Contaminated Land Assessment and Remediation

Contaminated land assessment and remediation identify, monitor, and remediate contaminated soil, sediment, and groundwater to eliminate risks to human health and ecosystems. This may include, among others, baseline environmental assessments before closure or redevelopment, soil and groundwater testing for hydrocarbons, heavy metals, and chemicals, sediment contamination surveys in harbor areas, remediation techniques (excavation, treatment, containment, bioremediation), and ongoing monitoring programs to verify effectiveness.

For DMC ports, contaminated land assessment and remediation can protect marine and coastal ecosystems, reduce pollution risks to fisheries and communities, enable safe redevelopment of brownfield sites, align with ASEAN Taxonomy expectations for pollution prevention, and improve public health and environmental quality.

Port sites commonly present legacy contamination from, among others, fuel storage and handling (petroleum hydrocarbons), bulk material handling (heavy metals, coal dust), chemical storage and transfer (industrial chemicals), historical shipyard activities (lead paint, asbestos, solvents), and cargo spillage. Sediment contamination in harbor areas may result from historical industrial discharges, anti fouling paint residues (including tributyltin), and cargo losses.

Systematic contaminated site assessment follows staged approaches. The ASTM E1527-21 Phase I Environmental Site Assessment standard provides a widely recognized methodology for identifying potential contamination through records review, site reconnaissance, and interviews (ASTM International, 2021). Phase II investigations involve sampling and laboratory analysis to characterize contamination extent and severity. The Australian National Environment Protection (Assessment of Site Contamination) Measure 1999, as amended in 2013, provides detailed guidance on assessment methodologies that DMCs can use as a reference (NEPC, 2013).

Remediation approaches vary based on contamination type, extent, and site future use. A peer reviewed review of brownfield remediation contrasts conventional approaches such as excavation and off site disposal (dig and haul) and pump and treat with lower impact options such as immobilization, bioremediation, in situ chemical treatment, and passive barriers (Hou et al., 2023). Selection depends on cost, timeline, effectiveness, and sustainability considerations.

For marine sediments, specific remediation options include, among others, dredging contaminated sediments for treatment or confined disposal, capping sediments in place with clean material to prevent exposure and migration, and natural attenuation monitoring where contamination is stable and risks are limited. Sediment remediation requires careful consideration of dredging induced resuspension. At Randle Reef in Hamilton Harbor, Canada, next to the Port of Hamilton, partners including the Hamilton-Oshawa Port Authority built a 6.2 hectare engineered containment facility, dredged the most contaminated sediment into it and capped the remaining sediment in place (Randle Reef Project, n.d.; ECCC, 2022). The facility is to become new port land once capped; the final capping stage is now scheduled for completion in 2027 (Canada Water Agency, 2026).

Ongoing monitoring verifies remediation effectiveness and detects any recurrence or migration. Monitoring programs typically continue for years or decades post remediation, particularly for sites with residual contamination managed through containment rather than removal. International brownfield redevelopment examples, such as Wynyard Quarter in Auckland, where contaminated soil at the former Wynyard Point tank farm was excavated and bioremediated on site in 2023, illustrate integrated contamination assessment, remediation, and redevelopment (Auckland Council, n.d.).