Japanese in Dispute over Acid Rain
TOKYO (AP) _ Thousands of acres of cedar trees are withering and dying in the mountains northwest of Tokyo in a blight that has sown controversy among Japanese scientists.
Some researchers say the damage is a symptom of acid rain.
The government disagrees, saying its tough environmental laws in recent years have minimized the risk of acid rain.
″It’s a grave problem ... and there is no will (to solve it),″ said Kyoichi Sekiguchi, researcher at the Gunma Institute of Public Health northwest of Tokyo.
Sekiguchi’s study of the region last year was the first to suggest a link between the damaged trees and acid rain. He now wants the government to conduct major, nationwide studies of acid rain.
Yoshio Yamanaka, assistant director of air pollution control at the government Environmental Agency, differs.
″We don’t know if acid rain has caused the (tree) damage or something else,″ he said. ″The cause and effect mechanism is not certain.″
Yamanaka concedes there have been few official studies of the problem compared with investigations in Europe and North America. But he maintains that nationwide damage from acid rain is not apparent.
Acid rain first gained notice in Japan when a series of acid showers from 1973 to 1976 caused more than 30,000 people n the Tokyo-Kyoto area to complain of eye and skin irritation.
The Environmental Agency conducted a five-year study of the phenomenon and the results gave impetus to the passage of a series of severe pollution control laws.
That legislation helped bring down the air levels of sulphur dioxide, a cause of acid rain, from a dangerous .06 parts per million in 1967 to .012 today, the agency says. The agency has sought to keep daily average levels down to 0.1.
But Sekiguchi contends that drops in levels of sulfur dioxide, which turns to sulphuric acid when exposed to sunlight and mixed with nitrogen oxide, do not mean Japan’s forests and lakes are free from danger. He said levels of nitrous oxide from factories, hydrocarbons from automobiles and other pollutants that can contribute to acid rain have increased.
In contrast to the government’s surveys that detected little or no damage, Sekuguchi found that 80 percent of the cedars over 30 feet tall in the 5,100- square-mile area he studied were ″heavily damaged″ by acid deposits. In 1974, the damage was ″limited to Tokyo and a small adjacent area″ near the city, he said.
In 1983, the government began a second five-year inquiry into the effect of acid rain on lakes and soil, although not on trees.
Interim results published this spring showed acidity levels of soil in sampling areas had not changed in three years, although 11 of Japan’s 97 largest lakes were ″acidic,″ with pH (acidity) levels of 5.6 or lower, and 23 others ″could easily become″ acid lakes. The lower the pH level, the higher the acidity.
However, the interim report said acid rain was not necessarily the cause, and that Japan’s many volcanoes and hot springs may have caused the acidity.
Motonori Tamaki, a research scientist at the Kobe Institute of Environmental Studies, said the government’s most recent study was too limited in scope, because it used data from only 14 sampling stations in seven of Japan’s 47 prefectures (states).
In his own 10-year study - the first nationwide probe of acidity in rain - Tamaki and his co-workers compiled results from 102 stations from 38 prefectures.
The results, released last year, showed average pH levels nationwide of 4.5; a level of 5.6 is considered acidic.
Gunma scientist Sekiguchi also said the government study had failed to account for the large size of Japan’s lakes. Smaller lakes like those in Europe show the affects of acid rain more quickly, he said, and the slight damage found in 11 large Japanese lakes should be a matter of great concern.
He added that growing industrialization in neighboring South Korea and China could aggravate acid rain problems in Japan in years to come.