**Acknowledgements**

Accordingly, regulatory programs worldwide are currently incorporating tests with endpoints that involve the effects of chemicals and the impact in specific metabolic pathways (Ankley et al., 2006). Toxicological end-points can be general biological responses such as survival or weight loss (Baylay et al., 2012), but specific biomarkers provide the accuracy that

Several issues immediately arise from the summary here presented, such as the need to perform field toxicological test, with natural soils rather than use artificial soils, as was the case with some of the studies listed in Table 1. Ecotoxigenomics can also benefit from the incorpo‐ ration of further analytical techniques. Techniques based on mass spectrometry are certainly required to understand the mechanisms involved in the alteration of metabolic pathways as response to toxicants. However, for screenings which merely require the detection of differ‐ ences between metabolic phenotypes, optical methods such as FT-IR would be suitable, particularly if extremely high sample throughput is required (Bundy et al., 2009). Although no data was available in the existing literature, Figure 2 illustrates the change in the fingerprint of organic compounds in a soil amended with different sources of carbon collected 10 after the application. While some of the groups of compounds might be merely related to the sources of carbon added, the variations in the signal associated to polysaccharides (600-1000 cm-1) can be associated to changes in the metabolic fingerprint of the soil system and therefore linked to microbiological activity in soil. Overall, the introduction of these results seeks to encourage further characterization of families of compounds in intact soil (or functional pools such as aggregates) in relation with soil processes, an approach that can find immediate application

**(a) (b)** 

**Absorbance**

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1.0 1.5 2.0 2.5 3.0

S SBL SBP SBM

Figure 2. Absorption spectra obtained by Fourier transform infrared spectroscopy (FTIR) for an agricultural soil (S), soil amended with fresh residues (a): dry leaf litter (SL), peanut shell (SP), maize residue (SM), and soil amended with biochar (b) derived from those feedstocks (BL, BP or BM). Spectra presented (after 10 d incubation) are the average of 5 spectra obtained

**Figure 2.** Absorption spectra obtained by Fourier transform infrared spectroscopy (FTIR) for an agricultural soil (S), soil amended with fresh residues (a): dry leaf litter (SL), peanut shell (SP), maize residue (SM), and soil amended with bio‐ char (b) derived from those feedstocks (BL, BP or BM). Spectra presented (after 10 d incubation) are the average of 5

**Wavenumber (cm-1)** 4000 3000 2000 1000

The variability of biological responses has been one of the main obstacles for their implementation in standardized risk assessment. However, the examination of changes in biological processes by accurate analytical techniques and powerful statistical tools has launched a new era in our understanding of the soil processes. The possibility of identifying the most sensitive metabolites for a certain toxicant and develop a tailored standardized

The variability of biological responses has been one of the main obstacles for their implemen‐ tation in standardized risk assessment. However, the examination of changes in biological

MCH-S thanks The University of Queensland for a postdoctoral research fellowship. JCJ-L thanks the European

The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the

Amiard-Triquet, C., Amiard, J.C., Rainbow, P.S., 2012. Ecological Biomarkers: Indicators of Ecotoxicological

Ankley, G.T., Daston, G.P., Degitz, S.J., Denslow, N.D., Hoke, R.A., Kennedy, S.W., Miracle, A.L., Perkins, E.J., Snape, J., Tillitt, D.E., Tyler, C.R., Versteeg, D., 2006. Toxicogenomics in Regulatory Ecotoxicology.

Baylay, A.J., Spurgeon, D.J., Svendsen, C., Griffin, J.L., Swain, S.C., Sturzenbaum, S.R., Jones, O.A.H., 2012. A metabolomics based test of independent action and concentration addition using the earthworm Lumbricus

Boer, M., Ellers, J., Gestel, C.M., Dunnen, J., Straalen, N., Roelofs, D., 2013. Transcriptional responses indicate attenuated oxidative stress in the springtail Folsomia candida exposed to mixtures of cadmium and

research program Marie Curie (FP7-PEOPLE-2011-IOF) for his PIOF-GA-2011-301550 grant.

spectra obtained for different samples of each treatment. Hernandez-Soriano et al., unpublished data.

was classically elusive for test with living organisms

474 Environmental Risk Assessment of Soil Contamination

in the assessment of biological responses to toxic compounds in soil.

for different samples of each treatment. Hernandez-Soriano et al., unpublished data.

**Wavenumber (cm-1)** 4000 3000 2000 1000

test is the ultimate goal pursued.

**Acknowledgments** 

manuscript.

**Absorbance**

0.0 0.5 1.0 1.5 2.0 2.5 3.0

S SL SP SM

**References** 

Effects. Taylor & Francis.

Environmental Science & Technology 40, 4055-4065.

rubellus. Ecotoxicology 21, 1436-1447.

phenanthrene. Ecotoxicology 22, 619-631.

MCH-S thanks The University of Queensland for a postdoctoral research fellowship. JCJ-L thanks the European research program Marie Curie (FP7-PEOPLE-2011-IOF) for his PIOF-GA-2011-301550 grant.

The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
