CONTENT;- 1.INTRODUCTION.2.ACUTE TOXICITY AND IT’S TREATMENT3.CHRONIC TOXICITY 4.DEFLUORIDATION METHOD5.ADVANTAGE AND DIS ADVANTAGES OF FLUORIDES6.CONCLUSSION.

INTRODUCTIONProlonged use of fluoride at recommended

level does not produce harmful physiological effect in human.

Excessive ingestion of fluoride over short period of time produce acute toxicity.

Excessive ingestion of fluoride over long period of time produce chronic toxicity.

W.H.O has recommended optimum level of fluoride in drinking water as 0.5 to 1.0ppm

ACUTE TOXICITY;-1.The amount of 35 to 70 mgF/kg body weight

of soluable fluoride is to be lethal.2.This is equivalent to 5 to 10 gms of sodium

fluoride for an adult weighing 70kg or 1.0 to 2.0 gm sodium fluoride for a child of 15kg.

3.Acute toxic effects are characterised by;- nausia vomiting diffuse abdominal pain diarrhoea excessive salivation

TREATMENT;-1 vomiting should be induced with syrup of

ipeac or digital or mechanical by stimulation of tongue or throat.

2.Subsequent effect should be made to decrease the absortion of fluoride by administering fluoride binding liquid like warm water, calcium hydroxide liquid ,anta acid cointaining alumunium or magnesium hydroxide.

3.The affected individual should be hospitalised and stomach should be throughly washed with additional lime water.

CHRONIC TOXICITY;-1.Chronic toxicity is due to a long term

ingestion of a smaller amount of fluoride which usually effects the hard tissue and kidney.

2. Chronic toxicity effects of excessive fluoride ingestion are;-

EFFECTS DOSAGE DURATION

DENTAL FLUOROSIS

2 times optimal Until 5 years(Excluding third molars)

SKELETAL FLUOROSIS

10-25mg/day 10-20 years

KIDNEY DAMAGE 5-10mg/day 6-12 months

Girl with severe skeletal fluorosis in Jharkhand

DENTAL FLUOROSIS

Lethal and safe dosages of fluoride for a 70 kg adult

CERTAINLY LETHAL DOSE( CLD) 5-10 gm NAF OR 32-64 mg F/kg

SAFELTY TOLERATED DOSE (STD) = ¼ CLD 1.25-2.5 gm NAF OR 8-16 mg F/kg

DEFLUORIDATION;-Defluoridation is ascientific means to improve

the quality of water with high fluoride concentration by adjusting the optimum level in drinking water.

METHODS1. Adsorption and ion exchange method;-Some substances adsorb fluoride ion by the

surface ,and it can exchange its negative ions such as OH- group for fluoride ions reducing the fluoride concentration in water.

This process depends on conditions like ph, temperature ,flow rate ,grain size of the

material.Commonly used materials;- Activated Alumina(Al2o3) Fluidized Activated Alumina

Activated Bauxite(hydrate of Al(OH)3)Tricalcium phosphate (TCP)

PRECIPITATION METHOD ;-In a high pH condition ,co-precipitation of

several elements in water with fluoride ions form fluoride salts, thus the fluoride concentration in water decreases.

These substances include;- 1. Alum (K Al(SO4)2.12H2O 2.Alum and lime(Cao) 3.Calcium chloride (CaCl2)

METHODS BASED ON MEMBRANE SEPARATION;-

In industrialized world ‘reverse osmosis’ process is well known.

All elements in water get diminished after filtration.

This method is claimed to be the best water purification process available.

Membrane Assisted Defluoridation Process for Safe Drinking Water

INDIAN TECNOLOGY FOR DEFLUORIDATION;-

1.NALAGONDA TECHNIQUE;-This technique first developed in india in

1975,is the most simplest,least expensive and easiest to operate of all the other methods of defluoridation .

The first community plant for the removal of fluoride from the drinking water was constructed in the district of Nalagonda in Andhra Pradesh ,in the town of Kathri,thus the name of the tecnology.

PROCEDURE;-Raw water is mixed with adequate lime and

alum. The amount of lime depends on the alkalinity of the raw water.

Alum solution is added after the addition of lime, stirred gently for 10 minutes and the flocs formed are allowed to settle. The floc formation and setting requires an houre.

Advantages of Nalagonda technology1.This method can be used both at domestic

and community level2.Operations are possible manually.3.It is cost effictive .4.Designs are flexible to use at different

location.5.Defluoridation meets with the standard laid

down by the Bureau of Indian Standard.

COMBINED NALAGONDA AND CALCINED MAGNESITE TECHNIQUE;-

This technique was introduced in Tanzania in 1985.

In this plant Nalagonda technique was passed through a filter bed consisting of calcined magnesite granules.

Fluoride was absorbed by the calcined magnesite granules thus further reducing the fluoride concentration in water.

There was a rise in pH over 10.0 and the treated water needed adjustment befor drinking .

This method was found to be impractical for rural regions

PRASANTI TECNOLOGY;-In Indian villages this method of utilizing

Activated Alumina is found to be most popular and cost effective material for defluoridation.

OTHER METHODS OF DEFLUORIDATION1.FISH BONE CHARCOLEResearches of the univesity of Roorkee

suggested practical application of fish bone charcole as a method of defluoridation.

2.DRUMSTICK PLANT (MORINGA CLEIFERA)

It reduces the water turbidity and has excellent coagulating and clarifying properties,

Defluoridation properties is mainly due to calcium and magnesium levels in the plant.

ASKALI- extract mycetial biomassResearches of osmania University ,Hyderabad

demonstrated the ability of this material from Aspergillus riger to bind fluoride from fluoride containing water.

TRICALCIUM PHOSPHATEIt produce a complex chemical reaction in the

process of defluoridation.

ADVANTAGES OF FLUORIDE’-1.Enhances enamel remineralization.2.Under acidic conditions will decrease the

rate of enamel demineralization.lowers solubility of enamel

3.Interfers with enzymatic process of bacteria.4.Interfers with attachment of odontopathic

organisms to teeth.

SYSTEMIC FLUORIDE.Source 1.drinking water or other beverages 2.fluoride tablet or lozenges 3.fluoride salts ,fluoride sugarADVANTAGES OF SYSTEMIC FLUORIDE

IN RECOMMENDED DOSE 1.low cost 2.no motivation or behavioural changes

nessary

DISADVANTAGES OF SYSTEMIC FLUORIDE;-

1.possibility of mild to moderate fluorosis if fluoride are ingested inadvertently.

2.fluoride toxicity.TROPICAL FLUORIDE SOURCE there are many source of tropical

fluoride available in the form of risens and gels.

ADVANTAGES OF TROPICAL FLUORIDE IN RECOMMENDED DOSE1.do not cause flurosis

2.cariostatic for people of all ages 3.easy to use .DISADVANTAGES OF TROPICAL

FLUORIDE 1.person must remember to use. 2.per capita cost is high compared to water

fluoridation.

Fluoride is a naturally occurring mineral that is found in water and some foods.

Fluoride enhances the tooth remineralization process. Fluoride found in a person's saliva will adsorb onto the surface of a tooth where demineralization (tooth decay formation) has occurred. This in turn actually attracts other minerals (such as calcium), thus helping to speed up the degree of remineralization (reformation of tooth mineral), thus helps to fight tooth decay.

But fluoride has toxic properties on the tooth and the bone in the form of dental and skeletal fluorosis , if ingested inadvertently.

CONCLUSSION

ARNAB KAR

C.R.R.I