Opus International Consultants (NSW) Pty Ltd - Transport for NSW ...

Preliminary Site Investigation at63 North Pde, Mt Druitt NSW A. D. Envirotech Australia Pty LtdA contaminant concentration in soil will be deemed acceptable if:all samples meet the specified acceptance criteria;the 95 % upper confidence limit (UCL) average concentration of each contaminant is belowthe acceptance criteria; orno individual exceedance is greater than 2.5 times the remediation acceptance criteria.If a location is found to have more than 2.5 times a contaminant‟s acceptable limit, then it will beclassified as a “hot-spot”, requiring further assessment, remediation, removal or management.If the calculated 95% UCL of the arithmetic average concentration of the contaminant is above theiracceptance criteria, then the soil will be considered contaminated, requiring further assessment,remediation, removal or management.If the 95 % UCL of the arithmetic average concentrations is below the acceptance criteria, and noconcentrations are at a “hotspot” level, slight elevations above the acceptance criteria may beconsidered to pose an insignificant human health risk since most of the site will be covered byconcrete and road-base.The Provisional Phyto-toxicity Investigation Levels (PPILs) are generic values based on phytotoxicitydata for plant response to specific contaminants in a sandy loam matrix. As soils areaccessible on the site, the contamination assessment must apply these criterion.There are currently no national or NSW guidelines for asbestos in soil. Enhealth have a documententitled „Guidelines for Asbestos in the Non-Occupational Environment‟ (2005), which gives someguidance on assessing and managing asbestos in soil although does not provide a thresholdconcentration or investigation level for asbestos.In consultation with WorkCover NSW and through the Enhealth (2005) „Guidelines for Asbestos inthe Non-Occupational Environment‟ document, ADE has adopted a conservative criterion forasbestos in soil being „no detectable asbestos‟ present in soils and/or no visible asbestos debris on site.4224 63 North Pde Mt Druitt PSI.v1 final Page 35