Comfortably numb: Ecotoxicity of the non-steroidal anti-inflammatory drug ibuprofen on Phaeodactylum tricornutum

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

“…Data regarding growth and biomarker activity/concentration was collected from previous published works [15,[23][24][25]43]. Phaeodactylum tricornutum Bohlin (Bacillariophyceae; strain IO 108-01, Instituto Português do Mar e da Atmosfera (IPMA) axenic cell cultures (kept under asexual reproduction circumstances) were placed to grow in f/2 medium [25], under continuous aeration in a phytoclimatic cabinet, at 18 ºC, set with a 14/10 h day/night photoperiod (RGB 1:1:1, maximum PAR 80 μmol photons m −2 s −1 ), a sine function to mimic sunrise and sunset, and maximum light intensity at noon, set to reproduce natural conditions [26].…”

“…Phaeodactylum tricornutum Bohlin (Bacillariophyceae; strain IO 108-01, Instituto Português do Mar e da Atmosfera (IPMA) axenic cell cultures (kept under asexual reproduction circumstances) were placed to grow in f/2 medium [25], under continuous aeration in a phytoclimatic cabinet, at 18 ºC, set with a 14/10 h day/night photoperiod (RGB 1:1:1, maximum PAR 80 μmol photons m −2 s −1 ), a sine function to mimic sunrise and sunset, and maximum light intensity at noon, set to reproduce natural conditions [26]. Exposure tests were preformed according to the Organization for Economic Cooperation and Development (OECD) guidelines for microalgae assays [27], as described in [15,[23][24][25]43]. Briefly cultures were exposed for 48 h. Final concentrations were chosen targeting to cover a concentration range not only environmentally relevant concentrations found in the literature, but also concentrations recognized to have substantial biologic consequences in P. tricornutum [28,29].…”

“…Growth inhibition concentration (IC50) was computed according to the OECD recommendations for microalgae inhibition test [27]. Biomarker analysis was preforned according to standard spectrophotometric procedures as described in [15,[23][24][25]43]. Briefly catalase (CAT), ascorbate peroxidase (APx) and superoxide dismutase (SOD) activities were assessed by spectrophotometric methodologies employing specific substrates as previously described [30][31][32].…”

“…Data on the exposure concentration and toxicity of five contaminants that inhibit the growth of the marine diatom P. tricornutum were obtained from previous studies [15,[23][24][25]43] and are presented at Table 1. According to the IC50 values, which refer to the exposure concentration capable to inhibit half the maximum growth in this marine diatom, SDS and fluoxetine are the most toxic compounds tested in P. tricornutum, with the lowest IC50 values of the tested cultures (< 50 g L -1 ).…”

“…In the present work, the suitability of three different multivariate indexes (BAI, IBR, and PCA-based indexes) was tested through the applicationof previously obtained oxidative stress biomarker data, using marine diatoms as study model. The impacts of pharmaceuticals (propranolol [22] , fluoxetine [23], ibuprofen [24], detergents (SDS), and herbicides (glyphosate [15]) on primary production and physiological fitness of the marine diatom Phaeodactylum tricornutum were used to understand the suitability of multivariate indexes in depicting dose responses and contaminant type, as well as to evaluate the performance and accuracy of each approach for future ecotoxicological trials. Summarily, we intended to produce an index that allows to better communicate toxicity results, providing an easy-to-understand framework, accessible to the managers and the general public.…”