REFERENCE DOCUMENTS - RAL25/0004 (As Published)

        4.          AREAS AND CHEMICALS OF ENVIRONMENTAL CONCERN
                    The following AEC have been identified, which are discussed below and detailed within Table 8,
                    and the CSM presented in Section 5:

                    •    AEC 1 - potential for night soil and bottles disposal over the northern portion of the site, based on the
                         desktop review and general area shown on Figure 13 in Section 3.16.

                    •    AEC 2 – potential for rubbish disposal over the southern portion of the site, based on the desktop
                         review and site walkover observations, and as shown on Figure 13 in Section 3.16 that should be
                         considered the minimum area of potential impact, which may extend over the entire southern portion
                         and possibly as part of the AEC 1 northern area.
                    •    AEC 3 - surface or groundwater migration pathways (including any springs) interacting with the
                         following potential contamination sources:
                         -    any AEC 1 and 2 contamination present on-site (or similar wastes extending beyond the
                              upgradient site boundary) that could migrate and impact deeper soil or groundwater at the site,
                              with potential to further migrate off-site
                         -    potential for the cemetery located upgradient to the west to be a source of contamination that, if
                              present, may impact the site primarily via groundwater migration.


                    Potential contaminants associated with historical waste disposal are wide ranging, comprising
                    aesthetically and geotechnically unsuitable solid wastes of varying materials, possible regulated waste
                    such as asbestos, tyres, nightsoil, chemical containers and residues, and interspersed soil impacted by
                    various materials or chemicals. This disposal was possibly semi-controlled in the case of AEC 1 and likely
                    uncontrolled in the case of AEC 2. Limited information was obtained by the desktop review regarding how
                    any waste disposal was managed or controlled.
                    Waste not containing putrescible waste is unlikely to generate landfill gas or leachate from the breakdown
                    of organic materials. Given the intervening time since deposition, risks associated with most biological
                    pathogens and current generation of organic leachates or landfill gas is low. Inorganic or chemically
                    persistent organic leachates may still be generated from percolation of rainwater or perched groundwater
                    subject to waste composition.
                    There is potential for contaminants to be mobile in the environment, including light and dense non-
                    aqueous phase liquids (LNAPL and DNAPL). LNAPL is lighter than water and will float on any surface or
                    groundwater it encounters. DNAPL vertical migration is not arrested by the presence of groundwater, and
                    they have a propensity to migrate vertically, however, their migration can be limited in clay rich soils.
                    With respect to LNAPL, DNAPL and other risks to groundwater, we note the half century or more since
                    deposition and natural attenuation factors that would mitigate some types of contamination. In addition,
                    permanent groundwater is likely to exist at a depth greater than 20mbgl. On this basis, any contaminants
                    from historical landfilling are likely to be concentrated within the fill profile and may have accumulated at
                    the base of the fill and interface with natural soil subject to mobility.
                    However, the potential for historical and current leachate generation and impacts such as to groundwater
                    from landfilling cannot be ruled out, nor the potential for surface wastes and chemical contamination to be
                    present or to have migrated off-site with any surface water flows such as during high intensity rainfall
                    event, or due to the footprint of the initial deposition area. No evidence of waste erosion or migration or
                    obvious surface expressions of groundwater was noted during the site walkover.


        125 Lot 105 SP118458 Cooroy DSI 12062024 Rev0                                                 Lot 105 SP118458, Cooroy, QLD, 4563
        12/06/2024                                                    27                           Detailed Site Contamination Investigation
Document Set ID: 23717062
Version: 0, Version Date: 01/01/1900