Protecting Contaminated Sites In Coastal Communities From The Effects Of Climate Change

In 2020, the U.S. experienced a record-breaking hurricane season with the highest-ever 30 named storms. In addition to increased frequency and intensity of hurricanes and major storm events, sea level rise has caused an average of 233% increase in tidal flooding across the U.S since 1950. Contaminated sites are particularly vulnerable to the extreme weather and sea level rise caused by climate change. According to a 2019 report by the U.S. Government Accountability Office (GAO), about 60% of the nation’s superfund sites are in areas at risk of climate change.

Contaminated sites in areas experiencing more frequent and intense flood events, such as those located in coastal communities, are particularly vulnerable. Flood waters can inundate contaminated sites and, once they subside, toxins can contaminate receding flood waters and spill into local communities, posing a threat to public health. For example, in 2017, Hurricane Harvey damaged part of the structure containing the San Jacinto River Waste Pits and floodwaters may have spilled dioxins, toxic chemicals that can cause cancer and nerve damage, into the local community in Houston.

Several aspects of contaminated media and the design of site remediation will be affected by climate change in coastal areas:

Changing precipitation patterns or sea-level rise will result in unexpected flooding that may impact the toxicity and mobilization of a contaminant and the transport and fate of the compounds. Drought and fire may damage the remedial or containment infrastructure and enhance the spread of contaminants through the failure of the enclosures due to settling ground or dispersion through the fire, heat and smoke. It is essential to evaluate, redesign and consider placement of remedial caps and other containment infrastructures to withstand erosion, site inundation and scouring.

Climate can undermine remediation techniques such as soil treatment where bioremediation may fail due to fluctuations in temperature, humidity or moisture resulting in a change in bacterial activity. Planned groundwater treatment needs remodeling and redesign through the altered rates of recharge and extraction with a wetter environment resulting from more run-off, greater dilution and thus increased mobility. In a drier environment, increased volatility with less dilution creates altered degradation rates both physical and microbial. Engineered in-situ solutions will need to be altered to accommodate changes such as soil washing limits with insufficient water or saltwater. Most natural attenuation models are not climate informed so remedial rates may be altered. Remediation planning needs to adapt and will have to be amended to accommodate the degradation/transformation of the contaminants as climate changes will impact the remedial efficacy.

As the effects of climate change increase, so should efforts to incorporate climate resiliency and adaptation into environmental remediation and clean up. The U.S. Environmental Protection Agency (EPA), recommends that owners of contaminated sites complete the following three actions to protect their sites from climate change:

1. Perform vulnerability assessments to evaluate the sites vulnerability to climate hazards;
2. Implement resiliency measures to secure the site and protect site personnel and the local community from exposure; and,
3. Assure long-term adaptive capacity by regularly reassessing and monitoring the site to ensure its continued climate resilience.

If you are concerned about the effects that climate change will have on your contaminated site, contact APTIM today. Our team of environmental remediation experts can help you assess your vulnerability, identify, and implement resiliency measures to protect your site and establish plans achieve long-term adaptive capacity.