126
was higher at near surface conditions, while being within the experimental error
limits at the higher pressure conditions. These data may be used in near-field and
far-field distribution modeling of the environmental fate of highly toxic BTEX
compounds derived from submarine oil spills and their impact on the ecosystem.
The parameters will also aid in the prediction of oil migration and dispersion away
from the spill thus helping to improve response strategies.
Keywords Submarine oil spill · High pressure · Partitioning · BTEX ·
Experimental simulation · Live oil
8.1 Introduction
An oil spill is defined as the accidental or intentional release of petroleum into the
environment. Over one million metric tonnes of petroleum enter the marine environment annually from marine transport, industrial sources, natural oil seeps, and
oil spills (GESAMP 2007). The environmental impacts from the release of these
large volumes of oil range from oiled shorelines and marine wildlife to intoxication
of organisms that ingest oil or are exposed to the organic compounds that partition
from oil to water phase. This chapter focuses on estimating the extent of partitioning
of organics between the oil and water phases following a submarine oil spill.
Chemical/physical partitioning occurs when a compound distributes itself to an
equilibrium state within a multiphase system, as a function of its interaction with
each individual phase. The extent of partitioning may be quantified in a two-phase
system using the partition ratio (Rice et al. 1993), which is the equilibrium ratio of
the compound concentration in the two phases (Sangster 1989; Bennett et al.
2003). In terms of oil-water systems, the magnitude of a partition ratio is influenced by the thermodynamics of dissolution, the physicochemical properties of the
oil (Bennett et al. 2007), and the bulk properties of the water system (e.g., salinity,
temperature; Bennett and Larter 1997). This study measures the partitioning of
benzene, toluene, ethylbenzene, and xylene (BTEX) as the organic compounds to
measure the partitioning behavior between the oil and water phases. BTEX compounds are abundant in most crude oils, and their environmental partitioning is
particularly important due to their toxic and carcinogenic properties (Mehlman
2006). In the past, the environmental fate of these compounds was mainly studied
in surface oil spills, during which the main portion of BTEX is rapidly transported
to the atmosphere via evaporation (National Research Council (NRC) 2003). In the
aftermath of the Deepwater Horizon (DWH) oil spill, which occurred at the
Macondo well in offshore Louisiana, Gulf of Mexico, at ~1500 m depth (Camilli
et al. 2010), the BTEX compounds were tracked in a subsurface plume at a depth
of 1100 m over 35 km away from the wellhead, shifting the focus to the subsurface
partitioning behavior of BTEX compounds from oil, under low-temperature and
high-pressure (i.e., deep water) conditions.
A. Jaggi et al.
was higher at near surface conditions, while being within the experimental error
limits at the higher pressure conditions. These data may be used in near-field and
far-field distribution modeling of the environmental fate of highly toxic BTEX
compounds derived from submarine oil spills and their impact on the ecosystem.
The parameters will also aid in the prediction of oil migration and dispersion away
from the spill thus helping to improve response strategies.
Keywords Submarine oil spill · High pressure · Partitioning · BTEX ·
Experimental simulation · Live oil
8.1 Introduction
An oil spill is defined as the accidental or intentional release of petroleum into the
environment. Over one million metric tonnes of petroleum enter the marine environment annually from marine transport, industrial sources, natural oil seeps, and
oil spills (GESAMP 2007). The environmental impacts from the release of these
large volumes of oil range from oiled shorelines and marine wildlife to intoxication
of organisms that ingest oil or are exposed to the organic compounds that partition
from oil to water phase. This chapter focuses on estimating the extent of partitioning
of organics between the oil and water phases following a submarine oil spill.
Chemical/physical partitioning occurs when a compound distributes itself to an
equilibrium state within a multiphase system, as a function of its interaction with
each individual phase. The extent of partitioning may be quantified in a two-phase
system using the partition ratio (Rice et al. 1993), which is the equilibrium ratio of
the compound concentration in the two phases (Sangster 1989; Bennett et al.
2003). In terms of oil-water systems, the magnitude of a partition ratio is influenced by the thermodynamics of dissolution, the physicochemical properties of the
oil (Bennett et al. 2007), and the bulk properties of the water system (e.g., salinity,
temperature; Bennett and Larter 1997). This study measures the partitioning of
benzene, toluene, ethylbenzene, and xylene (BTEX) as the organic compounds to
measure the partitioning behavior between the oil and water phases. BTEX compounds are abundant in most crude oils, and their environmental partitioning is
particularly important due to their toxic and carcinogenic properties (Mehlman
2006). In the past, the environmental fate of these compounds was mainly studied
in surface oil spills, during which the main portion of BTEX is rapidly transported
to the atmosphere via evaporation (National Research Council (NRC) 2003). In the
aftermath of the Deepwater Horizon (DWH) oil spill, which occurred at the
Macondo well in offshore Louisiana, Gulf of Mexico, at ~1500 m depth (Camilli
et al. 2010), the BTEX compounds were tracked in a subsurface plume at a depth
of 1100 m over 35 km away from the wellhead, shifting the focus to the subsurface
partitioning behavior of BTEX compounds from oil, under low-temperature and
high-pressure (i.e., deep water) conditions.
A. Jaggi et al.