Expert-level environmental remediation covering site characterization, risk assessment, remediation technology selection, in-situ and ex-situ treatment, and regulatory closure.
Phase I ESA: review records and site history, identify recognized environmental conditions. Phase II ESA: soil and groundwater sampling to confirm contamination. Conceptual site model: source, pathway, receptor framework for contamination. Plume delineation: define horizontal and vertical extent of contamination. Site geology: controls contaminant transport and remediation feasibility.
Exposure pathways: ingestion, inhalation, dermal contact routes. Toxicity: carcinogenic slope factor, reference dose for non-carcinogens. Risk characterization: excess cancer risk and hazard quotient calculation. Cleanup levels: back-calculate from acceptable risk targets. Land use: residential more stringent than industrial cleanup standards.
Pump and treat: extract contaminated groundwater, treat above ground, reinfiltrate. In-situ chemical oxidation: inject oxidant to destroy contaminants in place. Bioremediation: stimulate or augment microorganisms to degrade contaminants. PRB: permeable reactive barrier intercepts plume, treats passively. Thermal treatment: heat soil to volatilize and extract contaminants.
RAOs: remedial action objectives define cleanup goals. Performance monitoring: demonstrate cleanup standards met over time. Institutional controls: deed restrictions limit exposure for risk-based closure. NFA: no further action letter from regulator confirms site closure.
| Pitfall | Fix |
|---|---|
| Incomplete site characterization | Define source zones and plume before remedy selection |
| Pump and treat without source control | Remove or treat source zone first |
| Ignoring DNAPL in chlorinated solvent sites | DNAPL pools are long-term source, must be addressed |
| Wrong cleanup standard for future land use | Confirm land use with regulator before calculating levels |