10 Conclusions
A larger body of evidence on biomarker responses in earthworms is provided by the
use of epigeic Eisenia spp. as model species of soil toxicity assessment. However,
due to the ecological role of anecic species, their inclusion as sentinels is highly
recommended because of their impact on soil physico-chemical and biological
properties and abundance in agroecosystems. Moreover, the deep-burrowing species
have shown themselves to be more sensitive to chemicals than the epigeic ones.
From a monitoring perspective and practicability, the use of whole tissue homogenates rather than particular tissues facilitates the protocols and has already been
validated for many parameters. The inclusion of biomarker measures using
non-destructive techniques (i.e. coelomocytes) also deserves consideration.
Amongst chemicals, traditional monitoring had focussed on pesticides and metalcontaminated soils. However, in recent years, other chemicals of increasing presence
in natural soils (e.g. pharmaceuticals, plastics, e-waste and associated chemicals)
have been targeted. This is especially relevant in countries enduring water scarcity as
they may use contaminated wastewater for crop irrigation. Outstanding from
amongst the more frequently selected biomarkers are early warning responses that
can lead to consequences at higher levels of biological organisation. Since from an
environmental perspective, contaminated soils endure many types of chemicals,
including pharmaceuticals to different extents, the use of general stress biomarkers
is encouraged, that is, immunological, oxidative stress exposure and effect and
neuro- and genotoxic biomarker responses as common effects revealed by those
experimental exposures. The development of state-of-the-art analytical protocols
will allow (1) the incorporation of metabolomics biomarkers to identify the endogenous metabolic processes likely to be affected by contaminants and (2) metabolite
identification, as suggestive of the xenobiotic metabolism pathways affected and to
favour further toxicity assessment of the identified by-products, as a more realistic
approach.
Acknowledgements To the EU Water JPI-2015 AWARE project (PCIN-2017-067), D. Nos and
D. Romano are thanked for their contribution to the project.
References
1. Rombke J, Jansch S, Didden W (2005) The use of earthworms in ecological soil classification
and assessment concepts. Ecotoxicol Environ Saf 62:249–265
2. Lionetto MG, Callisi A, Schettino T (2012) Earthworm biomarkers as tools for soil pollution
assessment. In: Hernandez-Soriano MC (ed) Soil health and land use management., ISBN
978-953-307-614-0. InTech, Rijeka, pp 305–332
3. Pelosi C, Joimel S, Makowski D (2013) Searching for a more sensitive earthworm species to be
used in pesticide homologation tests – a meta-analysis. Chemosphere 90:895–900
4. Pelosi C, Barot S, Capowiez Y, Hedde M, Vandenbulcke F (2014) Pesticides and earthworms.
A review. Agron Sustain Dev 34:199–228
Biomarkers in Earthworms
333
A larger body of evidence on biomarker responses in earthworms is provided by the
use of epigeic Eisenia spp. as model species of soil toxicity assessment. However,
due to the ecological role of anecic species, their inclusion as sentinels is highly
recommended because of their impact on soil physico-chemical and biological
properties and abundance in agroecosystems. Moreover, the deep-burrowing species
have shown themselves to be more sensitive to chemicals than the epigeic ones.
From a monitoring perspective and practicability, the use of whole tissue homogenates rather than particular tissues facilitates the protocols and has already been
validated for many parameters. The inclusion of biomarker measures using
non-destructive techniques (i.e. coelomocytes) also deserves consideration.
Amongst chemicals, traditional monitoring had focussed on pesticides and metalcontaminated soils. However, in recent years, other chemicals of increasing presence
in natural soils (e.g. pharmaceuticals, plastics, e-waste and associated chemicals)
have been targeted. This is especially relevant in countries enduring water scarcity as
they may use contaminated wastewater for crop irrigation. Outstanding from
amongst the more frequently selected biomarkers are early warning responses that
can lead to consequences at higher levels of biological organisation. Since from an
environmental perspective, contaminated soils endure many types of chemicals,
including pharmaceuticals to different extents, the use of general stress biomarkers
is encouraged, that is, immunological, oxidative stress exposure and effect and
neuro- and genotoxic biomarker responses as common effects revealed by those
experimental exposures. The development of state-of-the-art analytical protocols
will allow (1) the incorporation of metabolomics biomarkers to identify the endogenous metabolic processes likely to be affected by contaminants and (2) metabolite
identification, as suggestive of the xenobiotic metabolism pathways affected and to
favour further toxicity assessment of the identified by-products, as a more realistic
approach.
Acknowledgements To the EU Water JPI-2015 AWARE project (PCIN-2017-067), D. Nos and
D. Romano are thanked for their contribution to the project.
References
1. Rombke J, Jansch S, Didden W (2005) The use of earthworms in ecological soil classification
and assessment concepts. Ecotoxicol Environ Saf 62:249–265
2. Lionetto MG, Callisi A, Schettino T (2012) Earthworm biomarkers as tools for soil pollution
assessment. In: Hernandez-Soriano MC (ed) Soil health and land use management., ISBN
978-953-307-614-0. InTech, Rijeka, pp 305–332
3. Pelosi C, Joimel S, Makowski D (2013) Searching for a more sensitive earthworm species to be
used in pesticide homologation tests – a meta-analysis. Chemosphere 90:895–900
4. Pelosi C, Barot S, Capowiez Y, Hedde M, Vandenbulcke F (2014) Pesticides and earthworms.
A review. Agron Sustain Dev 34:199–228
Biomarkers in Earthworms
333