18-Env-B4 Site Assessment and Remediation · May 2014
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams — May 2014 — 04-Env-B4 / Site Assessment and Remediation. 3 hours duration; open-book exam (any non-communicating calculator permitted). The paper is split into Section A (five questions, candidates asked to answer three) and Section B (three questions, candidates asked to answer two), each question worth 20 marks. All eight questions are solved below for completeness.
Reference texts. Suthersan & Payne, Remediation Engineering: Design Concepts (CRC Press); Gavaskar, Gupta, Sass, Janosy & O'Sullivan, Design Guidance for Application of Permeable Reactive Barriers for Groundwater Remediation (Battelle/EPA, 2000); ASTM E1527 Standard Practice for Phase I Environmental Site Assessments and ASTM E1903 Standard Practice for Phase II ESA; Mercer & Cohen (1990), “A review of immiscible fluids in the subsurface,” Journal of Contaminant Hydrology; Freeze & Cherry, Groundwater; Davis & Cornwell, Introduction to Environmental Engineering (6th ed.); Ontario Reg. 153/04 under the Environmental Protection Act (Record of Site Condition regime); BC Environmental Management Act — Contaminated Sites Regulation.
Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.
A Record of Site Condition (ROSC), filed under Ontario Regulation 153/04 (Environmental Protection Act) — or its functional equivalent in other provinces, such as a Certificate of Compliance/Approval in Principle under BC's Contaminated Sites Regulation — is a publicly registered document confirming that a property's environmental condition, as established by Phase I/Phase II assessment and, where needed, confirmed remediation or risk management, meets the standard applicable to its proposed future use. It is triggered whenever land use is changing to something more sensitive, and a former refrigerator-manufacturing plant redeveloping to parkland and housing is precisely that trigger.
Refrigerator manufacturing historically involved several distinct contaminant classes: PCB-containing capacitors, ballasts and hydraulic/transformer oil; chlorofluorocarbon (CFC) refrigerants and foam-blowing agents from insulation manufacture; chlorinated solvents (TCE/PCE) used for metal degreasing prior to painting or plating; and metals from any plating or finishing operations. The site's industrial-use standards (the ones it likely operated under) are far less protective than the standards that apply to residential occupancy or to a public park, because those uses assume direct, repeated human contact with soil (children on parkland, backyard gardening on low-density residential lots) that an industrial floor slab does not. A ROSC forces exactly that comparison: it requires the environmental condition to be demonstrated against the standard for the most sensitive proposed use, and here the mix — park, high-density housing, and low-density housing — spans a range of sensitivity (a paved/managed park surface and a high-rise footprint typically involve less soil contact than a low-density lot with private yards and gardens), so either the whole site is remediated/managed to the most stringent applicable standard, or the ROSC is filed on a parcel-by-parcel basis matched to each portion's actual end use, each independently confirmed.
The municipality has several tools available to move a Brownfield of this type from proposal to built redevelopment: (i) make the ROSC (or provincial equivalent) a hard pre-condition of any building permit or zoning approval for the change of use, consistent with its statutory obligation to do so before permitting more sensitive occupancy; (ii) establish or apply a Brownfields Community Improvement Plan (CIP) offering tax-increment financing, development-charge deferrals or exemptions, and grants/low-interest loans that offset the remediation cost premium relative to greenfield development, since that cost gap is usually the single biggest barrier to redevelopment proceeding; (iii) where full removal of contamination to generic standards is impractical (a large industrial footprint can be very expensive to fully remediate), work with the developer and the provincial regulator on a risk-assessment pathway supported by a Certificate of Property Use imposing institutional and engineering controls — e.g., a vapour barrier and sub-slab depressurization under the residential blocks, or an engineered soil cap under the park — registered on title so future owners remain bound; (iv) coordinate infrastructure and stormwater planning around any residual contamination or engineered controls; and (v) run the required public consultation given the shift to residential and park use, so community concerns about the industrial legacy are addressed as part of the approval, not after occupancy begins.
