18-Env-B4 Site Assessment and Remediation · December 2019
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams — December 2019 — 18-Env-B4: Site Assessment and Remediation (3 hours, open book). Instructions: answer FOUR of the FIVE Section A questions and ONE of the TWO Section B questions; all eight questions (A-1–A-5, B-1, B-2) are answered in full below as a complete study resource. Each question is worth 20 marks.
Reference texts: Nyer, E.K., Practical Techniques for Groundwater and Soil Remediation; Fetter, C.W., Contaminant Hydrogeology (2nd ed.); Leeson, A. & Hinchee, R.E. (1997), Soil Bioventing: Principles and Practice; CSA Z768-01, Phase I Environmental Site Assessment; British Columbia Contaminated Sites Regulation (Environmental Management Act); Ontario Regulation 153/04 (Records of Site Condition); Canadian Council of Ministers of the Environment (CCME), National Classification System for Contaminated Sites and Canada-Wide Standard for Petroleum Hydrocarbons in Soil; Karickhoff, S.W. (1981), organic-carbon partitioning correlations.
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 closed heavy-industrial automotive assembly plant is a textbook Phase I ESA candidate: decades of solvent-based degreasing, paint booths, quench pits, hydraulic systems, USTs/ASTs and metal-finishing operations are all plausible historical uses.
Type of preliminary assessment. A Phase I Environmental Site Assessment (CSA Z768-01, the Canadian standard) should be completed first: a non-intrusive desktop and field review comprising historical records/aerial-photo review, a title/regulatory-database search (spill reports, waste-generator registrations, storage-tank registry), a site reconnaissance walkover, and interviews with past owners/operators/regulators. Its purpose is to identify Areas of Potential Environmental Concern (APECs) — here, almost certainly the degreasing/solvent-use areas, paint shop, any USTs, and hydraulic/quench-pit locations — without yet collecting samples.
Are samples required? Not at the Phase I stage itself. However, given the site's known heavy-industrial history, a Phase I is very likely to identify one or more APECs, which then triggers a Phase II ESA (intrusive investigation) before redevelopment can proceed. Yes, samples will be required in practice for this site.
What kind of samples. Soil borings and monitoring wells targeted at each identified APEC: soil and groundwater samples for chlorinated and petroleum solvents (degreasing areas), metals (paint booths, metal finishing, plating if present), and petroleum hydrocarbons (any UST/AST footprint); soil-vapour samples if the redevelopment includes occupied buildings, given the solvent history and the vapour-intrusion pathway this raises.
Clean-up standards. Redevelopment of a former Ontario industrial site for a change of use requires a Record of Site Condition (RSC) under Ontario Regulation 153/04, filed against the applicable Ontario Table 1–9 Site Condition Standards. The governing table is selected by the property's actual/proposed land use (residential vs. industrial/commercial), soil texture (coarse vs. fine), and whether a potable groundwater use applies — a residential redevelopment of the Oshawa lands would use the more stringent Table 2/3 residential standards rather than the industrial/commercial standards that applied to the plant's own operating history. Where a value is not addressed by the O.Reg. 153/04 tables, CCME Canada-Wide Standards provide a defensible supplementary benchmark.
