PART 4: Significant Pollution and the Significant Possibility of Significant Pollution of the Water Environment
A.38 Section 78A(9) defines pollution of the water environment in terms of the direct or indirect introduction into the water environment of substances which may give rise to harm to human health or the quality of aquatic ecosystems or terrestrial ecosystems directly depending on aquatic ecosystems, result in damage to material property or impair or interfere with amenities and other legitimate uses of the water environment.
A.39 Section 78A(2) provides that land is to be considered contaminated land for the purposes of Part IIA only in cases where pollution resulting therefrom is significant or where there is a "significant" possibility of significant pollution or harm occurring.
A40 Section 78A(5) provides that what pollution is to be regarded as significant and whether the possibility of significant pollution being caused is significant shall be determined in accordance with this guidance.
A.41 Section 78A(2) requires that if significant pollution of the water environment results in significant harm or a significant possibility of significant harm, the land should be identified as contaminated.
A.42 Before determining that significant pollution of the water environment is being, or is likely to be, caused, the local authority should be satisfied that a substance is continuing to enter, or is likely to enter, the water environment. For this purpose, the local authority should regard something as being "likely" when it is judged more likely than not to occur. The term "continuing to enter" should be taken to mean any entry additional to that which has already occurred.
A.43 Land should not be designated as contaminated where:
(a) a substance is already present in the water environment; and
(b) entry of that substance from land into the water environment has ceased; and
(c) it is not likely that further entry will take place.
A.44 If a substance is present in a source material which is immiscible with water, entry means actual dissolution of the substance from the material into the water environment.
WHAT POLLUTION IS TO BE REGARDED AS "SIGNIFICANT"?
A.45 Significant pollution is determined by assessing the potential for impact/harm/damage associated with the substance in the water environment. The pollution needs to be attributable to the pollutant linkage on its own, or where it contributes to significant pollution in conjunction with other sources, the land in question must be a material contributor to the resultant pollution of the water environment.
A.46 In determining whether pollution of the water environment is "significant pollution of the water environment" for the purposes of section 78A(2)(b), the local authority shall have regard to the following:-
Measures of significant pollution
- Whether there is a breach of, or failure to meet, any statutory quality standard for the water environment at an appropriate pollution assessment point. In the absence of any suitable UK or EU standard, other international standards can be used where demonstrated to be appropriate;
- Whether there is a breach of, or a failure to meet, any operational standard adopted by SEPA for the protection of the water environment;
- Whether the pollution results in an increased level of treatment for an existing drinking water supply to ensure it is suitable for use, and to comply with the requirements of Council Directive 98/83/EC on the quality of water intended for human consumption. The potential for an increased level of treatment must also be considered for future use in drinking water protected areas as defined in sections 6 and 7 of the Water Environment and Water Services (Scotland) Act 2003;
- Whether the pollution results in an increased level of pre-treatment of water abstracted for industrial purposes;
- Whether the pollution results in:-
- deterioration in the status of a water body or failure to meet good status objectives, as defined in the Water Framework Directive 2000/60/EC; and/or
- the failure of a Protected Area to meet its objectives, as defined in the Water Framework Directive 2000/60/EC;
- Whether there is a significant and sustained upward trend in the concentration of pollutants in groundwater being affected by the land in question;
- Whether there is a material and adverse impact on the economic, social and/or amenity use associated with a particular water environment.
Scale of significant pollution
To assist in determining a site specific minimum threshold to filter out lower priority cases, and to highlight the most serious and pressing problems first, failure of the standards above shall be determined with reference to the following factors:-
- The extent and longevity of the resultant pollution:
- The area/volume of water impacted;
- Whether the period of time for which the water will be affected will be very short ( e.g. hours, days, weeks compared with months, years, decades); and
- The characteristics of the pollutants such as persistence, toxicity, potential for bioaccumulation; also carcinogenicity, mutagenicity and teratogenicity.
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