Beryllium in food and drinking water--a summary of available knowledge.

In an overall evaluation of the situation published by IARC in 1993, beryllium and beryllium compounds are identified as carcinogens to humans. This prompted the initiation of this study on beryllium which reviews the situation up to 1998 on the aspects: properties and applications, toxicity, analytical procedures for food and drinking water, reference materials, occurrence in food and drinking water and estimates of daily dietary exposure. Special emphasis is put on analytical aspects and levels of beryllium in food and drinking water.

The oral nitrate and nitrite intake in The Netherlands: evaluation of the results obtained by HPIC analysis of duplicate 24-hour diet samples collected in 1994.

In spring and autumn of 1994 duplicates of 24-h diets were collected from 123 respondents. One of the goals of this study was to determine the amount of nitrite and nitrate in the duplicates of 24-h diets to establish the oral daily intake of these analytes. For this purpose an HPIC/UV method for the determination of nitrate and nitrite in duplicate diets was developed and validated. The sample preparation procedure was derived from the in-house method used for the determination of nitrate and nitrite in human blood plasma. The sample is diluted with water, deproteinized with Carrez reagent, followed by chromatographic clean-up on an SPE C18-column. Both the nitrate and the nitrite results are quantitative. The recovery for nitrite was on average 104% (n = 21, spiking levels: 0.84-95 mg/kg) and for nitrate on average 103% (N = 21, spiking levels: 1.8-404 mg/kg). Samples of duplicates of 24-h diets were analysed according to the method developed. The median intake of nitrite calculated from the samples collected in spring 1994 was 0.6 mg/person day (range < 0.1-6.1 mg/person/day). For the samples collected in autumn 1994 these figures were < 0.2 mg/person/day (range < 0.1-16 mg/person/day). The mean intake of nitrate was 73 mg/person/day (range 7-322 mg/person/day) in spring 1994 and 87 mg/person/day (range 1-310 mg/person/day) in autumn 1994. The overall mean intake of nitrate in 1994 was 80 mg/person/day. The daily intake for nitrate was higher than that found in the duplicate diet study carried out in 1984/1985, when an average daily intake of 52 mg/person was measured. The intake of nitrite was also higher than found in the duplicate diets collected in 1984/1985. The findings of the study are discussed in the context of the ADI for nitrate and nitrite as well as the outcome of other recent European intake studies.

Twenty-four-hour duplicate diet study 1994; nitrate and nitrite: method development and intake per person per day.

In spring and autumn of 1994 duplicates of 24-h diets were collected from 123 consumers (respondents). One goal of this study is to determine the amount of nitrite and nitrate in the duplicates of 24-h diets in order to establish the oral daily intake of these analytes. For this purpose a HPIC/UV method for the determination of nitrate and nitrite in duplicate diets was developed and validated. The mean intake of nitrate is 80 mg NO3- ion/person per day and the median intake of nitrite is 0.1 mg NO2- ion/person per day. The daily intake for nitrate as well nitrite is higher than found in the duplicate diets collected in the 1984/1985 study.

Cadmium and atherosclerosis in the rabbit: reduced atherogenesis by superseding of iron?

This study evaluated the effect of dietary cadmium (Cd) on atherosclerosis in the rabbit. Cholesterol was added to the diet to initiate and/or accelerate atherogenesis. Cd was added to the diet at two dose levels. Uptake of Cd was 55 micro gram/kg body weight (BW)/day at the low dose level and 1350 micrograms/ kg BW/day at the high dose level. Five groups of rabbits were fed five different diets for 9 months: (1) basal diet without additional constituents; (2) background diet, which was basal diet to which cholesterol had been added; (3) the low-dose level Cd diet, which was background diet to which 2 mg Cd/kg had been added; (4) high-dose level Cd diet, which was background diet to which 50 mg Cd/kg had been added; and (5) basal diet to which 50 mg Cd/kg had been added. Dietary cholesterol increased blood total leucocyte count, serum and liver total cholesterol concentrations, serum total bilirubin concentration, low-density lipoprotein vitamin E concentration and induction of atherosclerotic plaques in the aorta and coronary arteries. Cd in the diet increased liver and kidney Cd concentrations in a dose-dependent way, decreased prothrombin time and temporarily increased urea and creatinine clearances. Slight kidney damage was induced by Cd only in animals fed the high-dose level Cd diet (with or without cholesterol). Dietary Cd partly counteracted the dietary cholesterol-induced increases of serum and liver total cholesterol concentrations, and tended to reduce plaque formation in the aorta. Dietary Cd in rabbits fed cholesterol-containing diets influenced cholesterol metabolism and tended to decrease atherosclerosis in a dose-related fashion. This is in contrast with limited epidemiological human data. Dietary Cd also decreased serum ferritin concentration and increased serum transferrin concentration. Free iron concentration is associated with myocardial infarction in man and augments the development of atherosclerosis in rabbits. It is concluded that the observed reduction in atherogenesis is related to dietary Cd-induced changes in cholesterol metabolism, increased rheology of blood and/or, most likely, reduced free iron concentration.

The mechanism of fluoride-induced hypocalcaemia.

1. Fluoride intoxication leads to sudden cardiac death which has been assumed to result from the accompanying severe hypocalcaemia. The aim of this study has been to investigate the suggestion that fluorapatite formation rather than CaF2 precipitation is responsible for this low calcium. 2. Measurements of free Ca2+ and F- ion concentrations in HEPES buffered solutions containing F-, Ca2+, and phosphate ions at different concentrations in the absence and presence of hydroxyapatite showed that the presence of hydroxyapatite enhanced the decrease of Ca2+ and F- concentration. 3. The ratio of Ca2+:F- clearance was 5:1 which is consistent with formation of fluorapatite. These results support the hypothesis that hydroxyapatite acts as a nucleation catalyst for fluorapatite formation and this process is responsible for the hypocalcaemia induced by fluoride intoxication. 4. The proposed mechanism explains also the metabolic acidosis which is frequently seen in cases of fluoride intoxication.

Bioavailability of inorganic arsenic from bog ore-containing soil in the dog.

In some parts of The Netherlands, bog ore-containing soils predominate, which have natural arsenic levels that exceed, by a factor of 10, existing standards for maximum allowable levels of inorganic arsenic in soil. These standards are based on the assumption that in humans the bioavailability of arsenic from ingested soil is equal to that from an aqueous solution. In view of the regulatory problem that the arsenic levels of these soils present, we questioned the validity of this assumption. To obtain a more realistic estimate, the bioavailability of inorganic arsenic from soil in a suitable animal model was studied. In this report, a study performed in six dogs in a two-way cross-over design is presented. The dogs received orally, in random order, arsenic both as an intravenous solution and as arsenic-containing soil. During a 120-hr period after administration urine was collected in 24-hr fractions. Levels of arsenic were determined using a method of wet digestion, isolation and complexation of arsine, followed by molecule absorption spectrometry. Within 120 hr after intravenous administration, 88 +/- 16% of the dose was excreted renally. After oral administration of arsenic-containing soil, only 7.0 +/- 1.5% was excreted renally. From the urinary excretion data for these two routes of administration, the calculated bioavailability of inorganic arsenic from soil was 8.3 +/- 2.0%. The results from this study demonstrate the need to reconsider the present risk assessment for arsenic in soil.

Aluminium determination in food matrices IUPAC check sample survey of analytical performance.

Aluminum has been determined by 24 laboratories in the context of a check sample survey. Samples studied were two duplicate diets, one of which was spiked with 15.87 mg Al/kg, and two blind duplicate milk powders. Target values for the duplicate diets were 11.80 and 27.90 mg Al/kg, respectively, and 15.65 mg Al/kg for the milk powders. Participants were requested to make only single determinations per sample. A two-step approach was used to assess the raw data. In the first step, those data were excluded that were outside a +/- 50% range of the duplicate diet spike and the target value for milk powder. Likewise, only one single data set per participant was accepted and results were ruled out stemming from procedures that have a detection limit of greater than 5 mg Al/kg. The remaining data were evaluated both statistically and in the context of the method performance parameters available. Best scores for aluminium were from laboratories applying wet-pressurized digestion in combination with electrothermal atomic absorption spectrometry. Results for laboratories applying dry-ashing for sample decomposition were unreliable. The overall performance for aluminium is very disappointing given the relatively high aluminium levels of the samples studied. Out of 24 laboratories 11 have one or more major problems with their aluminium determination. They should dramatically improve or replace their methodology for this element.

Some elements in domestic and imported fresh fruits marketed in The Netherlands.

Sodium, potassium, arsenic, selenium and tin have been determined in 38 different types of domestic and imported fresh fruits. All samples (n = 242) were analysed for Na und K whereas a limited number of samples (n = 85) of each fruit type was selected for the determination of As, Se and Sn. The median contents, in mass fractions of the edible portion, found for fresh fruits are: Na less than 0.001%; K 0.17%; As 4 micrograms/kg; Se 2 micrograms/kg and Sn less than 0.05 mg/kg. The corresponding 90th percentile values are: Na 0.002%, K 0.34%; As 12 micrograms/kg; Se 10 micrograms/kg and Sn 0.10 mg/kg. Results for selenium reported here differ substantially from those given for a number of fresh fruits in the German Food Composition Tables 1986/1987. The average consumption of 129 g fresh fruit by Dutch citizens in the age category of 22-75 years contributes, in general, marginally to the total daily dietary intake of sodium, arsenic, selenium and tin. Fresh fruit can contribute substantially, up to 23%, to the average oral daily intake of potassium.

Chronic toxicity and carcinogenicity of bis(tri-n-butyltin)oxide (TBTO) in the rat.

In a 106-wk toxicity and carcinogenicity study, groups of 60 male and 60 female weanling Wistar rats were fed 0, 0.5, or 50 mg bis(tri-n-butyltin)oxide (TBTO)/kg diet. In males, feed consumption was increased in all treated groups and increased water consumption occurred at 5 and 50 mg/kg. During the second year, body weight decreased in the 50-mg/kg males, while the females in that group showed no weight gain. Excess mortality was confined to the 50-mg/kg group towards the end of the study. Haematological changes, comprising anaemia, lymphocytopenia and thrombocytosis were noted mainly at the high-dose level. Also, signs of decreased kidney function and increased plasma enzyme activities (alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase) were noted. No effects on serum hormone concentrations (thyrotropin, follicle stimulating hormone, luteinizing hormone or insulin) were observed, except for a decrease in the free thyroxin:thyroxin ratio in both sexes at the high-dose level. Higher serum IgM and IgA levels were present at 50 mg/kg, while, in females, IgG was decreased. At 50 mg/kg, the ovaries, adrenals, spleen (females), heart (males), pituitary, liver and kidneys were increased in weight, but the thyroid weight was decreased in females. The total tin concentrations in liver and kidneys showed a dose relationship and, in general, the concentrations were similar after 1 and 2 yr. Non-neoplastic histological alterations after 1 yr consisted of a decrease in the cell height of the thyroid follicles in all dose groups, with a reduced number of psammoma bodies at 50 mg/kg, a decrease in splenic iron content at 5 (females only) and 50 mg/kg, and a slight bile-duct activation. After 2 yr, only the thyroid changes were still present. In addition, at 2 yr, vacuolation and pigmentation of the proximal tubular epithelium and nephrosis were enhanced at 50 mg/kg. The incidence of benign tumours of the pituitary was significantly elevated and enhanced at 0.5 and 50 mg/kg. At 50 mg/kg increases in pheochromocytomas in the adrenal medulla and in parathyroid adenomas (males) were noted, while adrenal cortical tumours were decreased (males). There was a low, non-dose-related incidence of pancreatic carcinoma. Other tumour rates were in line with control data. It is concluded that lifetime feeding of 50 mg TBTO/kg diet induces toxicity in various organ systems. An increase in some common tumours was found at the high dose, probably due to hormonal or immunological changes.(ABSTRACT TRUNCATED AT 400 WORDS)

Reference-material-based collaborative test of flame atomic absorption spectroscopic determination of calcium and magnesium in foods and biological materials.

A flame atomic absorption spectroscopic (FAAS) method is described for the determination of calcium and magnesium in a wide variety of foods and biological substrates. Results for reference materials (n = 9) are presented that demonstrate the validity of the procedure. Samples are digested with nitric acid at 150 degrees C in a pressure decomposition vessel, diluted and adjusted to pH 2 with ammonia. Lanthanum chloride solution is added to suppress phosphate interferences and the ionization of calcium and magnesium in the AAS flame. Additional dilutions are made as appropriate, whereupon the atomic absorption of calcium and magnesium is measured in an oxidizing air-acetylene flame. The wavelength settings for calcium is 422.7 nm and for magnesium 285.2 nm. The method was tested in a collaborative trial involving a milk powder practice sample and four test samples, all of which were reference materials. Participants were requested to carry out duplicate determinations exclusively. Results were obtained from 12 laboratories. However, the results of 3 laboratories had to be rejected for various reasons. The remaining set of data was statistically evaluated according to ISO 5725; the method of analysis proved to be precise and accurate. Coefficients of variation values for calcium ranged from 1.19% to 4.44% within laboratories (CVr) and from 5.30% to 15.9% between laboratories (CVR). For magnesium, the corresponding values were CVr, 1.07% to 3.52% and CVR, 3.07% to 5.99%. The method is recommended for the determination of calcium and magnesium at the levels considered in foods and biological substrates.

Speciation of arsenic in Dutch total diets: methodology and results.

In the last decade 311 duplicate portions of the 24-h diet of Dutch citizens were collected and lyophilized. All samples were assayed for total arsenic and, in addition, the 20 samples which ranked highest in total arsenic were selected for arsenic speciation i.e., the separate determination of organic-bound arsenic and inorganic arsenic. For the determination of total arsenic, the test portion is wet-digested and the digest reduced with KI/SnCl2/Zn to give AsH3 which is measured by molecular absorption spectrometry. Inorganic arsenic is also measured as AsH3 after acid extraction of the test portion and subsequent NaBH4 reduction of the extract. The residue of the acid extraction and the NaBH4-reduced extract are combined, wet-digested and the digest reduced with NaBH4 to give AsH3 originating from organic-bound arsenic. Samples spiked at different levels with inorganic and organic-bound arsenic were analysed and gave recoveries for inorganic arsenic of 94% to 122% (n = 6) and for organic-bound arsenic of 87% to 104% (n = 6). On average, the inorganic fraction is 30% of the total arsenic intake; range 3% to 50% (n = 14). The inorganic arsenic fraction decreases with increasing level of total arsenic intake. The highest oral inorganic arsenic intake was 60 micrograms; the tolerable daily intake (TDI) for a 60-kg individual is 120 micrograms inorganic arsenic. Organic and inorganic arsenic measured were summed and compared with the results of the total arsenic determination; differences were less than 15%. (Since inorganic arsenic is a contaminant and not an additive, the abbreviation TDI is preferred here over ADI (acceptable daily intake) which is retained for additives.)

Preparation and stability of ampouled polycyclic aromatic hydrocarbon solutions.

A 1-year stability study of ampouled polycyclic aromatic hydrocarbon (PAH) solutions was carried out. Two solutions of seven pure PAHs were prepared, one in acetonitrile and one in toluene, and ampouled. Solutions were tested for mass concentration and impurities before and after ampouling. No differences were found. After 0, 3, 6, 9 and 12 months, three ampoules were selected for analysis from the acetonitrile and the toluene lots stored at +20 degrees and at -20 degrees C. The acetonitrile solution was analysed by high performance liquid chromatography and the toluene solution by glass capillary gas chromatography. The results demonstrate that both solutions were stable and no contamination occurred during storage.

Collaborative test of the fluorimetric determination of selenium in a test solution, milk powder and bovine liver.

Results are reported for an inter-laboratory test conducted to assess precision (repeatability, reproducibility) and accuracy of a collaborative method for the fluorimetric determination of selenium (Se). The seven participating laboratories analysed one test solution, four samples of milk powder and two samples of freeze-dried bovine liver. Each set of samples comprised three duplicates: two colorant-disguised milk powders and one code disguised freeze-dried bovine liver. Two of the milk powders were enriched with 90.7 micrograms/kg Se as seleno-DL-methionine. One set of results had to be rejected because the laboratory involved did not adhere to the collaborative method. Results from a second laboratory contained both stragglers and outliers. The five remaining laboratories performed the method satisfactory. Results from these laboratories were statistically evaluated according to ISO 5725. The average coefficient of variation within a laboratory (repeatability) was 4.8% and between laboratories (reproducibility) 6.0% for the milk powder and bovine liver samples. Recovery for the test solution, target value 120 micrograms Se/1, was 96% and the average recovery for the Se enriched milk powder was 88%. The mean result for the milk powder was 98.9 micrograms/kg (n = 10), coefficient of variation (CV) 6.7%, and for Se enriched milk powder 178.3 micrograms/kg, coefficient of variation (CV) 3.6%. For freeze-dried bovine liver, these results were 238.4 micrograms/kg and 4.1% respectively.

[Arsenic, cadmium, mercury, lead and selenium in slaughtered animals: an overview of a 10-year study]. / Arseen, cadmium, kwik, lood en seleen in slachtdieren: een overzicht van 10 jaar onderzoek.

A large number of organs of slaughtered animals were examined for heavy metals, arsenic and selenium during the period from 1970 to 1980. In the present paper, the arsenic, cadmium, mercury, lead and selenium levels determined in porcine and bovine kidneys and livers as well as in porcine brain are reviewed. The following median levels (in mg/kg of fresh product) of the various elements were determined: (table; see text) In a number of cases, organs and meat from the same animal were studied; the levels in meat were much lower than those in organs in every case. A constant ratio between the levels of the elements in meat and those in organs was not observed.

Simple fluorimetric determination of selenium in food and biological materials. A validation study.

A method for the determination of selenium in food and biological materials has been developed. The method involves sample decomposition in a closed system at 150 degrees C with nitric acid, perchloric acid treatment of the digest, reduction of selenium to the tetravalent state with hydrochloric acid followed by Se-2,3-diaminonaphthalene (DAN) complex formation and extraction in a single-step operation. Performance characteristics of the method (accuracy and repeatability) were extensively tested for eleven reference materials and ten practice samples covering both a wide variety of matrices and a wide range of selenium content. Almost all results for reference materials were within the 95% confidence range of the certified value or the best estimate thereof. The coefficient of variation for all samples ranged from 2.3 to 10.1%, average value 4.7%. Average recovery for spiking experiments-levels 0.060, 0.075 and 0.150 micrograms/g was 102%; range 84-114%.

Toxicity of bis(tri-n-butyltin)oxide in the rat. I. Short-term effects on general parameters and on the endocrine and lymphoid systems.

Male and female Wistar rats were fed bis(tri-n-butyltin)oxide (TBTO) at 0, 5, 20, 80, or 320 mg/kg diet for 4 weeks. Clinical signs and decreases in feed and water consumption were observed in the 80 and 320 mg/kg groups. The serum transferase activities (alanine amino transferase and aspartate amino transferase were increased at 20 (males only), 80, and 320 mg/kg. The serum glucose and liver glycogen concentrations were lowered in the 320 mg/kg group. At 80 and 320 mg/kg the serum IgG level was reduced and IgM level was increased. Compared to controls the mean relative weight of the thymus was decreased at 20 (males), 80, and 320 mg/kg. In the groups receiving 80 or 320 mg/kg microcytic anemia was found. The white blood cell counts were decreased, due to the reduction in the number of lymphocytes in the 80 (males) and 320 mg/kg groups. The concentration of neutrophilic granulocytes was increased in the highest dose group. Histopathologic effects included a dose-related lymphocyte depletion of thymic cortex and of T lymphocytes in spleen and mesenteric lymph nodes. In the spleen also depletion of iron stores was found, and in the medullary sinuses of mesenteric lymph nodes, rosettes of erythrocytes were found around mononuclear cells; the occurrence of rosettes increased with dose from 5 to 80 mg/kg, and appeared to be the most sensitive parameter. A low incidence of areas of liver necrosis with inflammatory reaction and bile duct hyperplasia was found in the 320 mg/kg group. A viral or bacterial etiology could be demonstrated for these liver lesions, but they appeared associated with TBTO-induced ulcerative inflammation of the common bile duct as shown in an additional study. In 6-week studies exposure of male weanlings to the 0, 20, and 80 mg/kg diets, the serum insulin concentration in the treated groups was decreased, although the response to glucose challenge was unaffected. The serum thyroxin and thyrotropin (TSH) concentrations were reduced, whereas the luteinizing hormone (LH) concentration was increased in the 80 mg/kg group. The concentrations of follicle-stimulating hormone (FSH) and corticosterone were not changed. The release of LH and FSH was enhanced in the 80 mg/kg group and a tendency toward reduced release was found for TSH. Using immunocytochemistry a dose-related reduction was found in the number and staining intensity of TSH-producing cells in the pituitary, correlating with histopathologically decreased activity of the thyroid.(ABSTRACT TRUNCATED AT 400 WORDS)