Land Contamination: Technical Guidance on Special Sites: Acid Tar ...
Land Contamination: Technical Guidance on Special Sites: Acid Tar ... Land Contamination: Technical Guidance on Special Sites: Acid Tar ...
7. HEALTH AND SAFETYKEY QUESTIONS ANSWERED IN THIS SECTION1. In what way are health and safety considerations influenced by the nature of acid tarlagoons?2. What are the specific issues for selection of working methods?3. What are the specific issues for selection of personal protective equipment?7.1 ScopeHealth and safety considerations are a statutory obligation for work on all contaminated sites.Within this section only specific health and safety issues which relates to work on acid tarlagoon sites is included. General guidance on health and safety issues for work oncontaminated sites can be found in HSE (1991); CIRIA (1996); Thomas Telford (1993); andBDA (1992).7.2 Specialist LegislationThere is no specialist legislation other than that which applies to conventional contaminatedland work.7.3 Specialist Working Methods and Equipment7.3.1 Working methodsWith regard to acid tar lagoons, the following factors will be relevant in developing workingmethods:• corrosive hazards from the acidity of the tars and associated soil and groundwatercontamination. Fresh acid tar has a sulphuric acid content of 65 per cent by weightand, even in old acid tar lagoons the potential for highly acidic conditions should notbe underestimated. Groundwater around a site in Derbyshire was found to have a pHless than 1, see Nesbit et al (1995);• the possibility of acidic vapours being generated (depending on the acid content of thetars, acidic vapours may either be emitted in situ or when excavations are performedinto the tar mass). Acid tar waste is frequently saturated with sulphur dioxide trappedin pores and this is easily released when the waste is disturbed. It can be released insudden puffs during excavation, see Grajczak (1995). This may also be an off-siteissue if, for example, houses are in close proximity;• toxicity considerations from hydrocarbons and other substances; and• stability issues dictate the need for particular control on access;R&D
• all personnel should follow a decontamination process that should consist of, at aminimum, the removal of overalls and boots, and the washing of hands and face.The relative importance of each of the above will depend to some extent on the kind of acidtar (e.g. whether there was pre-treatment to reduce acidity) and the age of the deposit. Withregard to stability issues, the lagoon surface may be relatively solid, especially during winter,while in summer, warming of the tars will lead to softening and expansion, leading to a loss ofbearing capacity and surface spreading. If there is sufficient local knowledge about aparticular site (e.g. if it is known to have been covered and is now tracked over by various sitevehicles) then it may be possible for staff to walk on the site surface. However, if there islimited/no local knowledge then sites must be considered unsafe and further informationshould be gathered to determine whether the site is safe to walk on.Further practical risk management issues to consider when undertaking site works on acid tarlagoons include the following:• access to the lagoons themselves should be restricted to prevent personnel fromwalking across the site and limited to those working on the site.7.3.2 Equipment• PPE should be worn at all times to protect the skin from acid burns and contact withhydrocarbons and heavy metals. In many cases the pH may be 2 or lower and in somecase below pH 1. Protective equipment should include acid resistant boots togetherwith disposable overalls and gloves as a minimum. On some sites the tars may be of amore hazardous nature requiring the use of gloves, boots, overalls etc. made ofchemical resistant (as well as acid resistant) materials (e.g. chlorinated polyethylene,viton, neoprene or PVC);• eye protection should also be worn. Where vapours are not a problem safety gogglesmay be sufficient. Full face masks may need to be worn dependent on the results ofvapour monitoring. Of particular concern are acidic vapours, also hydrogen sulphideand sulphur dioxide as well as lighter hydrocarbons which may be present within thetar.As indicated previously, Table B.1 in Appendix B provides a list of contaminants that couldbe present within acid tar lagoons and this can be used in health and safety planning.R&D
- 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 and 30: The chemicals listed in Table B.1,
- Page 31 and 32: 4.2.3 Common mistakesIt is possible
- 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: 6.4 ValidationThe principles of val
- Page 59 and 60: Verschueren (1983) Handbook of Envi
- Page 61 and 62: USEPA. Innovative Site Remediation
7. HEALTH AND SAFETYKEY QUESTIONS ANSWERED IN THIS SECTION1. In what way are health and safety c<strong>on</strong>siderati<strong>on</strong>s influenced by the nature of acid tarlago<strong>on</strong>s?2. What are the specific issues for selecti<strong>on</strong> of working methods?3. What are the specific issues for selecti<strong>on</strong> of pers<strong>on</strong>al protective equipment?7.1 ScopeHealth and safety c<strong>on</strong>siderati<strong>on</strong>s are a statutory obligati<strong>on</strong> for work <strong>on</strong> all c<strong>on</strong>taminated sites.Within this secti<strong>on</strong> <strong>on</strong>ly specific health and safety issues which relates to work <strong>on</strong> acid tarlago<strong>on</strong> sites is included. General guidance <strong>on</strong> health and safety issues for work <strong>on</strong>c<strong>on</strong>taminated sites can be found in HSE (1991); CIRIA (1996); Thomas Telford (1993); andBDA (1992).7.2 <strong>Special</strong>ist Legislati<strong>on</strong>There is no specialist legislati<strong>on</strong> other than that which applies to c<strong>on</strong>venti<strong>on</strong>al c<strong>on</strong>taminatedland work.7.3 <strong>Special</strong>ist Working Methods and Equipment7.3.1 Working methodsWith regard to acid tar lago<strong>on</strong>s, the following factors will be relevant in developing workingmethods:• corrosive hazards from the acidity of the tars and associated soil and groundwaterc<strong>on</strong>taminati<strong>on</strong>. Fresh acid tar has a sulphuric acid c<strong>on</strong>tent of 65 per cent by weightand, even in old acid tar lago<strong>on</strong>s the potential for highly acidic c<strong>on</strong>diti<strong>on</strong>s should notbe underestimated. Groundwater around a site in Derbyshire was found to have a pHless than 1, see Nesbit et al (1995);• the possibility of acidic vapours being generated (depending <strong>on</strong> the acid c<strong>on</strong>tent of thetars, acidic vapours may either be emitted in situ or when excavati<strong>on</strong>s are performedinto the tar mass). <strong>Acid</strong> tar waste is frequently saturated with sulphur dioxide trappedin pores and this is easily released when the waste is disturbed. It can be released insudden puffs during excavati<strong>on</strong>, see Grajczak (1995). This may also be an off-siteissue if, for example, houses are in close proximity;• toxicity c<strong>on</strong>siderati<strong>on</strong>s from hydrocarb<strong>on</strong>s and other substances; and• stability issues dictate the need for particular c<strong>on</strong>trol <strong>on</strong> access;R&D <str<strong>on</strong>g>Technical</str<strong>on</strong>g> Report P5-042/TR/04 46
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