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GO Contaminated Land Solutions
Remediation for commercial and residential use.
Case study: Freeport designer outlet, Alcochete.
It can therefore be adapted and applied to other settings
The UK regulatory framework is based upon:Risk assessment and Suitability for use
parkland
commercial
residential
The first step was to visit the site of the former tyre factory
A site walk over was undertaken;
including a climb to the top of the water tower
A Desk Top Study was undertaken
Orangegrove
Factory
Scrub
Past land usage, geology and hydrogeology were investigated
Design of site investigation and testing regime
Considerations for testing regime
-Likely contaminants identified in DTSHydrocarbonsAsbestosHeavy metalsPCB’s
-Relevant Environmental Quality Standards
Portuguese & UK
- How many samples on what pattern?
Consideration of site specific itemsFreeport designer outlet
Wells (pathway)underground tanks (source)
Culvert
(pathway)
Tejo estuary environmental zone (receptor)
SOURCE PATHWAY RECEPTOR
Transformer
Asbestos sheets
Leaking tanks
Fly tipping
Alluvial deposits
Groundwater
Soil
Air
Culvert
Human &fauna by:
Ingestion,
Inhalation,
Skin absorption
River Tejo
Flora - by
root take up
Property
Pollution linkage example
source
Tejo estuary potential receptor
contaminated soil
unsaturated zone
saturated zone (aquifer)
ground water flow
leaching
Potential groundwater pollution linkage
Computer modelling is undertaken by specialists if required
Assessment of site investigation results
The results for each contaminant are analysed statistically to obtain:
- A picture of the whole site
- 95% certainty of compliance
The Remediation Strategy addressed
- Contaminants identified
- Remediation proposals
- Areas requiring further investigation
- Protection of receptors during construction
- Monitoring of groundwater
- Validation testing
- Records to be kept
Frequent monitoring visits were made as demolition and site clearance progressed
Leakage had occurred from some underground tanks
The soil contaminated with hydrocarbons was placed in windrows on polythene sheeting
Validation sampling after removal of extent of assumed contamination
Location Ref. Description Comments
VS 1 Weigh bridge This location was found to be free from contamination.
VS 2Above-ground fuel oil
tank
The discovery of high concentrations of TPH at a nearby location (VS 5) meant that the area as a whole had to be excavated extensively, making sampling at this particular location impossible . However, as this location is found within an area that was sampled extensively on previous occasions (specifically, at sampling locations VS 3, VS 4, RL 6 and RL 7), it is considered that samples taken at these locations are representative of conditions at this particular location (see comments for these locations).
VS 3Below-ground fuel oil
tank
Concentrations exceeding the ICRCL guideline levels for boron, for land uses where plants are grown, were found at this location. However, as boron is considered to be a contaminant which is phytotoxic but not normally hazardous to human health, and this area is to be predominantly hard surfaced, this is not considered to be a problem.
VS 4Gravel catchment pit
area This location was found to be free from contamination.
VS 5Below-ground water
tank
When this tank was being demolished it became evident that the surrounding soils were contaminated, and a spot sample taken at the time confirmed the presence of high concentrations of TPH (see results from City Analytical Services in Appendix D.1) (omitted). Subsequently the area was excavated until no visual evidence of contamination was apparent and the excavated material was placed on impermeable pvc sheeting in order to undergo a process of bio-remediation until deemed to be fit for appropriate disposal. Windrowing material taken to CITRI, Setubal (ref. Appendix K).
VS 6a Concrete tank This location was found to be free from contamination.
VS 6b (water and soils)
Water holding tank (ETAR)
With the exception of benzo(ghi)perylene and fluoranthene, the analytical laboratory reported concentrations of arsenic, cadmium, chromium, PCB, benzene, ethylbenzene, xylene, dichlorobenzene, 1,2,4,5-tetrachlorobenzene, and 1,2,4-trichlorobenzene as being below the limit of detection of the analytical instrument, for a water sample taken from water that was found within this tank. Faecal streptococci, e-coli and other (total) coliforms were also found to be present. However, the results showed that the quality of the water was acceptable for disposal into the environment, in accordance with current Portuguese legislation (see Descrição das Actividades 30 de Março de 2001, and Descrição das Actividades 6 de April de 2001) (omitted). Soil samples taken subsequently from the excavation were found to be free of contamination.
VS 7Below-ground fuel
tank This location was found to be free from contamination.
VS 8Gravel catchment pit
area
Slightly elevated levels of boron were found at this location. However, as boron is considered to be a contaminant which is phytotoxic but not normally hazardous to human health, it is believed that this is not of concern within the context of the proposed development (see comments for VS 3). Other than the above, the location was found to be free from contamination.
VS 9Below-ground fuel
tank
Elevated levels of TPH (mineral oils) were detected. The location will be excavated further to remove the contaminated soils; following this, it will be re-tested for validation. Contaminated material deposited at CITRI, Setubal (ref. Appendix K).
VS 10 Pigment tank This location was found to be free from contamination.
VS 11 Settlement tank This location was found to be free from contamination.
Including the post remediation testing
The Validation Report was completed
And documentation to demonstrate appropriate disposal of potentially hazardous materials
Demonstrating the site’s suitability as a 75,000m2 retail and leisure development
GO Contaminated Land Solutions
We provide:
- A client focused environmental consultancy
- A project specific cost effective service
We have:- Considerable breadth of experience
- Some 15 years of working on projects involving contaminated land
- Gas works
- Petrol filling stations
- Sewage works
- Scrap yards
- Hospitals
- Industrial sites
- Water treatment works
- Potential unexploded ordnance
Experience includes the following:
This old water works required surveys of flora and fauna as well as a contaminated land remediation strategy.
Services include:
-Desk top studies
-Ecological surveys
-Remediation strategies
-Environmental impact assessments
- Retail
- Industrial
- Leisure
- Residential,
both with and without private gardens
And a variety of end uses:
GO Contaminated Land Solutions