Surface functionalization of a chalcogenide IR photonic sensor by means of a polymer membrane for water pollution remediation.

Rapid, simultaneous detection of organic chemical pollutants in water is an important issue to solve for protecting human health. This study investigated the possibility of developing an in situ reusable optical sensor capable of selective measurements utilizing a chalcogenide transducer supplemented by a hydrophobic polymer membrane with detection based on evanescent waves in the mid-infrared spectrum. In order to optimise a polyisobutylene hydrophobic film deposited on a chalcogenide waveguide, a zinc selenide prism was utilized as a testbed for performing attenuated total reflection with Fourier-transform infrared spectroscopy. To comply with the levels mentioned in health guidelines, the target detection range in this study was kept rather low, with the concentration range extended from 50 ppb to 100 ppm to cover accidental pollution problems, while targeted hydrocarbons (benzene, toluene, and xylene) were still detected at a concentration of 100 ppb. Infrared measurements in the selected range showed a linear behaviour, with the exception of two constantly reproducible plateau phases around 25 and 80 ppm, which were observable for two polymer film thicknesses of 5 and 10 µm. The polymer was also found to be reusable by regenerating it with water between individual measurements by increasing the water temperature and flow to facilitate reverse exchange kinetics. Given the good conformability of the hydrophobic polymer when coated on chalcogenide photonic circuits and its demonstrated ability to detect organic pollutants in water and to be regenerated afterwards, a microfluidic channel utilising water flow over an evanescent wave optical transducer based on a chalcogenide waveguide and a polyisobutylene (PIB) hydrophobic layer deposited on its surface was successfully fabricated from polydimethylsiloxane by filling a mold prepared via CAD and 3D printing techniques.

Water-accommodated fractions of heavy and light oils impact DNA integrity, embryonic development, and immune system of Japanese medaka at early life stages.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants generally found in complex mixtures. PAHs are known to cause pleiotropic effects on living organisms, including developmental defects, mutagenicity, carcinogenicity and immunotoxicity, and endocrine disruptions. The main goal of this study is to evaluate the toxicity of water-accommodated fractions (WAFs) of oils in two life stages of the Japanese medaka, larvae and juveniles. The deleterious effects of an acute exposure of 48 h to two WAFs from Arabian light crude oil (LO) and refined oil from Erika (HO) were analyzed in both stages. Relevant endpoints, including ethoxy resorufin-O-deethylase (EROD) activity, DNA damage (Comet assay), photomotor response, and sensitivity to nervous necrosis virus (NNV) infection, were investigated. Larvae exposed to both oil WAFs displayed a significant induction of EROD activity, DNA damage, and developmental anomalies, but no behavioral changes. Deleterious effects were significantly increased following exposure to 1 and 10 µg/L of LO WAFs and 10 µg/L of HO WAFs. Larval infection to NNV induced fish mortality and sharply reduced reaction to light stimulation. Co-exposure to WAFs and NNV increased the mortality rate, suggesting an impact of WAFs on fish defense capacities. WAF toxicity on juveniles was only observed following the NNV challenge, with a higher sensitivity to HO WAFs than to LO WAFs. This study highlighted that environmentally realistic exposure to oil WAFs containing different compositions and concentrations of oil generated high adverse effects, especially in the larval stage. This kind of multi-marker approach is particularly relevant to characterize the toxicity fingerprint of environmental mixtures of hydrocarbons and PAHs.

Toxicity evaluation of water-accommodated fraction of heavy and light oils on the rainbow trout fish cell line RTL-W1.

Fish are currently used models for the toxicity assessment of chemicals, including polycyclic aromatic hydrocarbons (PAHs). Alternative methods including fish cell lines are currently used to provide fast and reliable results on the toxic properties of chemicals while respecting ethical concerns about animal testing. The Rainbow trout liver cell line RTLW1 was used to analyze the effects of two water-accommodated fractions from two crude oils: Arabian Light crude oil (LO) and refined oil from Erika (HO). Several toxicity endpoints were assessed in this study, including cytotoxicity, EROD activity, DNA damage (comet and micronucleus assays), and ROS production. RTL-W1 cells were exposed for 24 h at two or three dilutions of WAF at 1000 µg/L (0.1% (1 µg/L), 1% (10 µg/L), and 10% (100 µg/L)) for cytotoxicity and EROD activity and 1% and 10% for ROS production and genotoxicity). Exposure of RTL-W1 cells to LO WAF induced a significant increase of EROD activity and ROS production and altered DNA integrity as revealed by both the comet assay and the micronucleus test for 10 µg/L of LO. On the other hand, HO WAF exhibited limited toxic effects except for an EROD induction for 1% WAF dilution. These results confirmed the usefulness of RTL-W1 cells for in vitro toxicological assessment of chemical mixtures.

Relevance of flounder caging and proteomics to explore the impact of a major industrial accident caused by fire on the Seine estuarine water quality.

On September 26th 2019, a major fire occurred in the Lubrizol factory located near the Seine estuary, in Rouen-France. Juvenile flounders were captured in the Canche estuary (a reference system) and caged one month in the Canche and in the Seine downstream the accident site. No significant increases of PAHs, PCBs and PFAS was detected in Seine vs Canche sediments after the accident, but a significant increase of dioxins and furans was observed in water and sewage sludge in the Rouen wastewater treatment plant. The proteomics approach highlighted a dysregulation of proteins associated with cholesterol synthesis and lipid metabolism, in fish caged in the Seine. The overall results suggested that the fire produced air borne dioxins and furans that got deposited on soil and subsequently entered in the Seine estuarine waters via runoff; thus contaminating fish preys and caged flounders in the Seine estuary.