Aquatic Use

Safety to the Environment

Safety to the environment is an important consideration when treating weeds in and around water. Roundup ProVantage and ProBio are particularly suitable for these areas. They give effective weed control, and are quickly broken down in soil or sediment into harmless natural substances. Roundup is non-residual, and does not harm animals, birds, fish, insects and other wildlife. More details on glyphosate and the environment can be found  on the glyphosate information portal


When Roundup is used correctly, only a small proportion of the spray reaches the water. Any herbicide which enters the water is rapidly broken down by microbes.

This was confirmed by monitoring sites after application. The amount of glyphosate found in slow-flowing water one hour after treatment, and in still water 12 hours after treatment, is barely detectable. At these sites, the variety and number of micro-organisms showed no significant change during the year after treatment.

Evidence suggests that Roundup has less effect than mechanical weed control on wildlife.

Government Approval

The Department of Environment, Food and Rural Affairs imposes strict control on the use of herbicides in aquatic areas.

Glyphosate, the active ingredient in Roundup Pro Biactive, is one of only two active ingredients approved for such use.

Before granting approval, DEFRA considers extensive data on the herbicide's characteristics, including its toxicology, degradation, persistence, and effects on invertebrates and fish. Roundup ProBio and ProVantage have favourable toxicological and environmental profiles.

For more details about glyphosate fate in the environment see

Safety to Operators and Wildlife

Roundup has very low toxicity to humans, animals, birds, fish and insects. It acts on an enzyme, which is found only in plants, preventing the plant from making proteins. The World Health Organisation rates glyphosate, the active ingredient in Roundup, as 'practically non-toxic', the lowest classification available.

There is no need to restrict public access after spraying with Roundup, and correctly treated water may be used for irrigation.


Users must consult the appropriate Environment Agency before applying Roundup herbicide in reservoirs, watercourses and waterways.

Roundup provides long-term control of aquatic weeds in ditches and drainage channels. It controls emergent and floating weeds including especially difficult to kill species such as reeds, rushes, sedges and grasses.

When used as directed there is little risk to spray operators, wildlife, or the environment. Roundup may be used in waters stocked with fish, if used in strict accordance with the recommendations.