American Journal of Anal yt ical Chemistry, 2011, 2, 46-52
doi:10.4236/ajac.2011.228123 Published Online December 2011 (
Copyright © 2011 SciRes. AJAC
Monitoring of Pesticide Residues in Commonly Used Fruits
in Hyderabad Region, Pakistan
Yawar Latif, Syed Tufail Hussain Sherazi*, Muhammad Iqbal Bhanger
National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, Pakistan
E-mail: *
Received November 2, 2011; revised December 5, 2011; accepted December 12, 2011
A market based survey was carried out to evaluate the level of 26 pesticides in some commonly used fruits in
Hyderabad region, Pakistan. Gas chromatography coupled with micro electron capture detector was used to
assess the levels of pesticide residues. Gas chromatography-mass spectrometry (GC-MS) was also applied
for the confirmation of results. Out of total 131 analyzed samples, 53 (40%) were found contaminated with
pesticide residues while only 3 (2%) samples were exceeded the MRLs of some pesticides. Chlorpyrifos and
dieldrin were detected in almost all analyzed samples. Residues of chlorpyrifos (1256 µg/kg) and endosulfan
sulfate (1236 µg/kg) were found higher in orange and apple samples, respectively. The findings of this study
provided important data about contamination of pesticide residue in some fruits sold in Hyderabad, Pakistan,
and recommended that monitoring studies should be expanded to other fruits grown in different agro climatic
regions, which may serve as basis for future policy about the standards and quality control of pesticides.
Keywords: Market Survey, Fruit Samples, Pesticides Residues, GC-μECD
1. Introduction
No doubt, the use of pesticides has resulted to increase
agricultural production worldwide but some persistent
pesticide residues have great potential of adverse impact
on the environment and human health. Application of
pesticides in modern agriculture has boosted farm pro-
ductivity [1]. Vegetables and fruits are commonly used
everywhere to meet the requirement of balance diet and
good health [2]. Pesticides contamination is a worldwide
public health concern and also a main international trade
problem [3]. Several pesticides are noxious substances
and can persistent in the environment for a long time.
Therefore, health point of view it is necessary to control
the application of pesticides on crops [4,5]. On the other
hand, different types of new pesticides have been intro-
duced in market during last few decades to enhance bet-
ter yield and quality of agricultural products [6]. How-
ever, levels of pesticides should be controlled at opti-
mum point due to their relative toxicity to the environ-
ment and human health [7]. Thus, maximum residue lev-
els (MRLs) for pesticides have established worldwide,
which usually guide to manage the quantity of pesticides
in foodstuffs.
Residues resulting from the inappropriate use of pesti-
cides on fruits have turn out to be most important con-
cern in many countries, as well as in Pakistan. Agricul-
ture sector is playing important role to support the eco-
nomy of Pakistan. Furthermore, recent production of fruits
in Pakistan is almost 4.7 million tons per anum and some
fruits are also exported to other countries. Contribution
of food stuff is about 13.2% in entire exports together
with fruits [8]. Use of pesticides in Pakistan is not well
controlled as compare to the developed countries due to
ineffective legislation, lack of awareness and inappropri-
ate pesticide management. Applications of chemicals to
manage pests are being adept in Pakistan since decades;
but, agro chemicals have acquired in 1954 with 254 met-
ric tons of formulation [9]. The reliance on pesticides is
apparent from the growing trend in its utilization from
665 metric ton in 1980 to 45,680 metric ton in 1999 [10],
and reached to 25000 metric ton in 2006 [11]. No statis-
tics data are available on the levels of pesticide residues
in fruits sold in rural and urban markets of Hyderabad
region, Pakistan, which is the eighth biggest city of the
state and second largest city of the Sindh province (on
the bases of population). Hyderabad city is situated on
the east bank of the river Indus and about 150 km away
from Karachi city. District Hyderabad contains huge urban
and rural areas. The literacy rate in rural area as compare
to the urban areas is very low, which is the main reason
of improper use of pesticides. They are completely un-
aware to the approach of integrated pest management
(IPM). Additionally, the use of incorrect or high dosage
of pesticides leads to the contamination of pesticides in
their agricultural products which may be health risk to
the consumer. Thus, the monitoring of pesticide residues
in fruits has become ever more essential requirement for
consumers, producers and institutions concerned with
standards and quality control management [12]. A mar-
ket based survey was conducted to investigate the possi-
ble contamination of fruits sold in the major markets of
Hyderabad region of Pakistan. The motive for the selec-
tion of Hyderabad district is that it is one of major com-
mercial centre for the agricultural produce especially
fruits, cotton, wheat, and vegetables.
2. Materials and Methods
2.1. Sample Collection and Preparation
For the evaluation of pesticide residues, a total of 131
samples of some fruits including apples, grapes and or-
anges were collected during the period of October 2010
-April 2011 from three different main fruit markets lo-
cated in urban areas of Hyderabad region, Sindh, Paki-
stan. The size of the sample of each fruit was between 2 -
3 kg. 17 samples of apple, 12 samples of grapes and 13
samples of oranges were purchased from the fruit market
No.1. Similarly 14 samples of apple, 14 samples of grapes
and 11 samples of orange were obtained from the fruit
market No. 2. While from the fruit market No. 3, 16
samples of apple, 15 samples of grapes and 19 samples
of oranges were purchased in different dates. Each sam-
ple of fruit was chopped and 200 g portion get homoge-
nized and kept in glass stopper bottle and stored under
freezing temperature until extraction.
2.2. Extraction and Cleanup
An aliquot from each sample (10 g) was weighed and
extracted twice with 20 ml ethyl acetate. Extracts were
kept in a sonicator for 2 min at 40˚C ± 2˚C. After sonica-
tion, extracts were filtered through a filter paper with the
assistance of suction pump. Residues were washed with
ethyl acetate (10 ml) and extracts were shifted into a
separatory funnel. The aqueous phase was discarded while
organic phase was passed through anhydrous sodium sul-
fate and evaporated to dryness in a rotary evaporator.
Residues were dissolved in ethyl acetate and cleaned-up
on SPE column containing 1 g of C18 preconditioned
with acetonitrile (3 ml) and water (5 ml). The extracted
residues were put on the top of column and eluted twice
with 5 ml of hexane-ethyl acetate (1:1, v/v). Eluate was
evaporated on a rotary evaporator and dissolved in ethyl
acetate and transferred to a glass tube and concentrated
under a gentle stream of air to a suitable volume. An
aliquot of the last extract was examined by GC-μECD
and identification of the residues was carried by the
standards and also by GC-MS.
2.3. Gas Chromatographic Analysis
Analysis of pesticide residues was carried out on an
Agilent (CA, USA) model 7890 A GC system coupled
with micro Electron Capture Detector (μECD), in com-
bination with automatic split-splitless injector model
Agilent 7683 B and 7683 Agilent autosampler. For the
separation of analytes a HP-5 glass capillary column (30
m × 0.32 mm × i.d., 0.25 μm film thickness) supplied by
Agilent Technologies, was installed. Injector and detec-
tor temperatures were set up to 250˚C and 310˚C respec-
tively. Temperature for column was programmed as; the
starting temperature was 70˚C for 0 min, after that raised
at a rate of 30˚C/min to 210˚C and seized for 2 min, then
from 210˚C to 250˚C at a rate of 25˚C /min with held for
2 min, then increased up to 290˚C with the rate of 30˚C
/min and lastly held for 5 min. Nitrogen (purity 99.99%)
was used as carrier gas with flowing at 1.2 ml/min.
For the confirmation of detected residues an Agilent
Technologies 6890 N network GC system equipped with
a 5975 inert MSD with the combination of Electron Im-
pact (EI) as source for ionization and Agilent 7683 au-
tomatic split-splitless injector, was employed. The tem-
peratures of ionization source and quadrupole were kept
at 230˚C and 150˚C, respectively. For identification, the
major ions (m/z) and retention times (tR) both were con-
sidered (Table 1).
3. Result and Discussion
Maximum residue levels (MRLs) of the selected pesti-
cides in different fruits were shown in (Table 2). For
allethrin, bromacil, bromophos-methyl and dialifos no
MRLs established so far. Data given in Table 3 shows
that 42 fruit samples including apple, grape and orange,
collected from fruit market No.1, were evaluated for 26
pesticides. In analyzed samples, level of chlorpyrifos was
found to be exceeded MRL with the highest concentra-
tion of 1256 μg/kg in apple, followed by disulfoton with
concentration of 398 μg/kg in orange, which was within
the MRL. Dieldrin was detected in 2 samples of apple
and 1 sample of orange. Maximum concentration (37
μg/kg) was observed in apple. Similarly, the fungicide,
triadimefon was found only in 2 samples of apple (114
μg/kg), which was below the MRL. Residues of insecti-
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cides, parathion (in 2 samples) and disulfoton (in 1 sam-
ple) were also detected in the orange samples. Maximum
levels of both pesticides were detected as 311 μg/kg and
398 μg/kg, respectively.
The levels of pesticides in 39 samples of fruits which
were collected from the fruit market No. 2 are shown in
Table 4. Similar to the results of market No. 1, chlorpyri-
fos was detected in higher concentration (1119 μg/kg ) in
orange and crossed the MRL, followed by endosulfan
sulfate with the concentration of 307 μg/kg in apple, and
Table 1. Pesticide names, chemical active group, usage, molecular we ight, retention times and selected MS main ions (m/z).
Pesticides Group Use MW tR, min MS
Selected ions (m/z)
Dichlorvos Organophosphate Insecticide 221 4.29 109, 145, 185
Phosdrin Organophosphate Insecticide 224 5.08 109, 127, 192
α-HCH Organochlorine Insecticide 288 6.68 111,181, 219
Dimethoate Organophosphate Insecticide 229 6.82 87, 125
β-HCH Organochlorine Insecticide 288 7.00 111,181, 219
γ-HCH Organochlorine Insecticide 288 7.10 111,181, 219
Disulfoton Organophosphate Insecticide 274 7.30 109, 157
δ-HCH Organochlorine Insecticide 288 7.38 111,181, 219
Chlorpyrifos Methyl Organophosphate Insecticide 322 7.65 208, 288, 286
Propanil Acylanilide Herbicide 218 7.69 161, 217
Metribuzin Triazine Herbicide 214 7.74 198, 144, 182
Parathion Methyl Organophosphate Insecticide 263 7.85 109, 263, 125
Heptachlor Organochlorine Insecticide 389 7.99 100, 272
Bromacil Uracils Herbicide 261 8.18 207, 205, 231
Malathion Organophosphate Insecticide 330 8.24 127, 158, 173
Parathion Organophosphate Insecticide 291 8.39 125, 291
Aldrin Organochlorine Insecticide 364 8.40 293, 263, 221
Chlorpyrifos Organophosphate Insecticide 349 8.41 197, 199, 258, 314
Triadimefon Triazole Fungicide 293 8.44 208, 128, 181
Bromophos Methyl Organophosphate Insecticide 366 8.65 331, 125
Allethrin Pyrethroid Insecticide 302 8.86 91,123, 136
Tolyfluanid Phenylsulfamide Fungicide 347 8.89 137, 238, 106, 63
Captan Phthalimide Fungicide 300 8.98 79, 264, 299
Bromophos Ethyl Organophosphate Insecticide 394 9.19 303, 359, 331
α-Endosulfan Organochlorine Insecticide 406 9.44 195, 241, 339
Dieldrin Organochlorine Insecticide 378 9.83 277, 345
β-Endosulfan Organochlorine Insecticide 406 10.37 195, 241, 339
DDT Organochlorine Insecticide 354 11.00 165, 235, 237
Endosulfan sulfate Organochlorine Insecticide 422 11.01 272, 387, 420
Dialifos Organophosphate Insecticide 393 12.73 76, 181, 357
Table 2. Maximum residue limits (MRLs) of targeted pesticides.
Pesticides MRLs, (µg/kg)a
Apple Grape Orange
Aldrin 50 100 50
Allethrin NE* NE NE
Bromacil NE NE NE
Bromophos Methyl NE NE NE
Bromophos Ethyl 50 50 50
Captan 15000 25000 15000
Chlorpyrifos 1000 500 1000
Chlorpyrifos Methyl 500 200 500
Dialifos NE NE NE
Dichlorvos 100 100 100
Dieldrin 50 100 50
Dimethoate 2000 2000 5000
Disulfoton 500 500 500
α-Endosulfan 2000 2000 2000
β-Endosulfan 2000 2000 2000
Endosulfan sulfate 2000 2000 2000
α-HCH 3000 3000 3000
β-HCH 3000 3000 3000
γ-HCH 3000 3000 3000
δ-HCH 3000 3000 3000
Heptachlor 10 10 10
Malathion 20 20 20
Metribuzin 100 100 100
Parathion Methyl 200 500 200
Parathion 500 500 500
Propanil 100 100 100
Tolyfluanid 5000 3000 50
Triadimefon 300 500 100
DDT 1000 1000 1000
Phosdrin 10 10 10
*NE = Not established, aAccording to Codex Alimentarius Commission and
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Table 3. Pesticide residue leve ls (µg/kg) found in fr uits c ollected from fr uit market No. 1.
Pesticide levels in (µg/kg)
Pesticides Apple Grape Orange
Contaminated Min-Max(µg/kg) Contaminated Min-Max(µg/kg)Contaminated Min-Max(µg/kg)
Chlorpyrifos 03 231 - 1256a 01 205 02 145 - 243
Parathion - - - - 02 102 - 311
Dieldrin 02 21 - 37 - - 01 13
sulfate 01 134 01 81 01 213
Triadimefon 02 37 - 114 - - - -
Disulfoton - - - - 01 398
aExceed the MRL.
Table 4. Pesticide residue leve ls (µg/kg) found in fr uits c ollected from fr uit market No. 2.
Pesticide levels in (µg/kg)
Pesticides Apple Grape Orange
Contaminated Min-Max (µg/kg)ContaminatedMin-Max (µg/kg)Contaminated Min-Max (µg/kg)
Chlorpyrifos 02 167 - 684 02 05 - 401 02 253 - 1119a
Parathion 01 73 - - - -
Dieldrin 02 11 - 34 - - 02 23 - 41
Endosulfan sulfate 02 14 - 307 01 15 01 117
Triadimefon 01 19 - - 01 34
aExceed the MRL.
also found in one sample of orange with concentration of
117 μg/kg. Only one sample of apple was contaminated
with parathion with the level of 73 μg/kg. While, dieldrin
was found in 2 samples of apple and 2 samples of orange
of the market number 2 with the concentrations of 34
μg/kg and 41 μg/kg, respectively, under MRL. The re-
sults also showed that, in 1 samples of apple and 1 sam-
ple of orange residues of the fungicide triadimefon were
detected with the concentrations of 19 μg/kg and 34
μg/kg, respectively.
The data given in Table 5 demonstrated pesticide resi-
due levels (µg/kg) found in fruits collected from fruit
market No. 3 of Hyderabad region. 50 fruit samples were
collected from this fruit market. In these samples, endo-
sulfan sulfate and chlorpyrifos were found to in greater
concentration of 1236 μg/kg and 1091 μg/kg in orange
and apple, respectively and chlorpyrifos was exceeded
the MRL. Chlorpyrifos also found in 2 samples of grapes
and 2 samples of orange with the level of 172 μg/kg and
882 μg/kg, respectively. The samples of apple and grapes
were also found to be contaminated with the residues of
insecticide endosulfan sulfate with concentrations of 210
μg/kg in apple and 55 μg/kg in grapes. The insecticide
parathion was the only pesticide found in orange fruit of
the main fruit market number 3 with concentration of 21
μg/kg. Dieldrin was the another insecticide found in 2
samples of apple with maximum concentration of 30
μg/kg and in 2 samples of orange with the concentration
of 41 μg/kg, which are under their MRLs. Residues of
disulfoton were detected in 1 sample of apple with con-
centration of 46 μg/kg and in 1 sample of orange with the
concentration of 31 μg/kg.
In this study, the residues of targeted pesticides were
evaluated in 131 samples of apple, grapes and orange
obtained from the three fruit markets i.e. towns Latifabad
(market number 1), Qasimabad (market number 2) and
main Hyderabad city (market number 3). In the analyzed
samples, 7 pesticides belonging to the different chemical
groups (organophosphates, organochlorines and triazole)
with different properties (6 insecticides and 1 fungicide)
were detected. Total number of samples collected from
each market, identified classes of pesticides and numbers
of samples above to the MRLs are illustrated in Tab le 6.
Out of total 131 samples analyzed, 53 samples (40%)
Table 5. Pesticide residue leve ls (µg/kg) found in fr uits c ollected from fr uit market No. 3.
Pesticide levels in (µg/kg)
Pesticides Apple Grape Orange
Contaminated Min-Max(µg/kg)ContaminatedMin-Max(µg/kg)Contaminated Min-Max(µg/kg)
Chlorpyrifos 03 328 - 1091a 02 26 - 172 02 345 - 882
Parathion - - - - 01 21
Dieldrin 02 14-30 - - 02 26 - 41
Endosulfan sulfate 01 210 01 55 03 13 - 1236
Disulfoton 01 46 - - 01 31
a Exceed the MRL.
Table 6. Total number of samples collected from all markets, frequencies of pesticides found and number of samples exceeds
Fruits Total samples Pesticide type Pesticide Name Frequency Above MRLs
Apple 47
Endosulfan sulfate
Grape 41 Insecticide Chlorpyrifos
Endosulfan sulfate
Orange 43
Endosulfan sulfate
contained detectable amount of pesticide residues, while
in remaining 78 samples (60%) no pesticide residues
were not detected. Out of which 3 samples (6%) were
exceeded the MRLs, whereas 50 samples (94%) con-
tained pesticide residues below the MRLs. Most fre-
quently detected pesticide was chlorpyrifos (insecticide)
found in 19 samples (36%), followed by the endosulfan
sulfate (insecticide) in 12 samples (23%) and dieldrin
(insecticide) in 11 samples (21%). According to the re-
sults, level of chlorpyrifos was exceeded from the MRL
in 2 samples. Out of 43, 22 samples of oranges (51%)
were found to be contaminated with pesticides with 1
sample (2%) above the MRL. Similarly, on the bases of
pesticides contamination, apple was found to be second
fruit, as 23 out of 47 samples (49%) were found to be
contaminated and 2 samples (4%) exceeded the MRLs.
Grapes was the commodity contained lowest number of
pesticides contamination i.e. 8 out of total 41 samples
(36%) found to be adulterated. No any contaminated
sample of grapes was found above to be above MRL.
The results of the study also shows that pesticides which
was detected in greater amount was chlorpyrifos with the
concentration of 1256 µg/kg (apple), followed by endo-
sulfan sulfate with level of 1236 µg/kg (orange), while
the concentrations of disulfoton, parathion, triadimefon
and dieldrin were 398 µg/kg (orange), 311 µg/kg (or-
ange), 114 µg/kg (apple) and 41 µg/kg (orange), respec-
tively. Frequent occurrence of pesticide residues in fruits
may be due to the lack of awareness of the growers about
the dosage, right ways of application and the suitable
interval between harvesting and pesticide treatment. The
carelessness or non-availability of correct guidance con-
cerning the pesticide application may be another reason
for pesticide residues in the fruit samples. These con-
taminated fruits are potential health risks to the consum-
ers. In terms of pesticide residues some of the samples
contained more than one residue. The rationale for that
might be that fruits cultivated in greenhouse conditions
are very much sensitive to pests and be required to for
consecutive applications of pesticide treatments, leaving
in result higher amount of residues that abided and de-
fended from quick degradation by direct sunbeams. In
Hyderabad region, the misuse or overuse of pesticides
and casual combinations of pesticides of different groups
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without any prior guidance and knowledge are become
serious problems. The improper use of pesticides shows
the way to terrific financial losses and dangers to human
health. Some studies have been already reported regard-
ing the pesticide residues in different fruits at different
periods [13,19]. Their data on fruits shows that the levels
of pesticide residues were greater as compare to present
study. Taken as a whole, consumption of pesticides in
the country was decreased from 41406 tons in 2003-2004
to 20394 tons in the period of 2006-2007. Decline in
number of samples not exceeding MRLs may be associ-
ated with decrease in quantity of pesticide consumption.
The outcomes of the present study authenticate the ex-
istence of pesticides such as chlorpyrifos, dieldrin, en-
dosulfan sulfate, parathion, disulfoton and triadimefon in
fruit samples which were applied in pre-harvest treat-
ment. To avoid adverse effects on public health it is a
necessity to set up control measures so as to make sure
that each pesticide should be below MRLs in the fruits to
be marketed. The study has presented significant infor-
mation regarding pesticide residues contamination on
fruits from Hyderabad region. On the bases of achieved
results, it is recommended that regular evaluation of pes-
ticide residue should be carried out on each fruit for the
planning and future policy about the formulation of
standards and quality control of pesticides.
4. Acknowledgements
Authors would like to thank National Centre of Excel-
lence in Analytical Chemistry, University of Sindh Jam-
shoro Pakistan, for the financial support to carry out the
present research work.
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