The distribution of chlorothalonil among the dissolved, labile sorbed, and bound residue states was monitored during an 18 day period in an aqueous slurry of an analyzed quartz sand soil from Simcoe, ON, Canada. The Simcoe soil is 90.−95.% quartz sand. The online HPLC microextraction method was used for this purpose, because it is the only available technique that can resolve the total amount of a pesticide in a soil into its dissolved, labile sorbed, and bound residue components. The processes for which the molecular level kinetics were determined included labile surface sorption and desorption and bound residue formation. At a reaction time of 14 days, the solution concentration of 0.75 × 10-6 M was 43.3% of the total chlorothalonil, 26.2% was in the labile sorbed state, and 30.5% was a bound residue. There were no chemical reactions and no biodegradation during the 18 day period. The kinetics of mass transfer among the three states were determined and are consistent with intraparticle diffusion. Although the amounts are small, it is suspected that the 5.−10.% nonquartz materials in the Simcoe soil contribute most of the sorption and bound residue effects.

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Chlorothalonil has been found to persist but not leach in some quartz sandy soils. For this effect to be understood, it is necessary for the numbers of occupied and empty surface sorption sites to be known. This requires that the labile surface sorption capacity θC, which is the total number of sites, be measured. Wetting effects might however, affect θC. The measurement of θC has been done only recently by very few laboratories, and the wetting effects have seldom been investigated. New analytical chemical methods are therefore required. On − line HPLC micro extraction has been used in the present work to develop a method for the titration of chlorothalonil onto the labile surface sorption sites. Two conclusions have been drawn from the measurements. The first is that θC is one to 2 orders of magnitude greater than it is for the previously reported cases. Second, the effect of wetting on bound residue formation reported by Belliveau and Langford () has been confirmed. These effects help to explain the behavior of chlorothalonil in the quartz sandy soils.

Gunshot residue (GSR) particles released from a firearm at the time it is discharged may be deposited onto nearby surfaces including the hands and clothing of the shooter and any bystanders. This study measured the relative amount of GSR detected on the shooter and on three bystanders in close proximity. Test-firings were conducted in duplicate using five different handguns with ammunition containing conventional lead, barium, and antimony based primers. Samples were collected from the right hand of the shooter 15 minutes after discharge. Bystanders were sampled 15 minutes after discharge and 2 hours after the initial sampling. A scanning electron microscope with an energy dispersive X-ray detector was used to analyze the samples. A high variability of GSR deposition was observed between firearm/ammunition combinations and between replicate firings. In some instances bystanders had similar concentrations of GSR on their hands to the shooter, making it impossible to distinguish between the two on the basis of particle numbers. Furthermore, after an additional 2 hours, most of the bystanders who initially had GSR particles on their hands had lost them through routine activity. The loss was comparable to what was expected from the hands of shooters based on information published in the literature. RésuméLes particules de résidus de tir dégagées lorsqu'une arme à feu est déchargée peuvent se déposer sur les surfaces à proximité, incluant les mains et les vêtements du tireur et des spectateurs. Cette étude mesurait la quantité relative de résidus de tir détectés sur le tireur et sur trois spectateurs à proximité. Les tirs d'essai ont été répétés utilisant cinq armes de poing avec des munitions à amorce conventionnelle de plomb, de baryum et d'antimoine. Des échantillons ont été recueillis sur la main droite du tireur 15 minutes après le déchargement. Des échantillons ont été recueillis sur les spectateurs 15 minutes après le déchargement, ainsi que deux heures après l'échantillonnage initial. Les échantillons ont été analysés à l'aide d'un microscope électronique à balayage couplé à un spectromètre à rayon X par dispersion en énergie. Une grande variabilité a été observée pour ce qui est du dépôt de résidus de tir entre différentes combinaisons d'armes à feu et de munitions, ainsi qu'entre les répétitions de tirs. Dans certains cas, les spectateurs avaient sur leurs mains des concentrations de résidus de tir similaires à celles recueillies sur le tireur, rendant impossible toute distinction entre les deux pour ce qui est du nombre de particules. De plus, après deux heures supplémentaires, la majorité des spectateurs qui, au Downloaded by [University of Otago] at 08:46 29 July 2015 90 départ, avaient des particules de résidus de tir sur leurs mains, les avaient perdues lors d'activités quotidiennes. La perte était comparable à celle attendue des mains du tireur, basée sur d'autres études publiées.

These two case reports describe migration of Implanon ® (the single-rod contraceptive implant). A review of the literature revealed true migration of Implanon to be rare. A change of practice locally is described.

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