Sampling and analytical methodology development for the determination of primary and secondary low molecular weight amines in ambient air

In this project, a sampling device and an analytical method have been developed to simultaneously analyse the most frequently found low molecular weight amines, including aliphatic, aromatic and alcohol amines. These amines are diethanolamine, ethanolamine, methylamine, isopropylamine, morpholine, dimethylamine, and aniline. A sampling device was developed using a 37 mm cassette with glass fibre filters impregnated with sulfuric acid. Immediately after sampling, the filter was transferred to vials containing a solution of dansyl chloride. Dansyl chloride was used for derivatisation because it forms aromatic sulfonamides that are fluorescent and easy to protonate for MS detection. The effect of using an internal standard made with the dansylated derivative of 1-(2-methoxyphenyl)piperazine (MOPIP) on the uncertainty and efficiency of the method was also evaluated. This internal standard was spiked directly onto filters. The coupling of HPLC/ESI-MS was used for the simultaneous analysis of all the derivatives. This method showed detection limits of about 0.03 microg mL(-1) to 0.3 microg mL(-1) of amine with an average expanded uncertainty of 3% to 6% depending on the amine. The methodology recoveries are close to 100% for all the amines, and the overall estimated expanded uncertainties vary between 10% and 13% depending on the amine. This new strategy will be useful in evaluating workplace air since a unique sampling system will be used, independent of the amine to be quantified.     

Dynamic extreme values modeling and monitoring by means of sea shores water quality biomarkers and valvometry

Water quality can be evaluated using biomarkers such as tissular enzymatic activities of endemic species. Measurement of molluscs bivalves activity at high frequency (e.g., valvometry) during a long time period is another way to record the animal behavior and to evaluate perturbations of the water quality in real time. As the pollution affects the activity of oysters, we consider the valves opening and closing velocities to monitor the water quality assessment. We propose to model the huge volume of velocity data collected in the framework of valvometry using a new nonparametric extreme values statistical model. The objective is to estimate the tail probabilities and the extreme quantiles of the distribution of valve closing velocity. The tail of the distribution function of valve closing velocity is modeled by a Pareto distribution with parameter ??_t,τ, beyond a threshold τ according to the time t of the experiment. Our modeling approach reveals the dependence between the specific activity of two enzymatic biomarkers (Glutathione-S-transferase and acetylcholinesterase) and the continuous recording of oyster valve velocity, proving the suitability of this tool for water quality assessment. Thus, valvometry allows in real-time in situ analysis of the bivalves behavior and appears as an effective early warning tool in ecological risk assessment and marine environment monitoring.     

Mercury Emissions from a Hazardous Waste Incinerator Equipped with a State-of-the-Art Wet Scrubber

Abstract

Over a six-week period, eleven tests were performed at the U.S. EPA Incineration Research Facility (IRF) in Jefferson, Arkansas to evaluate the fate of trace metals fed to a rotary kiln incinerator equipped with a Calvert Flux-Forcer/Condensation Scrubber pilot plant as the primary air pollution control system (APCS). Test variables were kiln temperature, ranging from 538 °C to 927 °C; waste feed chlorine content, ranging from 0% to 3.4%; and scrubber pressure drop, ranging from 8.2 kPa to 16.9 kPa. Mercury was among the six hazardous constituent trace metals fed to the IRF’s pilotscale rotary kiln incineration system as part of a synthetic waste feed. This paper focuses on the test results solely with respect to mercury.

As expected, mercury behaved as a very volatile metal throughout the tests; it was not detected in any kiln ash samples. Scrubber collection efficiency for mercury ranged from 67% to >99%, averaging 87%; this was somewhat lower than expected and may be attributable to low scrubber loadings.

The ability to collect and analyze representative scrubber water samples appears to have been affected by the waste feed chlorine content; detection of mercury at higher concentrations during high waste-chlorine-content tests is thought to be largely the result of the formation of mercuric chloride, a more water-soluble species, during those tests. As a result, no firm conclusions may be drawn regarding the true impact of waste feed chlorine content on mercury partitioning to the scrubber water. As expected, no significant relationship was observed between kiln exit-gas temperature and mercury partitioning, nor was there a significant relationship with scrubber pressure drop.     

In vivo exposure of Mytilus edulis to living enteric bacteria: a threat for immune competency?

Mussels are widespread in coastal environments and experience various physical, chemical, and bacteriological conditions. Owing to the increase of coastal urbanization, mussels are now commonly exposed not only to indigenous bacteria, but also to enteric bacteria originating from pulsed and chronic sewage discharges into coastal environments. Due to its broad resilience to environmental variations, the blue mussel Mytilus edulis is commonly used as an indicator of environmental quality in bio-monitoring programs. However, since mussel immune system capabilities may be affected by the presence of exogenous fecal bacteria in coastal seawater subjected to sewage discharges, we aimed to determine the effect of in vivo bacterial challenges on mussels' immune competency by using two exogenous enteric bacterial strains, Escherichia coli and Enterococcus faecalis, and an indigenous bacterial strain Vibrio splendidus (as control). Bacterial strains were tested individually, by injection into the posterior adductor muscle at three different cell densities (10², 10³, and 10⁴ cells). Unlike classic in vitro experiments using higher bacterial concentrations, neither the enteric bacteria nor the indigenous strain induced significant increase or decrease of either cell-mediated (phagocytosis, reactive oxygen species, and NO _x production) or humoral components (prophenoloxidase-like, acid phosphatase, and l-leucine-aminopeptidase production) of the immune system. This study demonstrates that, at low concentrations, E. coli and E. faecalis do not represent an additional threat that could impair M. edulis immune competency and, as a consequence, its potential of survival in coastal areas subjected to sewage discharges.     

Flow cytometric measurement of the clearance rate in the blue mussel Mytilus edulis and the development of a new individual exposure system for aquatic immunotoxicological studies

Animals in poor health condition are not relevant biological models. The current study focused on the use of the clearance rate of Mytilus edulis to assess the gross physiological condition of individuals maintained in stressful experimental conditions. This approach was developed in a new, highly controlled experimental exposure device designed to investigate individual responses in aquatic ecotoxicological studies. Both clearance rate values and immune parameters analysis indicated that the health condition of mussels kept in 50ml tubes for 24h or 48h was not altered compared to controls, while most parameters were depressed after 72h. Moreover, this study confirms the relevance of flow cytometric for the measurement of clearance rate compared to techniques utilizing microscopy. Current results prompted us to perform further 24h chemical exposure using this "in tubo" device.     

L'utilisation de souches de micro-organismes de collection pour l'etude de la biodegradabilite des pesticides

Use of Microbial strains from collection in the study of pesticide biodegradability. 5 different herbicides and 1 metabolite of herbicide were subjected to biodegradation by different microbial strains and simultaneously by soil suspensions.To take account of possible co-metabolisme a supplementary source of carbon was added in the culture media. Results were discussed.