AChE activity and LPO as endpoints [48]. The responses observed were variable
and dependant on whether they had addressed single or co-exposures, with the
authors stressing the importance of assessing the biochemical responses to realistic
mixtures.
Several copper oxide (CuO)-engineered nanomaterial (ENM) variants were
spiked in artificial soil (freshly prepared and after 1 year of ageing), and the toxicity
displayed in E. fetida was evaluated after 14 days in terms of GSH content, SOD
activity, the osmoregulatory capacity indicator Na
+
/K
+
-ATPase activity and histology [49]. Their results revealed a coating-dependent difference in ENM toxicity to
earthworms which was also modified after a year of soil ageing, and, in both cases,
osmotic disturbance was revealed as the most sensitive endpoint.
Nickel oxide nanoparticles (NiO-NP) toxicity was assessed in the same earthworm model at a range of concentrations, 5, 50, 200, 500 and 1,000 mg kg
À1 , in soil
after 28 days. Biomarkers related to oxidative defences (CAT, POD and SOD),
damage (as oxidised DNA and lipids) as well as histological examination of the
whole tissue were evaluated [50]. Their results were also seen as dose dependant,
and while POD activity, MDA (LPO) and 8-OHdG (DNA damage) levels increased,
CAT and SOD defences decreased. Histology analyses also confirmed alterations of
the epithelium layer, microvilli and mitochondria as well as potential adverse effects
on the gut barrier.
8 Biomarkers of Plastics, Plasticisers and E-Waste-Related
Exposures
The presence of plastic in natural soil is an issue of increasing concern especially for
earthworm populations from natural and agricultural soils such as L. terrestris. Thus,
this species was the sentinel selected for assessing microplastic exposures in natural
soils polluted with polyester microfibres (MF) derived from textile laundering.
During the 35-day trial, some gene expression endpoints related to metal, oxidative
stress and general stress markers were considered [51]. The highest percentage of
MF in soil (1%) caused a significant reduction in cast production and hsp70 gene
expression and an increase in the expression of mt-2, although metal content was not
seen as a relevant contributor in the most polluted soil.
Phthalates are important plastic additives that in some cases can represent >50%
of the polymer mixture (e.g. PVC) from which they can be easily released and be
toxic to organism inhabiting polluted soils [52]. Phthalate exposures have been
studied in the model E. fetida in standardised 28-day exposures. Di-n-butyl phthalate
(DBP) was evaluated over time under a gradient up to 100 mg kg
À1 dry soil, and
several biomarkers related to antioxidant defences (SOD, CAT GST, POD and GSH
content) and the indicator of LPO damage (MDA formed) were considered [53]. In
general, the activity of certain enzymes (SOD, CAT, POD) showed a downward
trend while LPO increased. The same experiment also included the measure of
328
M. Solé
and dependant on whether they had addressed single or co-exposures, with the
authors stressing the importance of assessing the biochemical responses to realistic
mixtures.
Several copper oxide (CuO)-engineered nanomaterial (ENM) variants were
spiked in artificial soil (freshly prepared and after 1 year of ageing), and the toxicity
displayed in E. fetida was evaluated after 14 days in terms of GSH content, SOD
activity, the osmoregulatory capacity indicator Na
+
/K
+
-ATPase activity and histology [49]. Their results revealed a coating-dependent difference in ENM toxicity to
earthworms which was also modified after a year of soil ageing, and, in both cases,
osmotic disturbance was revealed as the most sensitive endpoint.
Nickel oxide nanoparticles (NiO-NP) toxicity was assessed in the same earthworm model at a range of concentrations, 5, 50, 200, 500 and 1,000 mg kg
À1 , in soil
after 28 days. Biomarkers related to oxidative defences (CAT, POD and SOD),
damage (as oxidised DNA and lipids) as well as histological examination of the
whole tissue were evaluated [50]. Their results were also seen as dose dependant,
and while POD activity, MDA (LPO) and 8-OHdG (DNA damage) levels increased,
CAT and SOD defences decreased. Histology analyses also confirmed alterations of
the epithelium layer, microvilli and mitochondria as well as potential adverse effects
on the gut barrier.
8 Biomarkers of Plastics, Plasticisers and E-Waste-Related
Exposures
The presence of plastic in natural soil is an issue of increasing concern especially for
earthworm populations from natural and agricultural soils such as L. terrestris. Thus,
this species was the sentinel selected for assessing microplastic exposures in natural
soils polluted with polyester microfibres (MF) derived from textile laundering.
During the 35-day trial, some gene expression endpoints related to metal, oxidative
stress and general stress markers were considered [51]. The highest percentage of
MF in soil (1%) caused a significant reduction in cast production and hsp70 gene
expression and an increase in the expression of mt-2, although metal content was not
seen as a relevant contributor in the most polluted soil.
Phthalates are important plastic additives that in some cases can represent >50%
of the polymer mixture (e.g. PVC) from which they can be easily released and be
toxic to organism inhabiting polluted soils [52]. Phthalate exposures have been
studied in the model E. fetida in standardised 28-day exposures. Di-n-butyl phthalate
(DBP) was evaluated over time under a gradient up to 100 mg kg
À1 dry soil, and
several biomarkers related to antioxidant defences (SOD, CAT GST, POD and GSH
content) and the indicator of LPO damage (MDA formed) were considered [53]. In
general, the activity of certain enzymes (SOD, CAT, POD) showed a downward
trend while LPO increased. The same experiment also included the measure of
328
M. Solé