Ask any local authority how they are implementing their Part IIA responsibilities and you will get a different answer. By now, all local authorities in Britain will have written and had approved their contaminated land strategy document which should set out how they plan to implement Part IIA in their own area. For many local authorities this will be a very broad set of statements, which stops far short of addressing the actual procedures that will be used to tackle the issue. How far local authorities have moved on from this point varies considerably - with some surging ahead while others watch the dust gather on the original documentation feeling unable, for one reason or another, to take the first steps in the practical implementation process.

The progress of any particular local authority seems to depend on a whole multitude of factors, including available funds, availability of data, format of data, type of software (if any), and perhaps most importantly staffing levels. There is a wide variation in the ability of different local authorities to provide these basic tools to those working with Part IIA issues, and this has left some local authorities feeling unsure as to how they should move into the implementation phase of this work.

Although funding was made available to help local authorities implement Part IIA, it was not "ring fenced", and as a result some seem to be working without any, or perhaps minimal additional funding for required purchases. Environmental health departments need an adequate toolkit to implement Part IIA, comprising of:

• personnel;
• data - both modern day and historical;
• a system for managing the data; and
• a system for implementing Part IIA in line with the contaminated land strategy document.
  

PERSONNEL

This is the key first requirement for Part IIA implementation. Discussions have shown that some departments that have been working towards Part IIA have been stopped in their tracks if additional responsibilities have been placed on their staff, or indeed if staff have moved their place of employment. Some local authorities have whole teams of people dealing with contaminated land, while others can release only part of an employee's time for Part IIA. As far as the implementation of the legislation is concerned, it is the completion of work relative to the objectives in the contaminated land strategy document that is important, and as long as some progress - however slow - is being made, then this is better than none at all.

Some initial strategies were written up within incredibly short time periods for Part IIA implementation, which may well have proved too challenging when it came down to actually doing the work. Others however, have stated that it will take five years or more to implement this legislation subject to annual review. Although this gives a lot of opportunity for procrastination, it also provides local authorities with limited resources a realistic goal to aim for when practically undertaking the required tasks.

DATA

The data requirement for successful implementation is fairly substantial. Not only is there a requirement to know the location of modern day land-use in order to identify those sensitive to historical contamination, but the whole substance of Part IIA is to identify and locate areas that have been under historical industrial use of some sort which may have caused contamination of the land in the past. Current environmental data detailing geology and water resources, for example, are also required in order to assess the likelihood of contamination moving away from the original industrial site via so called "contamination pathways" affecting modern day sites at more remote locations.

To assist environmental health practitioners with Part IIA implementation, the following data will be helpful:

• Historical maps:
  Information about the industrial history within a local authority area is the starting point for implementing Part IIA. The local authority may well hold archive copies of historic maps charting the development of the borough or district, and if not held at this level, there may well be rich archives at county level. If such archives do not exist, then this mapping can still be purchased, the most commonly quoted supplier being Landmark. The cost will vary according to the size of the area under consideration and could be substantial. In some cases discounts have been offered when different local authorities work together and arrange a bulk purchase. Mapping can be purchased in different digital formats suitable for specific GIS and other electronic mapping systems. Some local authorities are making use of student labour to create digital datasets from existing paper mapping which has proved a cost-effective alternative.

• Aerial photography:
  This is a useful resource to have whether in paper or digital format. However, purchase from external suppliers is likely to carry a considerable cost if the photography is fairly recent. Aerial photographs allow the assessment of features such as slopes (if viewed stereoscopically), land use and ground cover (for example, to assess the integrity of a landfill cap) without having to visit the site.

• Geological maps:
  Geological information is key to understanding the groundwater situation for a site. Highly permeable geology will allow water to pass through it, whereas an impermeable rock will not. This is important when considering the existence of contamination pathways underneath potentially contaminated sites. This data may already exist at the local authority. If not, it can be purchased from the British Geological Survey (BGS).

• Environment Agency data:
  This is available in digital format from the EA on CD. It contains many data sets, including water management boundaries, licensed waste disposal sites and licensed water abstractions, which are sensitive receptors for contamination.

• English Nature data: This is freely downloadable off the website (www.english-nature.co.uk) in formats compatible with Microstation (.dgn), MapInfo GIS, and .DXF (generic). There are two options for data download. One is 100km2 (comprising SSSI, special areas of conservation, special protection areas, Ramsar sites, ancient woodlands, and national nature reserves). The other is all England datasets (comprising the same data except for the exclusion of ancient woodlands and the inclusion of natural areas, and character areas).

As the above list, which is by no means exhaustive, shows the data requirements are considerable. The environmental health department's financial position, and the software investment that it is faced with will have a significant impact on the quantity and format of data that can be utilised. The data could all be digital and integrated into a inter-departmental GIS, or it could be mainly paper mapping which can either be used in this format, or could be digitised for a local GIS using students or volunteer workers. The importance of investing in good digitising hardware and software should not be underestimated.

A SYSTEM FOR MANAGING DATA

While it may seem that a GIS software system has to be used for Part IIA, it can be approached without one. The decision has to be made between making the financial investment - in order to make use of such technology - as opposed to working outside an electronic system and accepting the considerably longer time-investment that will be necessary to approach this task manually. Some of the more affluent local authority departments are considering bespoke software systems from external suppliers, which are designed to integrate into existing software and database systems whereas others are trying to work out how simple spreadsheets can be put to good use.

Once the decision on the type of system to manage Part IIA has been made, if GIS is to be used, there are many different systems to choose from. Some of the well-known systems such as ESRI's, ArcView and MapInfo may cost slightly more than others. However, they bring with them advantages, such as more compatible partner extension packages, some of which are specifically designed to help with the implementation of Part IIA and can also be incorporated into the strategy. Cheaper, yet less compatible GIS systems can be implemented, but will probably remain as stand alone systems that are used in single departments.

Besides the purchase of GIS software, there is also the issue of whether the local authority has been able to recruit and retain technical staff with the knowledge and training to utilise the systems to their full advantage. This should not be ignored if the full benefit of GIS is to be gained both for Part IIA and for subsequent projects.

A SYSTEM FOR IMPLEMENTING PART IIA

The implications of how this is done in line with the contaminated land strategy document is not often fully appreciated until the job has been under way for some time, and some of the difficulties and prioritisation issues are being dealt with. When prioritising the risk associated with the identified potential source sites, the most important thing is to treat them all in the same way. If certain data sets are incomplete, it is better not to use that information at all. If it is applied to some sites and not others, the assessment of risk across all the sites will not then be comparable. If certain data is not considered for all sites, at least the integrity of the relative risk defined for each site is maintained.

Unfortunately, regardless of the resources available to each environmental health department, the size of the job facing the majority of authorities is fairly similar. Admittedly, some large unitary authorities with a rich industrial history do have a greater than average land contamination problem to tackle, while some smaller authorities with many greenfield areas, could have a relatively small number of potentially contaminated sites to deal with. It would, however, be fair to say that managing Part IIA responsibilities is acknowledged as a significant task for the majority of authorities who have actually sat down to assess exactly what it really involves.

Many different approaches are being used to assess the level of risk that historical contaminative land use poses to modern day receptor sites and these tend to relate to the issues already discussed. In the case of local authorities that have adopted the Contaminated Land Risk Analyst (CLARA) model, the amount of automation adopted within ArcView GIS, and the amount of digital as opposed to paper-based data to use, is for the local authority to decide.

CASE STUDY

Darlington BC, which uses the CLARA system, is a fairly typical local authority, which has employed a single staff member to take responsibility for risk screening all sites. According to Tracy Hilton, technical officer at Darlington BC, a data trawl and initial investigation revealed that Darlington has over 2,000 sites that require both screening for pollutant linkages and prioritisation for inspection. The council decided that an efficient way to handle the sites would be to place them into categories based on their nearest identifiable receptor areas, ie areas of land with a potentially contaminative source and having a relevant receptor nearby such as residential property with gardens, controlled waters, ecological systems etc. By doing this, says Ms Hilton, the source areas are then ready for risk assessment using a system of priority based upon the sensitivity of its nearest receptor. The risk screening process involves the following: defining the receptor themes; screen digitising the source areas using GIS; loading the source themes into CLARA; and performing systematic risk assessments.

As Ms Hilton explains, the risk assessment software chosen must be able to handle this approach and provide robust risk screening. It is also important that it has a scoring system, which is sensitive enough to generate a discernible final output score without showing the clustering of similarly ranked sites. "CLARA has shown to provide this because the default land use types and scores supplied with the software can be customised," says Ms Hilton. "We wanted to test this by adding categories of land use adapted from the Department of Environment industry profiles which were assigned a score of between 1-10, dependant on the potential seriousness of the hazard associated with the type of industry." The council also wanted to trial the risk assessment software so as to avoid making a purchase and finding out several months later that the software could not meet its specific needs.

According to Ms Hilton, CLARA uses a thorough questionnaire dialogue, which provides a robust and comprehensive risk-screening tool and takes account of local development, groundwater, surface water, air quality and human health. The programme operates at the GIS interface, which means that historical and modern data sets can be used for analysing particular sites. An authority can, for example, load a data set of landfill information straight into CLARA and commence risk assessment. "The programme is also excellent for handling data-in-the-making, for example, the source data sets digitised in-house," says Ms Hilton. "If a risk assessment is required for a particular site, it can be loaded into the relevant theme in CLARA and the risk assessment process undertaken while simultaneously adding new information to that theme as it unfolds. This is because CLARA updates the scores and rankings of each site as changes and additions are made."

As Darlington BC has found, CLARA also has an in-built reporting facility, which allows the efficient storage of site information and the option to send secure reports to relevant stakeholders. The council's experience in using CLARA as a risk assessment programme shows that a methodical approach, making best use of available resources, can be used to implement a thorough and defensible approach to the Part IIA legislation. Hopefully, Darlington BC's experience will give some comfort to other local authorities that feel that they have neither the budget nor the personnel to deal with their Part IIA responsibilities properly.

Dr Jo Gilman is senior consultant with Conestoga-Rovers & Associates (UK) Ltd.