Upload
abhijeet-kadu
View
142
Download
3
Tags:
Embed Size (px)
Citation preview
FLUORIDE TOXICITY AND DEFLUORIDATION:.
11/27/08
Fluorides
2
, we know that even very low levels of fluoride in water and air are damaging to certain species of plants. y High doses are well known to be poisonous to animals and humans. y Sodium fluoride, the most commonly used fluoridating agent, is used as a RODENT POISON.y y
Therefore, the question lingers,
3
HOW SAFE ARE FLUORIDE PRODUCTS AND FLUORIDATION FOR PEOPLE??!
gf
FLUORIDE A BOON OR CURSE??????
Fluoride Dosey y
y
y y
The dose is determined by how much fluoridated water you consume in a day. The dose is determined by how much fluoride you also take in from other sources (dental products, consumer products, air, food, bathing/showering). The dose is influenced by how well your body filters/eliminates toxic substances(e.g. kidney status/function). The dose is cumulative over a lifetime. The dose is relative to body size and age (babies consume more water per body weight/mass than do adults).
What Is Optimum Dose
y
1 mg per day as per The Dean Curve
In 1942 Trendly Dean first produced the seminal research used to promote the hypothesis that naturally-occurring calcium fluoride in water prevents cavities
.
INTRODUCTIONProlonged use of fluoride at recommended level does not produce harmful physiological effect in human. y Excessive ingestion of fluoride over short period of time produce acute toxicity. y Excessive ingestion of fluoride over long period of time produce chronic toxicity. y W.H.O has recommended optimum level of fluoride in drinking water as 0.5 to 1.0ppmy
Toxicity of fluorides Double edged sword Acute toxic dose y CLD- 5-10g Naf (32-64mgF/kg body wt) = 70kg (Hodge& smith 1965) y STD(Safely Tolerated Dose) 8-16 mgF /kg y To prevent accidental poisoning of infant weighing 10kgs not more than 264mg of fluoride should be given.y
Acute fluoride toxicityInitial symptoms(100mgF) y nausea, abdominal cramps, vomiting , diarrhea, tearing, mucous discharge from nose increased salivation, convulsion, dehydration and thirst- fatalityy y
Generalized weakness, spasm of extremities, tetany Rise plasma k, fall in plasma ca (cardiac arrhythmia), ,pulse- thready, low B.P Coma- death (acute F poisoning)
Factors affecting acute toxicityCation of the compound- SnF y Route of administration y Age younger animals tolerate >2.5 timesF (mornstad 1975) y Rate of absorption disodium mono fluoro phosphate y Acid-base status pH of solution/gastric acidy
SYSTEM AFFECTED
SIGNS AND SYMPTOMS
GASTROINTESTINAL
NAUSEA,CRAMPS,VOMITTING, DIARRHEA,ABDOMINAL PAIN.
NEUROLOGICAL
PARAESTHESIA,PARESIS,TETANY, CNS DEPRESSION,COMA.
CARDIOVASCULAR
WEAK PULSE, PALLOR,SHOCK, CARDIAC IRREGULARITIES
BLOOD CHEMISTRY
ACIDOSIS,HYPOCALCEMIA AND HYPOMAGNESEMIA.
Treatment of acute fluoride toxicityy y y y
Reduce amt of F induce vomiting 1% Cacl/ca gluconate Inform emergency dept Transport to hospital
Hospital y Establish patent airway,Iv line y Monitor & maintain cardiovascular circulation y Gastric lavage y Blood samples y Fluid replacement y O2 therapy, ca replacement, glucose, artificial resp, hemodialysis
Emergency treatment for fluoride overdosemgF/kg body wt 5mg/kg
>15mg/kg
Chronic fluoride toxicityy
Fluorosis an endemic disease in geographic areas where the content of F ion in the drinking water >2ppm Dental fluorosis- specific disturbance of tooth formation caused by excessive fluoride intake Enamel fluorosis- developmental phenomenon due to excessive fluoride ingestion during amelogenesis
y
y
FLUOROSISFLUOROSISENDEMIC HEALTH PROBLEM y AFFECTING 23-26 NATIONS AROUND THE GLOBE.yAUSTRALIA,ARGENTINA,ALGERIA,BANGLADESH, CHINA,EGYPT,ETHIOPIA,IRAQ, IRAN, INDIA,JORDAN,JAPAN,KENYA,LIBYA,MORACCO, MEXICO,NEWZEALAND,PALESTINE,PAKISTAN, SYRIA,SENEGAL,TURKEY,THAILAND,UGANDA, UNITED ARAB EMIRATES.
GUIDELINE1.5MG/LITRE IS DESIRABLE UPPER LIMIT. y DUE TO HIGH PREVALENCE OF DENTAL FLUOROSIS SENEGAL REDUCE IT TO 0.6MG/LITREy WHO
IN DEVLOPED COUNTRY WATER FLUORIDATION y IN DEVLOPING COUNTRY- WATER CONTAMINATED WITH FLUORIDE(IN INDIA 0.5- 48 MG/LITRE y PROMOTING FLUORIDATED DENTAL PRODUCT IN INDIA NEEDS REEVALUATION..y
FLUOROSIS- INDIAN SCENARIO FLUOROSISCRIPPLING CONDITION OCCURS DUE TO ENTRY OF FLUORIDE y CLINICAL MANIFESTATION DEPENDS ON AGE, NUTRITIONAL STATUS, EFFICACY OF KIDNEY TO EXCRETE ETCy
yAP-16/23 GUJ-18/19 RJS-32/32 KAR-18/27 ORI-18/32 PNJ-14/17
yy y y y y
y
IN INDIA y 20/35 STATES AND UNION TEROTORIES y HIGHLY ENDEMIC ARE y AP, GUJRAT, RAJASTHAN, KARNATKA, ORISSA, PUNJABy
HISTORICAL PERSPECTIVE-EARLY 1930-FARMERS OF AP(NELLORE DIST)- OBSERVE IT IN CATTLE. y CATTLE BECOME INEFFICIENT WITHIN 6 MONTH DUE TO JOINT PAINy
MAGNITUDE OF PROBLEMy
66.62 MILLION PEOPLE ARE SUFFERING, OF WHICH 6MILLION ARE CHILDREN BELOW 14 YRS.
FLUORIDE DOES NOT CHANGE COLOR, SMELL OR TASTE . y VICTIMS ARE USUALLY OF RURAL AREA, AND ARE NOT AWARE THAT IT IS CAUSED BY DRINKING WATER. y IS NOT CURATIVE BUT CAN BE PREVENTED.y
FLUORIDE ENTER THE BODY THROUGH FOOD AND WATER. y EVEN THE AREA IS FLUORIDE SAFE ,COSUMPTION OF STORED DIETARY FOOD FROM THAT AREA CAN CAUSE FLUOROSIS. y EG.. DRIED SEAWEED, TEA, SARDINES, SHRIMP CRAB, WHEAT GERM, EGG SOYBEAN ETC.y
INGESTED ABOVE THE LIMIT OF BODY TOLERANCE , THREE FORM OF FLUOROSIS MAY APPEAR. y SKELETAL y DENTAL y NON SKELETAL.y
Dental fluorosis
Clinical features of DFy
Earliest stage: Thin white striae across the enamel surface snow cap phenomena
y
y
Fine white linesbroader- white scattered areas
y
Irregular, opaque cloudy areas
y
Brownish discoloration
y
Chalky white
y
Enamel defects
y
Corroded areas
y
Total loss of surface enamel
Variables affecting prevalence & severity of DFFluoride concentration in water y Amount ingested/ bioavailaibility y Daily total F intake y Nutritional status of individualy
Assessment of DF within individuals & populationsDistribution within permanent dentition (Larsen 1985,Manji1986)
Pre eruptive- all surfaces, post eruptive y Posterior teeth- premolar & 2nd molary
Distribution within primary dentition (Thylstrup 1978) y Less DF y Distribution within dentition y Mild DF diff, less pronounced striae of retzius
Mild fluorosis on cervical third of primary molars
Permanent teeth
Mild to moderate fluorosis of primary dentition
Loss of tooth structure
Pitting & staining
Cosmetic treatment of DFMild- repair Mod- severe DF y prosthetic replacement y Rubbing teeth with 18% HCL (with/without heat) y Hydrogen peroxide y Croll 1989- micro abrasion/ grinding
Skeletal fluorosis
Skeletal fluorosis1937 State of madras, India (Shortt et al)- >8ppm y Fl dosage- 20-80mgF/day- 10-20yr (madras, Punjab)y
Symptoms- severe pain in back bones, joint, hips, stiffness in joints & spine y Advanced- Outward bending of legs, hands- knock- knee syndrome y Severe- crippling fluorosis- spine rigid, joints stiffen
Non skeletal health hazardsDestruction of stomach & intestinal lining (mucosa). F+HCl =HF+Cl High concentration causes Nervousness & Depression, Muscle Weakness & stiffness. Early destruction of RBCs causes anemia. soft tissues like ligaments, blood vessels tend to harden and calcify and the blood vessels may be blocked. Excessive fluoride intake since early childhood would reduce mental work capacity (MWC) (case study). May causes cancer (less clearly defined).
DefluoridationIt is scientific means to improve the quality of water with high fluoride concentration by adjusting the optimum level in drinking waterOR
It is the process of removing excess , naturally occurring fluorides from drinking water in order to reduce the prevalence and severity of Fluorosis
Why Defluoridation
Recommended Values for Fluoride in Drinking WaterWHO: 0.1 to 0.5 ppm y US Standard: 0.6 to 0.9 ppm y Bureau of Indian Standard: Max. Limit 0.5 ppm MPL 1.5 ppm y WHO(1963): 0.7 to 1.2 ppm (Prevention of Dental Caries)y
Following criteria need to be considered for defluoridation in developing countries.Fluoride removal capacity y Simple design y Easy availability of required materials and chemicals y Acceptability of the method by users with respect to taste and costy
Techniques for Defluoridation:y Ion
Exchange Process y Addition of Chemicals to water during treatment y Adsorption y Electrolytic de-fluoridation y Electro dialysis
Chemical Addition/ Precipitation Method y Alum y Alum & Lime y Lime Softening y Calcium Chloride
Adsorption/Ion Exchange
a. Anion Exchange b. Cation Exchange
Some substances adsorb F ion by the surface & it can exchange ils negative ions such as OH_ group for F ions Thus conc, of F in water decreases. The process depends on: pH, temp.,flow rate,grain size of material
Polystyrene Anion Exchange Resins
Adsorption/Ion Exchange commonly used materials areActivated Alumina y Fluidized Activated Alumina y Activated Bauxite y Zeolite y Tricalcium Phosphate y Superphosphatey
Activated Bone char y Magnesite y Activated Carbon y Palan carbon y Charcoal y Clay and Soil y Bricksy
Methods based on membrane separation:Reverse osmosis process y All elements in water diminished after filtration y Best water purification process available y But expensiveas 30% of raw water is lost during the processy
Indian Technologies for DefluoridationNalgonda Technique y Prasanti Technology (Activated Alumina) y Red Mud y Magnesium Oxide y Clay Minerals (Montmorillonite)yy y y y y y
Combined Nalgonda and Calcined Magnesite Technique Fish Bone Charcoal Mycetial Biomass Tricalcium Phosphate Tamrind Seed Drumstick Plant(Moringa Cleifera)
NALGONDA TECHNIQUENawalkhe and Chandola (1975)National Environmental Engineering Research Institute, Nagpur (NEERI)
NALGONDA District in ANDHRA PRADESH
TOWN IN KATHRI
MATERIALSy ALUM
(ALUMINIUM SULPHATE)
10% to 40 L/buckety LIME
(CALCIUM OXIDE) 1/20th Dose of Alum POWDER
y BLEACHING
3 mg/L
Raw estimation of required dosage of alum.A preliminary estimate is made on the amounts of alum needed using the formula developed by Dahi et al. 1995: y A = (Fr - Ft) V/(a Ft 1/b) Where: y A is the amount of alum required, g. y Fr is the fluoride concentration in the raw water, mg/l. y Ft is the residual fluoride concentration in the treated water, mg/l. y V is the volume of water to be treated. y a is the sorption capacity constant, y b is the sorption intensity constanty
PROCEDURE
FLOCCULATION
SEDIMENTATIO N
FILTRATION
Salient features of Nalgonda techniquey y y y y y
y
No regeneration of media No handling of caustic acids and alkalis Readily available chemicals used in conventional municipal water treatment are only required Adaptable to domestic use Flexible up to several thousands m3 / d Applicable in batch as well as in continuous operation to suit needs simplicity of design, construction, operation and maintenance Local skills could be readily employed
y y y y y y
Higly efficient removal of fluorides from 1.5 to 20 mg/L to desirable levels Simultaneous removal of color, odor, turbidity, bacteria and organic contaminants Normally associated alkalinity ensures fluoride removal efficiency Sludge generated is convertible to alum for use elsewhere Little wastage of water and least disposal problem Needs minimum of mechanical and electrical equipment
Applicable in batch as well as in continuous operation to suit needs simplicity of design, construction, operation and maintenance y Local skills could be readily employedy
No energy except muscle power for domestic equipment y Economical - annual cost of defluoridation (1991 basis) of water works out to Rs.20/for domestic treatment and Rs.85/- for community treatment using fill and draw system based on 5000 population for water with 5 mg/L and 400 mg/L alkalinity which requires 600 mg/L alum dose. y Provides defluoridated water of uniform acceptable qualityy
DISADVANTAGESy
FLOCS SLOWLY RELEASE FLUORIDE REMOVES SMALLER PORTION OF FLUORIDE CATHARTIC EFFECT DEMENTIA DISEASE REMNANT - ENVIRONMENTAL HEALTH PROBLEM REGULAR ANALYSIS OF FEED AND WATER
y
y
y
y
y
Combined Nalgonda and Calcined Magnesite TechniqueTANZANIA (1985) PILOT PLANT COMPLETED 1990 MAGNESITE Chambogo in Same District Loborosite in Kiteto District Longido in Monduli District
CALCINED MAGNESITEPortions of RAW Magnisite burned at 900 C CRUSHED TO 0.5 TO 1mm PACKED IN PLASTIC BUCKETS
In this plant the Nalgonda technique was passsed through a filter bed consisting of these granules,thus further reduclng F conc.
PROCEDURESEDIMENTED WATER
CALCINED MAGNESITE GRANULES FILTER BED
ADVANTAGESy
CHEAPER SUBSTITUTE MORE REFINED TECHNOLOGY FLUORIDE LEVELS ARE MUCH LOWER THAN NALGONDA TECHNIQUE
y
y
DISADVANTAGESy
RISE IN pH OVER 10.0 WATER NEEDED FURTHER TREATMENT IMPRACTICAL FOR RURAL REGION CALCINED MAGNESITE NEEDS REGENERATION
y
y
y
Hand pump attached Defluoridation Unit
DOMESTIC DEFLUORIDATION UNIT:
DIP REGENERATION:
BIOsorbentsy
Drumstick Plant (Moringa Cleifera) Tamrind gel Aloe vera HydrillaVerticillata (Royale Plants) Duck Weed (Spirodella Polyrrhiza)
y
y
y
y
Tamarind Gely
The concentration of fluoride from solution of sodium fluoride of 10 mg/L could be brought down to 2 mg/L by the addition of tamarind gel alone and to 0.05 mg/L by the addition of small quantity of chloride with the tamarind gel.
A rare earth metal-based inorganic adsorbent, Cerium- Iron adsorbent (CFA), was developed and its performance for fluoride removal from water was evaluated. y Results show that rare earth metal adsorbents had a relatively high adsorption capacity and good kinetic property for fluoride ion removal. The highest capacity was obtained at pH 3, then it decreased with the increase of pH.y
Other Methodsy Fish
Bone Charcoal Biomass Phosphate
y Mycelial
y Tricalcium
Fruits having anti-oxidant potential. anti(Gooseberry, F: Euphorbiaceae), y Mangifera indica(L) (Mango, F: Anacardiaceae), y Averrhoa carambola (L) (Star fruit, F: Oxalidaceae) y Limonia acidissima (L) (Wood apple, F: Rutaceae). y Fluoride toxicity causes oxidative stress which can be relieved by these fruits.y
PREVENTION BETTER THAN CURE
Methods on the Horizon1.Antiplaque agents and detector enzyme GTF may be inhibited Some plants & fungal products Controlled Release Devices(CRD) Prophy paste with ACP(Amorphous Calcium Phosphate) Lyre-Jet Intraoral camera with plaque detector
2.Altering Surface Morphology/Increasing tooth resistance Surface acting polymeric agent for surface adhesive binding Two step procedure by enhancing F uptake 5%NaF white varnish Toothpaste with proprietary system New pit &fissure sealant with ACP
3.Lasers: CO2 lasers 4.Benign microorganisms/Replacement therapy Use a thorn to draw a thorn philosophy 5.SAP(Self Assembling Polypeptides) helps in promoting enamel remineralization Used as a pacifier for young children against baby bottle caries Also used in mouth rinses & dentifrices
6.Chewing gum 7. Tooth friendly sweets 8.Microdentistry 9.Teledentistry 10.Indegenious products
CARIES VACCINEDefination: A vaccine has beed defined as a suspension of attenuated or killed microorganisms administered for the prevention,amelioration or treatment of infectious disease.(Stedmans dictionary,1990).
How It Works?It keeps the patient in the state of readiness. So secondary immune response can be mounted more rapid & effective.
Routes Of AdministrationThe various routes include: 1.Oral route 2.Systemic route 3.Active gingivo-salivary route 4.Active Immunization i)Synthetic peptides ii)coupling with cholera toxin subunits iii)Fusing with Salmonella iv)Liposomes
5.Passive Immunization i)Monoclonal antibodies ii)Bovine milk and whey iii)Egg-yolk antibodies iv)Transgenic plants v)An apple a day keeps the tooth doctor away