Humans seem to produce arsenobetaine and dimethylarsinate after a bolus dose of seafood.

Seafood is the predominant food source of several organoarsenic compounds. Some seafood species, like crustaceans and seaweed, also contain inorganic arsenic (iAs), a well-known toxicant. It is unclear whether human biotransformation of ingested organoarsenicals from seafood result in formation of arsenicals of health concern. The present controlled dietary study examined the urinary excretion of arsenic compounds (total arsenic (tAs), iAs, AB (arsenobetaine), dimethylarsinate (DMA) and methylarsonate (MA)) following ingestion of a single test meal of seafood (cod, 780 µg tAs, farmed salmon, 290 µg tAs or blue mussel, 690 µg tAs or potato (control, 110 µg tAs)) in 38 volunteers. The amount of ingested tAs excreted via the urine within 0-72 h varied significantly among the groups: Cod, 74% (52-92%), salmon 56% (46-82%), blue mussel 49% (37-78%), control 45% (30-60%). The estimated total urinary excretion of AB was higher than the amount of ingested AB in the blue mussel group (112%) and also ingestion of cod seemed to result in more AB, indicating possible endogenous formation of AB from other organoarsenicals. Excretion of iAs was lower than ingested (13-22% of the ingested iAs was excreted in the different groups). Although the ingested amount of iAs+DMA+MA was low for all seafood groups (1.2-4.5% of tAs ingested), the urinary DMA excretion was high in the blue mussel and salmon groups, counting for 25% and 11% of the excreted tAs respectively. In conclusion our data indicate a possible formation of AB as a result of biotransformation of other organic arsenicals. The considerable amount of DMA excreted is probably not only due to methylation of ingested iAs, but due to biotransformation of organoarsenicals making it an inappropriate biomarker of iAs exposure in populations with a high seafood intake.

Origin and age of the Eisenkappel gabbro to granite suite (Carinthia, SE Austrian Alps).

The northern part of the Karawanken plutonic belt is a gabbro-granite complex located just north of the Periadriatic lineament near the Slovenian-Austrian border. Petrographic and geochemical studies of the Eisenkappel intrusive complex indicate that this multiphase plutonic suite developed by a combination of crystal accumulation, fractional crystallization and assimilation processes, magma mixing and mingling. The mafic rocks are alkaline and have within-plate geochemical characteristics, indicating anorogenic magmatism in an extensional setting and derivation from an enriched mantle source. The mafic melts triggered partial melting of the crust and the formation of granite. The granitic rocks are alkalic, metaluminous and have the high Fe/Fe + Mg characteristics of within-plate plutons. Temperature and pressure conditions, derived from amphibole-plagioclase and different amphibole thermobarometers, suggest that the analysed Eisenkappel gabbros crystallized at around 1000 ± 20 °C and 380-470 MPa, whereas the granitic rock crystallized at T ≤ 800 ± 20 °C and ≤ 350 MPa. Mineral-whole rock Sm-Nd analyses of two cumulate gabbros yielded 249 ± 8.4 Ma and 250 ± 26 Ma (εNd: + 3.6), garnet-whole rock Sm-Nd analyses of two silicic samples yielded well-constrained ages of 238.4 ± 1.9 Ma and 242.1 ± 2.1 Ma (εNd: - 2.6).

Factors influencing intestinal cadmium uptake in pregnant Bangladeshi women--a prospective cohort study.

Experimental studies indicate that zinc (Zn) and calcium (Ca) status, in addition to iron (Fe) status, affect gastrointestinal absorption of cadmium (Cd), an environmental pollutant that is toxic to kidneys, bone and endocrine systems. The aim of this study was to evaluate how various nutritional factors influence the uptake of Cd in women, particularly during pregnancy. The study was carried out in a rural area of Bangladesh, where malnutrition is prevalent and exposure to Cd via food appears elevated. The uptake of Cd was evaluated by associations between erythrocyte Cd concentrations (Ery-Cd), a marker of ongoing Cd exposure, and concentrations of nutritional markers. Blood samples, collected in early pregnancy and 6 months postpartum, were analyzed by inductively coupled plasma mass spectrometry (ICPMS). Ery-Cd varied considerably (range: 0.31-5.4microg/kg) with a median of 1.1microg/kg (approximately 0.5microg/L in whole blood) in early pregnancy. Ery-Cd was associated with erythrocyte manganese (Ery-Mn; positively), plasma ferritin (p-Ft; negatively), and erythrocyte Ca (Ery-Ca; negatively) in decreasing order, indicating common transporters for Cd, Fe and Mn. There was no evidence of Cd uptake via Zn transporters, but the association between Ery-Cd and p-Ft seemed to be dependent on adequate Zn status. On average, Ery-Cd increased significantly by 0.2microg/kg from early pregnancy to 6 months postpartum, apparently due to up-regulated divalent metal transporter 1 (DMT1). In conclusion, intestinal uptake of Cd appears to be influenced either directly or indirectly by several micronutrients, in particular Fe, Mn and Zn. The negative association with Ca may suggest that Cd inhibits the transport of Ca to blood.

Cadmium body burden and increased blood pressure in middle-aged American Indians: the Strong Heart Study.

Cadmium (Cd) is an environmental pollutant that has been associated with cardiovascular disease in populations, but the relationship of Cd with hypertension has been inconsistent. We studied the association between urinary Cd concentrations, a measure of total body burden, and blood pressure in American Indians, a US population with above national average Cd burden. Urinary Cd was measured using inductively coupled plasma mass spectrometry, and adjusted for urinary creatinine concentration. Among 3714 middle-aged American Indian participants of the Strong Heart Study (mean age 56 years, 41% male, 67% ever-smokers, 23% taking antihypertensive medications), urinary Cd ranged from 0.01 to 78.48 µg g-1 creatinine (geometric mean=0.94 µg g-1) and it was correlated with smoking pack-year among ever-smokers (r2=0.16, P<0.0001). Participants who were smokers were on average light-smokers (mean 10.8 pack-years), and urinary Cd was similarly elevated in light- and never-smokers (geometric means of 0.88 µg g-1 creatinine for both categories). Log-transformed urinary Cd was significantly associated with higher systolic blood pressure in models adjusted for age, sex, geographic area, body mass index, smoking (ever vs never, and cumulative pack-years) and kidney function (mean blood pressure difference by lnCd concentration (ß)=1.64, P=0.002). These associations were present among light- and never-smokers (ß=2.03, P=0.002, n=2627), although not significant among never-smokers (ß=1.22, P=0.18, n=1260). Cd was also associated with diastolic blood pressure among light- and never-smokers (ß=0.94, P=0.004). These findings suggest that there is a relationship between Cd body burden and increased blood pressure in American Indians, a population with increased cardiovascular disease risk.

Determination of bromide, bromate and other anions with ion chromatography and an inductively coupled plasma mass spectrometer as element-specific detector.

An implementation of the Dionex IonPac AS12A analytical column with an element-specific ICP-MS detection is described for the simultaneous determination of halogen and oxyhalogen anions, sulfate, phosphate, selenite, selenate and arsenate. The chromatographic separation was achieved in less than 4 min with an aqueous 11 mM (NH4)2CO3 (pH 11.2, adjusted with aqueous ammonia) as eluent. Special emphasis was given to optimize the ICP-MS detection conditions for the reliable detection (RSD<5%) of bromate and bromide at a bromine concentration level of 1.0 microg l(-1) with 50 microl sample injection volume. In order to achieve the highest detector response for bromine species an ultrasonic nebulizer equipped with a membrane desolvator had to be employed. The detection limits (S/N=3, sample injection volume 50 microl) obtained with the IC-ICP-MS after the optimization were 0.67 microg l(-1) for BrO3-, 0.47 microg l(-1) for Br-, 69 microg l(-1) for ClO2-, 4 microg l(-1) for Cl-, 47 microg l(-1) for ClO3-, 13 microg l(-1) for SO4(2-), 36 microg l(-1) for PO4(3-), 0.4 microg l(-1) for SeO3(2-), 0.3 microg l(-1) for SeO4(2-), and 0.4 microg l(-1) for AsO4(3-).

Selenium-enriched sprouts. A raw material for fortified cereal-based diets.

The selenium supply in almost all European countries, including Austria and Germany, is below the recommended daily intake. In these countries, selenium fortification of foods and the use of selenium supplements are quite popular to compensate for low Se intake from diets. In general, wheat (Triticum aestivum) is known to be a good source for bioavailable selenium, and many studies have been performed to enrich selenium in wheat by selenium fertilization of the soil. In the present work, the process of sprouting was investigated as an alternative to enrich selenium in wheat. Sprouting was chosen because it additionally improves the nutritional value of seeds, for example, by a higher vitamin content, a better quality of protein, and some other parameters. Wheat, alfalfa (Medicago sativa), and sunflower (Helianthus annuus) seeds were germinated for 5 and 7 days in solutions containing selenate. The selenium sensitivity of the sprouts was tested by measuring visible germination levels and seedling development. Uptake rates were studied by determination of total selenium using inductively coupled plasma mass spectrometry (ICP-MS). Metabolism of the absorbed selenium was analyzed by determination of selenium species in extracts of the sprouts using anion exchange HPLC coupled to ICP-MS. It was shown that sunflower sprouts were the most resistant and had the highest uptake rates (up to 900 mg/kg), but almost 100% of the selenium was extracted with water and found to be nonmetabolized selenate. Wheat and alfalfa were less resistant and enriched selenium up to concentrations of 100 and 150 mg of Se/kg of dry mass, respectively. The metabolism of the selenate was inversely related to the total uptake rates. At low Se enrichment (approximately 1-2 mg of Se/kg), <20% of the total selenium content within the sprouts remained as inorganic selenium, indicating a high metabolism rate. With increasing uptake the amount of selenate increased to approximately 40-50%. However, with the method used it is possible to produce sprouts containing certain amounts of selenium, which might provide substantial proportions of bioavailable selenium. In combination with the generally high nutritional value of sprouts, they might serve for production of improved cereal-based diets.

Uptake of arsenic-betaines by the mussel Mytilus edulis.

Mussels (Mytilus edulis) were exposed to trimethyl(carboxymethyl)arsonium bromide (arsenobetaine, C-1 betaine), trimethyl(2-carboxyethyl)arsonium bromide (C-2 betaine), or trimethyl(3-carboxypropyl)arsonium bromide (C-3 betaine). Arsenic was accumulated by the mussels in all cases but the efficiency of uptake decreased with the number of methylene units in the carboxyalkyl group. Arsenobetaine (C-1 betaine) was the most readily accumulated, followed by the C-2 betaine (70% as efficient as arsenobetaine) and the C-3 betaine (approximately 7%). Chromatographic analysis (HPLC-ICPMS) of extracts of the mussels demonstrated that the arsenic compounds were accumulated unchanged. A 46-day depuration period which followed exposure did not significantly reduce the arsenic concentration in any of the three groups. Comparison with previous data on accumulation of arsenic compounds by M. edulis indicates that uptake may be influenced by the presence of a quaternary arsonium group and the zwitterionic nature of the arsenic-betaines.

Occurrence of organo-arsenicals in jellyfishes and their mucus.

Water-soluble arsenic compound fractions were extracted from seven species of jellyfishes and subjected to analysis by high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) for arsenicals. A low content of arsenic was found to be the characteristic of jellyfish. Arsenobetaine (AB) was the major arsenic compound without exception in the tissues of the jellyfish species and mucus-blobs collected from some of them. Although the arsenic content in Beroe cucumis, which preys on Bolinopsis mikado, was more than 13 times that in B. mikado, the chromatograms of these two species were similar in the distribution pattern of arsenicals. The nine species of jellyfishes including two species treated in the previous paper can be classified into arsenocholine (AC)-rich and AC-poor species. Jellyfishes belonging to Semaostamae were classified as AC-rich species.

Arsenic biotransformation by the brown macroalga, Fucus serratus.

The brown alga Fucus serratus was maintained in aquaria with added arsenate (0, 20, 50, and 100 microg As/L, four individuals per treatment) for up to 19 weeks. Biotransformation of arsenic by Fucus was monitored by high-performance liquid chromatography/inductively coupled plasma mass spectrometry and liquid chromatography/electrospray mass spectrometry analysis of aqueous extracts of algal frond tips removed periodically throughout the experiment. Major arsenic species monitored were arsenate, arsenite, methylarsonate, dimethylarsinate, and the four arsenosugars 1 to 4 found naturally in Fucus. Algae accumulated arsenate readily and transformed it into several arsenic compounds depending on the exposure concentration. At 100 microg As/L, the major metabolite was arsenite with smaller quantities of methylarsonate and dimethylarsinate, but only traces of arsenosugars were formed. In contrast, the 20-microg-As/L group accumulated only small quantities of arsenite and methylarsonate, while dimethylarsinate and arsenosugars were major arsenic metabolites. At 50 microg As/L exposure, algae had significant quantities of all arsenic metabolites monitored. Arsenate was toxic to the algae at 100 microg As/L but had no obvious detrimental effect at 20 microg As/L. The data are consistent with a process of arsenate detoxification by reduction and alkylation; at higher exposures, however, the alkylation processes become saturated, leading to an accumulation of arsenite and subsequent toxicity.

Pleural effusions and sera from patients with benign or malignant diseases.

In pleural effusions and sera from 66 patients copper and zinc were quantified by inductively coupled argon plasma-mass spectrometry after mineralizations in a closed-pressurized microwave unit with a mixture of concentrated nitric acid and 30% hydrogen peroxide. Total protein, pH, leukocyte count, lactate dehydrogenase, glucose, C-reactive protein, ceruloplasmin, and alpha1-antitrypsin were determined in many of the effusions. All but four effusions had concentrations of copper (range 58-1720 microg/kg) and zinc (range 27-1001 microg/kg) that were lower than the concentrations in the corresponding sera. Very high concentrations of zinc (1930-6470 microg/kg) were characteristic for thoracic empyemata. In the scatterplots of serum copper versus effusion copper, serum zinc versus effusion zinc, and serum copper/effusion copper versus serum zinc/effusion zinc no clearly delineated regions were noticeably useful for identifying malignant effusions. Similar plots of the concentrations of copper or zinc versus the eight clinical laboratory parameters or plots of clinical parameter versus clinical parameter failed to be of diagnostic value. Statistically highly significant correlations (p < or = 0.05, n > 45, r2 > 0.25) were observed for 9 of 28 pairs of the clinical parameters, for total protein and copper in the effusions and zinc in the effusions and for ceruloplasmin and copper in the effusions. Among the patients suffering from benign or malignant effusions, 52% had zinc concentrations in the sera below the low limit of the normal range (600 microg/kg). Supplementation of such patients with zinc should be considered.

Concentrations of copper, zinc, manganese, rubidium, and magnesium in thoracic empyemata and corresponding sera.

In this study, a number of selected trace elements and clinically relevant parameters were compared between thoracic empyemata and the corresponding sera for a better understanding of the trace element distribution between these two compartments. Serumempyema pairs were obtained from 13 patients and quantified for selected and essential trace elements, namely copper (Cu), zinc (Zn), manganese (Mn), rubidium (Rb), and magnesium (Mg), by inductively coupled plasma-mass spectrometry (ICP-MS). In addition, the concentrations of the following clinical laboratory parameters were analyzed by standard methods: total protein, leukocyte count, lactate dehydrogenase, glucose, pH, and the C-reactive protein. Individual concentrations of the elements determined in the empyemata were frequently higher than in pleural effusions of any other benign or malignant condition except for Cu. Serum Cu exceeded the normal range (600-1400 microg/kg) in 6 out of 13 patients (median 1410 microg/kg). In the empyemata, Zn concentrations (median 2000 microg/kg) were characteristically higher than in the sera (median 450 microg/kg) and exceeded the upper limit for serum (1200 microg/kg) in 8 of the 13 patients. Manganese concentrations in the empyemata (median 2.7 microg/kg) were also higher compared to corresponding sera, although they stayed within the limits considered normal for serum of healthy adults (upper limit 2.9 microg/kg). Rubidium was also moderately higher in most empyemata (median 290 microg/kg) and exceeded the upper limit for serum (560 microg/kg) in two patients. The median concentration of the essential element magnesium was higher in the empyemata (23 mg/kg) than in the sera (21 mg/kg). However, all serum Mg concentrations except three remained within the normal range (17-22 mg/kg). Removal of large amounts of empyematous fluid may deprive the body of trace elements and can cause suboptimal or deficient trace element status and homeostasis. Recuperation will be accelerated by compensatory supplementation of trace elements. Therefore, selective medication with adequate trace element compounds in patients with thoracic empyema can be generally recommended for zinc. The other elements need not necessarily be monitored or substituted, because of their stable concentrations in the serum. Rb may have a biological impact, but deficiency symptoms in man are not clearly defined.

Antimony leaching from cot mattresses and sudden infant death syndrome (SIDS).

1. Polyvinyl chloride (PVC) cot mattress covers from SIDS cases were investigated as potential sources of soluble (potentially ingestable) antimony in the cot environment. 2. Body fluids (urine, saliva) and proprietary domestic detergents/sterilizing fluids markedly enhanced leaching of antimony from PVC. Release of antimony was also enhanced at both low and high pH and by elevated temperature. The extent of antimony leaching did not correlate well with PVC content of this element. 3. These data do not support the assumption that postmortem analysis of antimony content proves exposure to gaseous antimony trihydride from mattress PVC. 4. Ingestion of antimony released from PVC could account for the high variability associated with reported detectable levels of antimony in liver from both SIDS and other infants. It could also explain suspected additional postnatal exposure to this element, which gives rise to elevated levels of Sb in the hair of some healthy infants.

Biovolatilization of antimony and sudden infant death syndrome (SIDS).

1. The aerobic filamentous fungus S. brevicaulis IMI 17297 methylated antimony from Sb2O3 substrate, with the formation of gaseous trimethylantimony (TMA). No evidence was found for the generation of other gaseous antimony compounds by this organism. 2. Biovolatilization of inorganic antimony was greatest during cultivation of the fungus on solid media at 25 degrees C, and occurred more readily from antimony (III) substrates than from antimony (V) substrates. 3. Under simulated cot environment conditions (CO2 enriched atmosphere, 33 degrees C) the fungus exhibited an altered morphology and a reduced capability to volatilize inorganic antimony from the pure compound. 4. No evidence of antimony biovolatilization from cot mattress PVC was found, unless antimony was released from PVC by heat treatment (at 80 or 100 degrees C). 5. These data suggest that normal cot environment conditions are non-optimal for volatilization of antimony by S. brevicaulis, and that Sb2O3 in cot mattress PVC is not bioavailable. 6. Cot mattress isolates of S. brevicaulis also volatilized antimony (not encapsulated by PVC), whereas those of other filamentous fungi (Penicillium spp., Aspergillus niger, Aspergillus fumigatus, Alternaria sp.) and of bacteria (Bacillus spp.) did not. 7. The oxidation products of TMA may be the true determinants of toxicity for biogenic antimony gases produced in an aerobic environment.

Evaluation of cot mattress inner foam as a potential site for microbial generation of toxic gases.

Recent reports of biovolatilisation of phosphorus and antimony by anaerobic bacteria and of leaching of phosphorus and antimony fire-retardant additives from PVC cot mattress covers, indicate that the polyurethane inner-foam of cot mattresses could be a site for generation of toxic gases of group 15 elements. A toxic gas hypothesis for sudden infant death syndrome (SIDS) involving polyurethane foam of cot mattresses was proposed and tested experimentally. Levels of antimony, phosphorus, arsenic and bismuth were determined at four sites for 44 SIDS and 50 control (no death) cot mattress foams. There was no evidence to suggest that the levels of these elements in cot mattress foam have a causal relation to SIDS. Leaching of antimony trioxide from PVC mattress covers could account for detectable levels of this element in 52% of the cot mattress samples analysed. Volatile forms of antimony, phosphorus, arsenic and bismuth was not detected in the headspace of mixed or monoseptic cultures of anaerobic bacteria containing polyurethane foam. Past microbial activity had given rise to involatile methylated species of antimony in some of the cot mattress foams tested (61%, n = 24). Abiotic oxidation of biogenic trimethylantimony together with physical adsorption of methylantimony forms to the polyurethane foam matrix could account for the apparent absence of "escaped" volatile antimony species in culture headspaces of incubation vial. There was no evidence to suggest that levels of trimethylantimony or total methylantimony forms in cot mattress foams have a causal relation to SIDS.

Milk consumption, smoking and lead concentration in human hair.

Trace elements in hair samples were examined in 79 medical and sports students in Vienna and 77 biology students in Rome (ages 19-31 years). Lead concentration was determined by inductively coupled plasma mass spectrometry. The effect of smoking on lead levels is confirmed. Those who consume milk and dairy products daily show a lower lead concentration than those who consume them occasionally, both overall and in smokers and non-smokers. The effects of milk consumption and smoking appear to be independent. It seems that smokers may not enjoy the protective effect of milk consumption to the same extent as non smokers.

Urinary excretion of arsenicals following daily intake of various seafoods during a two weeks intervention.

The excretion pattern of arsenic (As) species after seafood intake varies widely depending on species ingested and individual handling. We have previously reported the 72 h urinary excretion of arsenicals following a single dose of seafood. Here, we report the excretion patterns in the same 37 subjects following 15 days daily consumption of either 150 g cod, salmon, blue mussels or potato (control), followed by a 72 h period with a low-As diet. In all seafood groups, total As (tAs) in plasma and urinary excretion of tAs, arsenobetaine (AB) and dimethylarsinate (DMA) increased significantly after the intervention. Confirming the single dose study AB and DMA excreted were apparently endogenously formed from other arsenicals ingested. Total tAs excretion was 1386, 763 and 303 µg in the cod, blue mussel and salmon groups, respectively; about twice the amounts after the single dose study indicating accumulation of arsenicals. In the cod group, rapid excretion after the single dose was associated with lower total As in blood and less accumulation after two weeks with seafood indicating lower accumulation. In the blue mussels group only, inorganic As (iAs) excretion increased significantly, whilst methylarsonate (MA) strongly increased, indicating a possible toxicological concern of repeated mussel consumption.

Argyria following the use of silver-coated megaprostheses: no association between the development of local argyria and elevated silver levels.

The aims of this study were to evaluate the incidence of local argyria in patients with silver-coated megaprostheses and to identify a possible association between argyria and elevated levels of silver both locally and in the blood. Between 2004 and 2011, 32 megaprostheses with silver coatings were implanted in 20 female and 12 male patients following revision arthroplasty for infection or resection of a malignant tumour, and the levels of silver locally in drains and seromas and in the blood were determined. The mean age of the patients was 46 years (10 to 81); one patient died in the immediate post-operative period and was excluded. Seven patients (23%) developed local argyria after a median of 25.7 months (interquartile range 2 to 44.5). Patients with and without local argyria had comparable levels of silver in the blood and aspiration fluids. The length of the implant did not influence the development of local argyria. Patients with clinical evidence of local argyria had no neurological symptoms and no evidence of renal or hepatic failure. Thus, we conclude that the short-term surveillance of blood silver levels in these patients is not required.

Major and minor arsenic compounds accounting for the total urinary excretion of arsenic following intake of blue mussels (Mytilus edulis): a controlled human study.

Blue mussels (Mytilus edulis) accumulate and biotransform arsenic (As) to a larger variety of arsenicals than most seafood. Eight volunteers ingested a test meal consisting of 150 g blue mussel (680 µg As), followed by 72 h with an identical, low As controlled diet and full urine sampling. We provide a complete speciation, with individual patterns, of urinary As excretion. Total As (tAs) urinary excretion was 328 ± 47 µg, whereof arsenobetaine (AB) and dimethylarsinate (DMA) accounted for 66% and 21%, respectively. Fifteen minor urinary arsenicals were quantified with inductively coupled plasma mass spectrometry (ICPMS) coupled to reverse-phase, anion and cation-exchange high performance liquid chromatography (HPLC). Thio-arsenicals and non-thio minor arsenicals (including inorganic As (iAs) and methylarsonate (MA)) contributed 10% and 7% of the total sum of species excretion, respectively, but there were large individual differences in the excretion patterns. Apparently, formation of thio-arsenicals was negatively correlated to AB formation and excretion, possibly indicating a metabolic interrelationship. The results may be of toxicological relevance since DMA and MA have been classified as possibly carcinogenic, and six of the excreted As species were thio-arsenicals which recently have been recognized as toxic, while iAs toxicity is well known.

Mobility of arsenic and its compounds in soil and soil solution: the effect of soil pretreatment and extraction methods.

The effect of soil extraction procedures and/or sample pretreatment (drying, freezing of the soil sample) on the extractability of arsenic and its compounds was tested. In the first part, five extraction procedures were compared with following order of extractable arsenic portions: 2M HNO(3)>>0.43 M CH(3)COOH>or=0.05 M EDTA>or=Mehlich III (0.2M CH(3)COOH+0.25 M NH(4)NO(3)+0.013 M HNO(3)+0.015 M NH(4)F+0.001 M EDTA) extraction>>water). Additionally, two methods of soil solution sampling were compared, centrifugation of saturated soil and the use of suction cups. The results showed that different sample pretreatments including soil solution sampling could lead to different absolute values of mobile arsenic content in soils. However, the interpretation of the data can lead to similar conclusions as apparent from the comparison of the soil solution sampling methods (r=0.79). For determination of arsenic compounds mild extraction procedures (0.05 M (NH(4))(2)SO(4), 0.01 M CaCl(2), and water) and soil solution sampling using suction cups were compared. Regarding the real soil conditions the extraction of fresh samples and/or in situ collection of soil solution are preferred among the sample pretreatments and/or soil extraction procedures. However, chemical stabilization of the solutions should be allowed and included in the analytical procedures for determination of individual arsenic compounds.

Adult-type hypolactasia and calcium availability: decreased calcium intake or impaired calcium absorption?

UNLABELLED: Adult-type hypolactasia, as mediated by a widespread genetic predisposition, not only reduces calcium intake but also calcium absorption in the presence of high amounts of lactose and may, therefore, promote osteoporosis. A lactose-reduced diet and lactose-free calcium supplements may reverse this imbalance. INTRODUCTION AND HYPOTHESIS: Adult-type hypolactasia (HL) defined by the LCT(-13910) polymorphism may reduce calcium intake by reducing dairy consumption and, therefore, promote osteoporosis. This study aimed to evaluate whether lactose also decreases intestinal calcium absorption in subjects with HL and whether lactose-reduced diet and lactose-free calcium supplementation as recommended could maintain bone mineral density (BMD). METHODS: Based on LCT genotyping, 73 postmenopausal women with and without HL underwent a conventional H(2) breath test with a concomitant oral strontium absorption test lasting 150 minutes, which closely reflects intestinal calcium absorption. In addition, we compared bone-specific laboratory parameters, lumbar and femoral BMD, and spinal radiographs to a similar bone assessment 5 years earlier. RESULTS: LCT genotyping and functional lactose malabsorption tests were highly correlated. Dairy product consumption was reduced by 80% in HL individuals. During concomitant lactose application, mean strontium absorption was blunted by 54% in HL subjects after 150 minutes (1272 +/- 629 microg/L vs. 2020 +/- 1130 microg/L in lactose tolerant subjects, p=0.001). Nevertheless, BMD in HL subjects remained stable with lactose-free calcium supplements during the observation period. CONCLUSION: Both decreased calcium intake as well as lactose-associated impaired calcium absorption may predispose subjects with HL to osteoporosis. Lactose-free calcium supplementation may help to maintain BMD in HL subjects.