in tissues of different living things. Chapter “Bioavailability and Bioaccumulation of
Pyrethroid Insecticides in Wildlife and Humans” shows a summary of these works.
Currently, there are data of pyrethroids accumulated in aquatic biota, in different
species of river fish, as well as in marine mammals such as dolphins. But pollution
also occurs in terrestrial biota. Pyrethroids are detected in eggs of a large variety
of birds. And finally, we must not forget that there are also studies in which
the presence of pyrethroids accumulated in human breast milk is reported. Based
on these new data, it is now necessary to evaluate the degrees of metabolization and
accumulation in tissues. There are no studies in this sense, and it would be important
to assess whether the degree of accumulation is important or can be considered
negligible. In any case, the concentration values of accumulated pyrethroids
in different organisms are similar to those found for other emerging pollutants. In
addition, the detection frequency is also very high, with a detection percentage
between 90 and 100%. All these remark the importance of including pyrethroids
in environmental quality and monitoring studies, given that, even at nonlethal
doses, pyrethroids are known as stressors and that the accumulation of pyrethroids
in living tissues deserves further studies.
In any case, the study carried out by Alonso et al. [8] indicates that, in
the case of marine mammals, pyrethroid metabolism could occur only when the
individual reach sexual maturity. That means that throughout the early period of
life, when growth and development is crucial, dolphins would be exposed to the
accumulation of pyrethroids in their organisms. Taking into account the potential
toxic effects of pyrethroids and the exposure to these pollutants in an early period of
life, the need for further studies related to exposure to these compounds becomes
clear. Likewise, the maternal transfer of pyrethroid insecticides has been also
observed by both gestational and lactation pathways. Therefore, it would also
be necessary to evaluate the impact of these pyrethroids during the development
of the fetus.
5 Human Exposure
The use of pyrethroids has increased over the past three decades and correspondingly
the opportunity for human exposure. Pyrethroids can enter the human body in
different ways: food ingestion, residential environment, and various environmental
media containing pyrethroid pesticides. Chapter “Indoor and Outdoor Pyrethroid Air
Concentrations” is focused on indoor and outdoor pyrethroid levels and human
exposure through inhalation, whereas chapter “Risk Assessment of Human Exposure to Pyrethroids Through Food” evaluates human exposure through food intake.
Finally, chapter “Human Risk Associated with Long-term Exposure to Pyrethroid
Insecticides” summarizes the human risk associated with long-term exposure to
pyrethroid insecticides.
The evaluation of the exposure to environmentally significant and healthrelevant compounds in indoor environments becomes a growing issue of concern
since people spend on average more than 80% of their time indoors. Moreover,
Conclusions and Future Trends
311
Pyrethroid Insecticides in Wildlife and Humans” shows a summary of these works.
Currently, there are data of pyrethroids accumulated in aquatic biota, in different
species of river fish, as well as in marine mammals such as dolphins. But pollution
also occurs in terrestrial biota. Pyrethroids are detected in eggs of a large variety
of birds. And finally, we must not forget that there are also studies in which
the presence of pyrethroids accumulated in human breast milk is reported. Based
on these new data, it is now necessary to evaluate the degrees of metabolization and
accumulation in tissues. There are no studies in this sense, and it would be important
to assess whether the degree of accumulation is important or can be considered
negligible. In any case, the concentration values of accumulated pyrethroids
in different organisms are similar to those found for other emerging pollutants. In
addition, the detection frequency is also very high, with a detection percentage
between 90 and 100%. All these remark the importance of including pyrethroids
in environmental quality and monitoring studies, given that, even at nonlethal
doses, pyrethroids are known as stressors and that the accumulation of pyrethroids
in living tissues deserves further studies.
In any case, the study carried out by Alonso et al. [8] indicates that, in
the case of marine mammals, pyrethroid metabolism could occur only when the
individual reach sexual maturity. That means that throughout the early period of
life, when growth and development is crucial, dolphins would be exposed to the
accumulation of pyrethroids in their organisms. Taking into account the potential
toxic effects of pyrethroids and the exposure to these pollutants in an early period of
life, the need for further studies related to exposure to these compounds becomes
clear. Likewise, the maternal transfer of pyrethroid insecticides has been also
observed by both gestational and lactation pathways. Therefore, it would also
be necessary to evaluate the impact of these pyrethroids during the development
of the fetus.
5 Human Exposure
The use of pyrethroids has increased over the past three decades and correspondingly
the opportunity for human exposure. Pyrethroids can enter the human body in
different ways: food ingestion, residential environment, and various environmental
media containing pyrethroid pesticides. Chapter “Indoor and Outdoor Pyrethroid Air
Concentrations” is focused on indoor and outdoor pyrethroid levels and human
exposure through inhalation, whereas chapter “Risk Assessment of Human Exposure to Pyrethroids Through Food” evaluates human exposure through food intake.
Finally, chapter “Human Risk Associated with Long-term Exposure to Pyrethroid
Insecticides” summarizes the human risk associated with long-term exposure to
pyrethroid insecticides.
The evaluation of the exposure to environmentally significant and healthrelevant compounds in indoor environments becomes a growing issue of concern
since people spend on average more than 80% of their time indoors. Moreover,
Conclusions and Future Trends
311