The integrated biomarker response revisited: optimization to avoid misuse

Abstract

The growing need to evaluate the quality of aquatic ecosystems led to the development of numerous monitoring tools. Among them, the development of biomarker-based procedures, that combine precocity and relevance, is recommended. However, multi-biomarker approaches are often hard to interpret, and produce results that are not easy to integrate in the environmental policies framework. Integrative index have been developed, and one of the most used is the integrated biomarker response (IBR). However, an analysis of available literature demonstrated that the IBR suffers from a frequent misuse and a bias in its calculation. Then, we propose here a new calculation method based on both a more simple formula and a permutation procedure. Together, these improvements should rightly avoid the misuse and bias that were recorded. Additionally, a case study illustrates how the new procedure enabled to perform a reliable classification of site along a pollution gradient based on biomarker responses used in the IBR calculations.

Contribution of pyrethroids in large urban rivers to sediment toxicity assessed with benthic invertebrates Chironomus dilutus: A case study in South China

“…An integrated biomarker response (IBR) index was calculated to summarize biomarker expression by integrating quantifications of individual biomarkers into a single value . First a Y value was calculated by the mean value of a biomarker ( X ) and mean (m) and standard deviation (SD) of the total biomarker values (Equation ).…”

Integrated biomarker response index used in laboratory exposure of the mussel Mytilus edulis to water accommodated fractions of crude oil

“…An IBR was calculated with biomarker data obtained in the WAFs exposure experiment by the method proposed by Devin et al [19] with minor modification. It was modified to use exposure group instead of site as a factor, aiming at reflecting changes in biomarkers as a whole.…”

“…It was first proposed by Beliaeff and Burgeot [18] and revised by Devin et al [19], as formula misuse and arbitrary choice of biomarkers sequence were the main problems in the application of the initial method. IBR method is an effective tool for visualization of biological effects of pollutants and simplifying the interpretation of relationships between multi-biomarkers and contamination levels [19]. It has become one of the most common integrative indexes developed in various field environmental biomonitoring programs and laboratory experiments [20,21].…”

An integrated assessment of pollution and biological effects in flounder, mussels and sediment in the southern Baltic Sea coastal area

“…Both indexes, CPI and IBR, have been viewed as useful tools for the assessment of health status of marine ecosystems (Beliaeff and Burgeot 2002;Lehtonen et al 2014;Marigómez et al 2013;Meng et al 2013). To take into account that the value of the IBR index depends to some extent on the biomarker order in the final step of calculations, all possible permutations of the standardized biomarker values were performed and median IBR/n values for each species at each site were calculated (Beliaeff and Burgeot 2002;Devin et al 2014). For flounder, IBR was based on the biomarkers reported here and those reported earlier (Table 1) which all were measured in the same individuals.…”