-term effects."
In addition to birds with smaller brains, scientists have found trees in the region growing in strange directions, their limbs twisting in unusual shapes. But they've also found unexpected resilience. Wildlife has made a comeback, with reportedly more than 60 different types of mammals roaming the area, including wild boar and elk.
A recently published study of 550 birds comprising 48 species living in the Chernobyl exclusion zone showed exposure to low-dose radiation had affected the size of their brains. Researchers from Europe and the United States found brain size was significantly smaller in younger birds.
After the 1986 nuclear disaster, the woods around Chernobyl became known as the Red Forest, as 400 hectares of pine trees withered and turned red. Such environmental devastation isn't, at the moment, expected in Japan.
"Humans tend to be actually more radiation-sensitive than plants or most animals," said Jacopo Buongiorno, an associate professor of nuclear science at the Massachusetts Institute of Technology. "The radiation levels that are being reported … are fairly low for humans."
With a report from ReutersReport Typo/Error