CDOIF Guidance

CDOIF

Chemical and Downstream Oil

Industries Forum

CDOIF is a collaborative venture formed to agree strategic areas for

joint industry / trade union / regulator action aimed at delivering

health, safety and environmental improvements with cross-sector

benefits.

3.2.4

Soil or Sediment (Land/Water)

[Refer to DETR 1999 Table 7]

For sediment, the DETR guidance refers to a change in overlying water quality - thus

sediment should be considered a pathway and the MATTE threshold to consider is the

one for the relevant overlying water or particular species.

For Soil, the level of harm that would constitute a MATTE is defined as follows:

Contamination of 10 ha or more of land which, for two growing seasons

or more, prevents growing of crops or the grazing of domestic animals or

renders the area inaccessible to the public because of possible skin

contact with dangerous substances;

Note The health effect above covers the impact on amenity

or,

Contamination of 10 ha or more of land by substances, preparations,

organisms or micro-organisms that results in a significant risk of adverse

effects on human health.

Note This definition is taken from DEFRA publication "The Environmental

Damage (Prevention and Remediation) Regulations 2009 Guidance for

England and Wales" and this also covers the impact on amenity.

NOTE: Land that is already contaminated

Refer to figure 2 below.

Where soil is already contaminated, a site-specific analysis of the potential impact of a

MATTE scenario may be required as this could have the potential to cause additional

contamination or suspend or reverse any existing recovery.

When completing this analysis, the following factors should be considered;

The pollutant from the MATTE scenario may not have the same chemical

nature/characteristics as any pre-existing pollutants, which may aggravate the

current contamination effects (e.g. solubilisation).

The pollutant from the MATTE scenario may suspend or reverse any existing

recovery (Reference: Environmental Damage Regulations).

In concluding the analysis;

If the potential MATTE scenario could exceed the MATTE thresholds in the

absence of any existing contamination, the receptor would be deemed as having

MATTE potential.

If the potential MATTE scenario does not alter the existing contamination

management (i.e. the existing pollution management system would not need to

Guideline – Environmental Risk Tolerability for COMAH Establishments v1.0

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