solinst dissolved phase plume lnapl product dissolution lnapl migration saturated zone contamination petroleum hydrocarbons diesel range organics DRO superimposed plumes contaminated aquifers organic contaminant depth profiles image
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solinst dissolved phase plume lnapl product dissolution lnapl migration saturated zone contamination petroleum hydrocarbons diesel range organics DRO superimposed plumes contaminated aquifers organic contaminant depth profiles image

Assessing the transport and fate of MTBE
amended petroleum hydrocarbons in the UK Chalk aquifer

G P Wealthall, S F Thornton and D N Lerner
Groundwater Protection and Restoration Group, University of Sheffield, UK
www.sheffield.ac.uk/gprg

 solinst dissolved phase plume lnapl product dissolution lnapl migration saturated zone contamination petroleum hydrocarbons diesel range organics DRO superimposed plumes contaminated aquifers organic contaminant depth profiles image
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solinst dissolved phase plume lnapl product dissolution lnapl migration saturated zone contamination petroleum hydrocarbons diesel range organics DRO superimposed plumes contaminated aquifers organic contaminant depth profiles image
solinst dissolved phase plume lnapl product dissolution lnapl migration saturated zone contamination petroleum hydrocarbons diesel range organics DRO superimposed plumes contaminated aquifers organic contaminant depth profiles image

| 1. Intoduction | 2. Site Characteristics | 3. The Chalk Aquifer | 4. Fracture Network Characteristics |
| 5. Hydrogeology | Source Term | 6. Dissolved Phase Plume | 7. Conclusions | Full Paper |
solinst dissolved phase plume lnapl product dissolution lnapl migration saturated zone contamination petroleum hydrocarbons diesel range organics DRO superimposed plumes contaminated aquifers organic contaminant depth profiles image
The LNAPL has migrated below the water table, with dissolution of the product resulting in contamination of the saturated zone with a range of petroleum hydrocarbons including diesel range organics (DROs), benzene, toluene, m/p-xylene & o-xylene (BTEX), MTBE, TAME and other aromatic compounds. Two superimposed plumes are present in the contaminated aquifer at this site:
• A mixed plume of DROs, BTEX, MTBE and TAME extending from the site to 40 mbfl and 30 m downgradient
• A plume of MTBE and TAME, extending from 40-115 m downgradient of the site to at least 41 mbfl
• The distribution reflects the early release of the more soluble oxygenates
• The plume of dissolved phase contaminants is sinking with increasing downgradient transport due to migration along horizontal bedding plane fractures (1-3º dip)
• A semi-confining hard ground (64 mbfl) may limit the depth of plume migration, if this hard ground is laterally continuous
 solinst dissolved phase plume lnapl product dissolution lnapl migration saturated zone contamination petroleum hydrocarbons diesel range organics DRO superimposed plumes contaminated aquifers organic contaminant depth profiles image

Selected organic contaminant-depth profiles at 30 m from the source (a-e) and 115 m from the source (f). Concentration expressed as ug L-1.
solinst dissolved phase plume lnapl product dissolution lnapl migration saturated zone contamination petroleum hydrocarbons diesel range organics DRO superimposed plumes contaminated aquifers organic contaminant depth profiles image
solinst dissolved phase plume lnapl product dissolution lnapl migration saturated zone contamination petroleum hydrocarbons diesel range organics DRO superimposed plumes contaminated aquifers organic contaminant depth profiles image
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