About half of China's marine zones were polluted last year, especially in the coastal areas, according to a survey released yesterday by the State Oceanic Administration.

Of the 18 coastal ecological monitoring zones, six were deemed unhealthy; seven, moderately healthy; and only five, healthy.

Heavily-polluted areas include Liaodong Bay in Northeast China, Bohai Bay in northern China, the Yangtze River estuary, Hangzhou Bay and coastal areas in Jiangsu Province in East China and the Pearl River estuary in southern China.

More than 27,000 square kilometres of sea was covered by 82 red tides, costing the fisheries industry a direct loss of more than 69 million yuan (US$8.6 million).

Thanks to monitoring and early warning systems, the red tides did not cause human loss or injury.

Coastal provinces account for 40 per cent of the country's population, and more than 473 million square kilometres of water is under China's sovereignty. The major pollutants are inorganic ammonia, active phosphate and petroleum. In some marine zones, heavy metals such as lead and cadmium exceeded safety limits.

"Waste-water discharge and overfishing are the two major reasons for ecosystem degradation in coastal marine areas," said Ma Deyi, director of the National Marine Environment Monitoring Centre.

Results from the country's 200 coastal monitoring stations indicate that more than 317 billion tons of waste water was discharged into the ocean from the mainland in 2005, almost twice as much as in 2000.

"Some 270 waste water discharge points were found in fishing areas, posing a great threat to seafood safety; and another 70 were found in scenic areas, threatening the environment of beaches," Ma said.

Source: China Daily