Remediating the site of a train derailment in northern British Columbia, Canada, called for an approach that would yield the maximum benefit for the environment while minimizing the impact and footprint of the remediation process.
In 2020, GHD assisted a Class I Railway client with a train derailment involving 20 railcars containing petroleum coke, a carbon-rich solid material derived from oil refining, released into a creek. Our work on this derailment is one of three remediation scenarios we will present at the 2022 Railroad Environmental Conference, November 2-3, 2022. Each show how a Net Environmental Benefit Analysis (NEBA) approach can be used to establish and achieve optimal project endpoints, balancing the desired end state of the remediation with the overall footprint of the remedy itself.
NEBA compares and ranks the net environmental benefit associated with multiple remediation alternatives. It stands in contrast to other ways of managing remediation projects, which are more focused on meeting numerical targets. NEBA supports meeting regulatory considerations and requirements but also considers a wider range of factors, such as impacts on the environment from the remediation work.
The question NEBA seeks to answer is: How much remediation is necessary before the solution causes more harm than the original problem?
The petroleum coke released during the 2020 derailment was not expected to demonstrate chronic toxicity to aquatic organisms in the creek because of its limited solubility. It did, however, have the potential to have a smothering effect by covering the creek bed. Recovery of much of the petroleum coke from the creek bed was required to mitigate impacts on the aquatic environment. Our approach was focused on recovering petroleum coke from the creek to the extent practical while minimizing disturbance to sediment. This included species within the sediment, like benthic organisms (a community of organisms that live on, in, or near the bottom of a waterbody) and aquatic habitat.
Once the practical limit of the recovery was reached a comprehensive sediment sampling program and ecological risk assessment were completed determining that the trace amounts of petroleum coke remaining in the creek did not pose a risk to the environment. Therefore, additional recovery would have had a limited benefit and was not warranted. Through a NEBA approach the impacts related to the derailment were addressed while minimizing disturbance to the aquatic environment.
Protecting communities with NEBA principles
In 2021, our team utilized the principles of NEBA in response to a wildfire in British Columbia for a Class I Railway client. The fire caused extensive damage to human habitation and infrastructure, including a vital rail bridge on one of Canada’s main cross-country rail lines.
Most of the wooden ties on the rail bridge were burned or charred, and pieces of guard rail, rail ties and small debris fell onto the embankment and into the river below. In consultation with local stakeholders, including Indigenous communities, we assisted the client with recovery work with NEBA principles in mind. This included an evaluation of the fate and transport of rail debris in the river to assess the potential risk to the environment and human health receptors as well as establish recovery endpoints.
In this scenario, the NEBA approach helps industry, property owners, regulators and other stakeholders determine the end of the remediation process – when no further work is required.
Micro forests: Nature-based remediation for brownfield sites
A third situation in which we recommend a NEBA strategy is the nature-based remediation of brownfield sites in urban areas. These sites often face a barrier to redevelopment due to investment risks, ownership constraints, risk of future liability claims and public stigma. And they also represent an opportunity to generate social, economic and environmental benefits on many levels. Developing micro forests enables these opportunities.
Micro forests are carefully selected native trees and other vegetation planted in high density to accelerate growth – a technique known as the Miyawaki method. This increases urban biodiversity, carbon dioxide (CO2) capture, improves the health and well-being of residents, increases resilience to storm events and flooding, and reduces erosion, dust and heat islands. In addition, through the process of phytoremediation – using plants to remediate contaminated soils and groundwater – the level of contaminants in the soil is reduced over time, ultimately increasing the sites’ potential uses. And as a result, adds value to the community. In this kind of project, NEBA demonstrates that the negative environmental impacts associated with the tree planting operations are minimal compared to the myriad of positive environmental impacts generated by the micro forest over several decades. In this scenario, the NEBA approach makes the case for a more sustainable, long-term land management approach.
Having a NEBA mindset provides the right tools to sustainability remediate
Today’s business context demands that companies not only have environmental compliance in mind but incorporate Environmental, Social and Governance (ESG) policies and objectives as well. ESG objectives touch on the broader impacts of their operations on communities and global environmental concerns such as climate change, habitat protection and biodiversity. When a site needs cleaning, whether in an emergency or longer term, gaining the support of remediation specialists with a NEBA mindset optimizes efforts and generates maximum environmental benefits aligning with today’s strategic business imperatives.
For more information please contact:
François Beaudoin
EHS Compliance, Business Group Manager
Francois.Beaudoin@ghd.com
Molly Corrigan
Emergency Preparedness & Response
Molly.Corrigan@ghd.com
Kristjana Zoras
Emergency Preparedness & Response
Kristjana.Zoras@ghd.com
