New Chinese Survey Reveals Extensive Coastal Pollution

November 7, 2012

Science

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Children swim through algae-choked waters off the coast of Qingdao, in eastern China’s Shandong Province. Photograph from AFP/Getty Images

A national marine survey of China’s marine resources paints a disturbing portrait of its current coastal environment. The survey was launched in 2004 by the Chinese State Oceanic Administration (SOA) and was finally completed last month.

The unpublished survey shows that roughly 90% of coastal cities suffer from intermittent water shortages. China’s mangrove swamps have decreased in area by 73% and its coral reefs have diminished by 80% since the 1950s. The coastal wetlands have also shrunk by 57%.

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A view of the algae-filled coastline of Qingdao, Shandong Province. Source: REUTERS/China Daily

One-third of the loss in coastal wetlands was due to land reclamation. In the past decade, there has been a continuous rise in pollutants discharged into river estuaries. Three-quarters of those discharges fail to meet regulatory limits. There are 48 estuaries contaminated with heavy metals, the insecticide dichlorodiphenyltrichloroethane (DDT) and petroleum hydrocarbons.

When these pollutants are combined with the run-off from chemical fertilizers and animal manure from farmlands, there is a build-up of excessive nutrients and harmful algal blooms in coastal waters.

Over the past 20 years, there have been 83 red tides a year. The report warns of a general decline in coastal fishery resources and the krill in the East China Sea are on the verge of being extinct, which will severely impact yellow croakers that feed on them.

The survey doesn’t go far enough in assessing coastal ecosystems, state some Chinese ecologists. Preliminary research has shown that coastal waters near Xiamen are more acidic, making it difficult for phytoplankton and the rest of the marine food web to survive. It’s unclear how widespread or serious the problem is, because studies so far are piecemeal.

[via Nature]

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