A preparative method for the isolation and fractionation of dissolved organic acids from bitumen-influenced waters.

The surface mining of oil sands north of Fort McMurray, Alberta produces considerable tailings waste that is stored in large tailings ponds on industrial lease sites. Viable strategies for the detoxification of oil sands process affected water (OSPW) are under investigation. In order to assess the toxic potential of the suite of dissolved organics in OSPW, a method for their extraction and fractionation was developed using solid phase extraction. The method successfully isolated organic compounds from 180 L of an aged OSPW source. Using acidic- or alkaline-conditioned non-polar ENV+ resin and soxhlet extraction with ethyl acetate and methanol, three fractions (F1-F3) were generated. Chemical characterization of the generated fractions included infusion to electrospray ionization ultrahigh-resolution mass spectrometry (ESI-UHRMS), liquid chromatography quadrupole time-of-flight mass spectrometry, gas chromatography triple quadrupole time-of-flight mass spectrometry, and synchronous fluorescence spectroscopy (SFS). Additionally, ESI-UHRMS class distribution data and SFS identified an increased degree of oxygenation and aromaticity, associated with increased polarity. Method validation, which included method and matrix spikes with surrogate and labelled organic mono carboxylic acid standards, confirmed separation according to acidity and polarity with generally good recoveries (average 76%). Because this method is capable of extracting large sample volumes, it is amenable to thorough chemical characterization and toxicological assessments with a suite of bioassays. As such, this protocol will facilitate effects-directed analysis of toxic components within bitumen-influenced waters from a variety of sources.

The toxicity of organic fractions from aged oil sands process-affected water to aquatic species.

The process of surface mining and extracting bitumen from oil sand produces large quantities of tailings and oil sands process-affected water (OSPW). The industry is currently storing OSPW on-site while investigating strategies for their detoxification. One such strategy relies on the biodegradation of organic compounds by indigenous microbes, resulting in aged tailings waters with reduced toxicity. This study assessed the toxicity of OSPW aged statically for approximately 18 years. Dissolved organics in aged OSPW were fractionated using a preparative solid-phase extraction method that generated three organic fractions (F1-F3) of increasing polarity. Eight aquatic species from different trophic levels were exposed to whole OSPW (WW) and the derived OSPW organic fractions to assess toxicity: Pimephales promelas, Oryzias latipes, Vibrio fischeri, Daphnia magna, Lampsilis cardium, Hyalella azteca, Ceriodaphnia dubia, and Hexagenia spp. Broad comparisons revealed that P. promelas and H. azteca were most sensitive to dissolved organics within aged OSPW, while WW was most toxic to L. cardium and H. azteca. Three cases of possible contaminant interactions occurred within whole OSPW treatments, as toxicity was higher than organic fractions for H. azteca and L. cardium, and lower for P. promelas. As such, the drivers of toxicity appeared to be dependent on the species exposed. Of the organic fractions assessed, F3 (most polar) was the most toxic overall while F2 (intermediate polarity) displayed little toxicity to all species evaluated. This presents strong evidence that classical mono-carboxylic naphthenic acids, mostly present in F1 (least polar), are not primarily responsible for the toxicity in aged tailings. The current study indicates that although the aged tailings source (≥18 years) did not display acute toxicity to the majority of organisms assessed, inorganic components and polyoxygenated organics may pose a persistent concern to some aquatic organisms.

Effect of ranitidine on the disposition of orally and intravenously administered triazolam.

The effect of orally administered ranitidine on the pharmacokinetic properties of orally and intravenously administered triazolam was determined. Twelve healthy males with a mean age of 35 years were enrolled in this four-way, randomized, crossover study. Each subject received a total of four treatments, each separated by one week. The treatments consisted of (1) one orally administered 0.25-mg triazolam tablet after treatment with ranitidine; (2) one orally administered 0.25-mg triazolam tablet, with no ranitidine pretreatment; (3) a 0.25-mg intravenous dose of triazolam after treatment with ranitidine; and (4) a 0.25-mg intravenous dose of triazolam, with no ranitidine pretreatment. Ranitidine pretreatment consisted of five 150-mg oral doses (as the hydrochloride salt) given every 12 hours; the last dose was given two hours before triazolam was administered. Blood samples were taken at intervals up to 12 hours after triazolam treatment. Serum triazolam concentrations were measured by modified high-performance liquid chromatography, and pharmacokinetic values were calculated. Pretreatment with ranitidine had no effect on the disposition of intravenously administered triazolam but significantly increased the area under the serum drug concentration-time curve of oral triazolam. Ranitidine pretreatment had no effect on triazolam's terminal elimination rate constant or on the time to reach maximum serum triazolam concentration. Ranitidine pretreatment increased the systemic availability of triazolam by increasing its absorption.

The pharmacist as a health consultant--ten years later.

Pharmacists remain a readily accessible and trusted source of information about health. In order to assess the quality of counseling on health matters and the progress of the profession in this activity over the last decade, a study similar to one reported in 1978 was conducted. We visited 46 community pharmacies and requested advice from the pharmacists concerning the proper treatment of an infant with diarrhea. Interviewers volunteered no additional information, but questions asked by the pharmacist were answered according to a predetermined hypothetical case involving an 18-month-old infant with diarrhea and vomiting. Findings include the following: approximately one-third of the pharmacists recommended a product without caution and less than 20 percent inquired about fever, nausea, vomiting, diet, or the infant's condition. We believe pharmacists should approach health counseling with an increased awareness of the harmful potential in providing inappropriate medical information.