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Sericol leak
Dear Mr Child,

Thank you for your e-mail dated 31st Oct 2008, received by this Department on 3rd Nov 2008, in which you requested additional information on the ‘Sericol pollution incident’, following publication of correspondence from the Environment Agency to Richard Card.

In your e-mail, you have expressed concern that the public safety issues aren't exaggerated and that the press receives accurate information. Thanet District Council will therefore be making this response publically available, alongside an associated press release to inform the public about the issues which you have raised.

In answer to the specific points raised in your e-mail. To the best of my knowledge:

5. "Which agency is monitoring the public health side of this and have there been surveys of the health of the people living and working in the effected area?"

It is important to make a distinction between the ongoing investigation into contamination of the groundwater & protection of the public water supply (as detailed in the Environment Agency’s response to Richard Card, dated 10th Oct 2008) and potential surface contamination at the site. As you will have noted from the EA’s letter, ‘solvents tend to move straight down through the Chalk*1 metre to the side was far enough away not to reveal any sign of a loss’.

Since the cyclohexanone spill originated from buried pipes/tanks, there has never been an issue with presence of cyclohexanone at the surface, other than for a brief period during drilling operations to install the remediation boreholes in the chalk column, when all appropriate safety measures were exercised/volatile organic compounds measured and found to be within acceptable exposure limits.

N.B. During the development of the East Kent Retail park in 1998, other areas of identified surface contamination at the former Sericol site were excavated and the contaminated material (a total of 178 loads) was removed to a licensed tip following stockpiling. The excavated areas were polythene lined, a clay layer inserted and backfilled with clean, inert material, in accordance with the remediation methodology. This means that there is no surface contamination remaining in the area which could affect end users of the site or have a further impact on groundwater resources.

To my knowledge and for the reasons outlined above (ie. there is no risk via direct ingestion or inhalation pathways), there have not been surveys of the health of people working in the area subsequent to the Sericol move. However, the agency responsible for regulating Health and Safety at work is the Health & Safety Executive, as it would have been during the time Sericol occupied the site. For your information, I am attaching two Health and Safety Commission reports quantifying the Occupational Exposure Limit Values for cyclohexanone, which include the derivation of the current figures and reference to the relevant animal studies. Please note that any monitoring of cyclohexanone in the workplace would need to take account of all potential sources (e.g. paints, varnishes, printing inks, etc*).

With respect to the public health risk posed from abstracting potentially contaminated groundwater. The Environment Agency is responsible for ensuring that appropriate remediation of the cyclohexanone in the chalk/groundwater is conducted and Southern Water have a duty to fully protect human health as a supplier of drinking water. The Rumfields water supply was not in use at the time the spillage was first discovered. However, due to the perceived risk from groundwater contamination, the water company took the decision not to switch on the Rumfields supply and that has remained the case to present date. Therefore, there is no chance whatsoever of potentially contaminated water entering the public water supply.

As you are aware, the Environment Agency are continuing to work with Sericol to remediate any remaining historic cyclohexanone contamination in the groundwater at the above using the best available technology, to ensure continued protection of groundwater resources and public health. This is being carried out in accordance with the methodology outlined in P20 (Methodology for the derivation of remedial targets for soil and groundwater to protect water resources) and R&D95 (Guidance on the assessment and monitoring of natural attenuation of contaminants in groundwater). Needless to say, any future decision by Southern Water to abstract water for public supply at Rumfields would take into account the full results of any investigation and only be reinstated if fit for purpose. Additionally, regular routine monitoring of drinking water would take place.

Please note. Where there exists the significant possibility of significant harm to human health, by reason of substances in, on or under the land, local authorities have powers under the Environment Protection Act 1990 to determine that land is contaminated and to serve remediation notices in order that appropriate remediation work is carried out. Under the guidance, certain sites are determined to be ‘special sites’ and come under the responsibility of the Environment Agency directly. The aim of this legislation is to compel the polluter to carry out specified works to remediate the contamination. As you are aware, Sericol acted properly by reporting the problem directly to the Environment Agency and implemented/is continuing to implement all necessary remediation works voluntarily and in full cooperation with the regulators.

6. "Is the vapour form the chemical spilt still coming out of the ground in the Westwood area?"

No, there are not any significant levels of cyclohexanone vapour being released to atmosphere in the Westwood area. As you will have noted from the Environment Agency’s response, during the initial stages of remediation at the site, in addition to pump and treat systems operated on-site to treat contaminated groundwater, a soil vapour extraction (SVE) system was used to remove solvent from the chalk column by applying a vacuum to a series of boreholes and by feeding heat generated back into the ground to aid volatilization. The cyclohexanone vapour was then recondensed in a treatment plant, which included a full vapour recovery system so that solvents were not discharged to air. SVE was stopped once negligible vapour recovery was achieved under vacuum from these boreholes.

However, the Environment Agency, Sericol and their consultants are continuing to monitor the site and to look at all available technologies for removing any potential remaining historic groundwater contamination. You will appreciate that there comes a time when the contamination being removed diminishes to such an extent that there is no benefit in continuing.

7. "Who is monitoring the private water abstraction boreholes?"

There are no private water boreholes in the area which could be affected and therefore no requirement to monitor these. The only abstraction point where a perceived risk to groundwater was identified is the public supply at Rumfields which was not switched on. Vide Q.5 or please contact the Environment Agency if you require any further information on groundwater monitoring in the area.

If you have any further questions in relation to the above, I would be grateful if you could give me a call on 01843 577081.

Yours Sincerely,

Morgan Sproates

Date:      Friday, 14 November 2008
Contact:      Cheryl Pendry
     Press and Media Manager
Tel:      01843 577 034
Fax:      01843 295 343

NEWS RELEASE           


Misleading and incorrect claims about the impact of a chemical leak in Thanet in the early 1990s have been set straight by Thanet District Council.

The council, responding to a request for information by Mr. Michael Child from Ramsgate, has made it clear that there is no chance whatsoever of potentially contaminated water entering the public water supply and that there is no risk to people living or working nearby.

The request for information has recently been made about a chemical spillage of a solvent called cyclohexanone at Sericol, which was discovered in 1994. The situation has been closely monitored by the Environment Agency, which is responsible for ensuring appropriate remediation measures are taken to deal with the spillage and Southern Water, who are responsible for protecting human health as a supplier of drinking water. Since the incident, Sericol has carried out remedial measures to remove the solvent from the chalk below the site.

Recently, there have been some incorrect reports and speculation about the incident, which the council is aiming to correct with a detailed response to questions that have been raised by Mr. Child.

The council's letter explains that there is no threat to the drinking water supply, as the supply from Rumfields was not even in use at the time of the incident and has not been used since the spillage was first discovered. This means that, even if the chemical had contaminated the groundwater, it could not have entered the public water supply. The letter explains that this situation will only change in the future if the water is determined to be fit for purpose.

In response to another question raised by Mr. Child about the safety of people living or working near to the site of the spillage, the letter makes it clear that the chemical spillage came from buried pipes and/or tanks, and therefore, it has never been present at the surface. The only exception to this is when boreholes were drilled into the chalk to clean up and monitor the chalk and groundwater, where appropriate safety measures were taken and volatile organic compounds were measured and found to be within acceptable exposure limits.

The letter also answers questions about whether any vapour form of the chemical is still being released from the ground. No significant levels of cyclohexanone vapour are being released into the atmosphere. The letter also explains that there are no private water boreholes in the area that could be affected.

Chief Executive Richard Samuel said: “These answers should help to set the record straight about this incident, which has been closely monitored over the years by the Environment Agency, with help from Thanet District Council and Southern Water. It's clear that measures have been in place all this time to ensure that there is no danger to the drinking water supply and explodes any myth that vapours may have been leaking into the atmosphere over the years. Public safety is our first concern and we felt that it was important to clear up confusion over this incident and show the safeguarding measures that have been in place for many years by the organisations involved in dealing with this.”