Harnessing Nature to Heal Contaminated Soil: Insights from the Santa Susana Bioremediation Study

In 2015, the U.S. Department of Energy (DOE) launched a pivotal investigation into the power of nature to clean up one of its most complex environmental challenges: the contaminated soils of Area IV at the Santa Susana Field Laboratory (SSFL). The DOE commissioned this study to evaluate bioremediation, a process that uses microorganisms to break down hazardous substances in the environment. As part of a suite of five treatability studies, this bioremediation study explored how bacteria and fungi might help reduce the need for costly and disruptive soil excavation and off-site disposal.

The study focused on four major classes of pollutants known for their persistence and toxicity:

• Petroleum hydrocarbons

• Polyaromatic hydrocarbons (PAHs)

• Polychlorinated biphenyls (PCBs)

• Chlorinated dioxins/furans

These contaminants were selected based on their prevalence at the site and their known susceptibility to microbial degradation.

To assess the feasibility of bioremediation, researchers conducted a two-pronged investigation:

Field Testing

• 30 soil samples were collected from various locations across Area IV.

• Scientists used traditional culturing and molecular techniques to identify native bacteria and fungi capable of degrading the target contaminants.

The DOE commissioned this study to evaluate bioremediation—a process that uses microorganisms to break down hazardous substances in the environment.

Laboratory Microcosm Experiments

• Soil samples were tested under controlled conditions to simulate natural attenuation.

• Researchers also explored enhanced methods:

• Biostimulation: Adding nutrients and surfactants to boost microbial activity.

• Bioaugmentation: Introducing specialized microbes known to degrade specific contaminants.

The results they found were promising:

• Biodegrading microorganisms were already present in the site’s soils, suggesting that natural attenuation is a viable strategy.

• Biostimulation and bioaugmentation significantly improved degradation rates in laboratory settings.

• Overall, the study supports bioremediation as a cost-effective and environmentally friendly alternative to traditional excavation and disposal methods.

To read the full DOE report, click here.