The Occurrence of Aluminum in Drinking Water

A random selection of 186 water utilities was used for this study in which raw and finished water samples were collected from each facility five times throughout a year and analyzed for iron and aluminum by atomic absorption techniques. The water samples were categorized by the supply source (ground, surface, or a combination of both), the type of water (raw, finished, or untreated distribution samples), and the type of coagulation used in the treatment process (aluminum sulfate, ferric chloride, other coagulants such as cationic polymers, or no coagulant). The samples were also categorized according to the 10 US Environmental Protection Agency regions and 4 population categories. The results indicate that aluminum is more likely to exist in surface waters than in groundwaters and that there is a 40-50 percent chance that alum coagulation increases the aluminum concentration of finished water above its original concentration in the raw water. Although aluminum is one of the most abundant elements in the earth’s crust and is found in human biological media, it does not appear to be necessary for sustaining life. The results of studies in which animals were exposed to aluminum under controlled conditions have demonstrated a relationship between certain neuropathological disorders and aluminum exposure.‘.’ Recently, evidence has been presented to support the speculation that there is a relationship between aluminum and both Alzheimer’s disease and dialysis encephalopathy in humans?.4 Davison et al5 found that kidney dialysis patients suffered dementia when their dialysis fluid contained an aluminum concentration of 80 pg/L. Removal of the aluminum from the fluid prior to dialysis decreased a patient’s chance of exhibiting the symptoms of dementia. Recent studiese-9 have also shown that the acidification of lakes and streams by acid rain has mobilized aluminum from the soil to the aquatic environment. These elevated levels of aluminum in the water may have serious ramifications for the fish living in these waters as well as for some birds whose diets are made up of insects from the shoreline of the affected streams and lakes.s-9 Because of the increasing concern over the health effects associated with aluminum and the increased bioavailability of aluminum, this study was designed to determine (1) the frequency of the occurrence of aluminum in natural waters that serve as sources of drinking water and (2) whether the source was groundwater or surface water. This study also examined the