1. Llwyneinion Acid Tar Lagoon
Dr Mark Burston
Technical Manager
Wednesday, 26 April 2017

2. Background
Assessment is being undertaken in line with the legal framework
An initial risk assessment identified uncertainties in the risks that the Acid Tar Lagoon may present
March 2006 meeting presented findings of this report
Enviros Consulting Limited was appointed by the Environment Agency to undertake the next stage of the assessment:
2.20(b) Visual Inspection & Limited Sampling for to assess risks to controlled waters

3. Key Aspects of Legislation
Part IIA of Environmental Protection Act 1990
Statutory Guidance
Strategic approach to inspection of land
Identification of land where contamination is causing unacceptable risks
Ensure land is returned to a condition whereby it is ‘suitable for its current use’

4. Source Area Being Investigated
Fullers Earth Tip
Lagoon

5. palisade security fence palisade security fence historical mine shafts
Conceptual Site Model
palisade security fence
surface water run-off
palisade security fence
Railway cutting
surface water
chemical drums
streams
No.2 Sst / Mudst ?
Half Yard Coal seam
Premier Coal seam
piezometeric groundwater level
No.3 Sst
historical mine shafts

6. Potential Pollution Linkages
vapour & dust
palisade security fence
vapour
palisade security fence
Railway cutting
surface water run-off
chemical drums
trespassing
surface water
dust
streams
No.2 Sst / Mudst
surface water
leaching to shallow groundwater ?
Half Yard Coal seam
historical mine shafts
Premier Coal seam
tar migration
piezometeric groundwater level
No.3 Sst
leaching to deeper groundwater

7. Pollutant Linkages - Human Health
Vapour and dust inhalation by site users X
Direct contact by site users / trespassers X
Vapour inhalation by off-site receptors: railway cutting & nearby property X
Dust inhalation by off-site receptors: footpaths & nearby property X / ?

8. Pollutant Linkages - Water
Lagoon surface water impacting streams ?
Lagoon surface water impacting shallow groundwater ?
Lagoon surface water impacting deep groundwater X
Dissolving tar impacting shallow groundwater ?
Dissolving tar impacting deep groundwater X
Physical tar migration impacting groundwater ?

9. Works Undertaken to Date
Testing of tar for leachability
Surface water features survey - what drains to what and where?
Surface water quality sampling programme initiated
Groundwater quality sampling programme initiated
Assessment of drum contents in Fullers Earth Tip
Assessment of dust monitoring protocols

10. Programme for Completion of Works
Groundwater and surface water sampling to assess if there are any seasonal variations (three further rounds of sampling in January, April and July 2007)
Further assessment of surface water movement
Dust sampling and analysis
Assessment of data
Reporting of works in September 2007