Here is a very recent article in Chinese news about the problem of pearl farming and pollution. Ironically, it is the pearl farming itself that is polluting the water supply!!
http://www.china.org.cn/english/environment/220656.htm
Tomorrow I am actually scheduled to go to Lake Memphremagog in eastern Quebec to speak with a researcher there and take pictures of the algae ridden lake. Hope it pans out. It should be interesting.
Slraep