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BOC Immingham Dissolved Acetylene Project Environmental Statement: Vol. 2 Main Text
Operation
Operational Phase Conceptual Site Model
7.72 An Operational Phase CSM has been developed to identify any changes to contamination
sources, receptors and pathways and a qualitative contamination risk assessment has been
carried out and compared with the baseline to identify potential impacts during the operational
phase. The methodology has been described earlier in this Chapter. Operation of the proposed
development could include the following potential changes to contamination sources, receptors
and pathways:
� changes to receptors:
- human receptors will now comprise site occupants and visitors.
- controlled waters and offsite receptors will remain the same as for the baseline,
- the development itself will be a new (property) receptor by direct contact with
contaminants in soil and shallow perched water groundwater (if present) and by
accumulation of vapours and ground gas into buildings and enclosed spaces;
� changes to contamination sources (if present) because of construction, which could include
removal or volatilisation of contaminants (source removal);
� importation of ‘clean’ material (if required) which would present pathway barriers to human
and offsite property receptors and reduce infiltration of rainfall and likelihood of leaching of
any contaminants already present from the unsaturated ground to the groundwater;
� changes to pathways which would include placement of large areas of hardstanding acting as
pathway barriers to human and offsite property receptors and reducing contaminant leaching
and run-off to surface water and groundwater receptors, or introduction of any below ground
storage areas which could form new pathways (it is noted that underground storage areas
are not expected for the Dissolved Acetylene Project);
� installation of passive or active ground gas solutions in infrastructure (if necessary) to prevent
accumulation of vapours and ground gas removing pathways to human and property
receptors;
� storage, transport (including above and below ground pipework and manually) and handling
of raw, intermediate, ancillary and waste materials (such as calcium carbide, sulphuric acid,
sodium hydroxide, acetone, glycol, biocide, softeners, paints, thinners, oils, fuels, lime,
chemically treated and wastewater etc.), which could leak spill be entrained in rainwater runoff,
potentially introducing contaminants into the ground or discharge to surface water;
� infiltration of any contaminated firewater to ground during an incident, potentially introducing
contaminants into the ground;
� leaking of contaminants from the Deluge lagoon to ground (following an incident);
� use of plant and equipment on the development site which could accidentally leak fuels and
oils and introduce new contaminants into the ground.
5100935.404 Environmental Statement August 2011 106