Effect of cadmium on the accumulation of arsenic in a marine green alga,Dunaliellasp.

To investigate the effect of cadmium on the accumulation of arsenic by Dunaliella sp., the arsenic accumulated in the alga was determined as a function of time for coexistence of the algae with arsenic and cadmium, with batch methodology. Growth of Dunaliella sp. was affected by addition of arsenic (Na₂HAsO₄.7H₂O) and cadmium (CdCl.2.5H₂O). Growth inhibition of Dunaliella sp. was accelerated by coexistence of arsenic and cadmium. The content of arsenic in Dunaliella sp. became a maximum at 15 h after exposure. The arsenic content in the cells was influenced by addition of cadmium to the solution; the arsenic content in the alga derived from growth in a 10 mg As dm ^?3 solution decreased from 2.7 mg g^?1 in the absence of cadmium to 0.35 mg g^?1 for the addition of 100 mg Cd dm^?3. Dunaliella sp. accumulated cadmium in large quantities but, in conditions of coexistence with arsenic and cadmium, the cadmium content in cells decreased with an increase in the concentration of arsenic in the growth medium Cadmium accumulation by Dunaliella sp. was observed in dead cells although arsenic accumulation was not observed. About 85% of arsenic in the cells was in the water-soluble fraction. On the other hand, about 42% of cadmium in the cells was in the water-soluble fraction, and about 55% was in a fraction soluble in cold trichloroacetic acid.     

Speciation analysis to unravel the soil-to-plant transfer in highly arsenic-contaminated areas in Cornwall (UK)

Two areas near derelict calciners in Cornwall (UK) were chosen to study the uptake of arsenic from arsenic-contaminated soil into indigenous plants (heather, Calluna vulgaris; blackberry, Rubus ulmifulmus; gorse, Ulex europaeus). With total arsenic concentrations in soil ranging from 1240 to 2860 mg kg^?1 at Site 1 (Tuckingmill), no adverse effects on the growth of the plants studied were observed. Very low soil-to-plant transfer factors (0.01 to 0.03) were found although they were much higher when the extractable soil arsenic concentrations were taken into account (0.1 to 1.1). In the central dump area at Site 2 (Bissoe, 9.78% [w/w] arsenic in soil), the only plant to grow was heather, although it was severely impaired. However, heather was thriving at the edge of the dump where higher soil arsenic concentrations were found (10.32% [w/w]), indicating that arsenic is not a growth-limiting factor in itself. Soil-to-plant transfer factors in the range 2 × 10^?5–9 × 10^?4 confirm that arsenic is indeed effectively excluded from uptake, even taking into account extractable soil arsenic concentrations (9 × 10^?4–1.2 × 10^?2).

Extraction of bioavailable arsenic from soil using 0.05 mol L^?1 ammonium sulphate yielded recoveries from 1.18 to 3.34% of the total arsenic, predominantly in the form of arsenate. Extraction of arsenic and its metabolites from plants was achieved with water or a water/methanol mixture yielding recoveries up to 22.4% of the total arsenic, with arsenite and arsenate the predominant arsenic species and a minor fraction consisting of methylarsonic acid, dimethylarsinic acid and trimethylarsine oxide. The identity of the remainder of the non-extractable arsenic species still has to be revealed. Although the data suggest that higher plants synthesise organoarsenic compounds it cannot be excluded that symbiotic organisms have synthesised these compounds.     

Selective substoichiometry for inorganic arsenic(V) by ion-pair extraction with pyrogallol/tetraphenyl-arsnium chloride and its application in the analysis of seaweed

Arsenic(V) is substioichiometrically extracted from 0.4–3 M sulfuric acid solutions into 1,2-dichloroethane with 1.0 × 10^?5 M teraphenylarsnium chloride in the presence of 2.0 × 10^?1 M pyrogallol. Reproducibility of the substoichiometric extractions with a constant amount of tetraphenylarsonium chloride is high (0.5% RSD). This substiochiometric extraction is very selective for arsenic(V) from arsenic(III), monomethylarsonic acid, and dimethylarsinic acid. The extraction combined with the isotope dilution principle was applied to the determination of arsenic(V) in an acid-digestd solution of a seaweed sample (Laminaria religiosa Miyabe) and to the determination of total arsenic in this sample.     

Determination of arsenic and arsenic compounds in natural gas samples

Organic arsenic compounds (trialkylarsines) present in natural gas were extracted by 10 cm³ of concentrated nitric acid from 1 dm³ of gas kept at ambient pressure and temperature. The flask containing the gas and the acid was shaken for 1 h on a platform shaker set at the highest speed. The resulting solution was mixed with concentrated sulfuric acid and heated to convert all arsenic compounds to arsenate. Total arsenic was determined in the mineralized solutions by hydride generation. The arsenic concentrations in natural gas samples from a number of wells in several gas fields were in the range 0.01–63 μ As dm^?3. Replicate determinations of arsenic in a gas sample with an arsenic concentration of 5.9 μ dm^?3 had a relative standard deviation of 1.7%. Because of the high blank values, the lowest arsenic concentration that could be reliably determined was 5 ng As dm^?3 gas. Analysis of nonmineralized extracts by hydride generation identified trimethylarsine as the major arsenic compound in natural gas. Low-temperature gas chromatography-mass spectrometry showed more directly than the hydride generation technique, that trimethylarsine accounts for 55–80% of the total arsenic in several gas samples. Dimethylethylarsine, methyldiethylarsine, and triethylarsine were also identified, in concentrations decreasing with increasing molecular mass of the arsines.     

Determination of arsenic in steel and cast iron by hydride-generation atomic absorption spectrometry

A procedure is described for the determination of arsenic in steel and cast iron by atomic absorption spectrometry after hydride generation with sodium tetrahydroborate. The samples are decomposed with a nitric/perchloric acid mixture. The data are evaluated directly against acidic standard solutions of arsenic(V). The limit of detection is about 1 μg g^?1 and the precision is better than 4% for concentrations exceeding 10 μg g^?1.     

Distribution and cycle of arsenic compounds in the ocean

In order to understand the distribution and the cycle of arsenic compounds in the marine environment, the horizontal distributions of arsenic(V) [As(V)], arsenic(III) [As(III)], monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA) in the Indian Pacific Oceanic surface waters have been investigated. This took place during cruises of the boat Shirase from Tokyo to the Syowa Station (15 November–19 December 1990), of the tanker Japan Violet from Sakai to Fujayrah (28 July–17 August 1991) and of the boat Hakuho-maru from Tokyo to Auckland (19 September–27 October 1992). Vertical distributions of arsenic in the west Pacific Ocean have also been investigated. The concentration of As(V) was found to be relatively higher in the Antarctic than in the other areas. Its concentration varied from 340 ng dm^?3 (China Sea) to 1045 ng dm^?3 (Antarctic). On the other hand, the concentrations of the biologically produced species, MMAA and DMAA, were extremely low in the Antarctic and southwest Pacific waters. Their concentrations in Antarctic waters were 8 ng dm^?3 and 22 ng dm^?3 and those in the southwest Pacific were 12 ng dm^?3 and 25 ng dm^?3. In the other regions the concentration varied from 16 ng dm^?3 (China Sea) to 36 ng dm^?3 (north Indian Ocean) for MMAA and from 50 ng dm^?3 (east Indian Ocean) to 172 ng dm^?3 (north Indian Ocean) for DMAA. As a result, with the exception of Antarctic and southwest Pacific waters, the percentages of each arsenic species in the surface waters were very similar and varied from 52% (east Indian Ocean) to 63% (northwest Pacific Ocean) for As(V), from 22% (northwest Pacific Ocean) to 27% (east Indian Ocean) for As(III) and from 15% (northwest Pacific Ocean) to 21% (north and east Indian Oceans) for the methylated arsenics (MMAA+DMAA). These percentages in Antarctic waters were 97%, 0.2% and 2.8%, respectively, and those in the southwest Pacific Ocean were 97% for As(V)+As(III) and 3% for MMAA+DMAA. The very low concentrations of the biologically produced species in Antarctic waters and that of methylated arsenic in southwest Pacific waters indicated that the microorganism communities in these oceans was dominated by microorganisms having a low affinity towards arsenic. Furthermore, microorganism activity in the Antarctic was also limited due to the much lower temperature of the seawater there. The vertical profile of inorganic arsenic was 1350 ng dm^?3 in surface waters, 1500 ng dm^?3 in bottom waters with a maximum value of 1700 ng dm^?3 at a depth of about 2000 m in west Pacific waters. This fact suggested the uptake of arsenic by microorganisms in the surface waters and the co-precipitation of arsenic with hydrated heavy-metal oxides in bottom waters. The suggested uptake of inorganic arsenic and subsequent methylation was also supported by the profile of DMAA, with a high concentration of about 26 ng dm^?3 in surface water and a significant decrease to a value of 9 ng dm^?3 at a depth of 1000 m.     

Biomethylation and biotransformation of arsenic in a freshwater food chain: Green alga (chlorella vulgaris)→shrimp (neocaridina denticulata)→killifish (oryzias iatipes)

Tolerance, bioaccumulation, biotransformation and excretion of arsenic compounds by the fresh–water shrimp (Neocaridina denticulata) and the killifish (Oryzias latipes) (collected from the natural environment) were investigated. Tolerances (LC₅₀) of the shrimp against disodium arsenate [abbreviated as As(V)], methylarsonic acid (MAA), dimethylarsinic acid (DMAA), and arsenobetaine (AB) were 1.5, 10, 40, and 150μg As ml^?1, respectively. N. denticulata accumulated arsenic from an aqueous phase containing 1 μg As ml^?1 of As(V), 10 μg As ml^?1 of MAA, 30 μg As ml^?1 of DMAA or 150 μg As ml^?1 of AB, and biotransformed and excreted part of these species. Both methylation and demethylation of the arsenicals were observed in vivo. When living N. denticulata accumulating arsenic was transferred into an arsenic–free medium, a part of the accumulated arsenic was excreted. The concentration of methylated arsenicals relative to total arsenic was higher in the excrement than in the organism. Total arsenic accumulation in each species via food in the food chain Green algae (Chlorella vulgaris) → shrimp (N. denticulata) → killifish (O. latipes) decreased by one order of magnitude or more, and the concentration of methylated arsenic relative to total arsenic accumulated increased successively with elevation in the trophic level. Only trace amounts of monomethylarsenic species were detected in the shrimp and fish tested. Dimethylarsenic species in alga and shrimp, and trimethylarsenic species in killifish, were the predominant methylated arsenic species, respectively.     

Determination of arsenic by hydride generation with a long absorption cell for atomic absorption spectrometry

A method is described for the determination of arsenic involving hydride generation and atomic absorption spectrometry with an improved long graphite-tube furnace capable of considerably higher temperatures than the conventional quartz-tube heaters. Arsine is generated with sodium tetrahydroborate, held in a nitrogen-cooled trap and then swept with helium into an alumina tube (19 cm long) placed within the graphite furnace. The optimum conditions for determination of arsenic are given. The detection limit is 0.2 ng ml^?1 with RSD of 2–3%. Results for various NBS Standard Reference Materials agreed well with expected values and were as follows: orchard leaves, 10 ± 1 μg g^?1; tomato leaves, 0.28 ± 0.03 μg g^?1; bovine liver, 0.046 ± 0.005 μg g^?1.     

A New Spectrophotometric Method for the Determination of Arsenic in Environmental and Biological Samples

Abstract

A simple and selective spectrophotometric method has been developed for the determination of trace amounts of arsenic using azure B as a chromogenic reagent. The proposed method is based on the reaction of arsenic(III) with potassium iodate in acid medium to liberate iodine. The liberated iodine bleaches the violet color of azure B and is measured at 644 nm. This decrease in absorbance is directly proportional to the As(III) concentration, and Beer's law is obeyed in the range 0.2–10 µg ml^?1 of As(III). The molar absorptivity, Sandell's sensitivity, detection limit, and quantitation limit of the method were found to be 1.12×10⁴ l mol^?1cm^?1, 6.71×10^?3 µg cm^?2, 0.02 µg ml^?1 and 0.08 µg ml^?1, respectively. The optimum reaction conditions and other analytical parameters were evaluated. The proposed method has been successfully applied for the determination of arsenic in various environmental and biological samples.     

Differential preconcentration of arsenic(III) and arsenic(V) with thionalide loaded on silica gel

2-Mercapto-N-2-naphtylacetamide (thionalide) on silica gel is used for differential preconcentration of μg l^?1 levels of arsenic(III) and arsenic(V) from aqueous solution. In batch experiments, arsenic(III) was quantitatively retained on the gel from solutions of pH 6.5–8.5, but arsenic(V) and organic arsenic compounds were not retained. The chelating capacity of the gel was 5.6 μmol g^?1 As(III) at pH 7.0. Arsenic retained on teh column was completely eluted with 25 ml of 0.01 M sodium borate in 0.01 M sodium hydroxide containing 10 mg l^?1 iodine (pH 10). The arsenic was determined by silver diethyldithiocarbamate spectrophotometry. Arsenic(V) was subsequently determined after reduction to arsenic(III) with sulphite and iodide. Arsenic(III) and arsenic(V) in sea water are shown to be < 0.12 and 1.6 μg l^?1, respectively.     

Observations on toxicologically relevant arsenic in urine in adult offspring of families with Balkan Endemic Nephropathy and controls by batch hydride generation atomic absorption spectrometry

The aim of this study was to develop a method for the characterization of internal exposure to arsenic, which is thought to play a role in the development of a kidney disease, known as Balkan Endemic Nephropathy, typical for a district in Bulgaria, and to investigate whether the As body burden differs in the offspring versus control individuals. For this case study, an analytical procedure for the determination of toxicologically relevant arsenic (the sum of arsenite, arsenate, monomethylarsonate, and dimethylarsinate) in urine by batch-type hydride generation atomic absorption spectrometry was developed. Optimization experiments for levelling off the sensitivity of inorganic arsenic and its mono- and dimethylated species in dilute HCl–L-cysteine medium were performed. The limit of detection for hydride forming arsenic fraction was 0.5?ng As, i.e. 0.25?µg?L^?1 in 10?mL of 1?+?4 v/v diluted urine. The relative standard deviation was typically 1.5–1.8% for aqueous solution and 2–6% for urine samples at 1.0?µg?L^?1 As. The sample throughput rate was 15?h^?1. No statistical correlation and cross-correlation between individuals case-control and sex at 95% confidence were found: controls (n?=?99), mean 3.5?±?2.1 (SD), range 0.9–10.4, median 3.0?µg?L^?1 As and cases (n?=?102), mean 3.6?±?2.2 (SD), range 0.5–11.0, median 3.2?µg?L^?1 As. On the basis of this study, arsenic can be excluded as a factor involved in BEN development.     

Highly sensitive inhibitory kinetics fluorescence method for determination of arsenic

A new and highly sensitive inhibitory kinetic fluorescence method for the determination of arsenic (III) has been established based on its inhibitory effect on the oxidation reaction of Acridine red (ADR) by KBrO₃ in sulphuric acid medium. The reaction has been followed by measuring the enhancement of fluorescence at 550?nm. It relies on the linear relationship where the change in the fluorescence (ΔF) versus added As(III) amounts in the range of 0–0.450?µg?mL^?1 is plotted, under the optimum conditions. The sensitivity of the proposed method, i.e. the limit of detection, is 2.1?×?10^?2?ng?mL^?1. The method is featured with good accuracy and reproducibility for arsenic (III) determination. This method was successfully applied for the quantitative determination of arsenic (III) in food products samples, and the relative standard deviations and the recoveries were in ranges of 2.31–2.83% and 90.0–107.2%, respectively. A review of recently published catalytic or inhibiting kinetic methods for the determination of arsenic (III) has also been presented for comparison. The mechanism of reaction was studied.     

The lon-chromatographic behavior of arsenite,arsenate, methylarsonic acid and dimethylarsinic acid on the hamilton PRP-X100 anion-exchange column

The HPLC separation of arsenite, arsenate, methylarsonic acid and dimethylarsinic acid has been studied in the past but not in a systematic manner. The dependence of the retention times of these arsenic compounds on the pH of the mobile phase, on the concentration and the chemical composition of buffer solutions (phosphate, acetate, potassium hydrogen phthalate) and on the presence of sodium sulfate or nickel sulfate in the mobile phase was investigated using a Hamilton PRP-X100 anion-exchange column. With a flame atomic absorption detector and arsenic concentrations of at least 10 mg dm^?3 all investigated mobile phases will separate the four arsenic compounds at appropriate pH values in the range 4–8. The shortest analysis time (?3 min) was achieved with a 0.006 mol dm^?3 potassium hydrogen phthalate mobile phase at pH 4, the longest (?10 min) with 0.006 mol dm^?3 sodium sulfate at pH 5.9 at a flow rate of 1.5 cm³ min^?1. With a graphite furnace atomic absorption detector at the required, much lower, flow rate of ?0.2 cm³ min^?1 acceptable separations were achievable only with the pH 6 phosphate buffer (0.03 mol dm^?3) and the nickel sulfate solution (0.005 mol dm^?3) as the mobile phase. To become detectable approximately 100 ng arsenic from each arsenic compound (100 μl injection) must be chromatographed with the phosphate buffer, and approximately 10 ng with the nickel sulfate solution.     

Determination of arsenic at the picogram level by atomic absorption spectrometry with miniaturized suction-flow hydride generation

A continuous-flow hydride generator is modified and miniaturized for the determination of picogram amounts of arsenic by atomic absorption spectrometry. A 300-μl sample is dropped into a teflon cup and pumped into an alkaline sodium tetrahydroborate stream, which is acidified in a reaction coil. The evolved hydride is swept with argon through a phase separator into an electrically-heated quartz absorption cell and the absorbance is recorded. To eliminate differences in sensitivity between arsenic(III) and arsenic(V) without prereduction by potassium iodide, it is important that arsenic(V) be mixed with tetrahydroborate prior to mixing with hydrochloric acid. The method has a detection limit of 0.08 ng As ml^?1 (24 pg) and the calibrations is linear up to 50 ng As ml^?1. The relative standard deviation for 10 replicate measurements is 5.4% for 0.5 ng As ml^?1. The addition of potassium iodide and hydroxylamine is confirmed to be effective in minimizing some interferences. The sampling rate is 90 h^?1. Results for NBS biological and steel reference materials demonstrate applicability of the technique.     

Speciation of Arsenic in Environmental and Biological Samples

A novel arsine generator glass assembly is constructed and reported for the spectrophotometric determination and speciation of arsenic in real samples. In an arsine generator, sodium borohydride is added dropwise to the acidic sample solution and arsine thus formed is reacted with silver diethyldithiocarbamate (Ag‐DDTC) ‐ Tritron‐X (TX‐100) solution in pyridine to form a red coloured complex. The complex showed the absorption maximum at λ_max 540 nm. The molar absorptivity of the method was found to be (1.55) × 10⁴ L mole^?1 cm^?1 at this wavelength. The presence of non‐ionic surfactant, i.e. TX‐100 in the Ag‐DDTC solution, makes the method ≈ 3 times more sensitive than the conventional Ag‐DDTC method. Beer's law is obeyed in the concentration range of 0.05–2.80 mg L^?1 of arsenic. The detection limit of the method was calculated to be 20 μg L^?1 As. Speciation of arsenite from other forms of arsenic in sample solutions was carried out by extraction of arsenite with Pb‐DDTC in chloroform, followed by spectrophotometric determination. After arsenite separation the sample is used for the arsenate determination. Total arsenic was determined by acid decomposition of the same sample. The speciation data were found to be comparable (±2%) with ICP‐MS, with better precision (< 1%). The method has been successfully applied for the speciation of arsenic in drinking water and dust samples of arsenic affecting the Rajnandgaon district of Chhattisgarh, India, and urine and blood samples of patients with arsenical diseases. Concentration of total arsenic in tube‐well water of this area was 3–6 times more than the permissible limit. Dust samples contained less amounts of arsenic than the ground water.     

Distribution of arsenic species in the freshwater crustacean Procambarus clarkii

The concentrations of total arsenic and arsenic species in the complete organism of the crayfish Procambarus clarkii and its various parts (hepatopancreas, tail, and remaining parts) were analyzed in order to discover the distribution of arsenic and its species. With this information it will be possible to establish where the chemical forms of this metalloid tend to accumulate and what risks may derive from the contents and species present in the edible parts of this crustacean. The total arsenic content in the complete organism and in the various parts analyzed ranged from 2.5 to 12 µg g^?1 dry mass (DM), with inorganic arsenic representing 18 to 34% of total arsenic. The arsenical composition varied according to the part of the crayfish considered. The hepatopancreas had the highest levels of total arsenic (9.2–12 µg g^?1 DM) and inorganic arsenic (2.7–3.2 µg g^?1 DM). The tail (edible part) had the lowest levels of both total arsenic (2.5–2.6 µg g^?1 DM) and inorganic arsenic (0.46–0.64 µg g^?1 DM). The predominant organoarsenical species were the dimethylarsinoylribosides: glycerol riboside in the hepatopancreas, sulfate riboside in the tail, and sulfonate and phosphate ribosides in the remaining parts. Copyright © 2002 John Wiley & Sons, Ltd.     

Biotransformation of arsenate to arsenosugars by Chlorella vulgaris

Chlorella vulgaris was cultivated in a growth medium containing arsenate concentration of <0.01, 10, 100 and 1000 mg l^?1. Illumination was carried out in 12 h cycles for 5 days. The health status of the culture was monitored by continuous pH and dissolved oxygen (DO) readings. Destructive sampling was used for the determination of biomass, chlorophyll, total arsenic and arsenic species. The chlorophyll a content, the DO and pH cycles were not significantly different for the different arsenate concentrations in the culture. In contrast, biomass production was significantly (p < 0.05) increased for the arsenic(V) treatment at 1000 mg l^?1 compared with 100 mg l^?1. The arsenic concentration in the algae increased with the arsenate concentration in the culture. However, the bioconcentration factor decreased a hundred‐fold with increase of arsenate from the background level to 1000 mg l^?1. The arsenic species were identified by using strong anion‐exchange high‐performance liquid chromatography–inductively coupled plasma mass spectrometry analysis after methanol/water (1 : 1) extraction. The majority (87–100%) of the extractable arsenic was still arsenate; arsenite was found to be between 1 and 6% of total extractable arsenic in the algae. In addition to dimethylarsinic acid, one unknown arsenical (almost co‐eluting with methylarsonic acid) and three different arsenosugars have been identified for the first time in C. vulgaris growing in a culture containing a mixture of antibiotics and believed to be axenic. The transformation to arsenosugars in the algae is not dependent on the arsenate concentration in the culture and varies between 0.2 and 5% of total accumulated arsenic. Although no microbiological tests for bacterial contamination were made, this study supports the hypothesis that algae, and not associated bacteria, produce the arsenosugars. Copyright © 2003 John Wiley & Sons, Ltd.     

Arsenic speciation in water and biota samples at trace levels by ion chromatography inductively coupled plasma-mass spectrometry

A sensitive, reliable, simple and rapid analytical method was developed for the determination of arsenite [As(III)], arsenate [As(V)] and arsenobetaine (AsB) species using ion chromatography combined with inductively coupled plasma-mass spectrometry (IC-ICP-MS). Inorganic and organic arsenic species were separated with an anion exchange column (Dionex AS9) and a 50 mM sodium bicarbonate mobile phase (pH 10) at a flow rate of 1.0 mL min^?1. %RSD values were found to be lower than 5.1% for all arsenic species. The limits of detection (LOD) obtained for As(III), As(V) and AsB were 16.5 ng L^?1, 14.1 ng L^?1 and 6.2 ng L^?1, respectively. The developed analytical method was tested using AsB certified reference material (NMIJ CRM 7901-a), and spring water certified reference material (UME CRM 1201) for accuracy check. This method was applied for the quantitative determination of arsenic species in different water samples and chicken samples as a solid matrix.     

A secondary laser cavity system for spectrophotometry of trace elements based on intracavit6y quenching and thermal lens effects

A system based on correlated cavities is described for quantitative measurements of small absorbances by means of intracavity quenching and the thermal lens effect. Theory suggesting the possibility of such measurements was confirmed experimentally. Methods for determining traces of arsenic and phosphorus in semiconductor silicon were developed; the procedures are based on the formation of reduced 12-molybdophosphoric and 12-molybdoarsenic heteropoly acids and measurement of absorbances either for aqueous solutions or for extracts into isobutanol. The total effect of intracavity quenching and thermal lensing was applied. The detection limits were 100 pg cm^?3 for arsenic and 10 pg cm^?3 for phosphorus. Layer-by-layer determination of phosphorus in silicon wafers was possible over a concentration range of 10¹⁵–10²⁰ atoms cm^?3, with a sample area of 1 cm² and layer thicknesses of 0.35–0.6 μm. The minimum detectable absorbance via the thermal lens effect was 5 × 10^?5, and that via the total effect of intracavity quenching and thermal lensing was 6 × 10^?6.     

Total and inorganic arsenic in dietary supplements based on herbs, other botanicals and algae—a possible contributor to inorganic arsenic exposure

The content of total and inorganic arsenic was determined in 16 dietary supplements based on herbs, other botanicals and algae purchased on the Danish market. The dietary supplements originated from various regions, including Asia, Europe and USA. The contents of total and inorganic arsenic was determined by inductively coupled plasma mass spectrometry (ICP-MS) and anion exchange HPLC-ICP-MS, respectively, were in the range of 0.58 to 5.0 mgkg^?1 and 0.03 to 3.2 mg?kg^?1, respectively, with a ratio between inorganic arsenic and total arsenic ranging between 5 and 100 %. Consumption of the recommended dose of the individual dietary supplement would lead to an exposure to inorganic arsenic within the range of 0.07 to 13 μg?day^?1. Such exposure from dietary supplements would in worst case constitute 62.4 % of the range of benchmark dose lower confidence limit values (BMDL₀₁ at 0.3 to 8 μg kg bw^?1 kg^?1 day^?1) put down by European Food Safety Authority (EFSA) in 2009, for cancers of the lung, skin and bladder, as well as skin lesions. Hence, the results demonstrate that consumption of certain dietary supplements could contribute significantly to the dietary exposure to inorganic arsenic at levels close to the toxicological limits established by EFSA.