Alzheimer’s Disease

The relationship of aluminium with Alzheimer’s disease is shrouded in controversy. At the second international symposium on geochemistry and health in London in April 1987, many specialists from the medical profession showed definite evidence of aluminium accumulation on the senile plaque cores of the brain of those suffering from the dementia termed Alzheimer’s disease.

In a well illustrated case study from Guam where the percentage of Alzheimer’s disease is very high, Prof. Dan Perl from Mount Sinai Medical School, New York showed the abundance of aluminium as well as silicon in the senile plaque cores, using laser mass spectroscopy.

Even though one cannot yet attribute a causal effect to aluminium, the observations on aluminium accumulation has led to investigation on the possible role of aluminium in the etiology of Alzheimer’s disease.

The recent work of Prof. Keerthi Tennakone and his team from Ruhuna University and IFS, published in the prestigious journal Nature was also highlighted in the symposium and this brought in a whole new dimension to the problem of aluminium uptake by the human body. Prof. Tennakone and his team discovered that even trace quantities of fluoride ions can catalyse the dissolution of metallic aluminium from cooking utensils.

Their work showed that even one part per million of fluoride present in the water may help in extracting dangerous concentrations of aluminium.

This discovery has understandably caused concern among the general public and the environmental geochemists have now yet another intriguing problem before them, ie. to probe the environmental geochemistry of aluminium and its relationship (if any) on the prevalence of Alzheimer’s disease, bearing in mind that aluminium is one of the most abundant elements in the environment and that fluoride-rich waters are also abundant, particularly in the dry zone.

The water factor and your heart

An awareness of the relationship between environmental geochemistry and the health of man, animals and plants is now being increasingly developed world-wide.

It is also realized that this is a complex problem requiring controlled interactive studies involving geochemists, epidemiologists, ecologists, medical and veterinary practitioners and others.

In a recent publication on Environmental Geochemistry and Health, by the Royal Society, it was stated that, “trace element toxicities and deficiencies in man are especially difficult to relate to the environment in developed countries. However, there are good expectations that direct evidence can be obtained more readily in developing countries and research in such territories is to be encouraged.”

Sri Lanka affords an almost ideal opportunity for the researcher on environmental geochemistry and health in view of the fact that the vast majority of the population of Sri Lanka live in intimate association with the actual physical environment.

This is to say that most people depend on the soil, water, plants and air in the immediate environment for their sustenance. A person who has been drinking water from his garden well for over 60 years and eaten food from plants grown on the soil of his garden will surely have his general health and the trace element budget of his body be governed to a very great extent by the environmental chemistry of the particular water and soil.

This idea can be extended to larger geographical regions and the incidence of certain diseases can therefore be corrected with elemental distributions in the physical environment. Environmental geochemistry is therefore now developing into a very useful tool in investigating regional health problems.

It must be noted that whereas much emphasis is laid on the pollution of the physical environment by man, the effect of the chemistry of the natural environment on the health of a population is also of equal importance. What is required is therefore a much closer interaction between geochemists on the one hand and on the other, professionals such as medical practitioners, epidemiologists and ecologists on the other, working on joint projects.

At the Royal Society meeting mentioned earlier, the clear need to differentiate between hazards due to the natural distribution of elements and due to those introduced by man’s activities was noted.
Water hardness

What level of lead could be expected be taken up by plants grown in a market garden close to a major road?

In Sri Lanka there are many and interesting geochemical situations that need detailed investigation. A few case studies can be highlighted here.

A very interesting relationship that has been observed in many countries is the negative correlation of cardiovascular disease incidence with water hardness, of that area. Deficiencies or excess in the content or availability of trace elements on the rocks and soils, or in water flowing through them, is often considered to be a possible cause of certain diseases, including cardiovascular diseases.

Several investigations have revealed that higher cardiovascular pathology is almost consistently associated with environments (rocks, soils or water) that are generally deficient in trace elements.

In Sri Lanka, the Northern Province, underlaid mostly by sedimentary limestone formations, has the highest water hardness as well as the total dissolved solids (TDS). Interestingly, it is this area in Sri Lanka which has the lowest cardiovascular disease rate.

Areas in the Central Highlands, on the other hand, have soft water and low total dissolved solids contents. Some of the highest cardiovascular death rates, are also found in these mineral deficient groundwater regions. Even though hardwater itself may not be the factor controlling cardiovascular diseases, epidemiological studies have consistently shown that there is a ‘water factor’ associated with hardwater the lack of which may be etiologically important.

The ‘water factor’ may well be a single trace element, a cluster or even, an indirect relationship. Looking for the water factor presents a special challenge to the geochemist and the epidemiologist. If the relation is causal and if the factor in the water can be determined and altered in a beneficial direction, a definite preventive health possibility could well be at hand.