Formation of PAH Derivatives and Increased Developmental Toxicity during Steam Enhanced Extraction Remediation of Creosote Contaminated Superfund Soil

Steam enhanced extraction
(SEE) is an in situ thermal
remediation technique used to remove and recover polycyclic aromatic
hydrocarbons (PAHs) from contaminated soils. However, limited studies
have been conducted on the formation of PAH derivatives during and
after SEE of PAH contaminated soils. Creosote contaminated soil samples
collected from the Wyckoff-Eagle Harbor Superfund site were remediated
with laboratory scale SEE. The samples were quantified for unsubstituted
PAHs and their derivatives and assessed for developmental toxicity,
pre- and post-SEE. Following SEE, unsubstituted PAH concentrations
decreased, while oxygenated PAH concentrations increased in soil and
aqueous extracts. Differences in developmental toxicity were also
measured and linked to the formation of PAH derivatives. Additive
toxicity was measured when comparing unfractionated extracts to fractionated
extracts in pre- and post-SEE samples. SEE is effective in removing
unsubstituted PAHs from contaminated soil, but other, potentially
more toxic, PAH derivatives are formed.