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BOC Immingham Dissolved Acetylene Project Environmental Statement: Vol. 2 Main Text
Contaminated Land
7.45 As discussed above, historical maps from 1888 to present day 9 indicate that the field has not been
developed and so the ground is not expected to be contaminated as a result of historical land use.
Ground Investigation (GI) works have been undertaken recently by ESG. The full GI report,
including the result of sampling for potential contaminants, will not be available until after the ES
has been finalised. However, ESG has confirmed that all soils encountered were natural, no
made-ground was described in the borehole logs, there were no visual or olfactory indications of
potential contamination and all soil vapour headspace readings were below instrument detection
(i.e. there was no indication of volatile hydrocarbon contamination in the soil). This supports the
view that the soil beneath the site is not likely to be contaminated, but this will be confirmed (or
otherwise) once the full GI Report has been received
Geology
7.46 Published geology shows the development site to be underlain by Estuarine Alluvium comprising
clay, silt and sand resting on Glacial Till (Superficial Deposits). These are underlain by the
Cretaceous White Chalk Formation (Bedrock).
7.47 Site-specific geology, based on preliminary borehole logs, provided by ESG, indicates that the
development site is underlain by:
� Estuarine Alluvium (Recent Deposits):
- stiff, brown and orange-brown, slightly sandy CLAY from surface to between 1.1 and
2.7 m bgl (0 to -0.88 m AOD), with a thickness of 1.1 to 2.7 m
- soft, brown-grey, silty CLAY becoming very soft and with occasional shell fragments
towards the base to between 6.4 and 8 m bgl (-4.48 to -6.54 m AOD), with a thickness of
4.2 to 6.2 m,
- either black, plastic, amorphous PEAT (BH1, BH4, BH5, BH7) to between 7.2 and 8.3 m
bgl (-5.56 to -6.57 m AOD) with a thickness of 0.5 to 1 m, or
- silty CLAY with PEAT (BH3, BH6, BH7) to 7 and 8.4 m bgl (-5.08 to -6.94 m AOD) with a
thickness of 0.4 to 0.6 m;
� Glacial Till (Superficial Deposits):
- firm to stiff, brown-grey, slightly sandy, slightly gravelly CLAY to between 9.1 and 14.5 m
bgl (-7.39 to -12.7 m AOD), with a thickness of 4.8 to 6.5 m where proved,
- medium-dense, grey, slightly clayey, slightly gravelly, fine- to coarse-grained SAND to
between 15.9 and 16.2 m bgl (-14.4 to -14.47 m AOD), with a thickness of 1.7 to 2.7 m
where proved, and
- stiff, grey, slightly sandy, slightly gravelly CLAY to between 18.2 and 18.4 m bgl (-16.47
to -16.94 m AOD) with a thickness of 2 to 2.5 m where proved; and
� Cretaceous White Chalk Formation (Bedrock):
- CHALK proved to 25.45 m bgl (-23.72 to -24.04 m AOD).
7.48 The intrusive investigation carried out on the adjacent BOC facility in 1990 proved a similar
geological sequence.
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