CIRIR programs: drilling and research opportunities at the Rochechouart Impact Structure

International audienc

Polycyclic aromatic hydrocarbon transformation with laccases of a white-rot fungus isolated from a Mediterranean schlerophyllous litter

International audienceThis study was conducted to investigate whether a laccase from a white-rot fungus isolated from Mediterranean forest litters was able to oxidise widespread pollutants such as polycyclic aromatic hydrocarbons (PAH). Six different isoforms from the constitutive laccase of Marasmius quercophilus strain19 were revealed using isoelectric focusing. In vitro studies showed that these laccase isoforms were able to transform anthracene and benzo(a)pyrene while naphthalene and phenantrene were not oxidised. This result on PAH transformation is linked to the ionisation potential (IP) of PAH: the laccases under study are able to oxidise PAH with IP b 7.55 eV. 2,2′-azino-bis-3-ehtylbenzothiazoline-6-sulfonicacid (ABTS) and hydroxybenzotriazole (HBT), were also used as mediators: percentages of anthracene and benzo(a)pyrene transformation were higher when ABTS was used and when mediators were pre-oxidised with laccases whatever the mediator used. Moreover, after an eight or fifteen-day culture of strain 19 with anthracene, the percentage of disappearance was 73 and 79% respectively. This study also highlights the fact that ABTS or one of its oxidised form, ABTS radical cation (ABTS U+), can be respectively oxidised or reduced through abiotic reactions. Thus, ABTS, because of its electrochemical characteristics, can hardly be considered as a relevant substrate to measure laccase activities in complex environments such as soils or litters where various abiotic reactions are likely to occur

Fate of carbamazepine and anthracene in soils watered with UV-LED treated wastewaters

International audienceWater disinfection technologies based on ultraviolet (UV) radiations emitted by Light-Emitting Diodes (LED), as a wastewater tertiary treatment, have been shown to be promising for water reuse. Here, we assessed the fate of two ubiquitous pollutants, carbamazepine and anthracene, in soil watered with either UV-LED treated wastewaters or irrigation water. After 3 months, anthracene and carbamazepine were transformed two and three times faster respectively, in soils watered with UV-LED wastewater than in soils watered with tap water (probably because of the addition of organic matter by the effluent). Laccase activity was induced in the presence of the pollutants and anthraquinone was found as anthracene product of oxidation by laccases. Moreover, the addition of these pollutants into soil did not affect the functional diversity of autochthonous microbial communities assessed by Ecolog plates. Cellulase, protease and urease activities increased in soils watered with UV-LED treated wastewaters (UV-LED WW), showing transformation of organic matter from the effluent and lipase activity increased by anthracene addition, confirming the potential role of these enzymes as indicators of hydrocarbon contamination

Impact of watering with UV-LED-treated wastewater on microbial and physico-chemical parameters of soil

International audienceSoil microbial activity Faecal indicator Catabolic activity Enzymatic activities a b s t r a c t Advanced oxidation processes based on UV radiations have been shown to be a promising wastewater disinfection technology. The UV-LED system involves innovative materials and could be an advantageous alternative to mercury-vapor lamps. The use of the UV-LED system results in good water quality meeting the legislative requirements relating to wastewater reuse for irrigation. The aim of this study was to investigate the impact of watering with UV-LED treated wastewaters (UV-LED WW) on soil parameters. Solid-state 13 C NMR shows that watering with UV-LED WW do not change the chemical composition of soil organic matter compared to soil watered with potable water. Regarding microbiological parameters, laccase, cellulase, protease and urease activities increase in soils watered with UV-LED WW which means that organic matter brought by the effluent is actively degraded by soil microorganisms. The functional diversity of soil microorganisms is not affected by watering with UV-LED WW when it is altered by 4 and 8 months of watering with wastewater (WW). After 12 months, functional diversity is similar regardless of the water used for watering. The persistence of faecal indicator bacteria (coliform and enterococci) was also determined and watering with UV-LED WW does not increase their number nor their diversity unlike soils irrigated with activated sludge wastewater. The study of watering-soil microcosms with UV-LED WW indicates that this system seems to be a promising alternative to the UV-lamp-treated wastewaters.

Effect of coupled UV-A and UV-C LEDs on both microbiological and chemical pollution of urban wastewaters

International audienceWastewater reuse for irrigation is an interesting alternative for many Mediterranean countries suffering from water shortages. The development of new technologies for water recycling is a priority for these countries. In this study we test the efficiency of UV-LEDs (Ultraviolet-Light-Emitting Diodes) emitting UV-A or UV-C radiations, used alone or coupled, on bacterial and chemical indicators. We monitored the survival of fecal bioindicators found in urban wastewaters and the oxidation of creatinine and phenol which represent either conventional organic matter or the aromatic part of pollution respectively. It appears that coupling UV-A/UV-C i) achieves microbial reduction in wastewater more efficiently than when a UV-LED is used alone, and ii) oxidizes up to 37% of creatinine and phenol, a result comparable to that commonly obtained with photoreactants such as TiO 2

Multivariate optimization of fecal bioindicator inactivation by coupling UV-A and UV-C LEDs

International audienceThe development of new technologies for water recycling is a priority for arid and semi-arid countries such as those of the Mediterranean basin. The aim of this study was to test the efficiency of UV-A and UV-C light emitting diodes (UV-LEDs) on bacteria inactivation. We used Escherichia coli and Enterococcus faecalis, bioin-dicators of fecal pollution typically found in urban wastewaters. An experimental design was performed to discriminate weight of factors influencing bacteria inactivation yields and reactivation phenomena. Four parameters were tested on simple bacterial cultures: pH, bacterial density, exposure time and wavelength. It appears that the exposure time and wavelength used have a significant effect on the response. The 280/ 365 nm or 280/405 nm coupled wavelengths, have the most important bactericidal effect, and we also note the absence of bacterial reactivation after 60 s of exposure to UV

Notice explicative de la Carte géologiques du Maroc (1/50 000), feuille Bou Azer

Carte géologique par BLEIN O., CHÈVREMONT Ph., RAZIN Ph., BAUDIN T., GASQUET D

Notice explicative de la Carte géologiques du Maroc (1/50 000), feuille Al Gloa

Carte géologique par SOULAIMANI A., ADMOU A., FEKKAK A., ÉGAL E., ROGER J., YOUBI N., RAZIN Ph., BLEIN O., BAUDIN T., CHÈVREMONT P