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Damage to Plants and Flowers by Fluoridated Tap Water

By John T. Webber

Five studies from four countries illustrate the damage to plants and flowers from water contaminated with fluorides at the concentrations used to artificially fluoridate public drinking water supplies.

STUDY No.1 Fluoride Damage to Gladioli Cuttings [1969]

From the Institute for Phytopathological Research at Wageningen in The Netherlands, Dr. F. Spierings reported damage to gladioli. In his work "Snow Prince'' gladiolus cuttings showed mean tip burning at 21.2mm when they were kept for 4 days in municipal 1ppm artificially fluoridated water as opposed to only 9.5mm of such damage in the controls maintained in non-fluoridated water. Flower stems from three other varieties gave similar results.

Dr. Spierings' paper appeared in Tuinbouw Meded., 32(3): 110-114, 1969 (Chem. Abstr., 71:88560g, Nov. 10,1969)

Reference: National Fluoridation News, U.S.A., Vol. XVI, No. 1, January-February 1970.

The respected science-news weekly New Scientist, Jan. 22, 1970, p.143 cited this study as "irrefutable evidence of the harmful effects of fluorine (at the 1ppm concentration) in water supplies, giving ... a powerful new argument against fluoridation."

The article notes that as water evaporates from the leaves the concentration of fluorine in them increases after four days to levels as high as 105 parts per million. "The root seems to provide a barrier to the uptake of bound fluoride which, in the cut stem, is translocated to the leaves and accumulates as the water is transpired. It only takes a short while for the accumulation to reach toxic proportions." The article notes that fluoridated water causes "disfigurement and damage to the leaves of gladioli in vases."

Reference: National Fluoridation News, U.S.A. VOL. XVI. No. 2, March-May 1970.

Leaf tips of the gladiolus variety "Snow Prince".

Left: After 4 days in 1 ppm fluoridated water; Right: After 4 days in non-fluoridated water (0.08ppm).

STUDY No.2 Fluoride Damage to Gladioli and Rose Cuttings [1970]

This study, by Associate Horticulturalist W.E. Waters, Ph.D., at the Bridge Ornamental Horticultural Laboratory of the University of Florida, Apopka, Florida, U.S.A., has found that of the many different ions present in various Florida well waters, dissolved fluoride is by far the most toxic to gladiolus and rose cuttings. (Wells in parts of U.S.A. are contaminated with fluorides after water seepage through fluorspar rock. Australia, an old continent, is almost totally free of this problem and well water in Australia is only rarely naturally contaminated with fluorides. Surface water supplies have little or no fluoride present. Only 0.7% of Australia's population have used naturally occurring water supplies contaminated with fluorides at even half the concentration "recommended" for artificial fluoridation of public water supplies. Reference: Fluoridated of Water in Australia 1979, Commonwealth Department of Health, p.23 - Editor).

The principal fluoride toxicity symptoms exhibited by gladiolus cuttings include delayed floret opening, petal discolouration and deterioration, and stem sheath burning. A decrease in vase life of about 20 per cent for each part per million fluoride in the holding solution was noted by Dr. Waters. His experiments were conducted at 75 degrees Fahrenheit under constant lighting and gave reproducible results with high significance levels.

Parallel findings were also reported by Dr. Walters in later studies with "Tropicana" roses. Marginal petal discolouration, delay or failure of bud opening, and premature collapsing of peduncles (flower droop) are the principal symptoms of fluoride toxicity in this species. Vase life is shortened on the average by 18 per cent for holding solutions containing 1ppm fluoride and 35 per cent for those containing 3ppm. Total soluble salts in the absence of fluoride have only minor effects on the keeping quality of both roses and gladioli.

Lowered Quality Index

In Dr. Water's studies a "flower quality index" scale of 1 to 10 was adopted. This assigns the number 10 to normal bud opening with no petal discolouration and the number 1 to severe petal burn with little or no bud or floret maturation after 4 days in the holding solution at 75°F under a light intensity of 100-foot candles.

Valeria gladiolus and Tropicana rose cuttings responded as follows to increasing fluoride concentration (from sodium fluoride) in distilled water (see picture):

Effect of fluoride in distilled water after 4 days of Tropicana rose cuttings. Photographs courtesy of Dr. W.E. Waters

NB. Please note that this image has been digitally enhanced due to poor scanning reproduction. The blooms on the left (at 0ppm F) show healthy growth with no wilting.

For commercial purposes. Dr. Waters estimates that a quality index of at least 9.0 is needed for gladiolus florets and at least 8.5 for cut roses. Thus even 1ppm fluoride in the holding solution is too deleterious for an acceptable product.

The reports of Dr. Waters' work were published in Proc. Amer. Soc. Horticult. Sci. 92:633-640, 1968; and Proc. Fla. State Horticult. Soc, 81:355-359,1968.

Reference: National Fluoridation News, U.S.A., Vol. XVI, No. 1. January-February 1970.

STUDY No.3 Fluoride Damage to Decorative Tropical Foliage Plants [1978]

This study summarises prior studies by University of Florida Agricultural Research Centre scientists in Apoka, Florida, U.S.A. They discovered that fluoride in irrigation water, superphosphate fertiliser and certain soil mixes caused serious foliar damage to a variety of tropical foliage plants.

Plants which showed marked sensitivity to fluoride included:

• Cordyline terminal is 'Baby Doll' (Baby Doll Ti)

• Dracaena deremensis 'Warneckii' (Warneck Dracaena)

• D. dereminsis 'Janet Craig' (Janet Craig Dracaena)

• Chlorophytum comosum (Spider Plant)

Fluoride is probably a causal agent of foliar damage to several other foliage plants including:

• Aspidistra e/af/or (Cast-Iron Plant)

• Calathea insignis (Rattlesnake Plant)

• C. Makoyana (Peacock Plant)

• Ctenanthe 'Dragon Tracks' (Dragon Tracks)

• Dracaena fragrans 'Massangeana' (Massangeana)

• D. marginata (Madagascar Dragon-Tree)

• D. Sanderana (Ribbon Dracaena)

• Maranta leuconeura erythroneura (Red-Nerve Plant)

• M. leuconeura Kerchoviana (Prayer Plant)

Nature of Damage

In the case of Baby Doll Ti the damage occurs as "small, brown necrotic lesions on the leaf tip which enlarge and coalesce until the whole leaf may become necrotic." In Warneckii Dracaena the necrotic areas develop "along the margins and also in white portions of leaves." In Janet Dracaena the damage "is exhibited by necrotic leaf tips which are usually bordered by a chlorotic band."

The extreme sensitivity of Baby Doll tip cuttings rooted in water was revealed when tap water containing only 0.25ppm fluoride caused "necrotic lesions on the leaf margins of the older leaves." Further studies disclosed similar damage "when the water contained fluoride concentrations as low as 0.15 parts per million" in propagation experiments (see Table).

Commenting on these findings in relation to fluoridation, the authors warn: "Growers using treated water for municipalities should also beware, because fluoride is usually added at 0.5 to 1.0 parts per million for tooth decay prevention."

Other Sources of Fluoride

Various soil mixes also produced foliar damage because of their high fluoride content. Perlite and German peat containing 17.2 and 3.9ppm of soluble fluoride respectively, caused substantial to severe necrosis. Pretreatment of these soil mixes with limestone or dolomite to raise the pH to 6.0-6.5 greatly reduced the availability of fluoride and the damage it caused to the plant. Prior leaching with low-fluoride water was also beneficial.

Superphosphate fertiliser, which contains approximately 1.5% (15,000 ppm) fluoride, was likewise found to be extremely toxic to these tropical plants. Greater transpiration and therefore larger fluoride intake also resulted from higher light intensities, low humidity, excessive air movement, and elevated temperatures (100°F vs. 80°F).

From their studies the authors make the following recommendations to growers of fluoride-sensitive plants:

1. Avoid use of superphosphate. (Obtain phosphorus from nonfluoride fertiliser.)
2. Elevate pH 6.0 to 6.5. (Add lime, dolomite or calcium to soil mix.)
3. Avoid soil mixes containing fluoride. (Test for soluble fluoride.)
4. Reduce transpiration, (Avoid high light intensities, excessive air movement high temperatures and low humidity.)
5. Eliminate fluoride in water. (Use water containing less than 0.10 ppm fluoride, especially for propagation of sensitive plants.)

R.T. Poole, CA. Conover, R.W. Henley and A.J. Pate, under the title "Fluoride Toxicity of Foliage Plants - A Research Review" in Volume 1, No. 7 (1978), of Foliage Digest, published by the Foliage Education and Research Foundation, Inc., P.O. Box Y, Apoka, Florida 32703.

Reference: National Fluoridation News, U.S.A., Vol. XXV, No. 1, January-March 1979.

STUDY No.4 Fluoridation - A Cause for Concern in Plant Nutrition - Prudence Leith-Ross [1977]

National Pure Water Association, Manchester, U.K.

The chief danger is likely to lie in the use of hydroponic cultures but, so far as can be ascertained, no research at all has been done with this or with plants grown in a sand and peat mixture which might also be susceptible.

Research by J.A.Tolley has shown that crops of cress (rape) became poorer and more stunted as the fluoride level in which they were grown increased.

This crop was selected because it grows quickly, is easy to handle and a good yield can be obtained within a small area. Using samples of Liverpool tap water, which contains fluoride at 0.1ppm for comparison, he made up solutions containing 1.0 and 4.0ppm (milligrams per litre), growing samples in each simultaneously under standard conditions of light and air.

Sparse and stunted

While the crop grown in ordinary tap water was healthy and prolific, growth in the other two samples was comparatively sparse and stunted, particularly the cress grown in the water containing the highest level. There were also signs of necrotic fluorosis on the roots of both these crops. This would indicate a considerable reduction in yield where fluoridated water is used for irrigation purposes, though obviously the effects on other crops are likely to vary.

Analyses were made to discover the actual amount of fluoride which had entered the fibres of the plant. These showed a considerable increase. The cress grown in the tap water with 0.1ppm contained 0.05mg per kg while the corresponding figures for the 1.0 and 4.0 concentrations were 0.2 and 0.4mg per kg respectively.

This experiment demonstrates clearly that plants are able to concentrate fluoride and possibly other poisons from the water supply and it seems possible that slower growing crops might assimilate even more.

Where a cumulative poison such as fluoride is concerned which has neither taste nor smell and with no known antidote, and which is considered so dangerous that its addition is banned by law from all foods except baking powder, the possible long-term effects on people eating such crops must cause concern, particularly in view of the fact that fluoride from water is only one of several sources of this chemical to be taken up by food crops.

Flowers which have proved sensitive to fluoridated water include freesias, gerberas, poinsettia bracts and dracaena cuttings. 1-12

Growing onion bulbs

An experiment with growing onion bulbs, placing them in fluoridated water, was carried out by Professor A.M. Mohamed of Missouri University.13 He found chromosomal aberrations after only six hours. Admittedly he used a strong concentration. It was a solution 180 times more concentrated than artificially fluoridated tap water. But the chemicals used in water fluoridation are of necessity highly soluble and little is known of the long term effects of water on the soil. That it might eventually affect the seed bearing quality of plants should not be overlooked. Because this does not happen in naturally fluoridated areas cannot necessarily count as reassurance, for natural fluoride nearly always occurs as the highly insoluble calcium fluoride.

Industrial pollution from fluoride occurs in many areas and cattle have been frequent sufferers through the years. Several farmers near the aluminium smelting plant at Invergordon lost herds through fluorosis because of polluted grazing. It is not unknown for Borough Environmental Health Officers to advise that fruit and vegetables cultivated in certain areas should be well washed before consumption. Residents in parts of Tamworth, for instance, have for some years been advised that all locally grown produce should be washed before being eaten because of high fluoride levels in fall-out from several brick and ceramic works and an aluminium recovery plant in the area.

Superphosphates

Not only do we have all this pollution but fluorine is also taken up from superphosphate fertilisers. An application of 1,000lb of superphosphate to one acre has been estimated to add approximately 17.5lb of fluorine, which would increase the soil content down to plough depth to 7.5ppm while a similar quantity of rock phosphate would roughly double the amount.14

In 1970 Soviet soil scientists reported that the regular application of superphosphates over a long period increased the fluorine content and decreased the productivity of certain crops, particularly maize.15 Similar fluorine accumulation in soils had already been noted in the United States.16

Amounts of fluorine in 28 plant products grown in Virginia on soils fertilised with superphosphate over a period of 15 years showed spinach containing 28.3ppm and lettuce and parsley 11.3ppm.16

A study at Aichi in Japan showed a jump in the fluorine levels of food during the seven-year period ending 1965, with pumpkin and watermelon increasing by 429 and 831 percent respectively.17 If these plants take up fluorine, it seems likely that marrow and courgettes will be similarly affected.

A correlation between the geographical distribution of mortality from gastric cancer and the fluorine content of the population's staple diet, rice, was also shown.17

Variety of factors

What happens when fluorine is added to the soil seems to depend on a variety of factors such as the form in which it is applied, the amount added at any one time, how much lime and phosphate are also present, the species of plants grown and the soil type and its geology.14

So, do we really want fluoride in the water supply as well? While there is no suggestion that its use would kill any crop, it is possible that in certain conditions yields might be reduced, as happened with Mr. Tolley's cress. Yields normally fluctuate from year to year and a grower might not immediately realise that fluoridation was the cause of a poor crop and would certainly find it hard to prove. Certainly it would seem advisable for much more research to be carried out before this additional pollutant is inflicted upon us.

References:

1. Hitchcock, A.E., Zimmerman, R.W., and Coe, R.R., 1962. Results of ten years' work (1951-1960) on the effects of fluoride on gladiolus. Contrib. Boyce Thompson Inst. 21 (5): 303-344.
2. Spierings, F., 1969. Injury to cut flowers of gladiolus by fluoridated water. Neth. J. Path. 75:281-286.
3. Marousky, F.J. and Woltz, S.S., 1971. Effect of fluoride and a floral preservative on quality of cut gladiolus. Proc. Florida State Hort. Soc. 84: 375-380.
4. Woltz, S.S. and Marousky, F.J., 1972. Effect of fluoride and a floral preservative on fluoride content and injury to gladiolus florets and injury to poinsettia bracts. Proc. Florida State Hort. Soc. 85:416-418.
5. Waters, W.E. 1968a. Influence of water salinity and fluorides on keeping qualities of 'Tropicana' roses. Proc. Florida State Hort. Soc. 81: 355-359.
6. Waters, W.E., 1968b. Relationship of water salinity and fluorides to keeping quality of chrysanthemums and gladiolus cut flowers. Proc. Am. Soc. Hort. Sci. 92:633-640.
7. Marousky, F.J. and Woltz, S.S., 1975. Relationship of floral preservatives to water movement, fluoride distribution and injury in gladiolus and other cut flowers. Acta Horticulturae. No. 41,171-182.
8. Sytsema, W., 1972. De invlood van fluor op levensduur en kwalheh van sn^biocmcn. Proefetation voor the HocnMSterij, Aafemeer, NcHwriands.
9. Roorda van Eysinga, J.P.N.L and Nederpd, W.A.C Het vaasleven van freesia op gefluorideerd water. Proefstat. Gr. Fr. teelt o. gl., Nallwijk, Intern rapport 5, 1972.
10. Bruyn, J.W. de, and Hulsman, A.N. Fluorschade bij gerbera-snijbloemen. Bedrijfsontw. 3,1972: 209-211.
11. Fluoride, 1970,v. 3, p. 66.
12. Neth. J. PI. Path. 75 (1969), 281-286.
13. Canadian Jnl. of Genetics and Cytology (1966), v. 8, 241.
14. Albert Schatz and Vivian Schatz. Use of Compost Instead of Chemical Fertilizer to avoid Fluorine Contamination of Soil, water and Food. Compost Science - Journal of Waste Recycling, March-April 1972. Vol. 13, No. 2.
15. Kudzin, Yu, K. and Pashova, V.T. Fluorine Content in Soil and Plants
after Prolonged Application of Fertilizers. Pochvovedeniye (U.S.S.R.), 2: 74-79,1970.
16. Robinson, W.O. and Edgington, G. Fluorine in Soils. Soil Science 61:
341-353, 1946.
17. Okamura, T and Matsuhisa, T. The Fluorine content in Favourite Foods of Japanese. Japanese Jour. Publ. Health 14: 41-47,1967.

STUDY No.5 Fluoride Injury in Cut Flowers [1990]

Dr. Rod Jones, Horticultural Research Institute, Knoxfield, Victoria, reports that concentration of 1ppm fluoride is known to damage cut gerberas and gladioli to such an extent that they become unsaleable only two to three days after harvest. Higher levels of fluoride can damage freesias, roses, tulips, snapdragons, chrysanthemums, Easter lilies and Asiatic lilies.

Fluoride injury is caused when flowers are held in tap water, as fluoride is readily taken up with water by the flower. Water is transpired from the flower petals, but fluoride remains, accumulates and changes tissues. Transpiration (or water loss from plant tissues) is greatest from petal tips, so more fluoride builds up here, and damage is most pronounced. Similarly, conditions that increase water uptake by cut flowers: high temperature, low humidity, constant air movement and light encourage fluoride injury.

Gerberas

The most sensitive flowers to fluoride are gerberas and gladioli; both are damaged by 0.5 to 1ppm fluoride. Fluoride injury, in the form of brown petal tips, is a common sight on gerberas in Melbourne's florist shops and can take only 12 to 24 hours to appear after harvest in sensitive
varieties.

Research at the Horticultural Research Institute, Knoxfield has proved that the level of fluoride in Melbourne water (0.5 to 1ppm) is high enough to damage gerberas. There is considerable variation in sensitivity to fluoride between gerbera clones, with pink and yellow varieties being the most sensitive.

Pre-harvest factors also appear to influence fluoride damage in cut gerberas. Geoff Cresswell, working with the N.S.W. Department of Agriculture, has found that calcium treatment of gerbera plants before harvesting effectively delays the onset of fluoride damage in the yellow gerbera variety "KGB".

Gladioli

Fluoride injury in gladioli starts on the petal margins of the lower florets three days after harvest and closely resembles the brown discolouration seen in gerberas. Severe fluoride injury in gladioli results in the failure of florets to open, and damage to petals, floret sheaths, leaves and stems. Damage is common in red and orange gladioli varieties and can be cause by fluoride levels as low as 0.25ppm. White/yellow varieties seem partially resistant.

Other Flowers

Fluoride also damages roses, tulips, freesias and poinsettias. The rose varieties 'Samantha', Tropicana' and 'Bridal Pink' were discoloured, with minor tears and abrasions in the petals becoming more pronounced after standing in vase water containing 2 or 4ppm fluoride for four days. Buds failed to open and bent neck was also induced by 2ppm fluoride. Similar fluoride concentrations caused injuries in freesias and tulips, while 4ppm fluoride damaged chrysanthemums, snapdragons, Easter lilies and Asiatic lilies.

Preventing Damage

The most effective way of preventing fluoride damage is to make sure fluoride-sensitive flowers are never placed in tap water. Rain water from areas with no air pollution by fluorides or de-ionised/distilled water is completely fluoride free and should always be used with most sensitive species, i.e. gerberas, gladioli and freesias. It is most important that growers place these species in fluoride-free water immediately after harvest, as only a few hours exposure to tap water can cause damage.
Rainwater should be used, or fit a water de-ioniser that removes fluoride from tap water. This is the cheapest and most effective way of treating tap water as there is no known chemical additive that can remove fluoride from vase water. Be careful when selecting water filters or de-ionisers as many of those available will remove fluoride.

Keeping flowers in conditions that reduce water uptake can reduce fluoride damage.

Reference: The Lower Link, Vol. 7, No 83, May 1990, ISSN 0815 • 4112.

The above studies consistently show fluoride damage to a variety of plant species and cut flowers caused by fluorides in water. In some sensitive species, less than half the fluoride concentration used to artificially fluoridate public drinking water supplies causes damage to flowers. In the same way that canaries provided a warning of dangerous levels of air pollutants to miners, sensitive plant species, damaged by fluorides, provide a warning to all mankind that the levels of fluoride used to artificially fluoridate drinking water supplies are dangerous to plant species. The 50 fold safety margin applied to most other poisons is ignored when fluorides are concerned, further confirming that fluorides are "the protected pollutant".

It is ironic that Health Departments and Governments, responsible for promoting artificial fluoridation on unwilling communities, ignore the wealth of evidence of damage to man caused by fluorides, in addition to damage to innocent plants and flowers such as shown in these studies.

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