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Experts Dispel Fears of Blue-green Algae Threat
Environmental authorities moved Tuesday to provide authoritative reassurance that Taihu Lake does not, as claimed in some quarters, face a threat from blue-green algae,according to today's China Daily.
The density of the algae in the freshwater lake in East China's Jiangsu Province has been exaggerated, said sources at the State Environmental Protection Administration.
The tap water supply from local water works surrounding the lake has not been seriously affected despite the fluctuating density, the sources said.
According to statistics released by the administration Tuesday, the quality of water in two major spots surrounding the Taihu Lake Basin is graded from level 2 to 3, including Wuxi in Jiangsu Province and Huzhou in Zhejiang Province.
The only exception is a section of the lake near Shanghai and bordering Jiangsu Province, where the water is graded level 5.
The average density of blue-green algae in the lake from mid-May to mid-July was below 25 million per litre, similar to that of the same period last year, according to the administration's surveys.
In mid-August, the average density was slightly higher than the year-ago period, but has fallen below last year's average since late August, they said.
In the most polluted waters of the lake, blue-green algae once reportedly reached 384 million per litre, the highest this year, but it is still much lower than the 760 million per litre in 1990, the worst ever reported in the lake.
Concentrations of blue-green algae covering an area of up to several square kilometres have recently been recorded in small parts of the lake due to strong winds and tidal currents, the officials said.
The government has, since 1998, been spending large sums on the purification of water in Taihu Lake to get it back to its original clean water level.
In recent years, hundreds of industrial polluters have been closed down around the lake, more than 660 hectares of enclosed fish ponds in and around the lake have been reduced, and 33 water treatment facilities have been set up at the lakeside.
The main pollutants in Taihu Lake are organic substances like nitrogen and phosphorous, which are responsible for the abnormal growth of blue-green algae, a water plant growing easily in polluted water with high concentrations of nitrogen and phosphorous.
Industrial waste water is the largest source of pollution, experts say. The second largest is domestic sewage from urban areas surrounding the lake.
The organic waste in the lake also comes from farm fertilizers used around the Taihu Lake Basin.
And the thriving fishing industry does some harm. In the area, farmers have created 66,000 hectares of fish ponds.
Only 20 to 30 per cent of the feed put into the water is eaten by the fish, and the rest becomes sources of pollution.
China Refutes Bombastic Report on Blue Algae Pollution
Some Chinese media have exaggerated the density of blue algae in Taihu Lake, east China's Jiangsu Province, said a source from China's State Environmental Protection Administration (SEPA).
"Recent reports carried by some media on the so-called 'worst pollution in Taihu Lake since the 1980s' have deviated from facts, " the SEPA official told a press conference Tuesday in Beijing.
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