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A laboratory incubation study was conducted to determine the effect of drinking-water treatment residuals (WTRs) on arsenic (As) bioaccessibility and phytoavailability in a poorly As-sorbing soil contaminated with arsenical pesticides and fertilized with triple super phosphate (TSP). The Immokalee soil (a sandy spodosol with minimal As-retention capacity) was amended with 2 WTRs (Al and Fe) at 5 application rates ranging between 0% and 5% wt/wt. Sodium arsenate and TSP were used to spike the soil with 90 mg As kg(-1) and 115 mg P kg(-1), respectively. Bioaccessible As was determined at time 0 (immediately after spiking), and at 6 and 12 months of equilibration using an in vitro gastrointestinal test, and As phytoavailability was measured with a 1-M KC1 extraction test. Arsenic phytoavailability decreased immediately after spiking (20% availability at 5% rate), but only after 6 months for the Al-WTR- and the Fe-WTR-amended soil, respectively. Arsenic bioaccessibility simulated for the stomach and intestine phases showed that the Fe-WTR was more effective than the Al-WTR in resisting the harsh acidic conditions of the human stomach, thus preventing As release. Both the phytoavailable As and the bioaccessible As were significantly correlated (p < 0.001) for soil spiked with either Al- or Fe-WTR. Both WTRs were able to decrease soil As bioaccessibility irrespective of the presence or absence of P, which was added as TSP. Results indicate the potential of WTRs in immobilizing As in contaminated soils fertilized with P, thereby minimizing soil As bioaccessibility and phytoavailability.

Recent changes in the European legislation of chemical-related substances have forced the scientific community to speed up the search for alternative methods that could partly or fully replace animal experimentation. The Sixth Framework Program project carcinoGENOMICS was specifically raised to develop omics-based in vitro screens for testing the carcinogenic potential of chemical compounds in a pan-European context. This paper provides an in-depth analysis of the complexity of choosing suitable reference compounds used for creating and fine-tuning the in vitro carcinogenicity assays. First, a number of solid criteria for the selection of the model compounds are defined. Secondly, the strategy followed, including resources consulted, is described and the selected compounds are briefly illustrated. Finally, limitations and problems encountered during the selection procedure are discussed. Since selecting an appropriate set of chemicals is a frequent impediment in the early stages of similar research projects, the information provided in this paper might be extremely valuable. Crown Copyright © 2008.

Recent changes in the European legislation of chemical-related substances have forced the scientific community to speed up the search for alternative methods that could partly or fully replace animal experimentation. The Sixth Framework Program project carcinoGENOMICS was specifically raised to develop omics-based in vitro screens for testing the carcinogenic potential of chemical compounds in a pan-European context. This paper provides an in-depth analysis of the complexity of choosing suitable reference compounds used for creating and fine-tuning the in vitro carcinogenicity assays. First, a number of solid criteria for the selection of the model compounds are defined. Secondly, the strategy followed, including resources consulted, is described and the selected compounds are briefly illustrated. Finally, limitations and problems encountered during the selection procedure are discussed. Since selecting an appropriate set of chemicals is a frequent impediment in the early stages of similar research projects, the information provided in this paper might be extremely valuable. Crown Copyright © 2008.

A sensitive spectrophotometric method for the determination of hydroxylamine is described. The method is based on the oxidation of hydroxylamine to nitrite using sodium arsenate under alkaline condition. The formed nitrite is determined based on the diazo coupling reaction between p-nitroaniline and N-(1-naphthyl)ethylenediamine dihydrochloride [NEDA]. The system obeys Beer's law over the concentration range 0-7 ?g of hydroxylamine at 545 nm and the colour is stable for 3 h. The molar absorptivity of the colour system is found to be 6.7?104 l mol-1 cm -1. The relative standard deviation is 1.2% for ten determinations at 4 ?g of hydroxylamine. Interferences due to various foreign ions have been studied and the method has been applied to the determination of hydroxylamine and its derivatives used in pharmaceutical formulations after hydrolysis. ? 2004 Pharmaceutical Society of Japan.