models that require only a reduced set of input data. Additionally, they are based
on conceptual outlines and easily understood, solvable algorithms, which produce
results that are easily handled and of simple, practical use, to the point that they have
been proposed for official procedures to evaluate chemical risks. Among the different approaches that constitute the theoretical foundations of the multimedia partition
models, that derived from the fugacity concept has proved to be one of the most
effective. The use of multimedia fugacity-based models is an approach that allows
the estimation of the dynamics and fate of single pollutants in the environment [37–
39]. Fugacity is defined as the chemical activity of a gas and expresses the tendency
to escape from one compartment to another. In these thermodynamic models, the
different behaviors of various chemical agents principally depend on their physical–
chemical (intrinsic) properties, contributing to the development of a better interpretation and understanding of the fate, transport, and degradation of pollutants released
into the ecosystem. Moreover, the use of this tool can be an important approach for
conducting risk assessment and improving chemical management [40–42], in which
predicting concentrations through multimedia fugacity-based models has proved to
be effective according to measured environmental concentrations (e.g., [43–45]).
On the other hand, one of the issues of a risk assessment of synthetic pyrethroids
in the marine environment is that they are used at very low concentrations that with
dilution in the marine environment reach very low levels, on the order of ng L
À1
units, which are actually very difficult to measure using traditional sampling
methods (i.e., grab sampling). In this chapter a method based on passive sampling
is introduced as a cost-effective way to address the analytical challenge of detecting
hydrophobic chemicals in the aquatic environment for risk assessment purposes.
More details are presented below (see Sect. 2.2.1).
2.1 Salmon Farm Models
The most prominent route of entry of veterinary medicines into the environment is
direct discharge of aquaculture chemicals. Surprisingly, little attention has been paid
in the open literature to chemical-based modeling efforts for aquaculture chemicals.
Most physical-based models have been developed as tools to predict the distribution
of particulate waste from fish farm cages to the seabed. These predictive particulate
waste distribution models, through Geographic Information Systems (GIS), have
enabled temporal deposition zones and salmon cage impacts on benthic ecosystems
to be visualized [46, 47]. More sophisticated fish farm models such as the
DEPOMOD model have independently described particle tracking and
resuspension, benthic responses, and fish growth and biomass to assess the impact
of salmon cages on marine environments [48–52]. Additionally, the DEPOMOD
model has been validated to assess the deposition footprint of antiparasitic drugs
added to feed after treatment of fish. In Scotland, the Scottish Environmental
Protection Agency (SEPA) uses a regulatory DEPOMOD-based model
(AutoDEPOMOD) to predict the concentration of in-feed antiparasitic medicine
Environmental Risks of Synthetic Pyrethroids Used by the Salmon Industry in. . .
183
on conceptual outlines and easily understood, solvable algorithms, which produce
results that are easily handled and of simple, practical use, to the point that they have
been proposed for official procedures to evaluate chemical risks. Among the different approaches that constitute the theoretical foundations of the multimedia partition
models, that derived from the fugacity concept has proved to be one of the most
effective. The use of multimedia fugacity-based models is an approach that allows
the estimation of the dynamics and fate of single pollutants in the environment [37–
39]. Fugacity is defined as the chemical activity of a gas and expresses the tendency
to escape from one compartment to another. In these thermodynamic models, the
different behaviors of various chemical agents principally depend on their physical–
chemical (intrinsic) properties, contributing to the development of a better interpretation and understanding of the fate, transport, and degradation of pollutants released
into the ecosystem. Moreover, the use of this tool can be an important approach for
conducting risk assessment and improving chemical management [40–42], in which
predicting concentrations through multimedia fugacity-based models has proved to
be effective according to measured environmental concentrations (e.g., [43–45]).
On the other hand, one of the issues of a risk assessment of synthetic pyrethroids
in the marine environment is that they are used at very low concentrations that with
dilution in the marine environment reach very low levels, on the order of ng L
À1
units, which are actually very difficult to measure using traditional sampling
methods (i.e., grab sampling). In this chapter a method based on passive sampling
is introduced as a cost-effective way to address the analytical challenge of detecting
hydrophobic chemicals in the aquatic environment for risk assessment purposes.
More details are presented below (see Sect. 2.2.1).
2.1 Salmon Farm Models
The most prominent route of entry of veterinary medicines into the environment is
direct discharge of aquaculture chemicals. Surprisingly, little attention has been paid
in the open literature to chemical-based modeling efforts for aquaculture chemicals.
Most physical-based models have been developed as tools to predict the distribution
of particulate waste from fish farm cages to the seabed. These predictive particulate
waste distribution models, through Geographic Information Systems (GIS), have
enabled temporal deposition zones and salmon cage impacts on benthic ecosystems
to be visualized [46, 47]. More sophisticated fish farm models such as the
DEPOMOD model have independently described particle tracking and
resuspension, benthic responses, and fish growth and biomass to assess the impact
of salmon cages on marine environments [48–52]. Additionally, the DEPOMOD
model has been validated to assess the deposition footprint of antiparasitic drugs
added to feed after treatment of fish. In Scotland, the Scottish Environmental
Protection Agency (SEPA) uses a regulatory DEPOMOD-based model
(AutoDEPOMOD) to predict the concentration of in-feed antiparasitic medicine
Environmental Risks of Synthetic Pyrethroids Used by the Salmon Industry in. . .
183