Aluminum Concentration In Water Research Articles

An introduction to critical loads

The critical loads approach to emission controls of gaseous pollutants is a concept with a short but eventful history. Despite difficulties with definitions and agreed values, its acceptance within the UN-ECE Convention on Long Range Transboundary Air Pollution has provided the impetus for developing methods to put critical loads to a practical use—the revision of the UNECE emission protocols for sulphur and nitrogen. Methodologies first focus upon quantifying a pollutant threshold at which harmful effects occur on particular sensitive receptors (usually biological species). This threshold is known as the critical load for deposited pollutants, and as the critical level for gaseous pollutants acting on receptors. To calculate a critical load, biological effects are usually ‘translated’ to critical chemical values, e.g. harmful eeffects on fish ‘translate’ to alkalinity or aluminium concentrations in water; thus, critical load calculations may be based upon the chemistry of a system. Such calculations may be performed using simple, steady-state models, whilst the use of more complex, dynamic models provides an insight into the past and future trends. Maps of critical loads can be drawn using calculated values, and maps of pollutant deposition data will then show geographical areas where critical loads are exceeded. Spatial emission-deposition models can identify sources contributing to areas of excess loads and quantify necessary emission reductions. Optimization procedures applied to such models can derive abatement strategies related to economic costs and critical load effects. The critical load calculations may also be used to underpin the setting of target loads; these are pollutant loads, determined by political agreement, which take account of social, economic and political considerations.

Assessment of aluminium mobilization and pathways in the birkenes catchment, southern norway

In spite of considerable research efforts the detailed mechanisms involved in acidification, and in particular those controlling aluminium concentrations in water, have not been satisfactorily established. In this paper, earlier work on acidification carried out in the Birkenes catchment in southern Norway is first reviewed. Temporal variations in acidity and aluminium concentrations in stream water are related to variations in ionic loadings. Addition of sodium bromide to two small soil plots in Birkenes resulted in high concentrations of H + in the organic horizon and of Al 3+ in the eluvial horizon. The experiment supports the hypothesis presented earlier that water pathways are of great significance in determining stream water chemistry. Suggestions for the improvement of existing models for calculating stream water aluminium concentrations are given.

GEOGRAPHICAL RELATION BETWEEN ALZHEIMER'S DISEASE AND ALUMINIUM IN DRINKING WATER

In a survey of eighty-eight county districts within England and Wales, rates of Alzheimer's disease in people under the age of 70 years were estimated from the records of the computerised tomographic (CT) scanning units that served these districts. Rates were adjusted to compensate for differences in distance from the nearest CT scanning unit and for differences in the size of the population served by the units. Aluminium concentrations in water over the past 10 years were obtained from water authorities and water companies. The risk of Alzheimer's disease was 1·5 times higher in districts where the mean aluminium concentration exceeded 0·11 mg/l than in districts where concentrations were less than 0·01 mg/l. There was no evidence of a relation between other causes of dementia, or epilepsy, and aluminium concentrations in water.

Aluminium in the Rivers Esk and Duddon, Cumbria, and their tributaries

Aluminium concentrations in water have been measured at several points in time for more than 50 sites distributed along the Rivers Esk and Duddon, Cumbria, and their tributaries. Total aluminium (Al total), inorganic monomeric aluminium (Al inorg) and organic monomeric aluminium (Al org) were measured using a modified Driscoll technique. Concentrations were found to vary with season (flow rate) and geographical variation was often high. High Al inorg concentrations (200–300 μg litre −1), associated with low pH levels, were commonly found in tributaries in the upper reaches of the valleys, at high flow rates, and in catchments containing little or no improved agricultural land. Two catchments in the Duddon valley appear to be affected by afforestation and had even higher levels of Al inorg (400–600 μg litre −1). Two catchments in Eskdale were sampled in more detail. It was found that water quality changed markedly after the tributaries flowed through improved pasture land. Al inorg concentration fell and pH values rose. Those changes were associated with increased Ca concentrations, possibly the result of agricultural liming.

Acid water and aluminium exposure: gill lesions and aluminium accumulation in farmed brown trout, Salmo trutta L.

Abstract. Brown trout, Salmo trittta L., from two fish farms, situated within acid‐susceptible areas in Sweden, were studied with respect to aluminium accumulation and gill pathology. The total aluminium concentrations, after liming of the water in both farms, were between 200 and 300μg/1 at sampling. Brown trout from a third farm in a non‐acidified area (total aluminium concentration of water 35μg/1 were included as a control. The aluminium concentrations in gills from farmed brown trout in acidified areas were approximately 20μg/g and 90μg/g wet weight respectively compared with approximately 2μg/g wet weight in control brown trout gills. Light‐ and electron microscopic examination disclosed two major types of gill lesions characterized by chloride cell hyperplasia in the secondary lamellar epithelium and enlargement of the intercellular spaces in the secondary lamellar epithelium. The difference in the aluminium speciation and accumulation may explain the difference in the gill pathology of farmed fish from acidified areas. The chloride cell hyperplasia together with a relatively low aluminium accumulation is considered to reflect a long‐term exposure effect.

Impact of effects of acid precipitation on toxicity of metals.

Acid precipitation may increase human exposure to several potentially toxic metals by increasing metal concentrations in major pathways to man, particularly food and water, and in some instances by enhancing the conversion of metal species to more toxic forms. Human exposures to methylmercury are almost entirely by way of consumption of fish and seafood. In some countries, intakes by this route may approach the levels that can give rise to adverse health effects for population groups with a high consumption of these food items. A possible increase in methylmercury concentrations in fish from lakes affected by acid precipitation may thus be of concern to selected population groups. Human exposures to lead reach levels that are near those associated with adverse health effects in certain sensitive segments of the general population in several countries. The possibility exists that increased exposures to lead may be caused by acid precipitation through a mobilization of lead from soils into crops. A route of exposure to lead that may possibly be influenced by acid precipitation is an increased deterioration of surface materials containing lead and a subsequent ingestion by small children. A similar situation with regard to uptake from food exists for cadmium (at least in some countries). Human metal exposures via drinking water may be increased by acid precipitation. Decreasing pH increases corrosiveness of water enhancing the mobilization of metal salts from soil; metallic compounds may be mobilized from minerals, which may eventually reach drinking water. Also, the dissolution of metals (Pb, Cd, Cu) from piping systems for drinking water by soft acidic waters of high corrosivity may increase metal concentrations in drinking water. Exposures have occasionally reached concentrations which are in the range where adverse health effects may be expected in otherwise healthy persons. Dissolution from piping systems can be prevented by neutralizing the water before distribution. Increased aluminum concentrations in water is a result mainly of the occurrence of Al in acidified natural waters and the use of Al chemicals in drinking water purification. If such water is used for dialysis in patients with chronic renal failure, it may give rise to cases of dialysis dementia and other disorders. A possible influence on health of persons with normal renal function (e.g., causing Alzheimer's disease) is uncertain and requires further investigation.(ABSTRACT TRUNCATED AT 400 WORDS)

Impact of Effects of Acid Precipitation on Toxicity of Metals

Acid precipitation may increase human exposure to several potentially toxic metals by increasing metal concentrations in major pathways to man, particularly food and water, and in some instances by enhancing the conversion of metal species to more toxic forms. Human exposures to methylmercury are almost entirely by way of consumption of fish and seafood. In some countries, intakes by this route may approach the levels that can give rise to adverse health effects for population groups with a high consumption of these food items. A possible increase in methylmercury concentrations in fish from lakes affected by acid precipitation may thus be of concern to selected population groups. Human exposures to lead reach levels that are near those associated with adverse health effects in certain sensitive segments of the general population in several countries. The possibility exists that increased exposures to lead may be caused by acid precipitation through a mobilization of lead from soils into crops. A route of exposure to lead that may possibly be influenced by acid precipitation is an increased deterioration of surface materials containing lead and a subsequent ingestion by small children. A similar situation with regard to uptake from food exists for cadmium (at least in some countries). Human metal exposures via drinking water may be increased by acid precipitation. Decreasing pH increases corrosiveness of water enhancing the mobilization of metal salts from soil; metallic compounds may be mobilized from minerals, which may eventually reach drinking water. Also, the dissolution of metals (Pb, Cd, Cu) from piping systems for drinking water by soft acidic waters of high corrosivity may increase metal concentrations in drinking water. Exposures have occasionally reached concentrations which are in the range where adverse health effects may be expected in otherwise healthy persons. Dissolution from piping systems can be prevented by neutralizing the water before distribution. Increased aluminum concentrations in water is a result mainly of the occurrence of Al in acidified natural waters and the use of Al chemicals in drinking water purification. If such water is used for dialysis in patients with chronic renal failure, it may give rise to cases of dialysis dementia and other disorders. A possible influence on health of persons with normal renal function (e.g., causing Alzheimer's disease) is uncertain and requires further investigation.(ABSTRACT TRUNCATED AT 400 WORDS)

Removal of dissolved aluminum (released by acid rain) using decaying leaves I. Effects of ph and species of leaves

Aluminum ion appears to be toxic to fish particularly at low pH levels. It is important, therefore, to try to remove aluminum ion from water. The short and long term effects of leaves on reducing aluminum concentration in water have been examined. The overall effect of pH on this process has also been studied. Five common species of leaves have been used and their capacities for removing aluminum from solution have been studied. Results showed that leaves absorbed aluminum in widely varying degrees, depending on the type of leaf and the pH of the solution.

Water purification and the incidence of fractures in patients receiving home haemodialysis supervised by a single centre: evidence for "safe" upper limit of aluminium in water.

Between 1968 and 1980 fractures occurred in 56 of 284 patients treated by home haemodialysis in the Sheffield area for longer than one year. Patients sustained four times as many fractures while using dialysate prepared with water containing more than 1.0 mumol aluminium per 1 (2.7 micrograms/100 ml) than while using water containing a smaller concentration. When aluminium was removed from water by deionisation the incidence of fractures diminished during the next year and no patient developed dialysis encephalopathy. These findings show that 1.0 mumol/l is a safe maximum concentration of aluminium in water for use in home haemodialysis. It can be detected by the colorimetric aluminium analyses used by many water authorities. When financial resources are limited it is expedient to reserve aluminium analyses by electrothermal atomic absorption for plasma from patients receiving regular haemodialysis. Ingestion of aluminium hydroxide contributes significantly to the increased plasma aluminium concentration of these patients.