Remediation of PAH-Contaminated Soils and Sediments: A ...

Abstract
Polycyclic aromatic hydrocarbons (PAHs) are the product of incomplete
combustion, i.e. the burning of fossil fuels, forest fires, coal tar, creosote, diesel
and cigarette smoke. These organic chemicals are found almost everywhere
and pose a risk for human health because of their potentially carcinogenic nature
and bioavailability in water, soil, sediment, and air resources that humans come
in contact with daily. Because PAHs are emitted naturally through forest fires
and volcanoes, microorganisms have the ability to breakdown PAHs and
contaminated sites can be remediated through microbial and environmental
manipulations. Previous research on remediation of PAH contaminated
resources have been conducted in situ (superfund and industrial sites), ex situ in
bioreactors, or in a lab setting with soils spiked with various levels of PAHs. Very
few studies have focused on the risk or cleanup techniques involved with the
transport and remediation of PAH contaminated materials, such as dredge
sediments.
The focus of this literature review is the degradation of PAHs in dredge
sediments placed in an upland setting, where anaerobic conditions exist during
initial dewatering and shift to aerobic conditions during soil formation. Dredging
operations involve the removal of underwater sediments to maintain ports and
waterways around the United States. Finding beneficial uses for the dredged
sediment, such as beach nourishment, dewatering for topsoil material,
aggregate, and fill, is an important component to these operations from an
environmental and economic viewpoint. Previously, clean dredged sediment
(without salts or organics) has successfully been placed in upland confinements
for dewatering and future use as agricultural soil. However, there is a limited
amount of clean dredge material, so there is a growing interest in accepting and
remediating contaminated dredge sediments from rivers and ports that have
been impacted with industrial byproducts and contain varying levels of PAHs.
This literature review provides information on:
� PAH chemistry
� behavior and PAH concentration ranges in different environments
� PAH bioavailability
� transfer, degradation and sequestration of PAHs in sediments and soils
� biological techniques for enhancing PAH degradation
� chemical techniques for enhancing PAH degradation
� regulations pertaining to dredge material contaminated with PAHs
� sampling and analytical methods
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