Tributyltin, an organotin, is ubiquitous in the environment. The consumption of contaminated marine species leads to human dietary exposure to this compound. Tributyltin is an endocrine disruptor in many wildlife species and inhibits aromatase in mammalian placental and granulosa-like tumor cell lines. We investigated the effects of tributyltin chloride exposure on pregnancy outcome in the Sprague-Dawley rat. Timed pregnant rats were gavaged either with vehicle (olive oil) or tributyltin chloride (0.25, 2.5, 10, or 20 mg/kg) from days 0-19 or 8-19 of gestation. On gestational day 20, dams were sacrificed, and pregnancy outcome was determined. Tributyltin and its metabolites (dibutyltin, monobutyltin) were measured in maternal blood by gas chromatography. Both tributyltin and dibutyltin were present in maternal blood at approximately equal concentrations, whereas monobutyltin contributed minimally to total organotins. Organotin concentrations increased in a dose-dependent pattern in dams, independent of the window of exposure. Tributyltin chloride administration significantly reduced maternal weight gain only at the highest dose (20 mg/kg); a significant increase in post-implantation loss and decreased litter sizes, in addition to decreased fetal weights, was observed in this group. Tributyltin chloride exposure did not result in external malformations, nor was there a change in sex ratios. However, exposure to 0.25, 2.5, or 10 mg/kg tributyltin chloride from gestation days (GD) 0-19 resulted in a significant increase in normalized anogenital distances in male fetuses; exposure from days 8-19 had no effect. There was a dramatic increase in the incidence of low weight (< or =0.75 of the mean) fetuses after exposure to 20 mg/kg tributyltin chloride. Delayed ossification of the fetal skeleton was observed after in utero exposure to either 10 mg/kg or 20 mg/kg tributyltin chloride. Serum thyroxine and triiodothyronine levels were reduced significantly in dams exposed to 10 and 20 mg/kg tributyltin chloride throughout gestation; in dams treated with tributyltin from GD 8-19, serum thyroxine concentrations, but not triiodothyronine, were significantly decreased at both the 2.5 and 10 mg/kg exposures. Thus, maternal thyroid hormone homeostasis may be important in mediating the developmental toxicity of organotins.

Research conducted in the mid-1990s indicated that the levels of Trans fats in Canadian diets were among the highest in the world. The consumption of Trans fats raises blood levels of low-density lipoprotein (LDL)-cholesterol, while reducing levels of high-density lipoprotein (HDL)-cholesterol. In June 2007, Health Canada called on the food industry to voluntarily reduce levels of Trans fats in vegetable oils and soft (tub)-margarines to &lt;2 of total fat, and in all other foods, to &lt;5. Industry must show satisfactory progress by June 2009, or Health Canada might have to introduce legislation to ensure that recommended limits are achieved. Since 2005, Health Canada has been performing a national assessment of prepackaged and restaurant foods that likely contain Trans fats. From 2005 to 2009, 1120 samples were analyzed, of which 852 or approximately 76 met the recommended Trans fat limits. As a result of reformulation, most of the products had decreased Trans + saturated fat content. The estimated average intake of Trans fatty acids (TFA) in Canada significantly dropped from the high value of 8.4 g/day in the mid-1990s to 3.4 g/day (or 1.4 food energy) in 2008. However, this TFA intake of 1.4 of energy is still above the World Health Organization recommended limit of TFA intake of &lt;1 of energy, which suggests that the Canadian food industry needs to put more effort into reducing the TFA content in its products, especially in tub-margarines, donuts, and bakery products.

In the past furan had been found to form in foods during thermal processing. These findings and a recent classification of furan as a possible human carcinogen prompted us to develop a simple isotope dilution method for its determination in foods. We also investigated effects of furan volatility, sample matrix and partitioning of furan between water and fat constituents of sample on the analytical determination of furan. The method is based on headspace sampling of a 2 ml vial containing 1 g of sample. For analysis, samples were spiked with d(4)-furan, homogenized in a blender at 0 degree C, with water if required, and sub-sampled to vials containing sodium sulphate. After equilibration at 30 degrees C, 50 microl of headspace was injected into the split/splitless injection port of a GC/MS (EI, SIM). The method is linear in the 0.4-1000 ng/g range with a limit of detection of 0.1 ng/g.

Mercury was detected in all analysed samples of swordfish, marlin, shark and tuna purchased from major supermarket outlets and fish retailers in three cities across Canada. Total mercury and methylmercury levels ranged up to 3845 and 2346 ng g(-1), respectively. Swordfish contained the highest levels, followed by shark, fresh/frozen tuna and marlin. Levels in canned tuna were considerably less than the other examined samples. Methylmercury was extracted with toluene from enzymatically hydrolysed samples after the addition of sulphuric acid and potassium bromide. An L-cysteine back-extraction was used to separate the methylmercury from most organic co-extractives. Analysis of methylmercury (as methylmercury bromide) was by gas chromatography with pulsed discharge detection.

An automated, simple, and reproducible method was developed for the determination of benzene in soft drinks, based on isotope dilution headspace gas chromatography/mass spectrometry in the selected-ion monitoring mode. The method was used to assess benzene levels in samples of 124 soft drinks and beverages. Benzene was not detected in 60% of the 124 products. The average benzene levels in 6 products exceeded the Canadian maximum acceptable concentration of 5 g/L for benzene in drinking water, and 2 of the 6 products had benzene levels above the World Health Organization guideline of 10 g/L. The highest level of benzene, 23 g/L, was found in a soft drink product specifically marketed to children.