FEATURE

Pesticide residue in organic andconventional food-risk analysis

During the era of green revolution in the late sixties, introduction of high yielding varieties, expansion ofirrigated areas, increased use of nitrogen, phosphorous, potassium (N, P and K) fertilizers; chemicalpesticides and higher cropping intensity drove India toward self-sufficiency in food production. Use ofchemical pesticides to control various insects, pests and diseases over the years destroyed many naturallyoccurring effective biological agents. Increased quantities of nutrients and pesticides in agricultural run offwaters in recent years has caused serious problem of water pollution. The ill effects of green revolutioninclude residues of extensively used chemical pesticides in various environmental components. Severalstudies showed that pesticides could cause health problem such as birth defects, nerve damage and cancer.Keeping in mind the problem of pesticide residues in various components of environment, the present studywas conducted on different organic farms and market samples (conventional farms). Four groups ofpesticides, i.e., organochlorine, carbamates, organophosphorous and pyrethrites were analyzed in wheatand rice samples. Presence of organochlorine pesticide residue was observed in two out of ten organicfarms, which were converted from conventional to organic practices few years ago. This was attributed toexcessive use of synthetic pesticides. Wheat and rice samples taken from market (conventional farm)showed significant level of pesticide residues. Method used for extraction of pesticides was validated withrecovery studies, which showed more than 80% recoveries for organochlorine, organophosphorous,carbamates and pyrithroids, respectively. Pesticide residue contamination of food was assessed for riskanalysis.

By Rekha, S.N. Naik, R. Prasad

INTRODUCTION

In the process of development of agri-culture, pesticides have become animportant tool as a plant protectionagent for boosting food production.But their indiscriminate use, apartfrom being an occupational hazard inthe developing world, has been posinga serious threat to human health.1

These agro-chemicals leave residuesin food and thereby produce ill effectswhen concentration exceeds the max-imum residue limit (MRL). Pesticideresidue in food and feed crops, meatand poultry, fish and aquaculture aswell as milk and milk products gener-ally arise from their indiscriminate usein various agricultural practices, grainsstorage and public health.2,3 Their

Rekha, S.N. Naik and R. Prasad areaffiliated with the Centre for RuralDevelopment and Technology, IndianInstitute of Technology, Delhi, India(Tel.: +91 11 26591157;fax: +91 11 26526135;e-mail: rekha_iitd@yahoo.com).

12 � Division of Chemical Health and Safety of the

Elsevier Inc. All rights reserved.

resistance to degradation has resultedin contamination universally found inmany soils.4–8 Such residues may becomprised of many substances, whichinclude any specified derivatives suchas degradation products, metabolitesand impurities that are considered tobe of toxicological significance. Thereis a great concern over growing inci-dence of cancer due to their excessiveuse.9

The prevailing agriculture system‘‘conventional farming or modern agri-culture’’ or industrial farming has deliv-ered tremendous gain in productivityand efficiency. Conventional farmingsystems varies from farm to farm butshare some common characteristicsincluding large capital investment,single/raw crop grown continuouslyover many seasons, extensive use ofpesticides, fertilizers, water and energyinputs, etc. Today, over 500 compoundsare registered worldwide as pesticides,or metabolites of pesticides.10

According to the Food and Agricul-ture Organization (FAO), more than500,000 tons of unused and obsoletepesticides are threatening the environ-ment and public health in many coun-tries.11 Public concern over pesticide

American Chemical Society

residues in food has been increasingduring the last decade. Recoveringfrom the euphoria of green revolution,India is also now battling from residualeffects of extensively used chemicalfertilizers and pesticides such asHCH, DDT, endosulfan, phorate andothers.

Pesticide residue pollution to thelocal environment (air, soil and surfacewater) affect the lives of birds, wildlife,domestic animals, fish, livestock andhuman beings. Human health hazardsvary with the type of the pesticides andalso with the extent of exposure. Mod-erate human health hazards from themisapplication of pesticides includemild headaches, flu, skin rashes,blurred vision and other neurologicaldisorders while rare, but severe humanhealth hazards include paralysis,blindness and even death.12 A studyby Repetto and Baliga13 showed thatpesticides can damage the humanimmune system by reducing the num-ber of white blood cells (WBC) anddisease fighting lymphocytes. Pingaliet al.14 found a greater probability ofeye and skin problems associated withon-site use of pesticides among riceproducers in the Philippines.

1871-5532/$32.00

doi:10.1016/j.chs.2005.01.012

Ideally, an alternative for economiccrop production without the use ofagrochemicals should be developed.One alternative to synthetic pesticideuse is organic farming. However, thisprocess is costly, labor intensive, andin some cases ineffective.15 Organicagriculture and food processingpractices are being widely used indeveloped countries (Germany, UK)and overall seeks the developmentof a food production system that issocially, ecologically and economicallysustainable.

The key principles and practices oforganic food production aims toencourage and enhance biologicalcycles within farming systems to main-tain and increase long time fertility ofsoil, to minimize all forms of pollutioncaused by fertilizers and pesticidesand to produce food of high qualityin sufficient quantity. Interest inorganic farming has grown appreciablyover the last few years in Europe inresponse to increasing customerdemands. The proportion of Danishagriculture land devoted to organicfarming increased from 0.2% to 5%in the period from 1988 to 1999. Themaximum number of organic farms inEurope is in Italy followed by Austria,Spain and Germany.16 Many studieshave been carried out regarding pesti-cide residue in food.17,18 The presenceof multiple pesticide residues in foodcrops has raised public concern andhas triggered work both in the USAand the UK to look at the potentialeffects of pesticide mixtures.19–21 TheGovernment of India has taken stepsto ensure the safe use of pesticides. The(Indian) Insecticide Act, promulgatedin 1968 and enforced on 1st August,1971 attempts to regulate the import,manufacture, sale, transport, distribu-tion and use of insecticides, with a viewto prevent risks to human beings oranimals. The domestic demand inIndia accounts for about 76% of thetotal pesticides used in the country asagainst 44% globally.

Present study was conducted todetermine the pesticide residues inorganically and conventionally grownfood crops available in the market.Further attempts were made to assessrisk-benefit associated with pesticideuse.

Chemical Health & Safety, November/Dece

MATERIALS AND METHODS

Site Selection

India has been divided into 16 agro-climatic zones out of which ten organicfarms were selected from different geo-graphical regions. For thepresent study,rice and wheat were collected fromthese organic farms. Samples of sameproducts were also taken from conven-tional farms (that is, market samples)adjacent to each organic farm. Theorganic farm included in this studyhad been certified by the respectivestate government. The conventionalfarm refers to the farm using fertilizersand pesticides for crop production.

SAMPLING PROCEDURE

One kilogram of each crop (wheat andrice) was taken as a representativesample of the produce, which wasstored in pre-cleaned amber glass con-tainer. Controlled conditions (tem-perature 20 8C) were maintained forall the samples before their final ana-lysis. All analyses were performed within one month of sampling.

ANALYTICAL METHODS

All the solvents used (hexane, acetone,petroleum ether, diethyl ether) in theextraction of pesticides were of HPLCgrade. The glassware used in theexperiments was cleaned with de-ionized water followed by solvent rin-sing. Acetone was used for the extrac-tion of pesticides from various foodcrops because of its effectiveness forpolar and non-polar pesticides from adiverse range of matrices, low toxicityand cost, miscibility with water andease of evaporation. The pesticidescommonly causing contamination ofcereals were selected for this studywhich includes organochlorine pesti-cide, i.e., endosulfan (Group I),organophosphates, i.e., phorate(Group II), carbamates, i.e., carbo-furan (Group III), and pyrethrins,i.e., permethrin (Group IV). Analyti-cal standards of these pesticides wereobtained from Baye India Ltd (purity>98%). A standard stock solution(1,000 mg/L) of each pesticide was

mber 2006

prepared in acetone and further solu-tions of 0.1, 0.2, 0.4, 0.8 and 1.0 mg/Lwere prepared by diluting the stocksolution.

RECOVERY STUDIES

Dry substrates were fortified withindividual pesticides with requiredaliquots of 0.1 and 0.05 mg/L (endo-sulfan), 0.1 and 1.0 mg/L (phorate),0.01 and 0.1 mg/L (carbofuran) and0.1 and 1.0 mg/L (permethrin) level inwheat and rice grains, kept for 4 hoursat normal room temperature(28 � 2 8C) for total absorption of pes-ticides. Wheat and rice samples wereground in a mixer (Remi-Mixie, India)to get a homogenous mixture. Forextraction of pesticides, a measuredquantity of ground sample (25 g)was agitated with known amount of35% H2O–CH3CN mixture (350 mL)on a magnetic stirrer (2MLH Scienti-fic System, Remi Equipments) for5 min in a glass-stoppered flask at200 rpm.22 The solution was filteredwith vacuum filtration system and thefiltrate was transferred in a 1,000 mLseparating funnel. The filtrate mixedwith 100 mL of petroleum ether wasshaken for 2–5 min. A known amountof saturated NaCl solution (10 mL)and distilled water (500 mL) wasadded to it to avoid froth formation.The contents of the separatory funnelwere again shaken for 2 min. The sol-vent layer was collected in a dry flaskcontaining 15 g sodium sulfate (anhy-drous) for 15 min and the volume ofpetroleum ether containing pesticideswas recorded. For complete extrac-tion of pesticides from the aqueouslayer, extraction step was repeatedthree times with 50 mL petroleumether.

Clean-up Procedure

The concentrated extracted samplescontain high content of co-extractiveswhich can damage the GC capillarycolumn, as well as resulting in amatrix enhancement effect. Same pro-cedure of clean up was used for for-tified as well as wheat and rice sample.To minimize this interference, cleanup was done using a glass columnhaving length 300 and 22 mm internal

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Table 1. Sampling sites and food crops analyzed

S. No. Sampling Sites Food Items

1 Grewal’s Organic farm (GOF), Sirsa, Hayana Wheat, rice2 Foundation for Sustainable Development (FSD), UP Wheat, rice3 Kanpur Goshala Society (KGS), UP Wheat4 Eco Farm (EF), Maharashtra Wheat5 Bhartendu, Uttar Pradesh Wheat, rice6 HASS, Uttranchal Rice7 Maa Danteshwari Herbal Products (MDHP)

Pvt. Ltd., ChhatisgarhWheat, rice

8 Dharohar Samiti (DS) (Baster), Chhattisgarh Rice9 JNB, Maharashtra Rice

10 JVP, UP Wheat, rice11 Market sample (MS) Wheat, rice

diameter. Column was packed withglass wool plugs at the bottom ontowhich 100 mm of Florisil (60–100 mesh) was placed between thelayers of anhydrous sodium sulfate.Florisil used was activated at 120 8Cfor 4 hours. The column was thenpre-wetted with petroleum ether andthe extracted solution (as explainedabove) was passed through the col-umn at a flow rate of 5 mL/min.

To strip of organochlorine pesticides(Aldrin, BHC, DDT, Heptachlor, PCB,Epoxide, Lindane and Mythoxychlor)and organophorous pesticides (Ethionand runnel) residues, 200 mL of 6%diethyl ether in petroleum ether waspassed through the column. The eluantwas collected in a conical flask havinga known amount of Na2SO4 (15 g).Another 200 mL of 15% diethyl etherin petroleum ether was used to desorborganochlorine pesticides (dieldrinand endrin) and organophorous pesti-cides (diazinon, methyl parathion andparathion) and collected in a separateconical flask. Similar treatment wasdone with 200 mL of 50% diethyl etherin petroleum ether to get organopho-sphorous pesticides (Malathion). Eachelute obtained with 6%, 15% and 50%diethyl ether in petroleum ether wasconcentrated using rotary evaporator(Heidolph Instruments Laboreta-4000, Germany) to a volume of2–3 mL. A final volume of 5 mL wasprepared in graduated tubes by dilutingwith hexane.

Estimation of Pesticide

The residues were analyses on Hewlett-Packard 5890 series II Gas Chromato-graph (GC) equipped with ElectronCapture Detector (ECD), NPD andfused silica gel capillary column. Theoperating conditions were detectortemperature, 300 8C, injection port250 8C; oven temperature 200 8Cfor initial 4 min and then ramped@ 5 8C/min to 300 8C final tempera-tures. The nitrogen was used, as carriergas with flow rate 15 mL/min. Injectionvolume was 2 mL.

RESULT AND DISCUSSION

Sampling was performed between themonths of May–December 2002. The

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sampling period for various crops wasdifferent as the samples were takenwhen the produce was ready for trans-portation to the market (harvestingtime varies from crop to crop). Thedetailed history for plant protectionschedule and other relevant informa-tion were obtained from the farmers atthe time of sample collection. Varioussampling sites selected for study arelisted in Table 1. These sampling siteswere selected so as to give a true repre-sentative picture of north and centralIndia. The climatic conditions such asrainfall, humidity and annual averagetemperature prevailing at these sam-pling sites are almost identical, sothat the agricultural practices usedcan be compared with each other.Wheat and rice are two most popularand commonly grown crops in Punjab,Haryana, Uttar Pradesh and Bihar.These four states of India collectivelycontribute to more than 65% wheat andrice production. As most of the sam-pling sites are situated in these statesso wheat and rice crops are selectedfor present study. Application of BHC,phorate and endosulfan is a commonpractice to protect the crop in conven-tional farming system. Table 2 presentssome of the physico-chemical charac-teristics of the general pesticides usedin conventional farming. In order toascertain the accuracy of the methodused for analysis of pesticide residue,recovery studies were also conducted.

Recoveries of pesticides were mea-sured by comparing peak areas of thesamples with external standards inacetone and matrix matched controlprepared from unfortified samples.

Chemical Health

The peak areas were compared usingHewlett-Packard Chemistation Soft-ware Version, A 03.34. Recoveries ofall pesticides were determined at dif-ferent fortification concentrations. Thepesticide recovery results are pre-sented in Tables 3 and 4. The recov-eries from wheat samples withendosulfan at 0.05 mg/L level variedfrom 84% to 100% with an average of94%. Recoveries from 0.1 mg/L levelwere slightly lower and varied from77% to 86% with an average of82.3%. The minimum detectable con-centration was 0.05 mg/L. Recoverywith Phorate at concentration of 1.0and 0.1 mg/L concentrations were80.3% and 91.9%, respectively. Withcarbofuran recovery at 0.01 mg/L was74.3% while it was slightly higher for0.1 mg/L (88%) fortification. Recoveryfor permethrin varied from 81.7%(0.1 mg/L) to 94.3% (1.0 mg/L). Incase of rice, recovery for endosulfanand phorate at 0.1 mg/L level variedfrom 80.6% to 86.6%. The recoveryfor carbofuran at 0.1 mg/L was88% but it was comparatively lower(72%) at 0.01 mg/L. Permethrin wasrecovered well (90.7%) at 1.0 mg/Lconcentration.

Among other pesticides used inIndia, 40% of all the pesticides usedbelong to organochlorine class of che-mical pesticides. The other majorcategory isorganophosphatepesticides.Monocrotophos, phorate, phosphami-don, methyl parathion and dimethoateare some of highly hazardous pesticidesthat are continually and indiscrimi-nately used in India. Pesticides aregenerally categorized based upon their

& Safety, November/December 2006

Table 2. Physicochemical characteristics of pesticides

PesticideChemical

Family Structure

WaterSolubility

at 20–25 8C(mg/L)

ToleranceLimitb

mg/kg (ppm)(Cereals)

ToleranceLimit (CodexAlimentarius)

(ppm)

Endosulfan Organochlorine 0.32 0.2 0.1

Phorate Organophosphorous 50 0.05 a

Dimethoate Organophosphorous 25 (g/L) a a

Malathion Organophosphorous 145 4.0 8.0

Parathion Organophosphorus 24 a a

Fenitrothion Organophosphorous 30 0.02 a

Permetherin Pyrithroids 0.2 a a

Deltamethrin Pyrithroids 0.002 0.5 a

BHC Organochlorine Insoluble 0.05 0.5

Carbofuran Carbamate 700 0.10 0.2

a Not prescribed.b PFA (The Prevention of Food and Adulteration Act, 1954, India).

Chemical Health & Safety, November/December 2006 15

Table 3. Percent recovery of pesticide in wheat

PesticideFortificationLevel (mg/L) Replicates

Recovery(mg)

Recovery(%)

AverageRecovery (%)

Endosulfan 0.10 1 0.086 86 82.32 0.077 773 0.084 84

0.05 1 0.049 98 94.02 0.050 1003 0.042 84

Phorate 1.0 1 0.80 80 80.32 0.79 793 0.82 82

0.1 1 0.094 94 91.92 0.093 933 0.086 86

Carbofuran 0.01 1 0.0080 80 74.32 0.0070 703 0.0073 73

0.1 1 0.087 87 88.02 0.090 903 0.087 87

Permethrin 0.1 1 0.087 87 81.72 0.077 773 0.081 81

1.0 1 0.92 92 94.32 1.02 1023 0.89 89

persistence in the environment. Orga-nochlorines are considered persistentpesticides. These pesticides have longenvironmental half-lives and can bioac-cumulate in humans and other animalsand thus biomagnify up to 70,000 timesin the food chain.23–29 Endosulfan isamong the most frequent contaminantsfound in food, soil or water in Europe.30

Residues of organochlorines (endo-sulfan, BHC) were found to be presentin all the conventionally grown marketsamples analyzed (Table 5). Pesticideresidues were well below the MRL.Wheat and rice samples taken fromKGS organic farm showed traces oforganochlorine pesticides, however,these could not be quantified as theresults are below the detection limitof the instrumentation. Interestingly,KGS Organic Farms practiced conven-tional farming until 2000, when theyconverted to organic methods. Astudy-conducted by Kumpulainen31

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stated that pesticide residue levelsauthorized in conventional agricultureare very low, most often below theminimum detection limit. Reinhardtand Wolf32 reported insignificant con-centration of pesticide residue inorganic produce. This resulted mostlyfrom environmental pollution fromnon-organic agriculture.33,34 All otherorganic samples taken were found tohave no pesticide residue in it. Similarcomparative studies were carried outand concluded that organic producecontain no pesticidal residues.35 Whenresidues are present they are typicallyof significantly lower incidence andlevels than those found in non-organicproduce.36 In a study-conducted byMajumdar,1 the seed samples of wheat,maize, sorgham and bajra obtainedfrom different places in Mysore (India)were found to be contaminated withvery high levels of DDT, BHC andcaptan. Market samples of wheat and

Chemical Health

pulses were analyzed for the presenceof pesticides at Hapur and found to becontaminated with DDT (83 mg/L)while the level of BHC was 63 mg/L.37 Tripathi38 reported that at Pant-nagar (India) all the samples of ediblegrains contained DDT. Organic farm-ing, which prohibits most syntheticpesticides and restricts the use of per-mitted natural pesticides, appears tooffer foods essentially free of pesticideresidues, and consumers perceiveorganic foods to be a lower-residuechoice.39

Organophosphorous compoundshave overtaken organochlorine com-pounds as the most used insecticides inthe recent decade. Phorate is amongstseveral systemic compounds, whichis generally applied near to roots ofseedling plants to give protectionagainst aphides and the virus disease.In the present study, the maximumconcentration of pesticide residue

& Safety, November/December 2006

Table 4. Recovery of pesticide in rice

PesticideFortificationLevel (mg/L) Replicates

Recovery(mg)

Recovery(%)

AverageRecovery (%)

Endosulfan 0.10 1 0.088 88 80.62 0.074 743 0.080 80

0.05 1 0.048 96 94.72 0.050 1003 0.044 88

Phorate 1.0 1 0.74 70 79.72 0.81 813 0.82 82

0.1 1 0.090 90 84.62 0.080 803 0.084 84

Carbofuran 0.01 1 0.0078 78 722 0.0070 703 0.0068 68

0.1 1 0.086 86 88.02 0.088 883 0.090 90

Permethrin 0.1 1 0.082 82 81.62 0.079 793 0.084 84

1.0 1 0.90 90 90.72 1.01 1013 0.81 81

was found in the wheat sample takenfrom conventional market (0.3 ppm).Permethrin is a pyrethroid insecticidewith a high level of activity againstLepidopterous pests. It is also effectiveagainst a wide range of Hemiptera, Dip-tera and Coleoptera. The compound isboth a stomach and a contact insecti-cide, and shows adulticidal, ovicidaland, particularly, larvicidal activity. Itis also extremely effective against thegreat majority of insects resistant tocommonly used insecticides, such as

Table 5. Residual pesticides in different m

Name of Pesticide

Organochlorine (endosulfan)Organophosphorous (phorate)CarbofuranPermethrin

Chemical Health & Safety, November/Dece

organochlorines and organopho-sphates.

Carbamate and pyrethroid insecti-cides are frequently employed to con-trol insects. These pesticides areparticularly useful for dealing withaphides and other pests, which havedeveloped resistance to organopho-sphorus compounds. Presence of car-bamates and pyrithroid was observedonly in market samples of rice whereasno trace of these pesticides wasfound in any of the organic sample.

arket samples

Pesticide Residue (mg/L)

Rice Wheat

0.02 0.30.04 0.0244.85 –0.02 0.05

mber 2006

The presence of frequent residues ofmany of the widely used syntheticinsecticides in foods has been welldocumented, and residue levels oftenapproach or exceed the safe limits.40

RISK-BENEFIT ASSESSMENT

Pesticides are widely used chemicalsubstances throughout the world inagriculture and public health. Becauseof their high biological activity, and insome cases of their persistence in theenvironment, the use of pesticides maycause undesired effect on human healthand to the environment. Simulta-neously, pesticides play a significantrole by keeping many dreadful diseases(malaria, dengue, encephalitis, filiaria-sis, etc.) away from society. Pesticidesplay a significant role in rural healthprogramme comprises of the controlof biting, irritating, noxious, annoying

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or contaminating insects and otherpests, which infest human and animals.Risk assessment is a crucial tool to pre-dict the likelihood of adverse effects toman and to identify the need of preven-tive measures for each group of popula-tion at risk, risk assessment allow todetermine the magnitude of the hazardposed by the pesticide product, doseresponse assessment, extent of expo-sure and characterization of risk.

The total cost-benefit picture frompesticide use differs appreciablybetween developed and developingcountries. For developing countries itis imperative to use pesticide, as no oneprefers famine, hunger and communic-able disease and therefore, it may beexpedient to accept a reasonabledegree of risk. There are some inherentdifficulties in fully evaluating the risksto human health due to pesticides. Asthere are a large number of humanvariables such as age, sex, race,socio-economic status, and diet, stateof health all of which affect humanexposure to pesticides. However, thegeneral public’s perception of the ben-efits of pesticides is almost universallynegative. Research in the area of riskperception has indicated that thepublic is strongly concerned aboutpotential hazard, such as pesticideresidue in food.41–44 The use of pesti-cides was perceived to be associatedlong term and unknown effects onhealth.45,42 But it was also associatedwith benefits such as cheaper food andless wastage.42 Although risk assess-ment process is complex but it is ascientifically based process consistingof hazard identification, hazard char-acterization, exposure assessment, riskcharacterization.

The objective of risk characteriza-tion is to evaluate the magnitude ofrisk to human health. In public healthpesticide applications constitute thehigh-risk population group. This groupis more liable to suffer from acute toxicmanifestations that may or may not befatal as in exposure to organopho-sphorus insecticides. They are liableto have greater risks for any chronictoxic infestations from cumulative orpersistent type of chlorinated pesti-cides intake by the body. The indirecthazards associated with pesticides aredue to their persistent nature by virtue

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of which they remain active in theenvironment for prolonged periodsand are finally incorporated in the foodchain; make their entry in to humanbody and also in to the body of variousother livestock in the biosphere. This isan inherent type of pesticide hazardthat affects all community. There aretwo types of information necessary forthe generation of intake data suitablefor risk characterization. Firstly, deter-mination of the consumption of thefoods that may contain the chemicaland, secondly, the concentrations ofthe chemical that may be present inthe different foods. The intake estimatefor a chemical or ingredient arisingfrom ingestion of any single food itemis the product of the concentration ofthe chemical/ingredient in the foodand the amount of the food consumed.The total intake for an individual fromfood is the sum of intakes from allrelevant foods. An additional consid-eration is whether all relevant sourcesof exposure have been identified, i.e.,not only the foods expected to containthe component in question, but alsoany non-food sources of exposure.These include drinking water, consu-mer products, occupational sourcesand general environmental sources.In India it was desirable as a prerequi-site to the enforcement of InsecticideAct, to evaluate the magnitude of pes-ticide pollution in the country andrelated health hazards to ensure theirsafe use for the benefit of the society.ICMR’s National Institute of Occupa-tional Health (NIOH), Ahmedabad,and several other national laboratories,farm universities and other R&D orga-nizations have been engaged in toxico-logical evaluation of pesticides,synthesis of safer molecules and evalua-tion of environmental contaminationdue to pesticides. But lack of adminis-trative regulatory capacity and agricul-tural development programs partiallycause the unsafe use of pesticides inthe developing countries.46

All human risk situations are a func-tion of a hazard and exposure to thathazard. If the hazard is small and fixedthen the risk will be proportional to theexposure, which can be reduced to below and occasional. When both hazardand exposure can be quantified with aconsiderable degree of confidence

Chemical Health

then a realistic estimate can be madeof the risk involved on consumingfoodstuffs containing some pesticideresidues. From the relationship

Risk ¼ Hazard� Exposure

It can be seen that zero risk can beachieved only if either the hazard orexposure approaches tozero.Sincepes-ticides are wide spread in worldwidefood production then zero hazard orzero exposure are not possible if eitheror both can be considerably reduced inpractice. After evaluation of exitingextensive data base on pesticide residuein commodities and diets it can beinferred that health risks from residuesare minimal when pesticides are usedaccording to authorized and prescrip-tive uses.

CONCLUSION

The results of the present study indi-cated that the pesticide residues of var-ious agrochemicals present in wheatand rice are the result of their indiscri-minate use for increasing crop produc-tion. The information on themonitoring of pesticide residues in foodcrops, though meager but provided aninsight into the present situation pre-vailing in the conventional market sam-ples. Recoveries of more than 88% wereobserved for all pesticides. Since notrace of pesticide residue was found inthe organic samples, the use of theseorganic wheat and rice is highly recom-mended. It was observed from the pasthistory of these farms that wheat andrice production under conventionalsystem was higher than organic but thishigherproduction isat thecostofhealthrisk and also poses other hazards toflora and fauna. Because of ban oncertain pesticides or their limited use,manufacturers are compelled to createand mass-produce effective yet lesstoxic pesticides. As this occurs, therewill be a gradual yet steady shift in thepesticides use worldwide, most assu-redly accompanied by a transitionallag in developing countries.

ACKNOWLEDGMENTSAuthors are thankful to the organicgrowers who provided samples and

& Safety, November/December 2006

background detail of agricultural prac-tice and Prof. B.K Guha for providinganalytical facilities for the work.Authors are also thankful to Dr. TonySarvinder Singh for his constant sup-port.

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