Yangtze and Pearl River estuaries have recently been identified as "dead zones" in a study produced by the United Nations Environment Program (UNEP).
The dead zones, actually low oxygenated expanses in the world's seas and oceans, are areas where nutrients from fertilizer runoff, sewage, animal waste and the burning of fossil fuels trigger algae blooms. These blooms require oxygen and take it from the water which in turn endangers other marine life.
The number and size of deoxygenated areas has risen each decade since the 1970s. Experts warn that this phenomenon is fast becoming a major threat to fish stocks and to people who depend on the sea for their livelihoods.
The major pollutants affecting China's seawater in 2005 were inorganic nitrogen and active phosphate, according to a report on marine environment pollution released this week by the State Environmental Protection Administration (SEPA). The report said 500,000 tons of ammonia nitrogen and 30,000 tons of phosphate from land-based activities ended up in the sea last year.
Eighty-two "red tides" -- a type of algal bloom occurred in China's seas in 2005 -- down 15 percent from the previous year, according to the UNEP report. Confirming earlier Chinese research the report found that large-scale red tides were concentrated in central Zhejiang Province, the Yangtze River estuary, Hangzhou Bay and north China's Bohai Bay .
In the Yangtze estuary last June one of these red tides affected more than 1,000 square kilometers of water resulting in more than 12 million fish dying. Residents in Shanghai were warned not to eat fresh fish as a safety precaution. Tests later confirmed the presence of toxic algae.
"China is making efforts to combat pollution from land-based activities," said Zhu Guangyao, vice-minister of SEPA, yesterday on the sidelines of the second intergovernmental review meeting of the Global Program of Action for the Protection of the Marine Environment from Land-Based Activities.
With about 80 percent of sea pollution coming from the land, most notably sewage, China has vowed to increase wastewater treatment in coastal areas from the current 50 to 70 percent in the next four years.
"UNEP will help China in capacity, technology and funds to protect its marine environment," said Achim Steiner, UN under-secretary-general and UNEP executive director.
UNEP estimated that the number of dead zones worldwide has climbed to 200. A full list will be available in 2007.
In addition to the two areas in China other such zones were found off Finland, Ghana, Greece, Peru, Portugal, Uruguay and the Western Indian (Ocean) Shelf.
(China Daily October 20, 2006)
