In 2012, Arctic cod (Boreogadus saida) were collected from offshore regions of the Beaufort Sea to determine the concentrations of CYP1A1 phase I metabolites of polycyclic aromatic hydrocarbons (OH-PAHs) in liver and to correlate measured concentrations with (i) morphometric measurements that are known to be indicative of fish health and, (ii) biochemical end points of health including vitamin A/E and metabolites and hepatic deiodinase activity (DI). Four ring OH-PAHs were detected in 90% of our samples with a mean liver concentration of 1829.2 ± 159.2 ng/g (ww). Total (∑) concentrations of 5/6-membered ring OH-PAHs in liver were smaller [mean of 931.6 ± 104.3 ng/g, (ww)] and detected less frequently (75%) than the 4-ring OH-PAHs. Fish length and liver weight were both negatively correlated to ∑ concentrations of 4-ringed OH-PAHs (p < 0.001). Liver somatic index was also negatively correlated to ∑4-OH-PAHs (p < 0.05) but not for ∑5/6-OH-PAHs (p > 0.1). There was a significant positive relationship between DI and 4-ring OH-PAHs (p < 0.05) in liver, suggesting an induction of this enzyme. No such correlation was observed for the 5/6-ring OH-PAHs. Retinyl palmitate (RP) was the only vitamin that could be measured in liver ranging from 0.230 to 26.3 ug/g (ww). No associations between RP and levels of the 4- or 5/6-ringed OH-PAHs were observed. Continued baseline studies are clearly warranted to further understand effects of OH-PAHs on fish health before planned exploration activities begin in this region.
The purpose of this study was to develop a method to quantify 4(5)-methylimidazole (4-MEI), a suspected carcinogen, in carbonated beverages by simple sample dilution and isotope-dilution reverse-phase LC-MS/MS. Isotope dilution using hexa-deuterated methylimidazole (d6-4-MEI) was used to quantify native 4-MEI and to assess matrix effects quantitatively. The accuracy of the method was assessed by intentionally fortifying a negative control sample at three doses: low, medium and high (replicates of n = 5 each) with a known amount of 4-MEI. The respective absolute error in each case was 18.7 ± 0.7%, 14.6 ± 2.8% and 21.1 ± 9.7%. Within-day (intra-) and day-to-day (inter-) repeatability, determined as the relative standard deviation by fortifying a negative control sample (n = 5), were 9.5% and 15.4%, respectively. Average ion suppression of d6-4-MEI in beer was 63.9 ± 3.2%, while no suppression or enhancement was seen in non-alcoholic samples. The instrument and method limit of detection were calculated as 0.6 and 5.8 ng ml(-1), respectively. 4(5)-Methylimidazole was quantified in a variety of store-bought consumer beverages and it was found that in many of the samples tested consuming a single can of beer would result in intake levels of 4-MEI that exceed the no significant risk guideline of 29 µg day(-1). Conversely, 4-MEI in the samples was orders of magnitude smaller than the European Food Safety Authority acceptable daily intake threshold value of 100 mg kg(-1) bw day(-1).
Background and objectives Glyphosate is an active ingredient in widely used herbicides; its residues have been observed in grain and grain‐based foods. This work investigated the fate of glyphosate and its degradation product aminomethylphosphonic acid (AMPA) in milling fractions of wheat and during the bread making process. Samples of wheat were pearled to obtain successive fractions representing outer kernel layers. Straight grade flour and bread were prepared from the two samples with the highest glyphosate concentration (2.1 and 2.8 mg/kg). Findings All pearling and milling product fractions, dough, fermented dough, bread crust, and bread crumb were analyzed for glyphosate and AMPA using solvent extraction with derivatization and liquid chromatography–tandem mass spectrometry. Glyphosate was the only residue detected in samples. On average, the pearling experiment demonstrated that 50% of the total glyphosate mass resided in the outer 17% of the kernels. Similarly, 81% of the total glyphosate mass in the wheat was associated with the bran, shorts, and feeds milling fractions. No changes in glyphosate concentration were observed during the preparation of dough, fermented dough, and bread. Conclusions Milling provides the best opportunity for reducing exposure to glyphosate, as the baking process did not affect glyphosate residues. Concentrations in bread made from straight grade flour will be approximately 4× lower than that made from whole grain flour. Significance and novelty The use of Canada Western Red Spring from commercial wheat shipments provide realistic glyphosate residue concentrations and also reflect the predominance of this type of wheat used in Canada and elsewhere for bread. Therefore, the outcomes from this study are particularly relevant for estimating consumers’ dietary exposure.
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