The mineral forms of phosphorus in three urban sewage sludges were characterized using highresolution solid-state phosphorus-3 1 nuclear magnetic resonance (NMR) coupled to a sequential extraction. The sludges studied were an anaerobically-digested and heat-treated sludge (ParisAchbres), an activated sludge (Briare) and an anaerobically-digested sludge (Nancy). NMR observations were conducted using both single-pulse and cross-polarization sequences in order to distinguish between 'lP nuclei far from 'H nuclei, and 31P located within a fraction of a nanometre of 'H. This approach showed that a complex mixture of P species was present in these sludges. A mixture of hydrogenated octocalcium phosphates and apatites was observed in the three samples. Monetite was present in the anaerobically-digested sludge and brushite in the activated sludge. Dehydrogenated condensed calcium phosphates (compounds with a Ca : P ratio higher than 1 .O such as fluorapatite or tricalcium phosphate) and dehydrogenated pyrophosphates were also probably present in the anaerobically-digested sludge. A poorly-ordered wavellite was observed in the three sludges after the HC1 extraction. However, results were inconclusive as to whether this mineral was present in the three sludges, or had been precipitated during the sequential extraction.

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A simple and rapid bioassay involving the gram‐positive bacterium Bacillus brevis was developed to detect and quantify furocoumarins (psoralen and angelicin) in Psoralea plants (Leguminosae). Small paper discs, soaked with furocoumarin standards or the corresponding plant samples, are placed on B. brevis lawns in Petri dishes and irradiated for 24 h with UVA. The diameter of the growth inhibition zone around the discs is very well‐correlated with the quantity of furocoumarin standard in the disc. Because psoralen is more phototoxic than angelicin, its detection limit (5 × 10−8 g/disc) was lower than angelicin (5 × 10−7 g/disc). Consequently, it is possible to dilute a crude plant extract in order to reach a detectable psoralen concentration whilst maintaining the angelicin concentration below its lower detection limit. In this condition, angelicin does not interfer with psoralen detection, and the growth inhibition is entirely due to psoralen. The bioassay was validated using a classical high pressure liquid chromatographic method and the correlation between the two techniques was satisfactory with plant samples. Therefore, the bioassay can be considered as a sensitive, simple, rapid and selective method to quantify psoralen in Psoralea plants.