http://news.yahoo.com/s/afp/chinaenvironmentpollutionwaterSHANGHAI (AFP) – Authorities in eastern China have said they will release 20 million algae-eating fish into one of the nation's most scenic lakes that has been ravaged by pollution.
Taihu Lake, which straddles Zhejiang and, has been severely polluted by sewage as well as industrial and , triggering a blue-green algae plague.
Authorities started using fish to try to clean up the lake in February last year when they released 10 million mostly green and silver carp into the water, after the algae tainted the drinking supply of millions of residents.
Over the next few days, around 20 million more algae-eating fish will be released into the water, the Taihu Lake Fisheries Management Committee said in a statement Monday.
The campaign, funded by the government and public donations, cost a total of 8.6 million yuan (1.3), according to the statement.
A silver carp can consume 50 kilogrammes (110 pounds) of algae and other plankton in its lifetime while gaining only one kilogramme in weight, authorities have said.
Millions of algae-eating fish have been used in the past to clean up Taihu and other lakes, with previous efforts hailed as a boon for the localdespite concerns over consumption of fish that have feasted on toxins.
Algae blooms, which are common on freshwater lakes in, are chiefly caused by the presence of untreated sewage containing high concentrations of nitrogen, a main ingredient in detergents and fertilisers.
China's environment has suffered severely amid the nation's breakneck economic growth over the past three decades.
This end-of-pipe "solution" can be ineffective:
Because they feed on plankton, they are sometimes successfully used as methods for controlling water quality, especially in the control of noxious cyanobacteria(blue-green algae). However, these efforts are sometimes not successful. Certain species of blue-green algae, notably the often toxic Mycrocystis, can pass through the gut of silver carp unharmed, and pick up nutrients while in the gut. Thus, in some cases blue-green algae blooms have been exacerbated by silver carp. Also, Mycrocystis has been shown to produce more toxins in the presence of silver carp. Silver carp, which have natural defenses to the toxins produced by blue-green algae, sometimes can contain enough algal toxins in their systems that they become hazardous to eat. (http://en.wikipedia.org/wiki/Silver_carp)