When a metal plating works was discovered to have been contaminating local residents' gardens, the environmental health department had to embark on a sensitive clean up operation. Charles Bradfield and Joanne Ellis look at the lessons learned.

Part IIA of the Environmental Protection Act 1990 (EPA) has been in place for over a year now.1 As local authorities start to implement their strategies for identifying contaminated land, candidate sites will be identified and it is likely that these will include a number of existing residential developments. Any supplementary assessment will require extremely sensitive handling with respect to the media and local residents. Recent enforcement action taken by Wokingham District Council under the pre-existing legal framework of statutory nuisance provides key practical lessons learned and a basis for comment on application of the new contaminated land regime.

INITIAL COMPLAINT
In January 1998, Wokingham DC received a complaint from local residents who were concerned that an adjacent metal plating works had contaminated their gardens. Soil samples were taken from two gardens of the residents concerned and these indicated the presence of elevated levels of cadmium to a maximum concentration of 88mg/kg. This level is significantly higher than the ICRCL trigger level of 3mg/kg and the Dutch standard of 12mg/kg.2 3 The Berkshire Health Authority was consulted and it was agreed as a precautionary approach that the occupants of the dwellings adjacent to the works should be advised not to eat any home grown vegetables or let young children play directly with the garden soil. Letters to this effect were sent to all properties whose gardens backed on to the metal plating shop, as well as the original two properties where the samples were taken. Following receipt of these letters, a number of residents contacted the local media and pressure was on to resolve the matter as soon as possible. Tenders were invited for an assessment of the level and extent of contamination in all 12 surrounding residential properties and the plating works itself. Applied Environmental Research Centre (AERC) was commissioned to carry out the assessment in May 1998.

RISK ASSESSMENT
A phased investigation was carried out to establish the extent and level of contamination and an assessment of the associated risk to residents of the adjoining properties. The investigation found high levels of heavy metal contamination, particularly cadmium up to 755mg/kg on the factory site and 550mg/kg in the neighbouring gardens. The assessment concentrated on cadmium as the principal hazard, as other elevated concentrations were proportionately low and generally associated with cadmium. In the absence of any mandatory guidance, and as the UK ICRCL guidance has no action level for cadmium, the Dutch criteria were used to assess risk. The Dutch standards give intervention values (IV) for soil concentrations calculated for a standard soil - for cadmium the IV is 12mg/kg. Site specific IV's were recalculated taking into account the percentage clay and organic matter which affects the availability of cadmium. Based on this, IV's for cadmium were taken as: topsoil 10mg/kg and subsoil/made ground 8mg/kg. In addition, the depth of contamination, the mobility of cadmium within the soil and analysis of edible vegetables collected from residents' gardens were also used to assess risk. Analysis of vegetable samples taken from the gardens found cadmium levels in some vegetables up to 0.57mg/kg. The maximum cadmium concentration in food recommended by the European Commission is 0.1mg/kg.4

LIAISON WITH HEALTH AUTHORITY
The risk assessment concluded that there was a moderate to high risk in four of the adjacent properties, with a level of contamination that was potentially injurious to the health, but a low risk in the rest. The results of the investigation were discussed with Berkshire Health Authority and the Guys and St Thomas Toxicology Unit. In two of the worst affected properties, residents had lived there for many years and had eaten a significant amount of home grown vegetables. As cadmium is a bio-accumulator, it was decided to collect blood and urine samples to establish whether there was any accumulation of cadmium within their bodies. Results showed no build up of cadmium.

CONSIDERATION OF ENFORCEMENT ACTION
As the new contaminated land regime was not yet in force, and there was no certainty as to when it may be, the serving of an abatement notice to require the remediation of the land was considered. To do this, the person responsible for the nuisance had to be identified and if this could not be established then any action would have to be taken against each individual owner. Following discussions with Counsel, it was considered necessary to carry out further investigation to confirm that the source of contamination was the plating site and to demonstrate that there was ongoing migration of the contaminant from the plating site to the gardens. For this purpose the history of the site was researched further and additional soil, water and vegetable samples were taken. The plating works had closed shortly after the initial investigation (although not as a consequence of the council's actions) but metal plating had taken place on the site since 1938, with houses being constructed after the works in the 1960s. The investigation showed the works and houses had been built on filled land which potentially could be a source of contamination. It was also a possibility that the contamination could have been caused by the dumping of waste from the works prior to construction of the houses. The integrity of the underground settlement tanks was also tested and found to be leaking at a rate of 0.117 litres/hour (12.8 litres over five days) which would have been a source of contamination over the years. Although, as the plant had now shut down, this would not be a contributory factor once the tanks had been emptied. Planning records showed that waste from the plant had gone to a soakaway in the east of the site until the late 1960s and this would have been a significant source of contamination. In order to demonstrate that the contamination had migrated from the works site into the gardens, and that there was ongoing migration across the boundary, further soil analysis and groundwater sampling was carried out to show that cadmium was leaching into the groundwater and hence in a mobile form. From leachate and soil fractionation tests it was concluded that cadmium was mobile and had a high potential for plant uptake; the raised cadmium levels found in the vegetable samples backed this up. The presence of other contaminants typically associated with electroplating within the adjoining gardens also indicated that the cadmium contamination had originated from the electroplating works.5 Contaminated land assessments carried out on a former petrol storage depot adjacent to the site showed that groundwater movement was in a north to south-east direction. The pattern of contamination found correlated with this.

SERVING NOTICE
It was concluded that it was highly probable that the source of cadmium was from the metal plating works and that there was a potential for the ongoing migration into neighbouring gardens. Hence, it was decided to serve an abatement notice under Section 80 of the Environmental Protection Act 1990 requiring the owners of the site, as the persons responsible for the contamination, to remediate the four affected gardens. They were also required to remediate the factory site itself, as there was a significant pool of contamination that could recontaminate the gardens. AERC prepared a remediation method statement that formed the schedule of works to the notice. It was considered that, as residential gardens were affected, "dig and dump" was the only feasible method of decontamination. Containment methods were considered for the factory site but would not have been practicable. As the notice required works to be carried out on land which was not owned by the person responsible, legal consents were obtained from the owners of the four affected houses. This enabled any contractors to enter the properties for the purpose of carrying out the works required by the notice. The notice gave three months for the works to be completed.

WORKS IN DEFAULT
The owners of the factory site were trying to sell the property to a developer who would then carry out the remediation works prior to developing it for residential use. Although there were a number of developers who had shown an interest in the site by the end of the specified time, the sale of the land, or the remediation of the site, did not appear imminent. Due to the potential cost of remediation, the decision to carry out works in default was put to the Environmental Services Committee and it was decided to proceed with the works. Supplementary credit approval had been provisionally agreed by the then DETR prior to this committee and that assisted members in their decision, especially when considering the financial liabilities for the council. The consultants prepared tender documents and five tenders were received - the lowest tender was accepted. AERC was employed as project manager for the remediation works and a relatively short time period of nine weeks was given for the contract to minimise disruption for the residents.

GARDEN RESTORATION
Prior to works commencing, the local authority and the contractors held discussions regarding the restoration of the gardens. Detailed photographic and written records of the contents of the gardens had to be made before the replanting of the gardens was agreed. Some residents wanted slight changes to the restored gardens and this was accepted where it did not increase the overall cost of restoration. As the works were being carried out in default of a notice, it was important that all works were reasonable so that they could not be appealed against when the costs were later reclaimed. The process of recording the original contents of the gardens and agreeing the restoration proved to be one of the most contentious and time consuming elements of the works. The whole process required close liaison between contractors and residents and eventually, the residents were asked to sign schedules of agreed works for the restoration in order to minimise any potential disputes after completion of the works. The residents were also asked to sign an agreement to allow the landscapers access for maintenance, which they required in order to provide the one year guarantee for the survival of the plants. Maintenance was particularly important as replanting was in the summer months, which reduced the chance of all plants surviving - particularly where fairly large trees were being planted.

THE WORK PROGRESSES
As with many remediation projects, additional pockets of contamination were found as works progressed. This caused problems as authorisation could only be given for works in accordance with the requirements of the notice; ie removal of cadmium to abate a statutory nuisance and not remediation of the site to make it suitable for residential use, although it was likely to be developed for housing. This meant that further risk assessments had to be carried out as remediation progressed and in some cases the contamination was not able to be removed; eg small pockets of cyanide found along the boundary of the site. The areas were marked so as to be easily identifiable should further remediation be required. In other cases, a practical judgement had to be made, often to the horror of the council's legal advisors.

RECLAIMING COSTS
Table 1 shows the approximate final cost of the remediation works. The notice to recover costs was served in February 2000 and was not appealed. While the value of the land was estimated as ú200,000, the company had no assets except the land itself and had considerable debts. Thus, the only possibility of recovering any of the council's costs was through the sale of the land and even then, it is unlikely that the costs will be fully recovered. The charge was placed on the land and formally recorded with the land registry. Although initially disputed by the mortgage companies, it has now been accepted that the council's charge takes priority over any other charges on the land. In the early stages management of the media became very important as in this case, there was already a neighbouring contaminated site that had generated a lot of local interest. When the initial letters were released to the media via the residents concerned, there was some comment that the council had tried to "cover it up". In fact, officers were trying to ensure that the residents were the first to hear any news, before the media. Following this, at each key stage, news releases were carefully co-ordinated so that residents, elected members, and the media received written information and verbal briefings at the same time. There was always pressure to give time periods for completion of each stage, so it was important that the time given was generous, as each stage seemed often to identify further problems that lengthened the process. A large number of calls were also received from concerned residents in the general locality, mainly stimulated by scare mongering literature which was distributed. As a result, newsletters were widely distributed at key stages by the council, keeping residents informed and providing contacts for further information. These seemed to be successful in addressing people's fears and the council received surprisingly few numbers of calls as a result. The issue of providing the public with information, while not blighting properties in the area, proved very difficult. To a certain extent, this had been taken out of the council's hands by the residents' contact with the media. Undoubtedly, the properties concerned were blighted and residents who were looking to move found their lives in limbo until works had been completed. During remediation work there are nearly always additional areas or types of contamination which had not been identified in the site investigation. Hence in writing any notice for decontamination works it is important to allow enough flexibility to tackle these problems as they arise while making the requirements specific enough so as not to leave the notice open to successful appeal. The reinstatement of gardens is an area which most contractors will have had little or no experience of, but which will be the most important from the residents' point of view. The appointment of experienced landscape gardeners is essential and input from the council's own landscapers proved valuable in drawing up specifications for reinstatement. The outstanding impression from completion of such a job is the amount of officer time involved not just during initial investigations but throughout the course of the works. The prospect that the new contaminated land regime may identify a number of sites that need remediation and involving a larger number of properties would have an enormous impact on the work of environmental health departments. If this problem had arisen today it would now be dealt with under the new contaminated land regime. As contaminant specific guidance is due to be released it is hoped that it will be easier to justify the conclusions of any risk assessment, although detailed site specific assessments would still be needed. However, until this guidance is released it will be problematic to proceed with any action under the new legislation. One concern when proceeding with the statutory nuisance enforcement was that the guidance would be released during the course of this action, which could then discredit the risk assessment if it contradicted its conclusions. However, no specific guidance was forthcoming following discussions with the DETR. In this particular case the site had been used for electroplating for at least 60 years, in that time there had been six owners as far as could be established. The accepted method of disposal and understanding of pollution have changed greatly in that time. The identification of appropriate persons, apportioning costs between liability groups and identification of groups that should be excluded from liability would become extremely complicated and time consuming under the new regime. The overall success of this job was helped by teamwork - both internally and with the contractors involved.The next cases will now be under the new legislative regime, and the authors look forward to some new learning experiences in this complex field of work. Joanne Ellis is Senior Advisor at Applied Environmental Research Ltd (AERC), an environmental consultancy based near Colchester, Essex. Chas Bradfield is Environmental Health Manager (Environmental Protection and Housing) at Wokingham District Council, a unitary authority in Berkshire. The opinions voiced by the authors in this article are their own and do not represent the views of their employers.

REFERENCES
1 HM Government, Environmental Protection Act 1990, HMSO.
2 Interdepartmental Committee on the Redevelopment of Contaminated Land (ICRCL), 59/83: Guidance on the Assessment and Redevelopment of Contaminated Land, DoE, 1983.
3 The Independent Environmental Health Co-operative, Target and Intervention Values for Soil and Groundwater in the Netherlands.
4 European Commission, draft Commission regulation setting maximum limits for certain contaminants in foodstuffs; amending commission regulation EC 194/97 of 31 January 1997, setting maximum limits for certain contaminants in food, EC, 1997.
5 DETR, Industry Profile Metal Manufacturing, refining and finishing works - electroplating and other metal finishing works, HMSO, 1995.
6 Johnson G., Scholes K., Exploring Corporate Strategy 5th Edition, Prentice Hall Europe, 1999. Readers may be interested in purchasing the WHO Environmental Health Pamphlet on "Contaminated land", available from the publications department for ú7.60 each. Tel: 020 7827 58823 or e-mail: publications@chgl.com