The amount of weed in the Lea in Hackney as you approach the main Olympic site has caused comment long before the Olympic Games were known to be coming to the Lea Valley.
Now a study by Thames21 and University College London suggests that this is caused by a very high level of phosphates. A clean up is suggested.
Further south there is good news about the revived reed bed at Cody Dock.
See pages112 to 115.