Determination of the effect of boiling on the biological properties of tap water by means of phytotesting

Abstract

Introduction. Dosimetric control revealed a significant decrease in the background level of ionizing radiation from tap water after boiling it in various household appliances. As natural doses of ionizing radiation are known to be necessary for the normal functioning of living organisms, it has been suggested that the boiling process may have an adverse effect on the biological properties of water. Materials and Methods. To confirm or refute the indicated assumption, the seeds of barley (Hordeum vulgare) were germinated on tap water, which was boiled in one of the household appliances (microwave oven, electric kettle, ordinary kettle), and measured the length of the roots and epicotyls in 4-day seedlings. Based on the data obtained, the average values of the respective indicators were calculated. Quantitative data were obtained on representative sample sizes and are statistically significant with a probability of 0.05. Results and Discussion. The data obtained during the experimental study indicate that boiled water had a positive effect on the growth of roots and epicotyls of barley seedlings. And if for epicotyls the differences in comparison with the control were statistically insignificant, then for the roots in all experimental variants of germination in boiled water was found a statistically significant increase in the average length of the roots compared to unboiled water (control). Thus, the average length of roots during germination of barley seeds in water boiled on a gas stove was 40.0 ± 4.1 mm, on water boiled in an electric kettle - 33.6 ± 4.6 mm and on water, boiled in a microwave oven, - 32,4 ± 3,5 mm, against 25,7 ± 4,9 mm in control. Thus, (i) boiled tap water, which was obtained in various ways, is able to stimulate growth processes during the germination of barley seeds; (ii) this phenomenon is observed in relation to root growth after all methods of water treatment; (iii) the greatest stimulation of root growth was caused by water boiled on a gas stove. In the second series of experiments to identify the possible effect of substances dissolved in tap water on its biological properties, a comparative analysis of the growth effects of unboiled tap water and distilled tap water (which underwent deep purification) was performed. The data obtained indicate that distilled water stimulates the growth of roots of barley seedlings comparative by unboiled tap water: when germinating barley seeds in distilled water, the average length of the roots of seedlings was 16.1 ± 3.33 mm, while in germinating on unboiled tap water - 9.35 ± 0.79 mm. The next stage of the study was to determine the effect of the level of water purification by boiling on the growth parameters of phytotest. The obtained results indicate that boiling distilled water on a gas stove helped to improve its growth qualities: seedlings grown on such water had an average root length more than 2 times higher than the control values. At the same time, distilled water, which does not underwent such treatment, stimulated less, albeit reliable, seedling root growth. Therefore, the level of tap water purification determines the appropriate degree of its stimulation of root growth processes of barley seedlings. Conclusions. Studies have shown a positive effect of boiled tap water on the average length of seedling roots. The magnitude of the effect depended on the type of device in which the boiling water was carried out. Boiled distilled water also promoted seedling root growth. Possible cause for improvement of growth qualities of water was removal or destruction in the process of boiling of gases and soluble substances which are either unfavorable for the growth of the plant organism or prevent the ice-like structures formation, in the microcavities of which are circulating monomers of water are available for aquapores of living organisms. At the same time, despite the growth-promoting effect, potentially boiled tap water may have mutagenic properties that the growth phytotest does not detect.