impact on the marine environment remains difficult to appraise due to lack of
comprehensive studies. Nevertheless, aquaculture arises as an important but poorly
understood environmental burden. Owing to their large organic carbon pool, sediments may act as a sink for pyrethroids and impair nontarget aquatic species.
Partitioning potential of pyrethroids is compared to that of other well-known legacy
pollutants in the light of their position in the phase space defined by key physicochemical properties (K OW and H
0 ). The transport and partition of pyrethroids away
from their source are strongly dependent on their half-life, but their quasi constant
emissions in urban and agricultural area may compensate for their degradation,
therefore sustaining the occurrence and behavior of some individual pyrethroids as
“quasi persistent organic pollutants.”
Keywords Air, Freshwater, Marine, Partition, Pyrethroids, Sediment, Transport,
Water
1 Introduction
A major change in the use of pesticides over the last 20 years has been the gradual
replacement of organophosphate and organochlorine pesticides by synthetic pyrethroids. The regulation and the ban of formerly used active agents have been
followed by an increased use of a wide variety of current-use pesticides such as
pyrethroids in agriculture and aquaculture [1]. Pyrethroids are also extensively used
in urban and industrial areas and livestock farms to control pests such as mosquitoes,
lice, and wood-destroying dwellers. In addition, synthetic pyrethroids have the
advantage of low cost, low mammalian toxicity, and shorter persistence in the
environment than other classes of pesticides [2].
The exposure mechanism leading to acute neuronal toxicity to insects and
crustaceans is through dissolved water in the water column and through pore water
in the sediments [3]. Other impacts have been reported and are related to trophic
transfer in food webs. Even though pyrethroids are degraded faster than other
pesticides, they have been shown to occur in water bodies, allowing their transfer
to the aquatic food webs [4]. Pyrethroids have hydrophobicities in the same range as
legacy organochlorine pesticides (log K OW from 4.8 to 7.0) and thus tend to sorb on
organic particles and sediments. Insecticides sorbed in particles may be consumed
by filter feeders and be transferred to higher trophic levels, or alternatively, particles
may consist in a reservoir for these pollutants, probably reducing their biodegradability in natural waters. As a result of biomagnification at high trophic levels,
negative impact of pyrethroids has been suggested causing immunity and estrogenic
disruption to mammalians [4].
The impact of pyrethroids is the result of both the exposure to dissolved pyrethroids and to particle-associated ones. A comprehensive understanding of pyrethroid impact to nontarget species starts with the understanding of pyrethroid
occurrence in the various environmental phases: dissolved water phase, particles,
and sediments. This chapter reviews the current knowledge on the occurrence of
82
L. Méjanelle et al.
comprehensive studies. Nevertheless, aquaculture arises as an important but poorly
understood environmental burden. Owing to their large organic carbon pool, sediments may act as a sink for pyrethroids and impair nontarget aquatic species.
Partitioning potential of pyrethroids is compared to that of other well-known legacy
pollutants in the light of their position in the phase space defined by key physicochemical properties (K OW and H
0 ). The transport and partition of pyrethroids away
from their source are strongly dependent on their half-life, but their quasi constant
emissions in urban and agricultural area may compensate for their degradation,
therefore sustaining the occurrence and behavior of some individual pyrethroids as
“quasi persistent organic pollutants.”
Keywords Air, Freshwater, Marine, Partition, Pyrethroids, Sediment, Transport,
Water
1 Introduction
A major change in the use of pesticides over the last 20 years has been the gradual
replacement of organophosphate and organochlorine pesticides by synthetic pyrethroids. The regulation and the ban of formerly used active agents have been
followed by an increased use of a wide variety of current-use pesticides such as
pyrethroids in agriculture and aquaculture [1]. Pyrethroids are also extensively used
in urban and industrial areas and livestock farms to control pests such as mosquitoes,
lice, and wood-destroying dwellers. In addition, synthetic pyrethroids have the
advantage of low cost, low mammalian toxicity, and shorter persistence in the
environment than other classes of pesticides [2].
The exposure mechanism leading to acute neuronal toxicity to insects and
crustaceans is through dissolved water in the water column and through pore water
in the sediments [3]. Other impacts have been reported and are related to trophic
transfer in food webs. Even though pyrethroids are degraded faster than other
pesticides, they have been shown to occur in water bodies, allowing their transfer
to the aquatic food webs [4]. Pyrethroids have hydrophobicities in the same range as
legacy organochlorine pesticides (log K OW from 4.8 to 7.0) and thus tend to sorb on
organic particles and sediments. Insecticides sorbed in particles may be consumed
by filter feeders and be transferred to higher trophic levels, or alternatively, particles
may consist in a reservoir for these pollutants, probably reducing their biodegradability in natural waters. As a result of biomagnification at high trophic levels,
negative impact of pyrethroids has been suggested causing immunity and estrogenic
disruption to mammalians [4].
The impact of pyrethroids is the result of both the exposure to dissolved pyrethroids and to particle-associated ones. A comprehensive understanding of pyrethroid impact to nontarget species starts with the understanding of pyrethroid
occurrence in the various environmental phases: dissolved water phase, particles,
and sediments. This chapter reviews the current knowledge on the occurrence of
82
L. Méjanelle et al.