I was under the impression that Roundup can't be used near water, but then when I looked at the Monsanto site for their various pesticides, the one they manufacture for use on aquatic plants has a higher percentage of glyphosate than in Roundup. Not like I'd take their word for anything except the noxious ingredients in their products.
I've searched for information to back up what I remember - that Roundup wasn't to be used near water because it would harm aquatic life, but I can't find any of that now. I do have a site that has a lot of information about pesticides, herbicides, etc, that may be a helpful starting place.
National Pesticide Information Center -
Quote:
NPIC provides objective, science-based information about pesticides and pesticide-related topics to enable people to make informed decisions. NPIC is a cooperative agreement between Oregon State University and the U.S. Environmental Protection Agency (cooperative agreement #X8-83560101). The information in this publication does not in any way replace or supersede the restrictions, precautions, directions, or other information on the pesticide label or any other regulatory requirements, nor does it necessarily reflect the position of the U.S. EPA.