Results from Two Interlaboratory Comparison Tests Organized in Germany and at the EU Level for Analysis of Acrylamide in Food

After the publication of high levels of acrylamide (AA) in food, many research activities started all over the world in order to determine the occurrence and the concentration of this substance in various types of food. As no validated methods were available at that time, interlaboratory studies on the determination of AA in food were of the highest priority. Under the boundary conditions of applying well-established evaluation schemes, the results of 2 studies conducted by the Federal Institute for Risk Assessment (BfR) in Germany and by the European Commission's Directorate General Joint Research Center (JRC) exhibited an overall acceptable performance of the participants in these studies. Nevertheless, many laboratories showed problems in determining AA in food with a complex matrix such as cocoa. The results of analysis also showed a broader variation of AA for samples with low AA concentrations and indicated a bias of the results obtained by gas chromatography–mass spectrometry without derivatization. Improvements of the performance of some laboratories appeared to be necessary.

Determination of the isoflavone composition and estrogenic activity of commercial dietary supplements based on soy or red clover

Dietary supplements high in isolated isoflavones are commercially available for human consumption primarily to alleviate menopausal symptoms in women. The isoflavone composition, quantity and importantly their estrogenic potency are poorly standardised and can vary considerably between different products. The aim of this study was to analyse the isoflavone composition of 11 dietary supplements based on soy or red clover using the HPLC/MS/MS technique. Furthermore, we investigated the transactivational potential of the supplements on the estrogen receptors (ER), ERα and ERβ, performing luciferase reporter gene assays. As expected, we found that the isoflavone composition varies between different products. The measured total isoflavone contents in various supplements were mostly comparable to those claimed by the manufacturers in their product information. However expressing the isoflavone content as isoflavone aglycone equivalents, soy-based supplements had a clearly lower quantity compared to the manufacturer information. All supplements transactivated more or less ERα and ERβ with a preference for ERβ. The transactivational efficiency exceeded partly the maximal 17β-estradiol induced ER activation. While the different soy-based supplements revealed similar transactivation potential to both ERs, red clover-based supplements differed considerably. We conclude that different commercial dietary supplements based on soy or red clover vary in their isoflavone composition and quantity. They are estrogenically active, although especially the red clover-based supplements show considerable differences in their estrogenic potential to ERα and ERβ. Thus, different isoflavone-rich products cannot be necessarily compared regarding possible biological effects.

Concentrations of strontium, barium, cadmium, copper, zinc, manganese, chromium, antimony, selenium, and lead in the liver and kidneys of dogs according to age, gender, and the occurrence of chronic kidney disease

This study was conducted to measure the concentrations of strontium (Sr), barium (Ba), cadmium (Cd), copper (Cu), zinc (Zn), manganese (Mn), chromium (Cr), antimony (Sb), selenium (Se), and lead (Pb) in canine liver, renal cortex, and renal medulla, and the association of these concentrations with age, gender, and occurrence of chronic kidney disease (CKD). Tissues from 50 dogs were analyzed using inductively coupled plasma mass spectrometry. Cu, Zn, and Mn levels were highest in the liver followed by the renal cortex and renal medulla. The highest Sr, Cd, and Se concentrations were measured in the renal cortex while lower levels were found in the renal medulla and liver. Female dogs had higher tissue concentrations of Sr (liver and renal medulla), Cd (liver), Zn (liver and renal cortex), Cr (liver, renal cortex, and renal medulla), and Pb (liver) than male animals. Except for Mn and Sb, age-dependent variations were observed for all element concentrations in the canine tissues. Hepatic Cd and Cr concentrations were higher in dogs with CKD. In conclusion, the present results provide new knowledge about the storage of specific elements in canine liver and kidneys, and can be considered important reference data for diagnostic methods and further investigations.

Concentrations of strontium, barium, cadmium, copper, zinc, manganese, chromium, antimony, selenium and lead in the equine liver and kidneys

The concentrations of specific elements in the equine liver and kidneys are of practical relevance since horses are not only food-producing animals, but also partially serve as an indicator for the environmental pollution, as the basic feed includes plants like grass, grain and fruits. In this study, the concentrations of strontium (Sr), barium (Ba), cadmium (Cd), copper (Cu), zinc (Zn), manganese (Mn), chromium (Cr), antimony (Sb), selenium (Se) and lead (Pb) were measured in the liver, renal cortex and renal medulla of 21 horses (8 male; 13 female; aged between 5 months-28 years), using inductively coupled plasma mass spectrometry. Comparable Cu and Zn concentrations were detected in the liver and renal cortex, while approximately 50% lower concentrations were measured in the renal medulla. The lowest Sr, Cd and Se, but the highest Mn, Sb and Pb concentrations were measured in the liver. The Ba concentrations were comparable in the renal cortex and medulla, but lower in the liver of the horses. Gender-related differences were observed for Cd, Mn and Cr, with higher Cd concentrations in the liver, but lower Mn concentrations in the renal cortex and lower Cr concentrations in the renal medulla of female horses. Age-related differences were detected for most measured elements, however, the animal number per age-group was only low. In conclusion, the present study provides important reference data for the storage of Sr, Ba, Cd, Cu, Zn, Mn, Cr, Sb, Se and Pb in the liver and kidneys of horses, which are of practical relevance for an evaluation of the exposure of horses to these elements, either via feed or the environment.

Liver and kidney concentrations of strontium, barium, cadmium, copper, zinc, manganese, chromium, antimony, selenium and lead in cats

Background

In order to provide new knowledge on the storage of strontium (Sr), barium (Ba), cadmium (Cd), copper (Cu), zinc (Zn), manganese (Mn), chromium (Cr), antimony (Sb), selenium (Se) and lead (Pb) in the feline organism, we measured the concentrations of these elements in the liver, renal cortex and renal medulla, evaluating also the impact of age, sex or the occurrence of a chronic kidney disease (CKD). The element concentrations in the tissues of 47 cats (22 male; 25 female; aged between 2 months and 18 years) were measured using inductively coupled plasma mass spectrometry.

Results

Cu, Zn and Mn were the highest in the liver, followed by the renal cortex and the renal medulla. The Cd concentrations were lower in the renal medulla compared to the renal cortex and the liver, and Sr was higher in the renal medulla compared to the liver. The Se concentrations in the cortex of the kidneys were higher than in the medulla of the kidneys and in the liver. Higher Cd concentrations were measured in the renal cortex of female cats, while no further gender-related differences were observed. Except for Cr, Sb and Se, age-dependencies were detected for the storage of all elements. The occurrence of a CKD also affected the storage of the elements, with lower concentrations of Ba (renal medulla), Zn (renal cortex; renal medulla) and Mn (liver; renal medulla), but higher Cd concentrations (liver; renal cortex) in diseased cats.

Conclusions

In conclusion, the present results provide new information on the accumulation of specific elements in the feline liver and kidneys, demonstrating a dependency on age and an impaired kidney function, but not on the sex of the animals.

Column and batch tests of sulfonamide leaching from different types of soil

Sulfonamides (SAs) and their metabolites present severe hazards to human health and the environment, mainly because of antibiotic resistance. Knowledge of their bioavailability, including their sorption to soils and their impact on the soil-groundwater pathway, is crucial to their risk assessment. Laboratory batch and column leaching tests are important tools for determining the release potential of contaminants from soil or waste materials. Batch and column tests were carried out with soils differing in particle size distribution, organic matter content and pH, each spiked with sulfonamides (sulfadimethoxine (SDM), sulfaguanidine (SGD), sulfisoxazole (SX)). In order to test the applicability of leaching tests to polar contaminants batch and column tests were also compared. In the column tests, release was found to depend on the properties of both soil and sulfonamides. The fastest release was observed for coarse-grained soil with the smallest organic matter content (MS soil; 100% decrease in concentration until liquid-to-solid ratio (L/S) of 0.9 L kg(-1) for all SAs). The slowest release was established for sulfadimethoxine (24.5% decrease in concentration until L/S 1.22 L kg(-1)). The results of the batch and column tests were comparable to a large extent, with slightly higher concentrations being obtained in the column test experiments of fine-grained soils with a high organic matter content.

Sulfadimethoxine and sulfaguanidine: their sorption potential on natural soils

Sulfonamides (SAs) are one of the oldest groups of veterinary chemotherapeutic agents. As these compounds are not completely metabolized in animals, a high proportion of the native form is excreted in feces and urine. They are therefore released either directly to the environment in aquacultures and by grazing animals, or indirectly during the application of manure or slurry. Once released into the environment, SAs become distributed among various environmental compartments and may be transported to surface or ground waters. The physicochemical properties of SAs, dosage and nature of the matrix are the factors mainly responsible for their distribution in the natural environment. Although these rather polar compounds have been in use for over half a century, knowledge of their fate and behavior in soil ecosystems is still limited. Therefore, in this work we have determined the sorption potential of sulfadimethoxine and sulfaguanidine on various natural soils. The influence on sorption of external factors, such as ionic strength and pH, were also determined. The sorption coefficients (K(d)) obtained for the sulfonamides investigated were quite low (from 0.20 to 381.17 mL g(-1) for sulfadimethoxine and from 0.39 to 35.09 mL g(-1) for sulfaguanidine), which indicated that these substances are highly mobile and have the potential to run off into surface waters and/or infiltrate ground water. Moreover, the sorption of these pharmaceuticals was found to be influenced by OC, soil solution pH and ionic strength, with higher K(d) values for soils of higher OC and lower K(d) values with increasing pH and ionic strength.

Leaf surface sesquiterpene alcohols of the potato (Solanum tuberosum) and their influence on colorado beetle (Leptinotarsa decemlineata Say) feeding

The structures of two previously unknown sesquiterpene alcohols of the potato (Solanum tuberosum) were assigned. The potato alcohols were obtained by steam-distillation, preparative column chromatography, and separation into fractions by HPLC on a silica gel column. The fractions were studied by GC-FID, GC-MS, and NMR spectroscopy. The potato sesquiterpene alcohols were identified as kunzeaol (6-alpha-hydroxygermacra-1(10),4-diene) and ledol. These two compounds were used in feeding tests with larvae and beetles of the Colorado potato beetle (Leptinotarsa decemlineata Say). In a bioassay, kunzeaol was found to act as a feeding attractant for the beetles.

Acrylamide–occurrence in mixed concentrate feed for dairy cows and carry-over into milk

During the preparation of cooked foods acrylamide is formed from asparagine and reducing sugars at high temperatures. By-products of oil, starch and sugar production, which may be found in animal feed, partially result from processing steps using heat treatment that are similarly likely to form acrylamide. Possibly, pelletizing during the processing of mixed concentrates may also be involved in acrylamide formation. Thus the occurrence of acrylamide in animal feed and the potential for carry-over into animal products should be tested. Independently of the feed matrix, 1.5 g per day of acrylamide was fed to a cow for ten days resulting in a mean concentration of 175 microg/kg of acrylamide in the milk. From the data obtained the mean carry-over was found to be 0.24%, and a mean half-life time of 2.8 h was estimated. This means acrylamide was rapidly transformed in the cow. The acrylamide concentrations in three commercial mixed concentrates were respectively 180, 145 and 140 microg/kg feed. To test the possible effect of pelletizing, the peripheral zones were separately analysed. No difference in concentration was observed. Based on the carry-over rate estimated in this study, a maximum concentration of approx. 0.2 microg/kg of acrylamide would be expected in milk from cows fed with such feeds.

Results from two interlaboratory comparison tests organized in Germany and at the EU level for analysis of acrylamide in food

After the publication of high levels of acrylamide (AA) in food, many research activities started all over the world in order to determine the occurrence and the concentration of this substance in various types of food. As no validated methods were available at that time, interlaboratory studies on the determination of AA in food were of the highest priority. Under the boundary conditions of applying well-established evaluation schemes, the results of 2 studies conducted by the Federal Institute for Risk Assessment (BfR) in Germany and by the European Commission's Directorate General Joint Research Center (JRC) exhibited an overall acceptable performance of the participants in these studies. Nevertheless, many laboratories showed problems in determining AA in food with a complex matrix such as cocoa. The results of analysis also showed a broader variation of AA for samples with low AA concentrations and indicated a bias of the results obtained by gas chromatography-mass spectrometry without derivatization. Improvements of the performance of some laboratories appeared to be necessary.

Effect of low dose mono-ortho 2,3',4,4',5 pentachlorobiphenyl on thyroid hormone status and EROD activity in rat offspring: consequences for risk assessment

Toxic equivalency factor (TEF) has been proposed to estimate the risk of polychlorinated biphenyl (PCB) congeners. However, ortho chlorine substitution in the two phenyl rings gives each PCB its own pattern of toxicity which is different from the mechanism of action of 2,3,7,8-tetrachlorodibenzo-p-dioxin. The present study evaluated the effect of prenatal and postnatal exposure to a low dose of the mono-ortho pentachlorobiphenyl PCB 118 on thyroid hormone concentrations and EROD activity in rats. Moreover, the tissue distribution of PCB 118 following one oral dose was evaluated. Sprague-Dawley rats were treated by gavage on GD 6 with 375 microg of PCB 118/kg b.w. Decreases in thyroxine and TSH levels were observed in dams at the end of lactation. Perinatal exposure to a low dose of PCB 118 permanently disrupted the hypothalamo-pituitary-thyroid (HPT) axis leading to a significant increase in thyroxine levels in offspring, as a 'thyroid resistance syndrome'. It is noteworthy that no changes in hepatic EROD activity were detected in dams at the end of lactation, even in the presence of high amounts of PCB in liver. Based on hepatic EROD activity (as a biomarker for aryl hydrocarbon receptor (AhR) induction), the mechanism of thyroid homeostasis disruption seems to be AhR-independent. Additionally, the 'thyroid resistance syndrome' observed in our study indicates the need for further detailed investigations on the HPT axis. We conclude that not only TEF, but also AhR-independent responses should be taken into account for risk assessment of mono-ortho PCB congeners.

PCDDs, PCDFs, PCBs, and other organochlorine compounds in human milk from Rio de Janeiro, Brazil

The levels of polychlorinated dibenzo-p-dioxins (PCDDs) and -furans (PCDFs), polychlorinated biphenyls (PCBs), and other organochlorine compounds were determined in a pooled sample of breast milk from 40 mothers (first lactation: 33; second lactation: 7, age: 15-38 years) living in the urban area of Rio de Janeiro County, Brazil, in 1992. Mothers were breastfeeding only one infant and milk was collected between 4 and 6 weeks after delivery. The results showed a dioxin equivalent concentration of 8.1 pg I-TEq/g milk fat. The levels of other chlorinated compounds (micrograms per gram of milk fat) were as follows: PCBs (total), 0.15; alpha-HCH, 0.001; beta-HCH, 0.27;gamma-HCH, 0.005; HCB, 0.012; DDT (total), 1.7; dieldrin, 0.023, and cis-heptachlor epoxide, 0.008. These results suggest that human background contamination by PCDD/Fs, PCBs, and HCB in Rio de Janeiro is lower than that generally found in industrialized countries.

Mass spectrometric characterization of Q1, a C(9)H(3)Cl(7)N(2) contaminant in environmental samples

Q1, a heptachloro component of unknown structure and origin, was recently identified as a major organochlorine contaminant in samples from Africa and the Antarctic. Gas chromatography in combination with low resolution mass spectrometry (LRMS) was applied to establish a molecular weight of m/z 384 including seven chlorine atoms. Three possible molecular formulae (C(11)H(7)Cl(7), C(10)H(3)Cl(7)O, and C(9)H(3)Cl(7)N(2)) were proposed which could not be distinguished by LRMS. In this presentation the molecular composition of Q1 was studied using gas chromatography in combination with high resolution electron impact ionization mass spectrometry. With the option of further heteroatoms (P, S, N, O, F, and Br), 17 molecular formulae were obtained for the molecular weight of 384 u. In the selected ion monitoring (SIM) mode, performed with a resolution of 16,000, highest response was found at 383.812 or C(9)H(3)Cl(7)N(2). 11 fragment ions detected in the low resolution full scan mass spectrum of Q1 were also investigated in the high resolution SIM mode. In every case, the nitrogen-variant showed highest abundance while the other 16 structural variants could be definitely excluded. These investigations revealed that the molecular formula of Q1 is C(9)H(3)Cl(7)N(2). No stable component with this molecular formula has ever been reported in the literature, to our knowledge. Copyright 1999 John Wiley & Sons, Ltd.

Lithium, sodium, potassium and rubidium cation concentrations during the development of certain organs of unborn rabbits

The distribution of lithium, sodium, potassium and rubidium in rabbit fetuses was determined during the last two weeks of gestation. Samples of eye, brain, lung, heart, liver and kidney were investigated. Co-actions between the ion pairs Li+/Na+ and K+/Rb+ could be discerned. The essential properties of lithium and rubidium for the fetal development of rabbits were examined by investigating the supply of the fetal organs with these elements. Correlations between organ differentiation processes and metal concentrations were established and compared with the results obtained for the fetal development of other vertebrates.

Time-dependent excretion of lithium, sodium, potassium, rubidium, magnesium and strontium in the urine of a multiple sclerosis patient

Field desorption mass spectrometry and stable isotope dilution have been used for direct trace analysis of metals in urine. Samples were collected over 24 h at 2 h intervals from a hospitalized multiple sclerosis patient. Quantitative determinations of Li+, Rb+, Mg2+ and Sr2+ from individual samples have been made and correlated with the amounts of urine excreted as well as with the time of day. The concentrations of Na+ and K+ were determined by flame photometry. The quantities of metals excreted in urine during the course of 24 h were 0.0129 mg for lithium, 4700 mg for sodium, 2100 mg for potassium, 1.4 mg for rubidium, 78.8 mg for magnesium and 0.2356 mg for strontium. The maximal absolute quantities excreted of all metals determined correspond with the largest volume of urine. The highest amounts of potassium, rubidium and strontium were found in urine during the daytime (8.00-20.00), whilst magnesium was excreted increasingly during the night hours (20.00-8.00). The excretion of lithium and sodium is fairly even over the entire 24 h period. It is noteworthy that similarities in the excretion profile and the concentration course are observed between Li+ and Na+ on one hand and between K+ and Rb+ on the other. Moreover, the lower concentration of Rb+ ions in urine of multiple sclerosis patients, in comparison to healthy individuals and clinical controls as reported previously, was confirmed.

Concentrations of electrolytes and trace metals in amniotic fluid and body tissues of rabbits during the last two weeks of gestation

Uterus and placenta of the mother animals, amniotic fluid as well as skin, ossified bone tissue and skeletal muscle of the fetuses were examined. The natural concentrations of Li+, Na+, K+, Rb+, Mg2+, Sr2+, Ba2+-ions were determined in the third and fourth weeks of gestation. The concentrations of trace metals down to 10(-9) g metal/g tissue could be determined, with a standard deviation of less than +/- 10%, by field desorption mass spectrometry. Correlations between lithium concentrations and bone growth were discerned. Differentiation-processes of the fetal skin were indirectly verified by the marked decrease of all metal ions with the progress of gestation. Concentration changes of metals in uterus tissue during gestation correspond to the changes in maternal serum at the same stage.

Determination of lithium and rubidium in physiological fluids and tissues of rabbits during the reproductive phase

1. The natural concentrations of lithium and rubidium were determined during the reproductive phase of rabbits by field desorption mass spectrometry. 2. Samples of serum, milk, amniotic fluid and placenta tissue were analysed. 3. The concentration changes in serum during the reproductive phase were between 2.61 and 5.02 micrograms/l for lithium and between 107.78 and 136.28 micrograms/l for rubidium. 4. Correlations between the concentration in maternal serum and bone growth of the fetus as well as the formation of milk were found. 5. Concentrations of 9.30 micrograms/l lithium and 1780.00 micrograms/l rubidium in the milk lead to the assumption that these trace metals are essential for the metabolism of the young rabbit.