The study on the effect of the pyrethroid treatment against sea lice in farmed
salmon reported no difference in the EF and R values obtained for a given species
farmed in several European countries and the Pacific Ocean [48]. However, Salmo
salar and Oncorhynchus mykiss showed selective bioaccumulation of the opposed
cis-cypermethrin enantiomer of the first cis pair eluted and different degrees of
preference for the same cis enantiomer of the second pair. These species also
showed opposing preferences for R cis/trans and R cis1/cis2 . These data reinforce the
hypothesis of species-depending selectivity in fish.
A third of the unhatched eggs from the wild birds from the Doñana region
were also analysed and showed R cis/trans > 1 [53] agreeing with the already
mentioned results for river fish and some human milk from Spain, Colombia and
Brazil [10, 43]. However, tetramethrin contradicted this trend, also agreeing with
the other studies.
The study showed equal accumulation for both cis enantiomers of cyhalothrin,
cypermethrin, permethrin and tetramethrin [53]. Gadwall eggs were an exception
for cyhalothrin and cypermethrin, and black kites, black-headed gulls and glossy
ibis were exceptions for permethrin. The EF trans of tetramethrin revealed selective
accumulation of trans-(1S,1R)-tetramethrin. This had also been observed in Spanish
human breast milk samples [63].
The analysis of human milk samples from Brazil, Colombia and Spain showed
higher accumulation of the cis isomer for esfenvalerate and permethrin and
the contrary for cyfluthrin, cypermethrin and tetramethrin [10]. It has already
been mentioned that the commercial mixtures available in Spanish markets
are usually rich in cis isomers [63]. This might imply that trans-cyfluthrin and
trans-cypermethrin were selectively accumulated in human milk. The cypermethrin
trend was stronger in the Brazilian and Spanish samples than in the Colombian ones,
indicating possible different exposures on those locations.
The human milk samples from Mozambique were compared to a commercial
mixture and the thatch material from indoor walls [59]. For permethrin, the
calculated EF values were 0.84 for commercial mixtures, 0.69 for thatch material
and 0.52 for human milk. This enrichment in trans-permethrin may reflect a
higher bioaccumulation of this isomer or a better metabolization of cis-permethrin.
This finding contradicts the distribution reported in the study of the previous
paragraph.
In 2009, seven human breast milk samples from the metropolitan area of
Barcelona (Spain), as well as eight domestic pesticides, one pet pesticide solution
and one human skin cream against crabs and scabies, were analysed [63].
The domestic pesticides contained racemic mixtures of the cis-tetramethrin pair,
the trans-tetramethrin pair and the cis-cypermethrin pair, while the cis-permethrin
pair was rich in (1S,3S)-permethrin (EF cis ¼ 0.35). The human milk samples
also showed a racemic mixture of cis-tetramethrin. However, they presented a
higher contribution, hence accumulation, of trans-tetramethrin (EF trans ¼ 0.32)
and (1R,3R)-permethrin (EF cis ¼ 0.43) than the domestic pesticides. Human
samples showed greater contribution of (1S,3S,αR)-cyhalothrin than the pesticides
(EF cis2 ¼ 0.20). Although the first cis pair of cypermethrin was present as a racemic
Bioavailability and Bioaccumulation of Pyrethroid Insecticides in Wildlife and. . .
217
salmon reported no difference in the EF and R values obtained for a given species
farmed in several European countries and the Pacific Ocean [48]. However, Salmo
salar and Oncorhynchus mykiss showed selective bioaccumulation of the opposed
cis-cypermethrin enantiomer of the first cis pair eluted and different degrees of
preference for the same cis enantiomer of the second pair. These species also
showed opposing preferences for R cis/trans and R cis1/cis2 . These data reinforce the
hypothesis of species-depending selectivity in fish.
A third of the unhatched eggs from the wild birds from the Doñana region
were also analysed and showed R cis/trans > 1 [53] agreeing with the already
mentioned results for river fish and some human milk from Spain, Colombia and
Brazil [10, 43]. However, tetramethrin contradicted this trend, also agreeing with
the other studies.
The study showed equal accumulation for both cis enantiomers of cyhalothrin,
cypermethrin, permethrin and tetramethrin [53]. Gadwall eggs were an exception
for cyhalothrin and cypermethrin, and black kites, black-headed gulls and glossy
ibis were exceptions for permethrin. The EF trans of tetramethrin revealed selective
accumulation of trans-(1S,1R)-tetramethrin. This had also been observed in Spanish
human breast milk samples [63].
The analysis of human milk samples from Brazil, Colombia and Spain showed
higher accumulation of the cis isomer for esfenvalerate and permethrin and
the contrary for cyfluthrin, cypermethrin and tetramethrin [10]. It has already
been mentioned that the commercial mixtures available in Spanish markets
are usually rich in cis isomers [63]. This might imply that trans-cyfluthrin and
trans-cypermethrin were selectively accumulated in human milk. The cypermethrin
trend was stronger in the Brazilian and Spanish samples than in the Colombian ones,
indicating possible different exposures on those locations.
The human milk samples from Mozambique were compared to a commercial
mixture and the thatch material from indoor walls [59]. For permethrin, the
calculated EF values were 0.84 for commercial mixtures, 0.69 for thatch material
and 0.52 for human milk. This enrichment in trans-permethrin may reflect a
higher bioaccumulation of this isomer or a better metabolization of cis-permethrin.
This finding contradicts the distribution reported in the study of the previous
paragraph.
In 2009, seven human breast milk samples from the metropolitan area of
Barcelona (Spain), as well as eight domestic pesticides, one pet pesticide solution
and one human skin cream against crabs and scabies, were analysed [63].
The domestic pesticides contained racemic mixtures of the cis-tetramethrin pair,
the trans-tetramethrin pair and the cis-cypermethrin pair, while the cis-permethrin
pair was rich in (1S,3S)-permethrin (EF cis ¼ 0.35). The human milk samples
also showed a racemic mixture of cis-tetramethrin. However, they presented a
higher contribution, hence accumulation, of trans-tetramethrin (EF trans ¼ 0.32)
and (1R,3R)-permethrin (EF cis ¼ 0.43) than the domestic pesticides. Human
samples showed greater contribution of (1S,3S,αR)-cyhalothrin than the pesticides
(EF cis2 ¼ 0.20). Although the first cis pair of cypermethrin was present as a racemic
Bioavailability and Bioaccumulation of Pyrethroid Insecticides in Wildlife and. . .
217