3 Biomarkers of Pesticide Exposure
The use of biomarkers in earthworms to assess soil contamination by pesticides has
received the largest body of attention and has already been accurately reviewed [3, 5,
6, 8, 17]. Studies by Sanchez-Hernandez and co-workers [17] have described the
tissue-specific differences in the CE sensitivity to organophosphorus pesticides.
Their studies provided evidence on the role of L. terrestris in improving soil quality
and increasing extracellular enzyme activities, including CEs, as well as soil microbial activity thanks to their casts’ contribution. As mentioned before, and for
biomonitoring of polluted soils, more recent studies using biomarkers measured in
whole tissue homogenates or coelomocytes will be given priority.
A Chilean field study assessing pesticide exposures in sites following conventional versus organic agricultural management practices selected L. terrestris as
sentinel. The study took place over the four seasons and in three tissues of the
earthworms’ gastrointestinal tract and demonstrated that CE measurements in this
species were adequate biomarkers of pesticide exposure [18]. Also the soil-dwelling
species A. caliginosa was selected in an experiment with soil spiked with two
insecticides: a commercial brand of a carbamate (Pirimor
® ) and Lorsban
® as organophosphate (OP). The aim of the study was to relate the neurotoxicity marker AChE
activity in whole tissue homogenate with an electrophysiological technique named
nerve conduction velocity (NCV) in medial giant fibres and therefore, to validate the
use of a conservative technique (NCV) to assess neurotoxicity [19]. In the attempt to
link biochemical (AChE and CE activities) to behaviour responses (burrowing,
casting and feeding) of ecological significance, the study of Jouni et al. [20] exposed
two endogeic earthworms, A. chlorotica and A. caliginosa, in soil contaminated with
the pesticide ethyl-parathion for 7 days. The in vivo and in vitro exposures to this
pesticide suggested that A. caliginosa was the most sensitive species [20]. The
measurement of activities in non-destructive coelomocytes of E. andrei in response
to two OP pesticide exposures (dimethoate and pirimiphos-methyl) was recently
validated [21]. In this study, responses of AChE and CE enzymes in whole tissue
homogenate were contrasted with those in this bio-fluid using the filter paper contact
assay [21]. Dendrobaena veneta, also an epigeic species, was selected for testing the
toxicity of three herbicides at three environmental concentrations in Petri dish
exposures using the filter paper contact test. Two trials of 7 and 28 days were
performed in which the biomarkers AChE, CAT, GST and LPO (measured as
MDA) were considered in addition to reproductive endpoints [22]. The associated
biomarker and toxicity responses were seen as herbicide- and dose-related. Toxicity
due to pyrethroid and bifenthrin was assessed in E. fetida for up to 28 days following
soil gradient exposures. Biomarkers dealing with oxidative stress and metabolism
(ROS formation, POD, SOD, CAT, GST and EROD activities) were measured and
their responses seen as concentration- and time-dependent [23]. Indigenous earthworm species from Nigerian soils, namely, Alma millsoni, Eudrilus eugeniae and
Libyodrilus violaceus, were the sentinels of a bioremediation study after the application of Roundup
® Alphée, a glyphosate-based herbicide (GBH) in potted soils,
Biomarkers in Earthworms
323
The use of biomarkers in earthworms to assess soil contamination by pesticides has
received the largest body of attention and has already been accurately reviewed [3, 5,
6, 8, 17]. Studies by Sanchez-Hernandez and co-workers [17] have described the
tissue-specific differences in the CE sensitivity to organophosphorus pesticides.
Their studies provided evidence on the role of L. terrestris in improving soil quality
and increasing extracellular enzyme activities, including CEs, as well as soil microbial activity thanks to their casts’ contribution. As mentioned before, and for
biomonitoring of polluted soils, more recent studies using biomarkers measured in
whole tissue homogenates or coelomocytes will be given priority.
A Chilean field study assessing pesticide exposures in sites following conventional versus organic agricultural management practices selected L. terrestris as
sentinel. The study took place over the four seasons and in three tissues of the
earthworms’ gastrointestinal tract and demonstrated that CE measurements in this
species were adequate biomarkers of pesticide exposure [18]. Also the soil-dwelling
species A. caliginosa was selected in an experiment with soil spiked with two
insecticides: a commercial brand of a carbamate (Pirimor
® ) and Lorsban
® as organophosphate (OP). The aim of the study was to relate the neurotoxicity marker AChE
activity in whole tissue homogenate with an electrophysiological technique named
nerve conduction velocity (NCV) in medial giant fibres and therefore, to validate the
use of a conservative technique (NCV) to assess neurotoxicity [19]. In the attempt to
link biochemical (AChE and CE activities) to behaviour responses (burrowing,
casting and feeding) of ecological significance, the study of Jouni et al. [20] exposed
two endogeic earthworms, A. chlorotica and A. caliginosa, in soil contaminated with
the pesticide ethyl-parathion for 7 days. The in vivo and in vitro exposures to this
pesticide suggested that A. caliginosa was the most sensitive species [20]. The
measurement of activities in non-destructive coelomocytes of E. andrei in response
to two OP pesticide exposures (dimethoate and pirimiphos-methyl) was recently
validated [21]. In this study, responses of AChE and CE enzymes in whole tissue
homogenate were contrasted with those in this bio-fluid using the filter paper contact
assay [21]. Dendrobaena veneta, also an epigeic species, was selected for testing the
toxicity of three herbicides at three environmental concentrations in Petri dish
exposures using the filter paper contact test. Two trials of 7 and 28 days were
performed in which the biomarkers AChE, CAT, GST and LPO (measured as
MDA) were considered in addition to reproductive endpoints [22]. The associated
biomarker and toxicity responses were seen as herbicide- and dose-related. Toxicity
due to pyrethroid and bifenthrin was assessed in E. fetida for up to 28 days following
soil gradient exposures. Biomarkers dealing with oxidative stress and metabolism
(ROS formation, POD, SOD, CAT, GST and EROD activities) were measured and
their responses seen as concentration- and time-dependent [23]. Indigenous earthworm species from Nigerian soils, namely, Alma millsoni, Eudrilus eugeniae and
Libyodrilus violaceus, were the sentinels of a bioremediation study after the application of Roundup
® Alphée, a glyphosate-based herbicide (GBH) in potted soils,
Biomarkers in Earthworms
323