A letter from the Environment Agency Friday 19th July

Dear Ellenbrook Area Residents Association


Thank you for your very detailed email on 4 July 2019 to our Chief Executive, Sir James Bevan and Chair, Emma Howard Boyd. James and Emma have read your email and asked me to respond on their behalf. They will also receive a copy of this response.​​ 


Thank you for clearly setting out your questions that I have responded to in turn below.​​ 


1.   ​​ Why are the EA and Affinity Water not objecting to the proposed quarry that runs a risk of contaminating the ground water source of public supplies in light of the recent media statements referred to above?


We have carried out a detailed assessment of the specific site conditions and operations proposed by Brett Aggregates at the Aerodrome Quarry (also known as Ellenbrook Fields Quarry or Hatfield Road Quarry) in the planning application dated February 2016. We have recommended planning conditions to the planning authority to make sure that adequate controls are in place, including a requirement for a Groundwater Management Plan.  This is to ensure monitoring of the water environment, including groundwater, takes place and regular reviews are carried out to make sure there is neither a vertical, nor a lateral spread of the contamination resulting from the activities.


With regard to the subsequent filling phases, appropriate conditions to protect groundwater are included in the environmental permit.


Our opinion is that the mineral extraction and landfill proposals can successfully manage the risk to water quality.



2.   ​​ Please supply to EARA up to date readings showing the level of bromate contamination on all the boreholes on Ellenbrook Fields.


The site is not yet operational and therefore we do not hold up to date information on the applicant’s borehole monitoring.​​ 


If you would like to write to​​ HNLenquiries@environment-agency.gov.uk​​ with a list of boreholes for which you would like recent data, we can provide available data for the surrounding area. However, we may not be able to do this by 24 July 2019, which you mention as a potential date for a planning discussion. Bromate pollution data is collected to characterise the whole of the groundwater contaminant plume and monitor its extent.​​ 

In your email, you show an Environment Agency map based on data between 2013 and 2017. The sampling density, other than at St Leonard’s Court itself, is insufficient to define groundwater quality at specific sites. For this reason, a developer is required to carry out their own groundwater quality monitoring to provide the necessary detail for their site. In the case of the Aerodrome Quarry, there is such a monitoring network in place.



3.   ​​ Why are the EA not objecting to the quarry continuing whilst still unsure of what ongoing remediation works are needed to effectively remove the bromate plume and prevent further loss of source water supplies?


As demonstrated through our recent consultation on groundwater pollution from the St Leonard’s Court contaminated land site under Part 2A of the Environmental Protection Act 1990 and the Contaminated Land Regulations, we are working to make sure that those responsible for the bromate and bromide groundwater pollution carry out appropriate remediation. Although the consultation is closed, you can find details at:​​ 


We can only object to development on the basis of the groundwater pollution plume if we believe the development will lead to an increased risk to groundwater which cannot be satisfactorily managed through planning controls.


We do not consider that the proposed development will prevent appropriate remedial activities from taking place.



4.   ​​ What plans do you have to reassure us that our health has not been compromised, nor has there been an increase in mortality rates, caused by the contamination being in our water before closure of the Bishops Rise WPS in circa 2000 and what steps will be taken to monitor the situation regarding our health ongoing.

The Environment Agency does​​ not have a remit for public heath aspects of water supply. Public Health England have responsibility for public health, nationally. Locally, both Public Health, Hertfordshire County Council and Environmental Health, Welwyn Hatfield Borough Council have responsibilities for aspects of public health.​​ 



5.   ​​ Who is accountable for the risks associated with the bromate plume including the risk to our water supply and the health risks to residents?


Affinity Water are responsible for public water supply; the independent regulator for their activities is the Drinking Water Inspectorate. Health risks are the responsibility of the health bodies mentioned under question 4 above. The Environment Agency protects the water environment, both groundwater and surface water. We do this through the regulation of activities such as discharges to ground, landfill and water abstraction and by providing our views on planning matters.



I understand your concerns and wish to assure you that we continue to work diligently to protect both groundwater quality and quantity within the contaminant plume and the surrounding area. If you have any further concerns, please do contact our area teams (HNLenquiries@environment-agency.gov.uk) who are happy to help with your enquiries.


Yours sincerely​​ 




Sam Lumb​​ 

Area Director for Hertfordshire and North London​​ 
Environment Agency | Alchemy, Bessemer Road, Welwyn Garden City, Hertfordshire, AL7 1HE​​