Asbestos fibres in beverages and drinking water

The Behavior of Polymeric Pipes in Drinking Water Distribution System-Comparison with Other Pipe Materials

The inner walls of the drinking water distribution system (DWDS) are expected to be clean to ensure a safe quality of drinking water. Complex physical, chemical, and biological processes take place when water comes into contact with the pipe surface. This paper describes the impact of leaching different compounds from the water supply pipes into drinking water and subsequent risks. Among these compounds, there are heavy metals. It is necessary to prevent these metals from getting into the DWDS. Those compounds are susceptible to impacting the quality of the water delivered to the population either by leaching dangerous chemicals into water or by enhancing the development of microorganism growth on the pipe surface. The corrosion process of different pipe materials, scale formation mechanisms, and the impact of bacteria formed in corrosion layers are discussed. Water treatment processes and the pipe materials also affect the water composition. Pipe materials act differently in the flowing and stagnation conditions. Moreover, they age differently (e.g., metal-based pipes are subjected to corrosion while polymer-based pipes have a decreased mechanical resistance) and are susceptible to enhanced bacterial film formation. Water distribution pipes are a dynamic environment, therefore, the models that are used must consider the changes that occur over time. Mathematical modeling of the leaching process is complex and includes the description of corrosion development over time, correlated with a model for the biofilm formation and the disinfectants-corrosion products and disinfectants-biofilm interactions. The models used for these processes range from simple longitudinal dispersion models to Monte Carlo simulations and 3D modeling. This review helps to clarify what are the possible sources of compounds responsible for drinking water quality degradation. Additionally, it gives guidance on the measures that are needed to maintain stable and safe drinking water quality.

Mobility of crocidolite asbestos in sandy porous media mimicking aquifer systems

Asbestos is widely recognized as being a carcinogen when dispersed in air, but very little is known about its exposure pathways in water and its subsequent effects on human health. Several studies have proved asbestos presence in groundwater but failed to assess its mobility in aquifer systems. This paper aims to fill this gap by studying the transport of crocidolite, an amphibole asbestos, through sandy porous media mimicking different aquifer systems. To this purpose, two sets of column test were performed varying the crocidolite suspension concentration, the quartz sand grain size distribution, and the physicochemical water parameters (i.e., pH). The results proved that crocidolite is mobile in quartz sand due to the repulsive interactions between fibres and porous media. The concentration of fibres at the outlet of the column were found to decrease when decreasing the grain size distribution of the porous medium, with a bigger impact on highly concentrated suspensions. In particular, 5-to-10-µm-long fibres were able to flow through all the tested sands while fibres longer than 10 µm were mobile only through the coarser medium. These results confirm that groundwater migration should be considered a potential exposure pathway while implementing human health risk assessment.

Degradation of asbestos - Reinforced water supply cement pipes after a long-term operation

Potable water supply system in major countries still uses a large proportion of asbestos-cement (AC) pipes for fresh drinking water delivery. Generally, after installation and initial purging, the AC tubes are believed to self-passivate by calcite scale and bio-film, especially when conveying hard water. However, the overall performance of AC tubes after decades of operation is significantly reduced and is still mainly unknown. In the current research, we investigated the AC water supply tube after 56 years of operation with high-hardness conveyed water. Our results show that asbestos fibres are emitted from degraded AC pipes as a result of wall softening due to calcium leaching from hydrated cementitious materials, resulting in the loss of mechanical stability. Although the water pumped into the system is not considered aggressive, the seasonal variations of water temperature and chemistry results in an interplay of calcite scaling and Ca leaching, the latter being the dominating process. By comparing the experimental observations with the long-term chemistry reports of the water supplied through the pipes, a positive relationship was established between the temperature and quality of the conveyed water with the corrosion and the calcite scale formation, which are dictating the emission of the fibres into the drinking water. In addition to the health risks posed by asbestos, these processes have many adverse effects on drinking water supply, such as pipe malfunction and destruction resulting in water loss, reduction of hydraulic capacity, microbial proliferation, and water quality deterioration, a topic of interest for global water industries process.

Ingested asbestos in filtered beer, in addition to occupational exposure, as a causative factor in oesophageal adenocarcinoma

Oesophageal adenocarcinoma has become much more common over the past 50 years, particularly in Britain, with an unexplained male to female ratio of > 4:1. Given the use of asbestos filtration in commercial brewing and reports of its unregulated use in British public houses in the 1970’s to clear draught beer “slops”, we have assessed the hypothesis that ingested asbestos could be a causative factor for this increased incidence. Importantly, occupational asbestos exposure increases the risk of adenocarcinoma but not squamous cell carcinoma of the oesophagus. The presence of asbestos fibres was consistently reported in filtered beverages including beers in the 1970s and asbestos bodies have been found in gastrointestinal tissue, particularly oesophageal tissue, at autopsy. There is no reported association between the intake of alcohol and oesophageal adenocarcinoma but studies would mostly have missed exposure from draught beer before 1980. Oesophageal adenocarcinoma has some molecular similarities to pleural mesothelioma, a condition that is largely due to inhalation of asbestos fibres, including predominant loss of tumour suppressor genes rather than an increase of classical oncogenic drivers. Trends in incidence of oesophageal adenocarcinoma and mesothelioma are similar, rising rapidly over the past 50 years but now plateauing. Asbestos ingestion, either from beer consumed before around 1980, or from occupational exposure, seems a plausible causative factor for oesophageal adenocarcinoma. If this is indeed the case, its incidence should fall back to a low baseline by around 2050.

Framework for assessment and phytoremediation of asbestos-contaminated sites

We examine the feasibility of phytoremediation as an alternative strategy to limit the exposure of asbestos in site with asbestos-containing materials. We collected soils from four locations from two sites-one with naturally occurring asbestos, and another, a superfund site, where asbestos-containing materials were disposed over decades-and performed ecotoxicology tests. We also performed two experiments with crop cultivar and two grasses from serpentine ecotype and cultivar to determined best choice for phytoremediation. Asbestos concentrations in different size fractions of soils varied by orders of magnitude. However, different asbestos concentrations had little effect on germination and root growth. Presence of co-contaminants such as heavy metals and lack of nutrients affected plant growth to different extents, indicating that several of these limiting factors should be considered instead of the primary contaminant of concern. Crop cultivar survived on asbestos-contaminated soil. Grasses from serpentine ecotype did not show higher biomass than the cultivar. Overall, these results showed that soil conditions play a critical role in screening different crop species for phytoremediation and that asbestos concentration has limited to no effect on plant growth. Our study provided a framework for phytoremediation of asbestos-contaminated sites to limit long-term asbestos exposure.

Asbestos Fiber Preparation Methods Affect Fiber Toxicity

To measure the toxic potential of asbestos fibers-a known cause of asbestosis, lung cancer, and malignant mesothelioma-asbestos minerals are generally first ground down to small fibers, but it is unknown whether the grinding condition itself changes the fiber toxicity. To evaluate this, we ground chrysotile ore with or without water for 5-30 min and quantified asbestos-induced reactive oxygen species generation in elicited murine peritoneal macrophages as an indicator of fiber toxicity. The toxicity of dry-ground fibers was higher than the toxicity of wet-ground fibers. Grinding with or without water did not materially alter the mineralogical properties. However, dry-ground fibers contained at least 7 times more iron than wet-ground fibers. These results indicate that grinding methods significantly affect the surface concentration of iron, resulting in changes in fiber-induced reactive oxygen species generation or toxicity. Therefore, fiber preparation conditions should be accounted for when comparing the toxicity of asbestos fibers between reported studies.

Assessment of asbestos exposure during a simulated agricultural activity in the proximity of the former asbestos mine of Balangero, Italy

The natural occurrence of asbestos (NOA) in rural areas is a serious concern for human health and the dispersion route of asbestos in the proximity of natural asbestos-rich settings has been marginally evaluated so far. NOA may affect air, but also water and soil quality. In rural areas population may be exposed to asbestos with a largely unknown impact on human health. This work investigates the potential exposure of a farmer cultivating a field nearby the largest former asbestos mine of Western Europe (Balangero, Italy). The concentration of waterborne asbestos in the stream used to water the field was measured (ca. 2×10(5) fibers per liter, ff/L) and the cultivated ultramafic topsoil characterized, evidencing a remarkable occurrence of chrysotile. The worker's personal exposure and the environmental fiber dispersion during a simulated agricultural activity (tillage) were quantified in two independent trials. During the trials, the worker was exposed to average concentrations of 16 and 26 ff/L, with a peak of 40 ff/L. These data inform about the possible exposure of an agricultural worker to asbestos concentration higher than the accepted threshold of 2 ff/L. The release of asbestos fibers into the environment was negligible (0-2 ff/L).

Mesothelioma in a wine cellar man: detailed description of working procedures and past asbestos exposure estimation

A pleural mesothelioma arose in an employee of a wine farm whose work history shows an unusual occupational exposure to asbestos. The information, gathered directly from the case and from a work colleague, clarifies some aspects of the use of asbestos in the process of winemaking which has not been previously reported in such details. The man had worked as a winemaker from 1960 to 1988 in a farm, which in those years produced around 2500 hectoliters of wine per year, mostly white. The wine was filtered to remove impurities; the filter was created by dispersing in the wine asbestos fibers followed by diatomite while the wine was circulating several times and clogging a prefilter made of a dense stainless steel net. Chrysotile asbestos was the sole asbestos mineralogical variety used in these filters and exposure could occur during the phase of mixing dry fibers in the wine and during the filter replacement. A daily and annual time weighted average level of exposure and cumulative dose have been estimated in the absence of airborne asbestos fiber monitoring performed in that workplace. Since 1993, the Italian National Mesothelioma Register, an epidemiological surveillance system, has recorded eight cases with at least one work period spent as winemaker. Four of them never used asbestos filters and presented exposures during other work periods, the other four used asbestos filters but had also other exposures in other industrial divisions. For the information hitherto available, this is the first mesothelioma case with exclusive exposure in the job of winemaking.

Alcohol and cancer: a review for psycho-oncologists

Researchers have documented a link between alcohol consumption and the development of certain types of cancers. In addition, the prevalence of alcoholism and comorbid psychiatric disorders has been well-documented both the general population and medical settings. The role of the psycho-oncologist in the assessment and management of alcoholism and comorbid psychiatric disorders is crucial to improving both treatment adherence and the quality of life of the patient. This paper will provide psycho-oncologists with a review of: (1) the relationship of alcoholism to cancer; (2) psychiatric comorbidity frequently encountered in alcoholics, as a key to assessment and management; and (3) the goals and strategies of management of alcoholic cancer patient.

Asbestos-related pleural thickenings in Japanese sake brewers

Asbestos was long used as an additive material for the filtration of many kinds of alcoholic beverages. There has been, however, only one case report of a distiller in Italy showing pleural thickenings and lung parenchymal fibrosis due to exposure to asbestos. We report a retired Japanese sake brewer who showed bilateral calcified pleural plaques on chest X-ray films. X-ray diffraction analysis and energy disperse X-ray microanalysis demonstrated the additive material used for sake filtration to be almost pure chrysotile. Furthermore, 17 cases showing probably asbestos-related pleural thickenings were found on examination of 235 chest X-ray films of male workers at different sake breweries. These findings indicate that Japanese sake brewers should be listed as workers at possible risk of asbestos-related health problems.

Pleural malignant mesothelioma in Tuscany, Italy (1970-1988): II. Identification of occupational exposure to asbestos

Following the finding of an unexpected cluster of mesotheliomas in textile workers, a surveillance system of malignant mesotheliomas was implemented in the region of Tuscany, Italy. This article reports on the investigation of 124 cases of mesothelioma diagnosed and reviewed by the Institutes of Morbid Anatomy and Histopathology at the Universities of Florence, Pisa, and Siena between 1970 and 1988. A complete occupational and asbestos exposure history was assessed through a semi-structured questionnaire directly administered to resident cases of Tuscany or, if deceased, to their closest living relatives, for a total of 100 interviews. The hypothesis of past occupational asbestos exposure was verified and documented. Seventy-two cases have been classified as occupationally exposed to asbestos; four were classified in the category of "possible domestic" exposure to asbestos. For two others, the role of other risk factors was stressed, and for 22 cases, either no asbestos exposure was found or the available data were not adequate to define it. The present study allowed identification of some unknown or scarcely known occupational asbestos exposures in the study area.

Hepatocellular carcinoma, alcohol, and cirrhosis: facts and hypotheses

Despite the epidemiological evidence of a correlation between ethanol abuse and hepatocellular carcinoma, some of the results of experimental and clinical studies remain controversial. Apart from inducing cirrhosis, which may be viewed as a precancerous liver lesion, ethanol may act as a cocarcinogen. Most investigations on this topic have focused on two aspects: ethanol's capacity to induce the cytochrome P-450-dependent microsomal biotransformation system and its interference with at least one DNA repair mechanism. Ethanol exposure enhances the capacity of mixed function oxidases to activate many chemical carcinogens, such as dimethylnitrosamine (DMN). On the other hand, ethanol exposure fails to influence DMN-induced liver carcinogenesis. The capacity of alcohol to inhibit DMN-demethylase activity has not been clearly demonstrated in experiments carried out with human tissue. In conclusion, both the effects of ethanol and their underlying mechanisms as regards liver carcinogenesis are open to debate. The link between ethanol abuse and hepatocellular carcinoma appears to be mediated mainly by its capacity to induce cirrhosis.

International Commission for Protection against Environmental Mutagens and Carcinogens. ICPEMC Working Paper No. 15/2. Metabolism and metabolic effects of ethanol, including interaction with drugs, carcinogens and nutrition

Different pathways of alcohol metabolism, the alcohol dehydrogenase pathway, the microsomal ethanol-oxidizing system and the catalase pathway are discussed. Alcohol consumption leads to accelerated ethanol metabolism by different mechanisms including an increased microsomal function. Microsomal induction leads to interactions of ethanol with drugs, hepatotoxic agents, steroids, vitamins and to an increased activation of mutagens/carcinogens. A number of ethanol-related complications may be explained by the production of its first metabolite, acetaldehyde, such as alterations of mitochondria, increased lipid peroxidation and microtubular alterations with its adverse effects on various cellular activities, including disturbances of cell division. Nutritional factors in alcoholics such as malnutrition are discussed especially with respect to its possible relation to cancer.

Effect of ethanol and vitamin A deficiency on epithelial cell proliferation and structure in the rat esophagus

An increased risk of cancer of the esophagus has been reported in alcoholics and in populations with low dietary vitamin A consumption. As cancer is a disorder of cell proliferation and differentiation, we have assessed the combined effects of ethanol and vitamin A deficiency on cell proliferation and structure of the esophagus. Weanling male rats were fed liquid diets with either a standard amount of vitamin A or lacking vitamin A for 8 wk. Littermates were pair-fed the same diets with carbohydrate (36% of calories) replaced by ethanol. Rats were given [3H]thymidine 1 h before death, and the labeling index of the proliferative basal cells was determined on radioautographs. In rats fed the normal vitamin A diet with or without ethanol, plasma vitamin A was normal. Hepatic vitamin A was markedly decreased, whereas esophageal vitamin A was increased after ethanol feeding. Ethanol feeding resulted in a twofold increase in basal cell labeling index (14.6 +/- 0.7 vs. 6.8 +/- 0.8; p less than 0.001). The thickness of the epithelium and the morphology of basal cells were not altered by ethanol feeding. In rats fed the vitamin A-deficient diet with or without ethanol, plasma vitamin A was extremely low, and hepatic and esophageal vitamin A were unmeasurable. The epithelium was thin (with a 50% reduction in thickness) and showed abnormalities of basal cells and increased production of keratohyalin granules, changes suggesting a disorder in the epithelial differentiation. This altered differentiation caused by vitamin A deficiency was not affected by ethanol consumption. Ethanol feeding again resulted in an increase in the basal cell labeling index (13.2 +/- 1.6 vs. 4.8 +/- 0.7; p less than 0.001). Vitamin A deficiency had no effect on basal cell proliferation. Therefore, the stimulatory effect of ethanol on cell proliferation is independent of vitamin A deficiency. Nevertheless, the combined actions of ethanol and vitamin A deficiency may have a synergistic effect on the susceptibility of the esophagus to carcinogens.

A quantitative study on the distribution of asbestos bodies in extrapulmonary organs

We made a quantitative study of the distribution of asbestos bodies (ABs) in 13 extrapulmonary organs. We selected 26 male subjects and subdivided them into three groups: Group I had 10(2) to less than 10(3) ABs per gram of wet tissue in their lungs; group II had 10 to 99 ABs; and group III had no ABs. In group I, one or more ABs were identified in at least 6 (53.8%) of the examined extrapulmonary organs. In group II, 23.7% of the examined organs had one or more ABs. In group III, no ABs were found. These results seem to indicate that with modest exposure in the lung, the other organs are often exposed to asbestos with some degree. Moreover, the number of AB in the esophagus was significantly larger than that in 9 of the other 12 organs in group I. The pancreas and the spleen were also supposed to be more preferential sites of exposure. However, the relationship between exposure and its effects in extrapulmonary organs remains to be elucidated.

Co-carcinogenic effect of asbestos and benzo(a)pyrene in the lung of hamster

Epidemiological reports indicate that occupational asbestos exposure and smoking habit make increase the incidence of lung carcinomas greatly. To elucidate the synergetic effect of smoking and asbestos exposure, hamsters were injected intratracheally with asbestos and benzo(a)pyrene(Bap), which is contained in cigarette smoke, singly or in combination. Tumor was not induced in the hamsters injected with asbestos or Bap alone except epithelial hyperplasia. On the other hand, 7 tumors out of 34 animals were found in groups injected with both asbestos and Bap from 12 months to 19 months after injection. Two of them were carcinomas. This result seemed to indicate synergetic effect of asbestos and Bap in causing carcinoma of the lung.

The effects of chronic ethanol consumption on carcinogen metabolism and on O6-methylguanine transferase-mediated repair of alkylated DNA

This article presents a review and update of recent experiments conducted in collaboration with Dr. C. S. Lieber on mechanisms underlying the increased cancer risk associated with alcohol abuse. Ethanol has been found to be a potent inducer of microsomal enzymes involved in carcinogen metabolism in a variety of rat tissues including liver, esophagus, lungs, and intestines. In some of these tissues, ethanol's inductive effect on microsomal cytochrome P-450 enzyme activity may result in enhanced levels of electrophilic metabolites of procarcinogens which are not readily detoxified. In addition, chronic ethanol feeding has been found to depress the activity of O6-methylguanine transferase, an enzyme involved in the repair of carcinogen-induced DNA alkylation. The effects of ethanol on carcinogen metabolism and on DNA repair would be expected to enhance the initiation phase of chemically induced cancers.

Quantitative assessment of chrysotile fibrils in the bloodstream of rats which have ingested the mineral under different dietary conditions

Samples of hepatic portal blood derived from control rats and from animals ingesting chrysotile asbestos were examined for the presence of mineral fibers. Only fibrils (97% less than 1 micron) were detected in the blood samples of both control and chrysotile-exposed rats. Total fibril counts per milliliter of blood revealed that in 6 out of 15 of the dietary experiments, the chrysotile-exposed groups had significantly higher counts than the equivalent controls. The actual quantity of chrysotile mineral (by counts or mass) which may be persorbed upon passage through the gastrointestinal tract and enter the blood stream is minute in comparison with the ingested dose.

Biological effects of ingested amosite asbestos, taconite tailings, diatomaceous earth and Lake Superior water in rats

Because amphibole fibers were found in Lake Superior and in Duluth municipal water, this study was initiated to evaluate the carcinogenicity of ingested asbestos. Groups of 22-30 Sprague-Dawley rats were fed asbestos and related materials during their lifetime and were examined at autopsy after spontaneous death. Test materials were unfiltered Duluth city tap water, municipal water reservoir sediment suspension, taconite plant tailings, amosite asbestos (a "low-dose" group at 20 mg/rat . day an a high-dose group at 300 mg/rat . day) and diatomaceous earth; a control group drank fiber-free well water or filtered city tap water. Autopsy studies revealed no significant increase in the incidence of malignant tumors in any experimental group compared with that in the control group.

Asbestos and drinking water in Canada

Samples of raw, treated and distributed tap water were collected from 71 municipalities across Canada and analyzed for asbestos content by transmission electron microscopy. Chrysotile asbestos was identified as the major asbestos type present in drinking water with some 5% of public water supplies containing asbestos at concentrations greater than 10 million fibres per litre. Improvement factors of up to 300 were observed for the removal of chrysotile fibres from drinking water during treatment, indicating that coagulation/filtration treatment is efficient for this purpose. In certain cases there is evidence to suggest that erosion of asbestos from pipe material is taking place. Age-standardized mortality rates for gastro-intestinal cancers were calculated for each city for the period of 1966 to 1976. Rates for the 2 localities with the highest (congruent to 10(8)/L) concentrations of asbestos fibres in treated drinking water were compared with the weighted average of the rates for the 52 localities with asbestos concentrations not significantly greater than zero. Eleven localities had intermediate concentrations of asbestos and six were too small for meaningful statistical analysis. Relatively high mortality rates were apparent amongst males in city 1 for cancer of the large intestine except rectum, and in both sexes in city 1 and males in city 2 for stomach cancer. It is felt that these findings are probably related to occupational exposure to asbestos. Further statistical analyses are required, however, before the significance of these observations can be fully assessed.

Asbestos fibres and the environment

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Asbestos fibers in normal and cancerous human kidneys

Exposure of general population of ubiquitously present asbestos has led investigators to monitor its health effects. This pilot study was undertaken to see if there was an association between kidney cancer and fiber concentration in the kidney. Results of transmission electron microscopic (TEM) analysis for asbestos fibers in normal and cancerous human kidney tissues collected from three Chicago hospitals are presented. Chrysotile fibers were recovered from autopsy or surgery tissues of normal and cancerous kidneys. The study did not indicate a definite association between carcinoma and fiber load of kidney of humans exposed to nonoccupational asbestos.

Out-of-hours visits in a group practice

In one year 1644 out-of-hours calls were undertaken by a partnership of eight doctors working in a deprived inner urban area and a deprived large council housing estate; of these calls 332 were performed between the hours of 11 pm and 7 am. The number of calls required in the housing estate, 1077, was about twice as many as in the inner urban area, although the same doctors were using the same criteria for a visit. The rate of visits of 107 per 1000 patients in the housing estate was much higher than in other published series. The reasons for this difference appeared to be related to the comparative youth of parents and the number of young children.

Ingested mineral fibers: elimination in human urine

Sediment in human urine examined by transmission electron microscopy contains amphibole fibers which originate from the ingestion of drinking water contaminated with these mineral fibers. The ingestion of filtered water results in the eventual disappearance of amphibole fibers from urine. These observations provide the first direct evidence for the passage of mineral fibers through the human gastro-intestinal mucosa under normal conditions of the alimentary canal.

Asbestos fibers in wines: relation to filtration process

Asbestos fibers were counted by using the transmission electron microscope in 42 wines from France and abroad. Fifteen samples were found to be significantly positive for chrysotile asbestos. Concentrations were in the range of 2--64 X 10(6) fibers per liter. Technical investigations showed that the abestos content of the wines was related to the process by which they were filtered. On the other hand, we found that abandoning the use of asbestos for filtering wines would not alter the wine from the enological point of view.

An outbreak of pleural mesothelioma and chronic fibrosing pleurisy in the village of Karain/Urgüp in Anatolia

The 575 inhabitants of the remote Anatolian village of Karain suffered 11 deaths from pleural mesothelioma in 1975/76 and there were five cases of fibrosing pleurisy. In the previous five years there had been 25 cases of mesothelioma. Calcified pleural plaques were common on survey radiography. Asbestos does not occur in the local soil or rock, nor is it handled in the village, but a few fibres were found in the water. Fibres were also found in the pleural tissue of two of five cases examined. Inhabitants of the neighbouring villages are free of mesothelioma.

Cancer mortality in relation to asbestos in municipal water supplies

The mortality experience of twenty-two municipalities in Quebec grouped by evidence of exposure to asbestos fibers in water supplies (known high, possible high, and probable low exposures) was evaluated. Excess mortality due to cancer of the stomach (males), pancreas (females), and lung (males) was observed in the two municipalities with known high exposures. The excesses among males have been due to occupational exposure to asbestos. The absence of excess mortality due to pancreatic cancer among males suggested that the excess among females was not due to waterborne asbestos. The study therefore did not reveal evidence of excess cancer mortality that could be attributed to exposure to asbestos in drinking water.

Asbestos and embryonic development

Chrysotile asbestos was administered to pregnant CD-1 mice in their drinking water and to Day 4 blastocysts during culture. Administration to pregnant mice did not affect embryo survival. In vitro administration of asbestos did not interfere with embryo implantation upon transfer of blastocysts to recipient females but did result in a decrease in postimplantation survival. These studies did not demonstrate asbestos to be teratogenic whether administered to the dam or to the blastocyst in vitro.

Quantitative relationship of fecal asbestos to asbestos exposure

A method is descirbed for isolating chrysotile fibers from feces and counting them with an electron microscope. The detection limit was 150,000 fibers per gram feces; average recovery was 85.5%. When the method was used to check the asbestos in feces of people subjected to industrial exposure vs. controls, the means were significantly different (p less than 0.02). Duplicate fecal samples were found to check within an average of +/- 31.1% of their means.

Asbestiform amphibole minerals: detection and measurement of high concentrations in municipal water supplies

Ashestiform amphibole minerals, which have been demonstrated to be associated with human health problems, have been detected in substantial quantities in municipal water supplies taken from western Lake Superior Water. The total concentrationl of amphibole minerals in the Duluth, Minnesota, water supply, as measured by x-ray diffraction for daily samples of suspended solids averages 0.19 milligram per liter with large fluctuations due to seasonal and climatological effects on lake circulation. Electron microscopic examination of these water samples confirms the presence of asbestiform amphibole fibers. A conservatiue estimate of the fiber count for 1973 Duluth water supply samples is (1 to 30) x 10(6) amphibole fibers identifiable by electron diffraction per liter of water with a mass concentration of 1 to 30 micrograms per liter.