Worries about the purity of tap water are boosting sales of bottled water and tea in Japan, leaving mountains of plastic behind in a country that is fast running out of garbage dumps.

Industry officials estimate consumption of small PET (polyethylene terephthalate) bottles will reach 3.5 billion to 4 billion this year, up from 2.2 billion last year and only 640 million in 1996. After years of self-restriction, Japanese industry started to manufacture the bottles two years ago after a surge in sales of bottled mineral water from France."It's a big headache," said Kohji Yokota, an official at the Tokyo municipal government. "Our current dumps will be full within the next one or two years. In Tokyo, we'll be running out of space for such facilities within the next 30 years."

The city government dumps about 4 million tons of household waste into Tokyo Bay each year, creating land for housing, offices, industry and parks. By the end of this century, it will have created about 570 acres from garbage. And unless something is done, the city will have used up its sea space in the next few decades.

To tackle the problem, the Japanese government introduced a law in April 1997 to encourage local government and industry to recycle PET bottles. It hopes for a dramatic boost in the plastic bottle recycling rate of about 3 percent last year - well below the 70 percent recycling rate for glass bottles, cans and paper.

However, there has been little progress, particularly in Tokyo where the soft drink industry and bottle makers have rejected a request by the municipal government to share the huge financial burden of collecting used bottles.

Faced with soaring consumption of PET bottles, the Tokyo government has asked retailers to install containers for collecting used bottles, which can be processed into PET flakes and turned into other products.

"The situation's so pressing that we've decided to do what the industry is supposed to do," said Yokota. "But its quantity is rising. In future we won't have enough money, no matter how large our tax revenue might become."

The industry, soft drink and PET bottle manufacturers agreed recently to build a new recycling plant in Tokyo to make shirts, fleece clothes and carpets out of used PET bottles, the third such facility in Japan. But it will not start operation until the next century. Industry officials also worry if there will be enough demand for such recycled products.

Meanwhile, the Japan PET Bottle Association estimates PET consumption, including large bottles introduced in 1977 for soy sauce, will grow to 282,000 tons this year from 250,000 tons last year and 203,000 tons the year before.