The literature indicates that the bioavailability of pyrethroids is considerably
lower than that of persistent organic pollutants (POPs) such as PBDEs (5–85%
percentage of desorption), DDT (70–90%) and hexabromocyclododecane (HBCD)
(around 90%) [20].
3 Bioaccumulation
The capacity of mammals of metabolizing pyrethroids has been regarded as one
of the best qualities of these pesticides. However, evidence of their bioaccumulation
has been reported in several publications.
3.1 Aquatic Organisms
Evidence of bioaccumulation in marine mammals was first found in 23 liver samples
of male Franciscana dolphins (Pontoporia blainvillei) from the Brazilian coast: São
Paulo (SP), n ¼ 12, urban area, and Rio Grande do Sul (RS), n ¼ 11, agricultural
area [7]. In order to avoid the high variation in the levels of lipophilic pollutants of
females (see Sect. 4), only male dolphins were included to assess the concentrations
of pyrethroid in different locations and through the life cycle of the dolphins [34, 35].
All targeted pyrethroids but resmethrin were detected in liver samples [7].
Cyfluthrin, deltamethrin and tralomethrin were found in 73–83% of the samples.
In RS, λ-cyhalothrin and tetramethrin were found in 82% of the samples, and
bifenthrin and fluvalinate were found in 91%. Total pyrethroid concentrations
ranged from 7.04 ng/g lw (adult, SP) to 68.4 ng/g lw (calf, SP). Permethrin
showed the highest concentrations, from 4.48 ng/g lw (adult, SP) to 54.6 ng/g lw
(calf, SP). The other compounds in decreasing order of concentrations were
cypermethrin (<25 ng/g lw); tetramethrin (<16 ng/g lw); deltamethrin, fluvalinate
and λ-cyhalothrin (<6 ng/g lw); fenvalerate and cyfluthrin (<4 ng/g lw); and
bifenthrin (<3 ng/g lw).
Greater pyrethroid concentrations were reported in urban areas (SP). This was
also true for individual bifenthrin and permethrin. It had been previously observed
in California that the urban run-off supposed a greater pyrethroid input than the
irrigation run-off [11, 36]. Conversely, deltamethrin levels were significantly higher
in calves from RS. Deltamethrin had been used in RS since the 1980s to control
stored grain insects [37].
A trend of pyrethroid concentrations according to the dolphins’ length was
suggested (Fig. 1) [7]. High concentrations were found in calves due to pyrethroids
accumulated via maternal transfer. Concentrations could dilute with the dolphins
growth and rise again from dietary intake. Finally, when individuals reach maturity,
that is, for adult individuals, they would be able to metabolize pyrethroids decreasing
their concentration.
Bioavailability and Bioaccumulation of Pyrethroid Insecticides in Wildlife and. . .
209
lower than that of persistent organic pollutants (POPs) such as PBDEs (5–85%
percentage of desorption), DDT (70–90%) and hexabromocyclododecane (HBCD)
(around 90%) [20].
3 Bioaccumulation
The capacity of mammals of metabolizing pyrethroids has been regarded as one
of the best qualities of these pesticides. However, evidence of their bioaccumulation
has been reported in several publications.
3.1 Aquatic Organisms
Evidence of bioaccumulation in marine mammals was first found in 23 liver samples
of male Franciscana dolphins (Pontoporia blainvillei) from the Brazilian coast: São
Paulo (SP), n ¼ 12, urban area, and Rio Grande do Sul (RS), n ¼ 11, agricultural
area [7]. In order to avoid the high variation in the levels of lipophilic pollutants of
females (see Sect. 4), only male dolphins were included to assess the concentrations
of pyrethroid in different locations and through the life cycle of the dolphins [34, 35].
All targeted pyrethroids but resmethrin were detected in liver samples [7].
Cyfluthrin, deltamethrin and tralomethrin were found in 73–83% of the samples.
In RS, λ-cyhalothrin and tetramethrin were found in 82% of the samples, and
bifenthrin and fluvalinate were found in 91%. Total pyrethroid concentrations
ranged from 7.04 ng/g lw (adult, SP) to 68.4 ng/g lw (calf, SP). Permethrin
showed the highest concentrations, from 4.48 ng/g lw (adult, SP) to 54.6 ng/g lw
(calf, SP). The other compounds in decreasing order of concentrations were
cypermethrin (<25 ng/g lw); tetramethrin (<16 ng/g lw); deltamethrin, fluvalinate
and λ-cyhalothrin (<6 ng/g lw); fenvalerate and cyfluthrin (<4 ng/g lw); and
bifenthrin (<3 ng/g lw).
Greater pyrethroid concentrations were reported in urban areas (SP). This was
also true for individual bifenthrin and permethrin. It had been previously observed
in California that the urban run-off supposed a greater pyrethroid input than the
irrigation run-off [11, 36]. Conversely, deltamethrin levels were significantly higher
in calves from RS. Deltamethrin had been used in RS since the 1980s to control
stored grain insects [37].
A trend of pyrethroid concentrations according to the dolphins’ length was
suggested (Fig. 1) [7]. High concentrations were found in calves due to pyrethroids
accumulated via maternal transfer. Concentrations could dilute with the dolphins
growth and rise again from dietary intake. Finally, when individuals reach maturity,
that is, for adult individuals, they would be able to metabolize pyrethroids decreasing
their concentration.
Bioavailability and Bioaccumulation of Pyrethroid Insecticides in Wildlife and. . .
209