Water organism such as zooplankton fish were used quite often as indicators for water quality in connection with chemically toxic substance in water. Several criteria could be used such as LC50, population index, and physiological phenomena. Bioassay that rely on this physiological phenomena was meant to measure the sublethal effect of the suspected toxic substance on the organisms. Further development of sublethal bioassay using filtering rate of Daphnia carinata (Cooley, 1977; McMahon, 1966) has taken place for a certain detergent. Yeasts cells tagged with P-32 were used as food for Daphnia carinata and the filtering rate was measured from the radioactivity of these crustaceans after a certain period of feeding time. Comparison was made between the feeding rate in the medium with and without the detergent and they appeared to be different.

A simple and rapid ultrasound-assisted in situ sorbent formation solid-phase extraction (UAISFSPE) coupled with electrothermal atomic absorption spectrometry detection (ET-AAS) was developed for preconcentration and determination of arsenic (As) in various samples. A small amount of cationic surfactant is dissolved in the aqueous sample containing As ions, which were complexed by ammonium pyrrolidinedithiocarbamate After shaking, a little volume of hexafluorophosphate (NaPF ₆) as an ion-pairing agent was added into the solution by a microsyringe. Due to the interaction between surfactant and ion-pairing agent, solid particles are formed. The alkyl groups of the surfactant in the solid particles strongly interact with the hydrophobic groups of analytes and become bound. Sonication aids the dispersion of the sorbent into the sample solution and mass transfer of the analyte into the sorbent, thus reducing the extraction time. The solid particles are centrifuged, and the sedimented particles can be dissolved in an appropriate solvent to recover the absorbed analyte. After separation, total arsenic (As(III) and As(V)) was determined by ET-AAS. Several experimental parameters were investigated and optimized. A detection limit of 7 ng L ⁻¹ with preconcentration factor of 100 and relative standard deviation for 10 replicate determinations of 0.1 µg L ⁻¹ As(III) were 4.5% achieved. Consequently, the method was applied to the determination of arsenic in certified reference materials, water, food and biological samples with satisfactory results.

Cet article est la synthese thematique d'une enquete menee en 1996 aupres de professionnels (industriels, fabricants et chercheurs) du nettoyage et de la desinfection dans les industries alimentaires sur le theme de la reduction de la consommation d'eau et de la production d'effluents polluonts, liee a ces operations. Dans cette optique, les produits chimiques recommandes sont les produits combines (detergent + desinfectant) encore trop peu utilises. L'utilisation de produits sous forme mousse ou gel permet aussi de reduire les quantites d'eau necessaires. Il semble interessant de generaliser les nettoyages prealables a sec (raclage, brossage avec aspiration, pousse a l'air comprime, etc...) permettant d'economiser de l'eau et des produits detergents, voire de recuperer de la matiere premiere. A l'inverse, les jets haute pression, tres repandus, sont a proscrire. Des efforts restent a faire (du point vue technique comme du point de vue de la mesure de leur efficacite) pour mettre au point et valider des methodes de desinfection plus "seches" (chimiques sans rincage, physiques a l'aide d'ultraviolets, d'ultra-sons ou de laser impulsionnel,...). Il apparait clairement que le nettoyage et la desinfection de surfaces non en contact avec les aliments demandent aussi une meilleure gestion de l'eau, et des etudes sur la necessite de certains rincages et desinfections sont fortement souhaitables. Enfin, des outils technologiques tels des capteurs pour le tri des flux ou des techniques separatives permettront de rationnaliser les consommations, de recycler l'eau et les produits (en particulier dans les systemes de nettoyage en place) et de reduire les rejets provoques par les operations de nettoyage et de desinfection