Question to the Department for Environment, Food and Rural Affairs:

To ask His Majesty's Government what assessment they have made of the Environment Agency’s decision to allow HS2 workers to use polymers for their work in the Colne Valley and the impact that this decision may have on the drinking water in Hillingdon and Hertfordshire, given the concern that monomer acrylamide can be residually present in the polymers.

The Environment Agency (EA) has not approved the use of polyacrylamide as a piling support fluid additive or as a flocculant for waste water treatment activities. Therefore, there is no polyacrylamide source from these activities.

The EA has approved the use of polymers in waste treatment activities, in the treatment of slurry spoil from tunnelling. Given that this product is used in treatment of the solid wastes, which have a waste water component that receives further treatment prior to discharge, there is a very low likelihood of carry over into the environment. Furthermore, this discharge is made to surface waters rather than groundwater, greatly reducing the potential risk to the drinking water aquifer. As a result of these assessments, the EA has concluded there is a minimal risk to the water environment from the acrylamide monomer.

Where risks are identified that would constitute a potential danger to human health, the EA would inform the relevant water company. Water companies in England have a duty to carry out assessments to identify any risks to the water supply from source to tap and in doing so they are required to consider the relevant activities that occur within the source catchment that may impact water quality. They will assess the quality of raw water sources for any element, organism or substance that they believe may adversely affect the supply and, where necessary, put mitigations in place to protect it.