Land Contamination: Technical Guidance on Special Sites: Acid Tar ...

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4. SITE CHARACTERISATIONKEY QUESTIONS ANSWERED IN THIS SECTION1. Which information sources should be used for the desk study?2. How should the investigation be approached?3. What are the main differences from a conventional contaminated land investigation?4. Are special sampling and sample handling procedures required?5. What should be analysed for, when and how?4.1 ScopeThis section provides information on the specific approach that should be followed whenconducting desk studies and site investigations on land associated with acid tar lagoons. Theoverall procedures involved in characterising contamination on such sites have many aspectswhich are common to other types of contaminated land site. Consequently any such genericguidance is explicitly excluded from the scope of this section which relates solely to theparticular issues which are exclusive to acid tar lagoons.4.2 Desk Study4.2.1 Key issuesAcid tar lagoons often show surface expression as a result of tars breaking through the groundsurface – the classic blackened ground without vegetation. This will be less apparent if thesite has been hard-surfaced or recently re-surfaced with gravel for example. A walk-oversurvey may allow the presence of tar to be identified and for an approximate area to beinferred. The ground surface is likely to be flat with surface expression related to thepresence of overburden only.It may also be possible to infer the extent of deposition from studying topography on oldhistorical maps or aerial photographs, for example, by looking for former voids near acid tarproducers that have been infilled.4.2.2 Operational time periodsIt may be possible to infer the likely size of an acid tar lagoon from knowledge of theproduction history of the refining site (see Section 2). For example, as a ‘rule of thumb’, thequantity of acid tars produced at a benzole refinery site is 10 per cent of the correspondingcrude benzole production on a weight-for-weight basis. Section 2 also gives probable averagequantities of tars for each type of refining process.R&D <strong>Technical</strong> Report P5-042/TR/04 20
4.2.3 Common mistakesIt is possible that coal tars could be mistaken for acid tars, as both will tend to give rise tobarren ground – the pH is the factor distinguishing acid tars. The mobility of acid tars andtheir propensity to flow upwards and laterally creates the potential for contamination of areaspreviously thought to be free of acid tars.4.2.4 Desk study check-list for acid tar lagoonsHave the following specialist information sources been approached?- Department of the Environment Industry Profile: Gas works, coke works and othercoal carbonisation plants, 1995.- Department of the Environment Industry Profile: Oil refineries and bulk storage ofcrude oil and petroleum products. 1995.Have historic maps and aerial photographs been studied to identify the location of formervoids that have been infilled?Has the likely source of the acid tars, in particular the nature of the process, beenestablished and any information on the production history and operational period ofproduction?Were any of the following features present on the site?:- black or dark brown staining, evidence of oozing tars or unvegetated areas;- weathered surface tars;- hollows/depressions;- clay/gravel/sand pits;- bunded areas;- odorous areas; and- areas of former fires.If yes to any of the above has the extent of these been established?4.3 Site Inspection and Investigation4.3.1 Site inspectionThe site inspection visits should always be based on the maximum available information thatcan possibly be obtained from the desk study phase and an initial conceptual model of the site.Although this is also the case with other types of contaminated land it is particularly importantwhen dealing with acid tar lagoon sites due to the explicit physical hazards that may bepresent. Site staff will need to be equipped with the relevant level of personal protectiveequipment (PPE) and trained accordingly (see Section 7 for health and safety aspects).As noted above, it may be possible by site inspection to gain an impression of the extent ofacid tar disposal from its surface expression. The aspects to look for include generally flatland (although this may have been modified by deposits of superficial wastes), absence ofR&D <strong>Technical</strong> Report P5-042/TR/04 21
Page 1 and 2: Land Conta
Page 3 and 4: CONTENTSFOREWORDiGLOSSARYii1. Intro
Page 5 and 6: FOREWORDPart IIA of the Environment
Page 7 and 8: CresolsCreosoteDCRDesorptionDesulph
Page 9 and 10: PVCRCRASelosafeSodium saltsSodium h
Page 11 and 12: 1. INTRODUCTION1.1 BackgroundThis r
Page 13 and 14: SECTION 2: INDUSTRIAL PROCESS/FACIL
Page 15 and 16: 1.5 Linkages Between the Gu
Page 17 and 18: 2.1.2 Overview of acid tar lagoon s
Page 19 and 20: Overall CommentsAcid tars can be of
Page 21 and 22: White Oil• Acid tar lagoons from
Page 23 and 24: Box 2.5 Scenario: Acid tar disposal
Page 25 and 26: 3. CHEMICAL AND PHYSICAL CHARACTERI
Page 27 and 28: Table 3.1 - General Physical Charac
Page 29: The chemicals listed in Table B.1,
Page 33 and 34: Geophysical methods, such as resist
Page 35 and 36: Investigation locations will need t
Page 37 and 38: • gas chromatography by simulatin
Page 39 and 40: 5.2.2 Water environmentThere is lit
Page 41 and 42: 5.3 Assessment of Investigation Dat
Page 43 and 44: 6. REMEDIATION ASPECTSKEY QUESTIONS
Page 45 and 46: 6.2.5 Solidification and stabilisat
Page 47 and 48: Box 6.1 Example of Remediation of A
Page 49 and 50: 6.3 Natural AttenuationNatural atte
Page 51 and 52: Table 6.1 - Remedial Options/Techni
Page 53 and 54: Table 6.2 - Remedial Options/Techni
Page 55 and 56: 6.4 ValidationThe principles of val
Page 57 and 58: • all personnel should follow a d
Page 59 and 60: Verschueren (1983) Handbook of Envi
Page 61 and 62: USEPA. Innovative Site Remediation

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