Correlation of cancer incidence with groundwater geochemistry in northern Finland

Abstract

The correlations of age-adjusted incidences of various forms of cancer with the geochemical composition of well water and other forms of groundwater in northern Finland have been studied using standard statistical methods. Available geochemical maps showing the hardness of the water and its uranium, iron and nitrate content and maps depicting the areal distribution of the incidences of ten forms of cancer, were decoded point by point to numerical concentration or incidence values by placing a transparent sheet carrying a regular rectangular grid over each. The grid covering the north of Finland (north of 65 ° N latitude) comprised 261 observation points distributed at regular intervals of about 25 km on the ground.The calculated Spearman product-moment and rank correlation coefficients between the geochemical and medical variables suggest that a strong, statistically significant (p<0.001) positive correlation prevails between the hardness of the water and several forms of cancer, especially total cancer (all forms of cancer combined) in the female population (r = 0.66). On the other hand, iron and, somewhat surprisingly, nitrates, which are commonly thought to promote cancer, show a low degree of correlation with the forms of cancer studied. Also, contrary to expectation, a negative correlation between most forms of cancer with groundwater uranium is indicated, a result which, because of its unexpectedness, calls for further research work based on larger data sets before a conclusion can be drawn that it can be interpreted as an implication of a trend that an appropriate level of uranium in the groundwater and the resulting gentle dose of natural radioactive irradiation can help to prevent the early development of cancer in human tissues and cells.The positive correlation between water hardness and most forms of cancer studied suggests that hard drinking water may be an initiator and promoter of cancer, although it is admitted that the establishment of a positive correlation between the geochemical and medical variables does not necessarily prove a cause-and-effect relationship between them.

Radiation hormesis — fact or fiction?

“…The same is true in India (Nambi and Soman, 1987) and Japan, where Mifune (1992) demonstrated low mortality rates for cancerous diseases (with 46-54% reductions) in Misasa, where hot baths in waters having radon activity levels as high as 400 Bq L -1 are fashionable. In Finland, I (Piispanen, 1991) observed statistically significant negative correlations between various types of cancer and the concentration of uranium in the groundwater (Table 1), and areas with high radon levels similarly do not coincide with areas with high incidences of lung cancer or leukaemia, a relationship known since 1984 (Castr~n, 1994).…”

“…Finland (Piispanen, 1991, negative. Even when areal differences in smoking habits are taken into consideration, the correlation remains essentially the same.…”

“…In addition to Cohen, cautious acceptance of the idea of radiation hormesis has recently been expressed by Sagan (1989), Piispanen (1991), Webster (1993) and Loken and Feinendegen (1993). Sagan's view is evident from his summary of the experimental and other work done on the topic up to 1989: 'The inquiry has raised the surprising possibility that very low doses of ionising radiation may not be harmful after all or may even have net benefits'.…”

“…Recently, the attitudes of a growing number of scientists and experts (Loken and Feinendegen, 1993 and the 42 references therein) seem to have started to move away (Sagan, 1989) from the categorically stagnant state imposed by the radiation paradigm, towards recognition and acceptance of a concept known as radiation hormesis, which states that low-level ionising radiation (LLIR) may be beneficial for human health. The current shift of opinion is obviously the result of an increasing number of scientific papers favouring the idea of radiation hormesis (Luckey had already collected some 1,200 references in 1980 and further references can be found in Loken and Feinendegen, 1993) which, among other things, brought to light the fact that there are often net benefits associated with LLIR and that there is often a negative correlation between the incidence of lung cancer, for instance, and the radon content of the ambient indoor or outdoor air (Cohen, 1991;Piispanen, 1991). On the other hand, reports arriving at diametrically opposite conclusions have also been published (Modan et al, 1989;Wolff, 1989;Henshaw et al, 1990;Upton, 1990;Pershagen et al, 1994), which indicates that opinions differ about the beneficiality of LLIR and that the topic as a whole is controversial.…”

Health effects of desalinated water: Role of electrolyte disturbance in cancer development

“…Annual deaths from stomach cancer were found to be correlated negatively with magnesium concentrations and positively with Mg 2 þ /Ca 2 þ ratios in well and tap water in 98 towns and cities in the Hyogo prefecture of Japan (Sakamoto et al, 1997). A strong, statistically significant (p o0.001) positive correlation was reported between the hardness of groundwater and several forms of cancer, especially total cancer (all forms of cancer combined) in the female population in northern Finland (Piispanen, 1991). A review of older studies by Zemla (1988) concluded that the quality of drinking water can have some influence on the frequency of stomach cancer incidence, especially among the population that had been using such water for a long time.…”