Table 5 : Fluoride concentration in the urine samples of cows from control (C) and fluoride contaminated (F) areas.

No. of cows examined	Age group of cows (yr.)	Fluoride concentration (ppm, w/v)
		Range			Mean
15	3-5	C	:	1.2-2.0	1.60
		F	:	11.8-23.0	14.03
12	5-7	C	:	1.0-2.2	1.95
		F	:	13.5-38.0	25.60
25	above 7	C	:	1.7-2.0	1.85
		F	:	22.6-36.0	29.87

Table 6 : Occurrence of dental lesion in cattle foraging around the alumium factory

Animal type	No. of animals examined	Dental score				Animals with normal teeth		Animals with fluorotic teeth
		0	1	2	3	No.	%	No.	%
Cow	84	12	26	14	32	12	14.3	72	85.7
Bullock	11	2	1	3	5	2	18.2	9	81.8
Buffalo	18	6	2	10	-	6	33.3	12	66.7
Total	113	20	29	27	37	20	21.9	93	78.1

Table 7 : Important findings of the Central Board - A.I.I.M.S. project on fluoride effects on human health.

1.	Atmospheric fluoride level was in the range of 54 to 135 micrograms per cubic meter of air (8-hourly average, one-week study),
2.	Fluoride in blood and urine of test persons was found higher than the normal ones in both pot room and non-pot room workers.
3.	Deforestation was seen around the aluminium factory.

Fluoride in Forage : Monthly variations in the F concentrations of forage and feed of cows maintained within the radius of 0.5 to 1 km of aluminium factory varied from month to month4. In an another study F concentration as high as 1400 ppm was observed in the fodder sample collected nearer to the factory (within radius of 1 km), however, the rest of the samples con­tained less fluoride (3.83 ppm) 12.

Fluoride in Cattle's Urine : F concentration in the urine samples of cows from control (C) and F contaminated (F) areas was found to be more in the cows of age 5 years and above unlike the younger ones (Table5)4. The urine fluoriduconcentration increased with the increase in the level of fluoride in the animal's ration and vice-versa (Figure 1)4.

Cattle Fluorosis : Out of 113 animals examined 85.7% of cows, 81.5% of bullocks and 66.8% of buffaloes grazing around the aluminium factory showed typical fluorotic lesions on their incisors (Table 6) . In an another observations near a fluoride factory (3 km away) the percentage of affected cattle was higher than at a place situated 5 km away12.

Fluoride & Human Health : Central Pollution Control Board and All India Institute of Medical Sciences, New Delhi have completed a project on fluoride pollution effects on human health at an aluminium factory. Important findings of the study are presented at Table 7.

Table 8 : Predicted values of fluoride concentrations in air for three reported safe levels of foliar F-accumulations

Exposure period	Measure of levels in air	Predicted avg. air F-concentration (± C.L.)a for 3 safe levels of foliar F - accumulations.
		20 ppm	35 ppm	40 ppm
1 year	u.g F / dm2 / 7 days	13.11 ±9.45	23.48 ± 10.06	27.3 ± 9.76
	u.g F / dm2 / 30 days	55.91 ±40.26	100.03 ±43.42	114.72 ±42.11
	u.g F / m3	0.43 ± 0.31	0.77 ± 0.33	0.89 + 0.32
2 year	u.g F / dm2 / 7 days	8.84 ±5.49	14.02 ±5.18	15.85 ±5.49
	u.g F / dm2 / 30 days	37.44 ± 23.68	60.17 ±22.37	67.74 ± 23.68
	ug F / m3	0.29 ±0.18	0.46 ±0.17	0.52 ±0.18
a C. L. = Confidence limits at 95% level.

AIR QUALITY STANDARDS & PREDICTED SAFE LEVELS FOR PLANTS AND ANIMALS : The criteria of human, plant and animal health have been used to setup air quality standards for fluoride emissions. The ultimate objective of setting up any air quality standards is to define levels of fluorides in the air which should produce any injury to the healthy plants, animals and humans, directly or indirectly. The plants are the primary accumulators of fluorides under polluted conditions and are consumed by animals and humans. As a result the levels of F-accumulation in plants, as a consequence of exposure to F-polluted air, should be an important criteriorvfor setting up air quality standards. The ambient air concentrations of fluoride and its effects on plant life vary with the kind of industry, levels and range of emissions, climatic conditions and physiographic factors. The ultimate factor which is an indicator of potential damage to plant.animals and human health is the accumulation levels of fluoride in vegetation.

In Canada and U.S.A. fluoride accumulation of 35 ppm to 40 ppm (dry weight basis) in vegetation have been recommended as safe levels for consumption by cattle. However, Israel recommended 20 ppm F level in vegetation which corresponds to the safe level of 10 ppm in urine of cattle.

Based on studies on evergreen plants Sidhu presented predicted levels of F-air concentrations (in Canada) in relation to three levels (20 ppm, 35 ppm and 40 ppm) of F-accumulations in foliage (Table 8)13.

CONCLUSIONS

The studies carried out in India, though limited, have showed that F-accumulation in vegetation exceeded the safe levels of 35 ppm to 40 ppm as recommended in U.S.A. and Canada. Fluoride in cattle's urine was also high and catties showed symptoms of fluorosis.

The data available in India needs to be updatec systematically for prescribing the air quality standard for fluoride and prediction of safe levels for vegetation and animals.

REFERENCES

1. Proc. 74th Annual Meeting of A.P.C.A., Phil.(Penn June,1981. pp.81.44.4.
2. Fluoride Emissions. 1982. Academic ' Press Australia, pp.177 -189.
3. Plant & Soil, 49: 653 - 656 (1978).
4. Environ. Physiol. Ecol..Plants, pp.399 - 406 (1978; B.S.M.P. Singh Publishers, Dehradun (India).
5. J. Occup. Med., 19:49-78(1977).
6. Proc. IV Internat. Clean Air Congress, Tokyo pp.116-119 (1977).
7. Fluoride. 5:18-21 (1972).
8. J. Environ. Biol. 4 (3) : 99- 102 (1983).
9. Indian J. Air Pollut. Control. 3(1) : 23 - 26 (1980).
10. Symp. Environ. Options for Developing Countries The Institute of Science, Bombay. Abstract No.95 pp.65.
11. Res. J. Plant & Environment. 5(2): 11 -14 (1989).
12. Symp. Environ. Options for Developing Countries The Institute of Science, Bombay. Abstract No. 94 pp.64.
13. Environment Canada. Canadian Forest Service. ISS No. 704 - 760. Information Report N-X-203.