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necessary to negate risks posed to receptors within the coastal shore environment; it is therefore proposed to extend the discharge outfall pipe to beyond the mean low water springs line, in order to maximise mixing within seawater and eliminate exposure of potential leachate within the coastal zone.
Consequently, with the above proposed mitigation measures in place, it is concluded that no risk is posed to the coastal and marine environments by potential emissions from the processed IBA deposition within the site.
Within the Preliminary Assessment, potentially complete pollutant linkages were identified.
The potential diffuse pathways between the processed IBA and groundwater has been extensively modelled using LandSim; the fate and transport of the source potential pollutants within the unsaturated zone underlying the waste, and the potential flow paths within the groundwater system have been assessed. The results of the modelling show that the discharge of leachate from the proposed landfilling of IBA residues will have no environmental impact on the marine waters in the vicinity of New Turkeyland Quarry.
Further potential complete pollutant linkages were identified in terms of secondary receptors such as marine coastal ecological environments. It is proposed to extend the discharge outfall pipe to beyond the mean low water springs line, in order to maximise mixing of potential leachate within seawater and eliminate exposure of leachate within the coastal zone. The above mentioned LandSim modelling, together with site specific Eco-Toxicity testing, shows that there will be no environmental impact on the marine waters in the vicinity of New Turkeyland Quarry.
It concluded that, with proposed mitigation measures in place, the resultant risks posed to the surface water, groundwater and coastal environments is negligible.
A detailed proposal for waste acceptance, characterisation and compliance monitoring is submitted within the accompanying Document NTL2/1: Operation, Monitoring and Control Plan. The potential risks to the environment posed by the inert waste and the processed IBA wastes have been thoroughly examined, and it is concluded that no significant risks exist.
The emphasis in the risk assessment should therefore be placed on the Waste Acceptance Procedures, and particularly the waste characterisation and compliance monitoring measures in place, to ensure that only inert waste and processed IBA waste [at tested and proven quality] is deposited at the site.
There have been no complaints or recognised instances of surface water or groundwater contamination at the site or within the vicinity of the site during existing infilling operations.
All wastes accepted at New Turkeyland Landfill will have been classified, and if needed, processed to FSQ prior to being received on the site.
This, together with the rigorous waste acceptance procedures proposed, will ensure that only inert material and processed IBA will be landfilled at New Turkeyland.
The procedures outlined within the WDL application will ensure that the existing uncontaminated nature of the geological strata, surface water, groundwater and coastal environment will remain so.
The Landfill [England and Wales] Regulations 2002 [and Amendments 2005] specify monitoring requirements for landfill sites. These requirements refer to all classes of landfill sites, in relation to groundwater, surface water and leachate. Monitoring plays an important role in providing information that will validate the conceptual model. Monitoring also provides information for other aspects of the risk assessment process including:
If required, it is proposed to continue monitoring from within the peripheral boreholes, as installed during the site investigation carried out by MJ Carter Associates in 1999 on behalf of DLGE. The boreholes are currently occasionally monitored, samples and tested by the IOM Government Laboratory; it is proposed that this situation will continue if required.
Trigger values for background levels of natural and anthropogenic contaminants will be based on previous water monitoring results carried out by DLGE EPU at this location. The following control levels are proposed:
Control Level 1 <10% increase in average recorded concentration Control Level 2 <50% increase in average recorded concentration Trigger Level >50% increase in average recorded concentration
Exceedances will be dealt with as set out below:
Table 6.1 Appropriate Action for Groundwater Monitoring Exceedances
| Appropriate Contingency Action | Following breach of: | ||
|---|---|---|---|
| Control Level 1 | Control Level 2 | Trigger level | |
| No action | • | ||
| Advise Site Management | • | • | |
| Advise EPU | • | ||
| Confirm by repeat sampling and Analysis | • | • | |
| Review existing monitoring information | • | • | |
| Review site management/operations, implement actions to prevent future failure of a trigger level | • | • | |
| Review assumptions in conceptual model | • | • | |
| Review existing hydrogeological risk assessment, control and trigger levels | • | ||
| Consult EPU about need for corrective action | • |
A Hydrogeological Risk assessment has been undertaken for the proposed IBA infilling operations at New Turkeyland Quarry to evaluate the scope and magnitude of potential impacts upon surface water, groundwater and coastal environments.
Potential receptors have been identified, along with potentially complete pollutant linkages within the conceptual site model. Each of these potential linkages has been thoroughly examined through a series of risk assessments and site specific data collection and analyses. It is concluded that, with proposed mitigation measures in place, the resultant risks posed to the surface water, groundwater and coastal environments is negligible.
It is proposed that only processed IBA of tested and proven FSQ is accepted at the site. The risk assessment therefore refers to the waste acceptance procedures as having the crucial role in managing the risk. The procedures are required to be robust in order to ensure that only permitted waste is deposited at the site.
If required, monitoring regimes will be established to allow verification that the current uncontaminated nature of the site and the surrounding environs remains so.
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