Evaluation of Multivariate Biomarker Indexes Application in Ecotoxicity Tests with Marine Diatoms Exposed to Emerging Contaminants

Abstract

Worldwide anthropogenic activities result in the production and release of poten-tially damaging toxic pollutants into ecosystems, thereby jeopardizing their health and continuity. Research studies and biomonitoring programs attend to this emerging problematic by applying and developing statistically relevant indexes that integrate complex biomarker response data to provide an holistic approach reflecting toxically induced alterations at the organism’s or population level. Ultimately, indexes allow simple result communication, enhancing policy makers understanding, so contributing for better resource and environmental managing policies. In this study three indexes , the Integrated Biomarker Response index (IBR), the Bioeffects Assessment Index (BAI) and the Principal Components Analysis (PCA), were evaluated for their sensitivity in revealing toxically induced stress patterns in cells of the diatom Phaeodactylum tricornutum under contaminant exposure. The set of biomarkers selected for index construction comprise the anti-oxidant enzymes APX, CAT and SOD, and the lipid peroxidation marker TBARS. Several significant inverse correlations with the concentration gradients applied, , was noticed for all indexes, though, the IBR excels for its reliability in delivering statistically significant dose-response patterns for four out of the five compounds tested.

LipidTOX: A fatty acid-based index efficient for ecotoxicological studies with marine model diatoms exposed to legacy and emerging contaminants

“…However, fatty acid profiles constitute a dataset composed of several quantitative variables that are not of easy understanding by a non-expert audience. This way and similarly to what has been previously proposed for other biomarker sets such as photochemical datasets (Cruz de and classical enzymatic biomarkers (Pires et al, 2021), the gathering of these variables into unifying indexes has previously provided consistent and reliable results, in translating the stress condition to which the organisms are subjected to. This approach involving fatty acid profiles was already undertaken to index development for macroalgae (Duarte et al, 2021a) and higher plants (Duarte et al, 2018a), but not yet for marine diatoms.…”

“…Contaminants, when occurring above certain thresholds, can induce physiological constraints to organisms (Anjum et al, 2016;Cruz de Carvalho et al, 2020b;Duarte et al, 2013;, leading to the triggering of feedback mechanisms that can be used as biomarkers of xenobiotic exposure, such as changes in antioxidant response systems (Duarte et al, 2013;Pires et al, 2021) -0,6 -0,4 -0,2 0 0,2 0,4 0,6 CAP1 -0,6 et al, 2018a;Duarte et al, 2021a). Although xenobiotic exposure affects the entire trophic web, triggers multiple and sometimes species-specific alterations, depending on the organisms affected (Brausch et al, 2012;Lopes et al, 2020;Pires et al, 2021;Roma et al, 2020), the impacts of xenobiotics acquire an even more critical aspect at the basis of the trophic web, imposing direct and indirect serious ecosystem shifts. These effects will impact directly the marine communities by affecting the phytoplanktonic compartment functioning and abundance, or due to the inevitable reduction of the energy fluxes (in the form of carbohydrates, fatty acids and other essential nutrients to the upper trophic levels) and oxygen provided by this group of organisms Cabrita et al, 2016;Feijão et al, 2020a).…”

“…For this purpose, there is also a rising need to perform ecotoxicological trials to produce relevant data to feed into these ERA models, enabling appropriate management and stakeholders' entities to perform an accurate environmental assessment. Emerging compounds such as pharmaceuticals, personal care products, biocides and nanomaterials impose serious threats to marine life, with recognized effects observed under current environmental concentrations (Brausch et al, 2012;Duarte et al, 2020b;Fonseca et al, 2021;Franzitta et al, 2020;Lopes et al, 2020;Pires et al, 2021;Roma et al, 2020).…”

“…The aforementioned impacts are felt throughout the trophic web, resulting in the most diverse array of effects according to the organisms affected (Brausch et al, 2012;Lopes et al, 2020;Pires et al, 2021;Roma et al, 2020). However, these effects are even more critical when they occur at the basis of the trophic chains, at the primary producers' level, directly and indirectly imposing serious ecosystem shifts.…”

“…Several studies have used this species as model to study the effects of a wide array of contaminants namely heavy metals (Cabrita et al, 2017;Cid et al, 1995), metal nanoparticles (Franzitta et al, 2020;Li et al, 2017;Wang et al, 2016), polycyclic aromatic hydrocarbons , biocides (Du et al, 2019), surfactants (Pavlić et al, 2005), ionic liquids (Chen et al, 2019) and pharmaceutical residues (Duarte et al, 2021c), among several others. Thus it is a highly relevant species for ecotoxicology purposes and the development of indexes based in its physiological response to contaminants is of added value for ecotoxicological studies (Duarte et al, 2021c;Pires et al, 2021;Rodrigues et al, 2021).…”