residues in the sediment beneath fish farm zones [53]. In addition, this regulatory
agency has developed a dispersion model in order to simulate the dispersing plumes
of cypermethrin pyrethroid after multiple releases during bath treatments (BathAuto
v5) [54]. However, for aquaculture there are not yet models that provide a comprehensive representation of diffusive and non-diffusive fluxes and fates of organic
chemicals in multiple environmental compartments. Under field conditions, the
sampling and analysis of chemicals is challenging; therefore, it is advantageous to
describe the chemical dynamics in different environmental compartments using less
complex multimedia fugacity models [39]. In fact, fugacity-based models have been
widely used for chemical risk assessment purposes such as assessment of persistent
organic pollutants (POPs) and emerging contaminants [41, 42], playing a key role in
science [40]. Thus, such multimedia models could provide a good understanding of
key transport processes, fates, and sinks of synthetic pyrethroids used in aquaculture
after their release into the marine ecosystem. Ng et al. [55] reported a first approach,
developing a fugacity-based dynamic one-compartment mass balance model, which
was used to assess polybrominated diphenyl ether (PBDE) uptake on an individual
salmon farm during a complete sea-cage production period.
A primary objective in environmental fate studies is to predict the concentrations
of synthetic pyrethroids released into the environment, with respect to space and
time variables. Our knowledge of the behavior of antiparasitic pyrethroids can be
used to model the space and time domains once emissions are known or estimated.
Each of the levels in a fugacity-based model allows different kinds of information to
be obtained. Level I can indicate the major environmental compartments where the
chemical goes and Level II gives an indication of the main loss process occurring in
the chemical agent in the simulated environment and provides some insights into
persistence and residence time, since time is involved. Level III gives an indication
of the most important transfer process within the different environmental compartments, since a non-equilibrium condition is imposed. For environmental risk purposes, this chapter argues that multimedia fugacity-based models (Level III) could
play a key role in helping determine the potential effects of synthetic pyrethroids
within a risk assessment perspective.
2.1.1 Description Fugacity-Based Model
A multimedia fugacity-based box model for synthetic pyrethroids was developed to
predict the dynamics and fate of typical bath treatments for salmon. Our fugacity
model considers a distribution-based model incorporating all environmental
compartments of interest (water, sediment, and fish), based on steady-state and
non-equilibrium condition fluxes during treatments. Environmental data inputs and
typical characteristics of salmon farms located in the Southern Chile are shown in
Table 2.
Chemical partitioning was described by the thermodynamic criterion of fugacity
( f ). Theoretically, fugacity is related to environmental concentration (C, mol m
À3 )
by the equation C ¼ ƒ Z, with Z the fugacity capacity of chemicals for each
184
F. Tucca and R. Barra
agency has developed a dispersion model in order to simulate the dispersing plumes
of cypermethrin pyrethroid after multiple releases during bath treatments (BathAuto
v5) [54]. However, for aquaculture there are not yet models that provide a comprehensive representation of diffusive and non-diffusive fluxes and fates of organic
chemicals in multiple environmental compartments. Under field conditions, the
sampling and analysis of chemicals is challenging; therefore, it is advantageous to
describe the chemical dynamics in different environmental compartments using less
complex multimedia fugacity models [39]. In fact, fugacity-based models have been
widely used for chemical risk assessment purposes such as assessment of persistent
organic pollutants (POPs) and emerging contaminants [41, 42], playing a key role in
science [40]. Thus, such multimedia models could provide a good understanding of
key transport processes, fates, and sinks of synthetic pyrethroids used in aquaculture
after their release into the marine ecosystem. Ng et al. [55] reported a first approach,
developing a fugacity-based dynamic one-compartment mass balance model, which
was used to assess polybrominated diphenyl ether (PBDE) uptake on an individual
salmon farm during a complete sea-cage production period.
A primary objective in environmental fate studies is to predict the concentrations
of synthetic pyrethroids released into the environment, with respect to space and
time variables. Our knowledge of the behavior of antiparasitic pyrethroids can be
used to model the space and time domains once emissions are known or estimated.
Each of the levels in a fugacity-based model allows different kinds of information to
be obtained. Level I can indicate the major environmental compartments where the
chemical goes and Level II gives an indication of the main loss process occurring in
the chemical agent in the simulated environment and provides some insights into
persistence and residence time, since time is involved. Level III gives an indication
of the most important transfer process within the different environmental compartments, since a non-equilibrium condition is imposed. For environmental risk purposes, this chapter argues that multimedia fugacity-based models (Level III) could
play a key role in helping determine the potential effects of synthetic pyrethroids
within a risk assessment perspective.
2.1.1 Description Fugacity-Based Model
A multimedia fugacity-based box model for synthetic pyrethroids was developed to
predict the dynamics and fate of typical bath treatments for salmon. Our fugacity
model considers a distribution-based model incorporating all environmental
compartments of interest (water, sediment, and fish), based on steady-state and
non-equilibrium condition fluxes during treatments. Environmental data inputs and
typical characteristics of salmon farms located in the Southern Chile are shown in
Table 2.
Chemical partitioning was described by the thermodynamic criterion of fugacity
( f ). Theoretically, fugacity is related to environmental concentration (C, mol m
À3 )
by the equation C ¼ ƒ Z, with Z the fugacity capacity of chemicals for each
184
F. Tucca and R. Barra