The Yangtze River and Pearl River estuaries have been listed as newly
registered "dead zones," according to a study released by the United Nations
Environment Programme (UNEP).
Dead zones, or low oxygenated areas in the world's seas and oceans, are
places where nutrients from fertilizer runoff, sewage, animal waste and the
burning of fossil fuels trigger algae blooms.
The algae blooms need oxygen and remove it from water, endangering other
The number and size of deoxygenated areas has risen each decade since the
1970s. Experts warn that these areas are fast becoming major threats to fish
stocks, and to people who depend upon fisheries for food and livelihoods.
The major pollutants affecting seawater off China were inorganic nitrogen and
active phosphate in 2005, according to a report on pollution of the marine
environment released this week by the State Environmental Protection
The report said 500,000 tons of ammonia nitrogen and 30,000 tons of phosphate
from land-based activities floated into the sea last year.
Eighty-two "red tides" one type of algal bloom occurred in China's seas in
2005, down 15 per cent 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 .
For example, last June in the Yangtze estuary a red tide influenced more than
1,000 square kilometres of water, resulting in the death of more than 12 million
fish. Residents in Shanghai were warned 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," Zhu
Guangyao, vice-minister of SEPA, said yesterday on the sidelines of the second
intergovernmental review meeting of the Global Programme of Action for the
Protection of the Marine Environment from Land-Based Activities.
With about 80 per cent of pollutants in the sea coming from land-based
activities, most notably sewage, China has vowed to increase wastewater
treatment in coastal areas from the current 50 per cent to 70 per cent 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
UNEP estimated that the number of dead zones worldwide has climbed to 200. A
full list will be available in 2007.
As well as the two areas in China, other dead zones were found off Finland,
Ghana, Greece, Peru, Portugal and Uruguay, as well as the Western Indian (Ocean)