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2.3.1 Site investigations
2.3.1.1 Need for investigations
A site investigation is crucial when assessing the risk a soil and/or groundwater contamination incident may pose towards the environment and human health. Therefore, considerable effort should be made to conduct a proper site investigation, especially if there is reason to believe the contamination might be serious and/or at a critical location such as an active aquifer or in the middle of an urban community.
This is the wrong place to cut costs. On average, the site investigation cost is small compared to the actual remediation. It may prove costly if new boreholes and sampling are needed over and over again. Doing it once properly is generally the least expensive way, as a well designed and performed investigation saves time by facilitating the permitting authority's decision-making, and may eliminate the need for further actions. A superficial and inadequate investigation report does not instil confidence and may lead to continuing requests from the authority to complete the investigation more thoroughly.
However, in an emergency situation such as a large gasoline spill or leak, there is not always time for a full-scale investigation. If the incident has happened in an area where there is no need to worry about underground utility conduits or sewers etc, then a quick soil venting operation may be the best solution, provided the environmental authority and fire brigade agree.
2.3.1.2 Role of the authorities
In most European countries, soil and groundwater remediation work is regulated. Commencing such work may require a report to the authority and often even a permit.
It is generally advisable to make contact with the authority before starting an intended remediation project, particularly in major contamination cases, where the authority may be able to offer help and advice in planning the site investigation and risk assessment, thus increasing the project's effectiveness and keeping the cost within limits. This, however, depends very much on the legislation and administrative practices in the area and, of course, the magnitude and severity of the matter.
2.3.1.3 Detailed site investigation guidelines
The Institute of Petroleum (UK) has published a document named "Guidelines for Investigation and Remediation of Petroleum Retail Sites," which covers all the essential points on this topic. The contents list can be found in appendix no. 13.pdf.
2.3.2 Practical advice
2.3.2.1 Need for consultant
If there is a soil and/or groundwater contamination problem (e.g. at a retail site), suspected or actual, it must be taken seriously, especially in those cases where the site sits on an aquifer, or is close to a community or private water supply. Also, the risk of migration to an adjacent lot should not be underestimated. Even if there has apparently been only a small leakage or spill, it must be dealt with promptly. Several small leaks left untreated may accumulate over years and could eventually pose a major problem.
Site investigation, risk assessment and potential remediation are not jobs for the layman - they require the services of a specialist. Comprehensive knowledge and understanding of the geological/hydrogeological, chemical, technical and safety aspects of the situation, as well as practical experience, are needed to perform those tasks properly.
Another very important factor is cost versus performance. Put simply, there is a lot of money at stake, as there can be a big difference in cost between various approaches to achieving the same mitigation or remediation result. These days most authorities accept the Risk Based Corrective Action principle, which means taking just those steps that are really needed to eliminate the actual risk. Further actions may not only be very expensive, but also unnecessary.
In most countries in Europe, soil and especially groundwater contamination must be reported to the authorities and necessary mitigation actions started. Understanding the legal requirements, practice and all the necessary procedures is not easy and therefore hiring an environmental consultant would be a wise move.
In most oil company-related retail chains, environmental and legal advice and guidance on these issues are available in-house. However, independent retail operators may have to find their own way. To help them, we have added a section to describe consultants' necessary qualifications and some other important elements, as well as how to find consultants.
2.3.2.2 Consultant's role
In the event of a large leak, overfill or other accidental release, either recent or in the past, which has caused considerable volumes of gasoline to get into the ground, a site investigation is needed to assess the risk to human health and the environment, and to initiate necessary actions.
The need for a site investigation may also arise when selling, buying, leasing, dismantling, shutting down or otherwise quitting or transferring the ownership or operational responsibility - and often also environmental liabilities at the same time - to another party.
The necessary qualifications for an environmental consultant include:
theoretical background in geology and hydrogeology
lots of experience in soil/groundwater investigation/remediation
risk-based problem solving approach
good reputation for getting things done, recent written references
consultant or consulting company in good financial shape
proven practical experience and knowledge of local regulations and authority: inexperience in this may be costly
good negotiating skills
willingness to take a strong stand if the problem owner is underestimating or even hiding the real problem
good office practices (standards, reporting, archives etc.)
It is in the problem owner's interest to define clearly and keep careful control of the consultant's work, especially in relation to costs, expected performance and contact with the authorities. A second opinion by another person experienced in such cases is advisable. Anything larger than a minor job should be awarded on a written contract only. The contract drafts are mostly written by consultants or their associations and therefore the problem owner should consult his own legal adviser.
2.3.2.3 How to find a consultant
The quickest and simplest methods are often the most effective: asking colleagues in the industry for their recommendations, or checking the local phone book's Yellow Pages.
If all the options above fail, one can turn to the local authorities or fire brigade for assistance and recommendations, as they have experience in working with consultants in such cases.
Also, the 112 number (Emergency Call Centre) may be able to help.
There are various other potentially useful sources:
European Options :
1) FIDIC
Clicking the link below opens the FIDIC website's front page. FIDIC is primarily a European Consulting Engineers' Association, but it does, however, cover several continents. The website contains a list of National Consultant Associations with contact details, including website links and e-mail addresses. There is also a search program to find environmental consultants with specific experience, for instance, in soil remediation in a specific country. Advice on how to select a consultant is also given, as well as suggestions for basic contracts.
Finding a suitable consultant directly from this website may be tedious. Therefore, it is advisable to contact the National Association, the communication information path is as follows:
Click www.fidic.org, / National Associations / Country.
2) EFCA
A similar service is available at www.efcanet.org, which opens the web site of the European Federation of Engineering Consultancy Associations (EFCA)
Click the www.efcanet.org, / Members / Members Directory / Country, and a country's associations website opens, indicating communication data. EFCA's Member National Associations' list can be downloaded by the PDF icon on EFCA's Home Page.
3) NICOLE
NICOLE, the Network of Industrially Contaminated Land in Europe, is a network for all aspects of industrially contaminated land. Its members come from industrial companies (problem holders), service providers/technology developers, universities and independent research organisations (problem solvers) and governmental organisations (policy makers). Click http://www.nicole.org
US options :
1) The Environmental Yellow Pages www.enviroyellowpages.com
2) DACON
This website is operated by World Bank and Inter-American Development Bank. It contains tender notices, information on on-going projects and a consultant list.
Click http://tenders.dgmarket.com/dacon, which selection opens a large consulting companies' list, arranged by country. There is also a search function.
3) Soil and especially groundwater problems are a hot topic in the United States, and there are large numbers of environmental consultants, some of whom have been developing and testing innovative remediation technologies - often with federal or state funding. Many of the American consultants have had offices in Europe for several years. European environmental consultants are usually well aware of technology developments in the USA.
There are several websites for American consultants, often sub-sites in very large websites, often titled Vendor Information. Those can be found especially on the EPA and API websites. For example, the Appendix C.24 Vendor Information System for Innovative Treatment Technologies (VISITT) can be opened by clicking http://www.frtr.gov/matrix2/appd_c/appd_c24.html
VISITT contains data on vendors of innovative remediation technologies to treat ground water in situ, soils, sludges, and sediments, including soil washing, thermal desorption, solvent extraction, bioremediation, and in situ vitrification. VISITT does not include established technologies such as incineration and ex situ ground water treatment. Technologies may be at the bench-, pilot- or full-scale. Each vendor profile includes company information, technology description, and applicable media, waste, and contaminants. Other information may include unit cost, performance, waste limitation, hardware and capacity, project names and contacts, treatability study capabilities, and references.
VISITT version 5.0 contains information on 350 technologies offered by 204 developers and vendors. About 73% of the technologies in VISITT are available commercially at full scale. About 70% of vendors provide performance data.
EPA's Technology Innovation Office has also developed a companion database to VISITT, called VendorFACTS, which contains data for site characterisation technologies.
Try these. The databases are large, especially the VISITT as it is linked with several other interesting US EPA and other websites. It also contains a formidable collection of information on various remediation technologies.
The websites are so large that getting lost is easy. It is advisable to take time and also have a notepad and pen handy to make notes of the browsing path and maybe also a printer to print the front pages of various websites to facilitate navigation next time.
2.3.3 Environmental risk assessment of the site
2.3.3.1 Introduction
Most competent authorities have accepted a Risk Based Corrective Action philosophy (RBCA), i.e. remediation is not usually required beyond what is necessary to eliminate the risk to human health from contaminants. This is an important philosophy with major implications for the cost of mitigation or remediation. The difference between doing everything possible and doing what is really needed can translate into a significant amount of money. Performing a site remediation to the point where the last gram of fuel components has been removed or destroyed on site may mean that the last gram is prohibitively expensive.
2.3.3.2 Site Assessment Studies
Numerous studies have been performed and reports published on Site Assessment. Two are provided here:
1) The American Petroleum Institute (API) approach
Strategies for Characterising Subsurface Releases of Gasoline Containing MTBE, API Pub. No: 4699.
The document uses the principles of risk-informed decision making to guide the assessment of sites affected by MTBE and other oxygenates. Risk-informed decision making considers risk factors related to sources, exposure pathways and receptors. The centrepiece of this approach is the development of a conceptual site model (CSM). A new decision framework developed by API helps the environmental site assessor to determine an appropriate starting point or an initial level of assessment from which the CSM can be confirmed.
Important risk factors are discussed in the report along with descriptions of characterisation tasks suggested for various levels of assessment. The report describes how current expedited site assessment techniques can be applied to the collection and field analysis of soil, soil gas and groundwater samples. A comprehensive guide to direct push assessment and monitoring tools, with emphasis on their proper use at MTBE-affected sites is also provided.
In addition to presenting state-of-the-art strategies for MTBE site assessment, the report is an excellent reference on the chemical and physical properties of oxygenates, their use in gasoline and behaviour in the subsurface environment. Analytical methods appropriate for MTBE detection are also discussed.
This report (pdf format) is available for downloading now at: http://api-epapi.org/filelibrary/4699c.pdf and it is free of charge.
2) Concawe, the European oil companies' association, has published a similar document, Report No: 2/97, which is more European. The Foreword, Contents list and Summary of the Concawe document are available in appendix no. 14.pdf..
The complete Concawe report 2/97 is available in appendix no. 15.pdf below. It is also downloadable.
Here are some reference documents :
Plume Formation Transport and Modeling.pdf
Presentation is a useful introduction to Conceptual Modelling Principles
Conceptualisation of hydrocarbon releases
- factors affecting plume length and concentration (physics, chemistry, biology, sampling)
- modelling considerations
- uncertainty in model calculations
- case studies
OnSite-Calculator.pdf
The US EPA developed on-site calculators accessible in internet are discussed. Very useful source of information.
Site Characterization.pdf
A useful introduction to leakage site assessment and characterization principles.
Several related website addresses are given for reference
Ex-Situ Bio for MTBE and TBA.pdf
Case studies give a good overview on soild/groundwater remediation in large leakage cases contaminating public drinking water sources. Includes site assessment and project management description.
Biodegradation and In Situ Bioremediation.pdf
The presentation gives an excellent overview on biotechnical in-situ processes capability and applicability in remediation of soil and groundwater contaminated by fuel oxygenates. Remediation cost elements are also discussed.
Ex-Situ Bio for MTBE and TBA.pdf
The presentation gives an excellent overview on several biotechnical ex-situ processes capability and appicability in remediation of groundwater contaminated by fuel oxygenates. Reactors and other equipment are described.
A Comparison of 3 Ex-situ Treatment Systems.pdf
An extensive remediation case study of a very large and difficult fuel contamination plume. SIte assessment and remediation methods and results have been described as well as general project management.
Monitored Natural Attenuation for MTBE & TBA.pdf
The presentation covers several issues in using MNA in MTBE and other fuel oxygenates in remediation of soil and groundwater. Conditions, where MNA is an acceptable method are described and similarly also situations where MNA should not be accepted as a sole process.
Useful information can be extracted from extensive case studies in this presentation.
Air Sparging.pdf
This presentation provides key information on the applicability, requirements and equipment of this remediation process as well as an extensive list of relevant information sources.
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