Document ID: chunk:federal_register_of_legislation:F2018L00053:body:0:p97
Version: federal_register_of_legislation:F2018L00053
Segment Type: other
Provision Reference: 
Character Range: 430636–433580

contaminants in solid media (soils, sediments and wastes) are also a source of contamination to ground and surface waters, and may provide an offsite environmental impact.

Capping Strategy for Filled Areas
The Harbour Trust considers that a capping strategy, supplemented by the excavation and offsite disposal of high level or gross contamination, is appropriate for the filled apron areas for the following reasons:
  * The heterogeneous nature of these materials means that it is not technically feasible to 'treat' these materials;
  * Large areas are already capped with concrete slabs such that the exposure to underlying soils is prevented;
  * The cost of removal of large volumes of materials to landfill, and replacement with clean soils would be prohibitive, and of limited benefit on ESD grounds;
  * The lands will remain in public ownership and an appropriate level of ongoing management will be applied; and
  * The lower cost of this strategy will allow remediation works to be undertaken at a greater rate, thereby allowing sooner and greater access to the island for the public and future users.
Capping may be achieved through the repair of existing pavements to form a continuous barrier and/ or installing new concrete or asphalt pavements of high integrity. Various capping systems would be appropriate depending on land use and environmental objectives. Those that have been used on the island include:
  * Asphalt and concrete – most suited to areas where a hardstand surface was required and/ or where it was appropriate to minimise water infiltration. This type of treatment has been implemented on the Southern Apron.
  * Soil/landscaped separation layer – most suited to parkland/ open space areas. This type of treatment has been implemented on the Eastern Apron.
  * Low permeability landscaped barrier (which has been implemented on the Northern Apron).
However, before capping, further requirements for implementation include:
 1. Building decontamination and hazardous materials removal works will be carried out prior to the commencement of any soil remediation works in an area. This will include removal and disposal of any remaining dangerous goods or materials. Following building decontamination programs in each area, any remaining hazardous materials, such as asbestos cement sheet in good condition will be managed in accordance with the hazardous materials registers and management plans being prepared for the island.
 2. Areas of high level or gross contamination or sources which may present potential unacceptable health risk or an ongoing source of contamination or off-site impact will be appropriately investigated and where required remediated, preferably by treatment and/or removal and disposal from the island. Gross contamination may include:
      + Any remaining asbestos materials in surface soils;
      + Concentrated washes in surface soils, such as grit blast wastes or where there