Arsenic pollution in the Yellowknife Area from gold smelter activities

Gold has been mined on a large scale at Yellowknife located in the sub-arctic North West Territories of Canada since 1938. The gold is associated with arsenopyrite ores, with necessitates the oxidation of the arsenic and sulphur by roasting at two Yellowknife smelters. Other metals are also present in the ore, notably antimony. As₂O₃ and SO₂ are emitted into the atmosphere. Large quantities of arsenic were liberated in the past and despite improvements in emission control, significant emission still occur. In order to assess the amount and extent of arsenic contamination in the local environment and the potential exposures and sources to man, soil samples and samples of the native vegetation were collected in and around the town of Yellowknife and the two smelters. Arsenic and antimony analyses were done by instrumental neutron activation analysis using the SLOWPOKE facility at University of toronto. Air-dried plant samples were bombarded at a neutron flux of 1·10¹²n cm²s and soil samples at 2.5·10¹¹n cm²s for 6 minute periods. The¹²²Sb and⁷⁶As-ray emissions at 559 keV were analysed after decay periods of 24–48 hours and compared with standard solutions and NBS standards. Zinc, copper, lead and cadmium analyses were done by atomic absorption spectrophotometry. Arsenic was found to be accumulated in the soils in the vicinity of the two smelters to levels of several thousand ppm. Concentrations greater than 500 ppm occurred in the soil of Yellowknife townsite, and greater than 50 ppm occurred at all sites sampled within 15 km of the town. Antimony levels were about 10% of arsenic and were highly correlated with arsenic. Zinc occurred to 500 ppm around the smelters. Compared with background levels, the foliage of several native species showed substantial arsenic accumulation, up to several hundred ppm in birch. Only 5–25% of this arsenic could be removed by careful washing. Evidence suggests the arsenic is taken up from the soil creating an ongoing arsenic contamination problem. Soil arsenic levels are also sufficiently high to inhibit root growth in soils over a very extensive area.     

Arsenic determination in soils and hair from schools in past mining activity areas in Ron Phibun district,Nakhon Si Thammarat province,Thailand and relationship between soil and hair arsenic

Arsenic (As) in soils and hair collected from schools in Ron Phibun district, Nakhon Si Thammarat province, Thailand, where former tin mining operation were located, was determined by hydride generation atomic absorption spectrophotometry. The relationship between As content in soils and hair with distance from secured landfill was also investigated. Soil and hair samples were collected from 6 schools in summer (February) and rainy season (July). For soils, silt+clay (<45 µm) fraction and sand (45 µm–2 mm) fraction were analyzed. The average concentrations of arsenic in soils during summer (21.70 ± 16.79 mg/kg) and rainy season (22.45 ± 14.17 mg/kg) were at the same concentration level. The average arsenic content in hair samples was 2.24 ± 0.05 mg/kg in rainy season which was higher than 1.05 ± 0.04 mg/kg in summer. It was found that arsenic contents in hair and soils are correlated with the distance from the secured landfill. Most importantly, a positive relationship between arsenic content in hair and soil was obtained for rainy season, which indicated that arsenic in soil corresponded to arsenic in hair. The cancer risk from soils ranged from 4.48 × 10^?7 to 2.06 × 10^?6 indicating low carcinogenic risk to school children.     

Arsenic concentrations and distribution in Chautauqua Lake sediments

In order to describe the occurrence and to investigate the sources of arsenic found in Chautauqua Lake sediments, 98 grab samples have been analyzed by neutron activation analysis. The arsenic concentrations were found to range from <0.5 to 58.75 ppm for 96 of the 98 samples with an overall average value of 22.10 ppm. The two other samples had concentrations of 140.0 and 306.0 ppm. High arsenic concentrations have been positively correlated with a decrease in the sediment particle size. Natural arsenic concentrations found in the soil and bedrock in the area do not explaint the observed concentrations in the lake sediment. The increase in arsenic appears to be related to the spraying of sodium arsenite as an aquatic pesticide during the period 1955–1963.     

Determination of arsenic in geological materials by x-ray fluorescence spectrometry after solvent extraction and deposition on a filter

Rock, soil, or sediment samples are decomposed with a mixture of nitric and sulphuric adds. After reduction from arsenic(V) with ammonium thiosulphate, arsenic(III) is extracted as the chlorocomplex into benzene from a sulphuric-hydrochloric acid medium. The benzene solution is transferred onto a filter-paper disc impregnated with a solution of sodium bicarbonate and potassium sodium tartrate, and the benzene allowed to evaporate. The arsenic present is determined by X-ray fluorescence. In a 0.5-g sample, 1–1000 ppm of arsenic can be determined. The close proximity of the lead L peak (2θ 48.73°), to the arsenic K peak (2θ 48.83°) does not cause any interference, because lead is not extracted under the experimental conditions. Arsenic values obtained are in agreement with those reported for various reference samples.     

Trace elements distribution and post-mortem intake in human bones from Middle Age by total reflection X-ray fluorescence

The purpose of the present work is to investigate the suitability of TXRF technique to study the distribution of trace elements along human bones of the 13th century, to conclude about environmental conditions and dietary habits of old populations and to study the uptake of some elements from the surrounding soil.In this work, we used TXRF to quantify and to make profiles of the elements through long bones. Two femur bones, one from a man and another from a woman, buried in the same grave were cross-sectioned in four different points at a distance of 1 cm. Microsamples of each section were taken at a distance of 1 mm from each other.Quantitative analysis was performed for Ca, Mn, Fe, Cu, Zn, Sr, Ba and Pb. Very high concentrations of Mn and Fe were obtained in the whole analysed samples, reaching values higher than 2% in some samples of trabecular tissue, very much alike to the concentrations in the burial soil. A sharp decrease for both elements was observed in cortical tissue. Zn and Sr present steady concentration levels in both kinds of bone tissues. Pb and Cu show very low concentrations in the inner tissue of cortical bone. However, these concentrations increase in the regions in contact to trabecular tissue and external surface in contact with the soil, where high levels of both elements were found. We suggest that contamination from the surrounding soil exists for Mn and Fe in the whole bone tissue. Pb can be both from post-mortem and ante-mortem origin. Inner compact tissue might represent in vivo accumulation and trabecular one corresponds to uptake during burial. The steady levels of Sr and Zn together with soil concentration lower levels for these elements may allow us to conclude that they are originated from in vivo incorporation in the hydroxyapatite bone matrix.     

Arsenic speciation in hair extracts

Ingested arsenic is known to be not only excreted by urine, but to be stored in sulphydryl-rich tissue like hair, nail or skin. We developed an extraction method for arsenic species from these tissues and studied the stability of different arsenic species during the extraction process. Inorganic and pentavalent methylated arsenic was found to be stable under the extraction conditions, whereas trivalent methylated arsenicals and the thio-analogue of DMA^V (DMAS) showed reduced stability. The absorption ability of hair for these different species was studied as well. Inorganic arsenic is better absorbed by hair than monomethyl- or dimethyl-arsenicals, whereby the trivalent forms are taken up better than the pentavalent forms. Independent of which methylated arsenical was used for the incubation, the pentavalent form was always the dominant form after extraction. Hair and nail samples from humans suffering from chronic arsenic intoxication contained dominantly inorganic arsenic with small and strongly varying amounts of DMA^V and MA^V present. DMAS was only found in some nail sample extracts containing unusually high amounts of DMA^V and is believed to be formed during the extraction process.     

An Investigation on the Effect of Arsenic Poisoning on Humans,Agriculture, and Fisheries

The purpose of this investigation is to try and understand the degree of arsenic poisoning in the waste water from agricultural chemical factories which release effluents into the waterways in their vicinity. The method of determination is to use the water samples, soil, fish, clams, shell-fish, etc. found in the areas along the canals and aqueducts and those which lie upstream, midstream, and downstream and also the hair samples of people living in the contiguous areas, to check for the levels of arsenic in them by emission spectroscopy. From the analysis during a one year investigation, we find that the level of As in the water creatures of Chungkang Stream and Lu-Er-Men Stream is much higher than in the other water areas of Taiwan such as along beaches and the other rivers; the levels in the hair of the people who live nearby these water courses have a certain degree of correspondence with their eating habits and the quantity of food eaten; however, even those people who eat relatively little have almost 3% As, beyond the 2 mg/kg limit allowed for human beings. We are fully aware of the high level of food contamination on Taiwan, and this fact has been taken into consideration. The effect of As contamination in the soil on agricultural produce does not seem to have any apparent relationship. By the way, the influence of the monthly average rainfall on As contamination in the soil is not obvious.     

Biological monitoring of arsenic in semiconductor workers

In the manufacture of integrated circuits involving semiconductors, various hazardous materials including arsenic compounds are used. This paper present an evaluation of the biological monitoring of arsenic in the urine, blood and hair of semiconductor workers. Eighty-two blood samples were obtained from research and development workers in a semiconductor factory. Thirty-one samples of urine were obtained from the same group of worker before and after a work period (one shift). Seventy-three hair samples were similarly obtained from the workers. The concentration of arsenic in each sample was determined by arsine (AsH₃) generation flame atomic absorption spectrometry after wet ashing of the sample. The mean concentration of arsenic in hair in these semiconductor workers was significantly higher than that of controls. The mean concentration of arsenic in hair from workers with a longer employment duration was higher than from those with a shorter employment duration. The mean concentration of arsenic in hair from workers engaged in epitaxial growth processes was higher than from workers engaged in other processes. The concentrations of arsenic in hair from semiconductor workers correlated with the duration of their employment. The mean concentration of arsenic in urine before a work a period (shift) was not significantly different from that of controls. The mean concentration of arsenic in urine after a work period was in fact lower than that of controls. The mean concentration of arsenic in blood was not significantly different from that of controls. The determination of arsenic in hair is therefore considered useful for the evaluation of relatively long-term exposure to arsenic in semiconductor workers.     

Studies in atomic-fluorescence spectroscopy-VII Fluorescence and analytical characteristics of arsenic, with a microwave excited electrodeless discharge tube as source

The construction of an electrodeless arsenic discharge tube and its use for atomic-fluorescence studies is described. Cool nitrogen-hydrogen and argon-hydrogen diffusion flames as well as normal premixed flames are considered as atom reservoirs and the atomic-fluorescence emission at 15 different wavelengths is evaluated. The diffusion flames give the largest emission signals at arsenic concentrations below 200 ppm, but show a premature curvature at higher concentrations because of the presence of an abnormally high density of arsenic atoms. Above 200 ppm of arsenic, the premixed air-acetylene flame is superior. The limit of detection at 1890 A is 0.2 ppm of arsenic in the nitrogen-hydrogen diffusion flame and 1.0 ppm in the airacetylene flame. A long path-length diffusion flame is also particularly useful in atomic-absorption measurements because it absorbs very little radiation in the far ultraviolet region and gives an abundance of arsenic atoms.     

微量元素砷与胃癌关系的研究

从福建省胃癌高(长乐市)、低发区(福安市)的土壤、水体及人体血清、头发、尿液采集的材料入手,分析了砷元素与恶性肿瘤关系。结果表明,胃癌低发区土壤、饮用水和人头发砷含量反比高发区高。可见在正常情况下砷不致癌,适量砷可抑制癌症。     

Mercury content of hair from normal and poisoned persons

Several hundred samples of human head hair were analyzed to establish the range and variation of mercury concentration in “normal” people and in persons ingesting organic mercury compounds. Instrumental neutron activation analysis was used. The 77 keV line of¹⁹⁷Hg was counted on a Ge(Li) detector. The pattern of concentration variation along hair was shown to be a more reliable criterion for hair individualization than average concentration values. The hair mercury contents of “normal” people in uncontaminated areas were 0.1–4 and 1–12 ppm, respectively. People who had ingested a mercury compound but showed no symptoms had hair mercury concentrations of from a few ppm to 300 ppm. Mild symptoms appeared with a 120–600 ppm hair mercury level, moderate with 200–800 ppm, and severe with 400–1600 ppm. There was no correlation with sex or age, except that infants showed more severe symptoms than expected, and people over 55 had mild or no symptoms with hair mercury levels of 1000 ppm and higher.     

Were Chinchorros exposed to arsenic? Arsenic determination in Chinchorro mummies' hair by laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS)

Chinchorros, a fishermen culture, who lived about 7000 years ago in the coastal region of the Atacama Desert in the northern outpost of present-day Chile, practiced an intricate system of mummification of their dead. The drinking water in this region is rich with arsenic, and the mummies were found in these arsenic endemic areas. Well preserved mummy hair samples provided a unique opportunity to explore the ancient arsenic exposure of the Chinchorros by laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) using a single hair strand without any elaborate sample preparation. Forty-six hair samples from mummies found in five burial sites around the Atacama Desert, Chile, were used for this study. After cleaning, hair strands were placed on mounting tape and ablated using a Nd-YAG UV laser coupled to ICP-MS. A suite of contemporary human hair from the same region with known arsenic concentrations was used for calibration of LA-ICP-MS. Satisfactory linear calibration functions were obtained for arsenic in hair. The method detection limit was 0.8 µg/g and the sample throughput for this method is ∼ 10 samples per hour. It appears that mummies from the Morro (Arica), Iquique and Camarones had the elevated concentration of arsenic in hair (AsH > 10 µg/g) in this sub-set of samples, where Morro had the broad distribution of As concentrations.     

Assessment of the plasma desorption time-of-flight mass spectrometry technique for pesticide adsorption and degradation on 'as-received' treated soil samples

The assessment of the plasma desorption time-of-flight mass spectrometry (PD-TOFMS) technique as a tool for direct characterization of pesticides adsorbed on agricultural soil is made for the first time in this study. Pellets of soils impregnated by solutions of three pesticides, namely norflurazon, malathion and oxyfluorfen, as well as deposits of these solutions onto aluminum surfaces, were investigated to this end. The yield values of the most characteristic peaks of the negative ion mass spectra were used to determine both the lowest concentrations detected on soils and limits of detection from thin films. The lowest values on soils are for malathion (1000 ppm range), and the largest for norflurazon (20,000 ppm), which is close to the limit of detection (LOD) found for the pesticide on the aluminum substrate (approximately 0.2 microg . cm(-2)). Different behaviors were observed as a function of time of storage in the ambient atmosphere or under vacuum; norflurazon adsorbed on soil exhibited high stability for a long period of time, and a rapid degradation of malathion with the elapsed time was clearly observed. The behavior of oxyfluorfen was also investigated but segregation processes seem to occur after several days. Although by far less sensitive than conventional methods based on extraction processes and used for real-world analytical applications, this technique is well suited to the study of the transformations occurring at the sample surface. A discussion is presented of the future prospects of such experiments in degradation studies.     

New human hair certified reference material for methylmercury and trace elements

A new human hair certified reference material (NIES CRM No. 13) for mercury speciation and trace element analysis was prepared at the National Institute for Environmental Studies (NIES), Environmental Agency of Japan. Scalp hair from Japanese males, which is identical with the original material for the previous human hair CRM (NIES CRM No. 5), was used. Special attention was paid to reduce contamination from a grinding vessel during the preparation procedure. A newly-prepared ceramic/Teflon disc mill was used for cryogenic grinding of the hair. 1, 000 bottles (3 g each) were produced after sieving and blending of the hair powder. Certified values for total mercury and methylmercury, as well as other trace elements of toxicological and nutritional significance (antimony, cadmium, copper, lead, selenium, and zinc), were determined based on analyses from extensive collaborations. Reference values for 12 elements (aluminium, arsenic, barium, calcium, cobalt, iron, magnesium, manganese, silver, sodium, sulfur and vanadium) were also given.     

Measurement of arsenic in sectioned hair samples by instrumental neutron activation analysis

In a recent Texas murder case, bundles of head hair from the female victim (aligned with all root ends together) were washed, cut into 7 mm sections, air-dried and weighed, activated in a nuclear reactor neutron flux, and then counted with a Ge(Li) detector/4096-channel gamma-ray spectrometer. In each of the 15 samples, the 559 keV gamma-ray peak of 26.3 hour⁷⁶As was measured. In the section closest to the scalp, an arsenic concentration of 107 ppm was found (cf. a normal level of about 1 ppm As). Barium ingestion was also possible so Ba was looked for, but not found. The victim's husband was found guilty of murder by chronic arsenic poisoning.     

Speciation of As(III), As(V), MMA and DMA in contaminated soil extracts by HPLC-ICP/MS

A method to separate and quantify two inorganic arsenic species As(III) and As(V) and two organic arsenic species, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), by HPLC-ICP/MS has been developed. The separation of arsenic species was achieved on the anionic exchange column IonPac AS11 (Dionex) with NaOH as mobile phase. The technique was successfully applied to analyze extracts of two contaminated soils, sampled at a former tannery site (soil 1) and a former paint production site (soil 2). The soils were extracted at pH values similar to the natural environment. Extractions were performed at different pH values with 0.3 M ammonium oxalate (pH = 3), milli-Q water (pH = 5.8), 0.3 M sodium carbonate (pH = 8) and 0.3 M sodium bicarbonate (pH = 11). No organically bound arsenic was found in the extracts. As(V) was the major component. Only up to 0.04% of the total arsenic contained in soil 1 were mobilized. The highest amount of extracted arsenic was found at the highest pH. In the milli-Q water extract of soil 1 As(III) and As(V) were found. High amounts of As(V) were found in the extracts of soil 2. Up to 20% of the total arsenic bound to soil 2 constituents were released. The results show that the mobilization of arsenic depended on the pH value of the extraction solution and the kind of extracted soil. Dramatic consequences have to be expected for pH changes in the environment especially in cases where soils contain high amounts of mobile arsenic.     

Arsenic accumulation and speciation analysis in wool from sheep exposed to arsenosugars

Wool or hair fibre is a metabolically dead material after it has left the epidermis. During growth the fibre in the root is a metabolically very active organ, which is highly influenced by the health status of the living being. Arsenic is one of the elements that is easily taken up by the cells of the root and stored in the fibre afterwards. Here we show that arsenic can quantitatively be extracted by boiling the wool fibre or hair in water. The high intake of arsenic species by the sheep of North Ronaldsay (the seaweed-eating sheep) leads to a high arsenic concentration in wool (mean 5.2+/-2.3 mug g(-1)). The wool of lambs of these sheep, which are not exposed to seaweed, contains about 10 times less arsenic, which is still elevated compared to uncontaminated wool. The arsenic species identified in wool extract are arsenite (As(III)), arsenate (As(V)), monomethylarsonic acid (MMA(V)) and monomethylarsonious acid (MMA(III)) as minor species. The major species is dimethylated arsenic DMA in its tri- and pentavalent form (dimethylarsinous acid (DMA(III)) and dimethylarsinic acid (DMA(V))) accounting for 85% of the specified arsenic in the wool which reflects the amount of dimethylated species (i.e. the arsenoribofuranosides) taken up by seaweed being the main food source of the sheep. However, there are unknown arsenic species in the extract, which are not eluting from a strong anion exchange column. In vitro incubation experiments with this kind of wool showed that it has reducing properties but no demethylation was recorded. The absorption ability of the wool for methylated arsenic species is negligible, while inorganic arsenic is easier to be absorbed in the fibre (11-17%). This means that the species integrity is only guaranteed in terms of the degree of methylation but not in terms of their redox status.     

Application of a linear ion trap/orbitrap mass spectrometer in metabolite characterization studies: Examination of the human liver microsomal metabolism of the non-tricyclic anti-depressant nefazodone using data-dependent accurate mass measurements

We report herein, facile metabolite identification workflow on the anti-depressant nefazodone, which is derived from accurate mass measurements based on a single run/experimental analysis. A hybrid LTQ/orbitrap mass spectrometer was used to obtain accurate mass full scan MS and MS/MS in a data-dependent fashion to eliminate the reliance on a parent mass list. Initial screening utilized a high mass tolerance ( approximately 10 ppm) to filter the full scan MS data for previously reported nefazodone metabolites. The tight mass tolerance reduces or eliminates background chemical noise, dramatically increasing sensitivity for confirming or eliminating the presence of metabolites as well as isobaric forms. The full scan accurate mass analysis of suspected metabolites can be confirmed or refuted using three primary tools: (1) predictive chemical formula and corresponding mass error analysis, (2) rings-plus-double bonds, and (3) accurate mass product ion spectra of parent and suspected metabolites. Accurate mass characterization of the parent ion structure provided the basis for assessing structural assignment for metabolites. Metabolites were also characterized using parent product ion m/z values to filter all tandem mass spectra for identification of precursor ions yielding similar product ions. Identified metabolite parent masses were subjected to chemical formula calculator based on accurate mass as well as bond saturation. Further analysis of potential nefazodone metabolites was executed using accurate mass product ion spectra. Reported mass measurement errors for all full scan MS and MS/MS spectra was <3 ppm, regardless of relative ion abundance, which enabled the use of predictive software in determining product ion structure. The ability to conduct biotransformation profiling via tandem mass spectrometry coupled with accurate mass measurements, all in a single experimental run, is clearly one of the most attractive features of this methodology.     

The study of human nails as an intake monitor for arsenic using neutron activation analysis

Arsenic is toxic to humans with the lethal dose being approximately 1 mg/kg/day. At much lower long-term exposures, arsenic is hypothesized to increase the risk of certain cancers. We have developed an irradiation position for the neutron activation analysis (NAA) of nail specimens for arsenic, in support of a case-control study involving New Hampshire residents consuming well water above the EPA Safe Drinking Water Standard of 0.050 ppm. Arsenic is bound to nail keratin through sulfhydryl groups proportional to intake providing a convenient means of integrating arsenic intake in population-based studies. Our objective was to develop the necessary facilities and procedures by which relatively small samples (i.e. 20 to 100 mg) could be accurately analyzed for arsenic, so that affordable nutritional epidemiology investigations, requiring large numbers of samples (>1000 in this case), could be undertaken. A high-flux reflector position, with minimal axial variation throughout the fuel cycle, suitable for pneumatic-tube irradiations, was characterized by measurement of the neutron flux distribution (thermal and epithermal) within the irradiation capsule over time. Results from application of the method to a case-control study of basal and squamous cell skin cancer will be presented.     

New human hair certified reference material for methylmercury and trace elements

 A new human hair certified reference material (NIES CRM No. 13) for mercury speciation and trace element analysis was prepared at the National Institute for Environmental Studies (NIES), Environmental Agency of Japan. Scalp hair from Japanese males, which is identical with the original material for the previous human hair CRM (NIES CRM No. 5), was used. Special attention was paid to reduce contamination from a grinding vessel during the preparation procedure. A newly-prepared ceramic/Teflon disc mill was used for cryogenic grinding of the hair. 1,000 bottles (3 g each) were produced after sieving and blending of the hair powder. Certified values for total mercury and methylmercury, as well as other trace elements of toxicological and nutritional significance (antimony, cadmium, copper, lead, selenium, and zinc), were determined based on analyses from extensive collaborations. Reference values for 12 elements (aluminium, arsenic, barium, calcium, cobalt, iron, magnesium, manganese, silver, sodium, sulfur and vanadium) were also given. Received: 8 February 1996/Accepted: 4 April 1996