Identification of hydroxylated metabolites in 2,2',4,4'-tetrabromodiphenyl ether exposed rats

Faeces from day 1-5 of orally administered 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) in rat have been analysed for hydroxylated metabolites. Six hydroxylated tetrabrominated diphenyl ethers, as well as three hydroxylated tribrominated diphenyl ethers found, were structurally identified. They were 2'-hydroxy-2,4,4'-tribromodiphenyl ether, 3'-hydroxy-2,4,4'-tribromodiphenyl ether, 4'-hydroxy-2,2',4-tribromodiphenyl ether, 6-hydroxy-2,2',4,4'-tetrabromodiphenyl ether, 2'-hydroxy-2,3',4,4'-tetrabromodiphenyl ether, 3-hydroxy-2,2',4,4'-tetrabromodiphenyl ether, 5-hydroxy-2,2',4,4'-tetrabromodiphenyl ether, 4'-hydroxy-2,2',4,5'-tetrabromodiphenyl ether and 4-hydroxy-2,2',3,4'-tetrabromodiphenyl ether. The analysis was performed using gas chromatography-mass spectrometry (GC-MS). The identification of the hydroxylated polybrominated diphenyl ether (OH-PBDE) metabolites in the rat faeces was supported by similar relative retention times (RRTs) versus 2,2',3,4,4',5-hexabromodiphenyl ether (BDE-138) on two columns of different polarities compared to the authentic references. The identification of the OH-PBDE metabolites was also supported by full scan electron ionisation mass spectra. Two of the identified OH-PBDE metabolites have identical structures as natural products, which previously have been isolated from marine sponges and an ascidian.     

Transfer of nutrients and labile metals from the continent to the sea by a small Mediterranean river

The contribution of small watersheds to coastal pollution in Mediterranean areas is still poorly known, and presents great variations along an hydrological year. This work deals with the characterization and quantification of Al, Fe, Zn, Cu, Pb, Si, NO(3)(-) and organic carbon transported from the continent to the sea by a small coastal river in the French Mediterranean area. Transported species were characterized both during rainy and dry periods. During non-rainy periods (base-flow), waters showed a low content of contaminants, whereas during heavy rain events, following dry periods, some metals and organic carbon reached concentrations that could affect biological populations. These contaminants were mainly found in the particulate fraction, originating from the runoff of surface waters, which represents the main process of pollution in urban areas.     

Degradation of CL-20 by white-rot fungi

In previous studies, we found that the emerging energetic chemical, CL-20 (C6H6N12O12, 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane), can be degraded following its initial denitration using both aerobic and anaerobic bacteria. The C and N mass balances were not determined due to the absence of labeled starting compounds. The present study describes the degradation of the emerging contaminant by Phanerochaete chrysosporium using ring-labeled [15N]-CL-20 and [14C]-CL-20. Ligninolytic cultures degraded CL-20 with the release of nitrous oxide (N2O) in amounts corresponding to 45% of the nitrogen content of CL-20. When ring-labeled [15N]-CL-20 was used, both 14N14NO and 15N14NO were observed, likely produced from -NO2 and N-NO2, respectively. The incubation of uniformly labeled [14C]-CL-20 with fungi led to the production of 14CO2 (> 80%). Another ligninolytic fungus, Irpex lacteus, was also able to degrade CL-20, but as for P. chrysosporium, no early intermediates were observed. When CL-20 was incubated with manganese peroxidase (MnP), we detected an intermediate with a [M-H]- mass ion at 345 Da (or 351 and 349 Da when using ring-labeled and nitro-labeled [15N]-CL-20, respectively) matching a molecular formula of C6H6N10O8. The intermediate was thus tentatively identified as a doubly denitrated CL-20 product. The concomitant release of nitrite ions (NO2-) with CL-20 degradation by MnP also supported the occurrence of an initial denitration prior to cleavage and decomposition.     

Influence of the very polluted inputs of the Tinto-Odiel system on the adjacent littoral sediments of southwestern Spain: a statistical approach

A spatial and temporal analysis (period 1990-2003) of 15 sampling points distributed along the southwestern Spanish coast permits to delimitate the influence area of the extremely polluted discharges coming from the Tinto-Odiel system in the bottom sediments of the adjacent littoral area. As, Cu, Pb and Zn are the main heavy metals transported by the freshwater runoffs toward the shallow shelf and present very high negative (r < -0.7) and significant (p < 0.001) correlations with the distance to the estuarine mouth. The statistical analysis (index of geoaccumulation, Pearson correlation matrix, cluster analysis) of their concentrations in the littoral sediments located between the Guadiana and Guadalquivir mouths delimitates three zones: (a) Zone 1 (from the estuarine mouth to 6 km to the east), characterized by moderate to strongly polluted bottom sediments and main responsible of the mean annual variations of the former heavy metals in the area studied; (b) Zone 2 (from 21.2 km to the west to 29 km to the east), characterized by moderate pollution levels; and (c) Zone 3, located near the Guadiana and Guadalquivir mouths, with very low As-Cu-Pb contents and unpolluted to moderately levels of Zn due to urban sewages or the presence of local low mobility areas for this element.     

Copper binding by peat fulvic and humic acids extracted from two horizons of an ombrotrophic peat bog

We studied the binding of Cu(II) to humic acids and fulvic acids extracted from two horizons of an ombrotrophic peat bog by metal titration experiments at pH 4.5, 5.0, 5.5, and 6.0 and 0.1 M KNO3 ionic strength. Free metal ion concentrations in solution were measured using an ion selective electrode. The amounts of base required to maintain constant pH conditions were recorded and used to calculate H+/Cu2+ exchange ratios. The amount of Cu(II) bound to the humic fractions was greater than the amount bound to the fulvic fractions and only at the highest concentrations of metal ion the amount of Cu(II) sorbed by both fractions became equal. The proton to metal ion exchange ratios are similar for all humic substances, with values ranging from 1.0 to 2.0, and decreasing with increased pH. The amount of Cu(II) bound is practically independent of the horizon from which the sample was extracted. The results indicate that the humic substances show similar cation binding behaviour, despite the differences in chemical composition. The copper binding data are quantitatively described with the NICA-Donnan model, which allows to characterize only the carboxylic type binding sites. The values of the binding constants are higher for the humic acids than for the fulvic acids.     

Spatial distribution of polybrominated diphenyl ethers in coastal marine sediments receiving industrial and municipal effluents in Kuwait

Polybrominated diphenyl ether (PBDE) concentrations were measured in surficial sediments from coastal sediments receiving industrial and municipal effluents in Kuwait. The summation PBDE concentrations varied by two orders of magnitude ranging from 80 to 3800 pg g(-1)dw. The congener distribution was dominated by BDE 183, with minor contributions from BDEs 154 and 153. The similarity between the congener profile to that of the technical octa formulation (Bromkal 79-8DE) suggests a source of this product in Kuwait. The observed gradient in concentration distribution, with high summation PBDE concentrations near the shore and an exponential decrease seaward, indicates that wastewater discharge from industrial activities in the study area is the primary source of these compounds in the sediments.     

Henry's law constant, octanol-air partition coefficient and supercooled liquid vapor pressure of carbazole as a function of temperature: application to gas/particle partitioning in the atmosphere

The Henry's law constant for carbazole was experimentally determined between 5 and 35 degrees C using a gas-stripping technique. The following equation was obtained for dimensionless Henry's law constant (H') versus temperature (T, K): ln H' = -3982(T,K)(-1) + 1.01. Temperature-dependent octanol-air partition coefficients (KOA) and supercooled liquid vapor pressures (PL,Pa) of carbazole were also determined using the GC retention time method. The temperature dependence of KOA and PL were explained by the following: log KOA = 4076/(T,K) - 5.65, log PL(Pa) = -3948(T,K)(- 1) + 11.48.The gas and particle-phase carbazole concentrations measured previously in Chicago, IL in 1995 was used for gas/particle partitioning modeling. Octanol based absorptive partitioning model consistently underpredicted the gas/particle partition coefficients (Kp) for all sampling periods. However, overall there was a good agreement between the measured Kp and soot-based model predictions.     

Effects of medium-pressure UV lamps radiation on water quality in a chlorinated indoor swimming pool

The aim of our study was to determine the impact of medium-pressure UV lamps radiation on water quality in a chlorinated indoor swimming pool. An indoor swimming pool was equipped with two medium-pressure UV lamps. We collected eight samples of water daily over a four-weeks period and measured total and free chlorine, pH, water temperature, bacteriological parameters, total organic carbon and trihalomethanes. During the first week, which served as control, medium-pressure UV lamps were turned off. During the next three weeks, medium-pressure UV lamps were kept on 24 h per day. The third week, we reduced the level of the injected chlorine into water, and the last week we also reduced the water renewal volume by 27%. Our results showed that bacteriological parameters remained within allowable french limits. When medium-pressure UV lamps were kept on, total, free and active chlorine levels were significantly increased (P<0.001), whereas combined chlorine level were significantly decreased (P<0.001 and P<0.05, respectively). The levels of chloroform and bromodichloromethane were significantly increased when medium-pressure UV lamps were kept on (P<0.001), whereas chlorodibromomethane and bromoform levels significantly decreased (P<0.05 and P<0.001, respectively). The additional formation of chloroform and bromodichloromethane may be explained by the increase in active chlorine and by radicalizing mechanisms initiated by UV radiation.     

The performance of an anaerobic sequencing batch biofilm reactor treating domestic sewage colonized by anoxygenic phototrophic bacteria

There are few reports on morphological characterization of microbial population colonizing anaerobic bioreactors and the aim of this work was to access such variable in an anaerobic sequencing batch biofilm reactor treating the University of Sao Paulo (Sao Carlos city, Brazil) domestic sewage. This pilot-scale reactor (1.2m3) has been treating 0.65 m3 of liquid waste under cycles of 8h. The ASBBR has the distinct characteristics of being filled with support material for biomass attachment with the aim of skipping the sedimentation phase during the operational cycles, as it is commonly observed in anaerobic sequencing batch reactors (ASBR). Physical, chemical and physico-chemical variables were accessed in the influent and in the effluent for performance evaluation. Microbial characterization was made by means of direct microscopy and samples were taken over 150 d with a 25 d period interval. The ASBBR attained approximately 60% of COD removal efficiency. Microscopic analysis of biomass showed the presence of anoxygenic phototrophic bacteria probably influencing the ASBBR performance in the domestic sewage treatment. It is very likely that the exclusion of phototrophic sulfur bacteria by efficiently restraining the light would enhance the bioreactor efficiency.     

Role of cyanobacteria in the biodegradation of crude oil by a tropical cyanobacterial mat

Cyanobacterial mats are ubiquitous in tropical petroleum-polluted environments. They form a high biodiversity microbial consortium that contains efficient hydrocarbons degraders. A cyanobacterial mat collected from a petroleum-contaminated environment located in Indonesia was studied for its biodegradation potential. In the field, the natural mat was shown to degrade efficiently the crude oil present in the environment. This natural mat demonstrated also a strong activity of degradation on model crude oil under laboratory conditions. In axenic cultures, the monospecific cyanobacterium Phormidium animale that constitute the bulk of the biomass did not exhibit any degradative capacity on hydrocarbons in the range of C13-C35 carbon atom number either in autotrophic or heterotrophic conditions. It was concluded that this cyanobacterial strain living on a heavily contaminated site had no direct effect on biodegradation of crude oil, the degradation activity being exclusively achieved by the other microorganisms present in the microbial consortium of the mat.