Imidacloprid Residues In Food Commodities and Daily Intake Estimation

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Analysis of Imidacloprid Residues In Food Commodities and Daily Intake Estimation.

Chapter 4

Chapter-4

Analysis of Imidacloprid in food commodities and daily intake estimation

4.1 INTRODUCTION

Imidacloprid is a systemic chloro-nicotinyl insecticide which blocks the microtinergic neuronal pathway, hence it is used for prevention of insects and pests like rice hoppers, aphids , ticks , white fly and termites. It is commonly used on vegetables and fruits like potato, cotton, sugar beets and soya bean. It is also used on plants like rice and maize. In the Indian market, Imidacloprid is available in the trade products- Gaucho and Confidor which are used for seed treatment and for leaf and soil treatment respectively (Kapoor et al., 2013). Its use as a substitution for other insecticides is increasing. It is mainly used on rice, cereals, maize potato, vegetables sugar beet, fruit and cotton (Arora , 2009). It is also used in seed treatment and dressing of soil (Jemec et al., 2007). Residual data of environmental fate of imidacloprid are conflicting, while some authors considered it as relatively still in soil and do not anticipate its escape to ground water (Tomlin, 1997 & Krohn and Hellpointner, 2002) .However some studies indicate the contrary statements (Armbrust and Peeler , 2002)

Increased use of pesticides have resulted in pollution of the environment and also caused effects on human health varying from short-term effects to long term effects. Short term effects include mild symptoms such as headaches and nausea while long term effects may include occurrence of diseases like cancer, reproductive harm, and endocrine disruption (Chen et al., 2011) .Due to the possible risk of pesticides for human health, its use in agriculture should be subjected to regular monitoring (Kapoor et al., 2013). The periodical analysis of pesticide residues in food commodities is essential for its judicial use in the interest of public health. Unfortunately, negligible data are available on the amount of imidacloprid in food commodities sold in local markets of Lucknow region in India (Kapoor et al., 2013).

In view of large scale use of imidacloprid and scarcity of Indian literature (Gajbhiye, et al., 2004) it is essential to assess present environmental load of imidacloprid residues in different food commodities as imidacloprid is supposed to be toxic chemical (Tomizawa and Casida, 2003 & 2005;Kapoor et al., 2010 & 2011; Bhardwaj et al., 2010) It is therefore imperative to analyze imidacloprid residues in vegetables, fruits, cereals, fruit juices and baby foods samples in and around, Lucknow city, India, during 2010-2011.The study also determines the estimated daily intake of imidacloprid exposure of local population of Lucknow city, India by consuming the above analyzed food commodities.

4.2 Methodology

Samples were collected during October 2010 to July 2011 from main markets of Lucknow city, India. Total of 250 samples of five different food commodities (vegetables, fruits, cereals, fruit juices and baby food) comprising 10 samples of each were collected. Analyzed fruits were apple, banana, orange, grapes and pomegranates. Vegetables selected for study were cabbage, cauliflower, tomato, potato, okra, brinjal, and capsicum; and cereals were wheat, rice and pulses. Fruit juices were mango, guava, pineapple, orange and litchi and baby foods coded as BF-1 to BF-5 were taken. Ingredients of baby food (BF1-5) are as follows: BF-1: wheat and Milk, BF-2: apple, wheat and milk; BF-3: banana, wheat and milk; BF -4: honey, wheat and milk; BF -5: rice, wheat and milk. Polythene bags were used for collection of samples. Samples after collection were transported to laboratory and were analyzed at the earliest or stored at 4â-¦C until analysis. Samples were subjected to HPLC and LC-MS analysis after proper clean-up and extraction of samples. Recovery studies and quality control was also done.

Detail methodologies are discussed in chapter 3

4.3 Results

4.3.1 Validation of method for determination of imidacloprid in different food commodities.

In this method recovery variability in different concentration of Imidacloprid (0.0625, 0.125, 0.25 and 0.5mg Kg-1) in different commodities ranges from 77.55 to 111% and RSD ranged from 5.22 % to 14.16%. The LOD for imidacloprid in the present study was in range from 0.004 to 0.01 mg Kg-1. The LOQ for imidacloprid in the present study ranged from 0.014 to 0.070 mg Kg-1. Calibration standard curves for HPLC was r2 =0.992. Standard chromatogram of imidacloprid by HPLC and its LC-MS analysis are shown in Fig 4.1 & 4.2

Fig 4.1: HPLC Chromatogram of standard of imidacloprid.

Fig 4.2: Detection of imidacloprid by mass spectrometry. MS/MS spectra of the m/z 256 parent ion, exhibiting the product ions of imidacloprid at m/z 209 and at m/z 175.

4.3.2 Analysis of Imidacloprid in different food commodities

Imidacloprid was detected in 44 samples out of 256 samples. In these, 8 samples were more than MRL (maximum residue limit) preset by Prevention of Food Adulteration Act. (PFA), Govt. of India 1954, CODEX., 2006. (Table 4.1 & Fig. 4.3)

Table 4.1: Maximum Residual Limit (MRL) of imidacloprid in different food commodities

Commodity

*MRL (mg kg-1) PFA/Codex

Grapes

0.5

Cabbage

0.5

Cauliflower

0.5

Potato

0.5

Wheat

0.05

Rice

0.05

Total 250 samples were analyzed for presence of imidacloprid in which 38 samples were found to be contaminated with imidacloprid, however only 6 samples showed concentration of imidacloprid above than their corresponding MRL (Fig 4.3 and table 4.2). The level of imidacloprid residues in various commodities were compared with their MRL. Presences of imidacloprid in fruits like apple were (0.02-0.26 mg kg-1), Banana (0.04 mg kg-1), Orange (0.01-0.13) and Grapes (0.04 - 0.78 mg kg-1). Imidacloprid in vegetables like cabbage was (0.08-0.89) mg kg-1, Cauliflower (0.45mg kg-1), Potato (0.19-1.32), Tomato (0.24-0.46) and Okra (0.11 mg kg-1) and Capsicum (0.45). Presences of imidacloprid in Cereals like Wheat I was 0.01-0.10 mg kg-1), Wheat II (0.02 - 0.10 mg kg-1), Rice I (0.01-0.05), Rice II (0.004-0.03) and Pulses (0.006 - 0.05 mg kg-1) (Table3.3). None of samples of fruit juices showed presence of imidacloprid. Also none of different baby foods were found to be contaminated with presence of imidacloprid. Maximum contamination was in cereals> vegetables>fruits (Figure 4.4).

Fig. 4.3 Number of samples detected with imidacloprid residues and number of samples detected with Imidacloprid greater than MRL values in all food commodities

Fig. 4.4 Presence of imidacloprid residues in different food commodities

Table 4.2: Mean Levels, concentration range and frequencies of imidacloprid residues in different food commodities.

Commodity

Samples

Mean

(mg /kg)

Residues range (mg /kg)

No of samples

No of samples above MRL(mg /kg)

Analyzed

Detected

Fruits

Apple

0.04±0.02

0.02-0.26

10

3

0

Banana

0.005±0.004

ND-0.04

10

1

0

Orange

0.02±0.01

0.019-0.13

10

4

0

Grapes

0.13±0.08

0.04-0.78

10

3

1(0.5)

Pomegranate

ND

ND

10

0

0

Vegetables

Cabbage

0.15±0.11

0.08-0.89

10

3

1(0.5)

Cauliflower

0.21±0.12

0.29-0.93

10

3

1(0.5)

Tomato

0.08±0.06

0.24-0.46

10

2

0

Potato

0.32±0.17

0.19-1.32

10

4

2(0.5)

Okra

0.01±0.01

ND-0.11

10

1

0

Brinjal

0.06±0.03

0.13-0.21

10

3

0

Capsicum

0.05±0.05

ND-0.45

10

1

0

Cereals

Wheat

0.01±0.01

0.01-0.10

10

3

1(0.05)

Rice

0.009±0.005

0.01-0.05

10

4

0

Pulses

0.008±0.005

0.016-0.05

10

3

0

Fruit juices

Mango

ND

ND

10

0

0

Guava

ND

ND

10

0

0

Pineapple

ND

ND

10

0

0

Orange

ND

ND

10

0

0

Litchi

ND

ND

10

0

0

Baby Foods

BF-1

ND

ND

10

0

0

BF-2

ND

ND

10

0

0

BF-3

ND

ND

10

0

0

BF-4

ND

ND

10

0

0

BF-5

ND

ND

10

0

0

Gross Total

250

38

6

Values represent mean ± se of 10 samples. Values in parenthesis indicate respective MRL (CODEX, 2005)

The EDIs have been calculated between 0.004 to 0.131 µg/kg body weight/day, while the hazard indices (EDI/ADI) ranged from 0.007 to 0.218 for the tested commodities (Table 4.3)

Table 4.3: Calculation of estimated daily intake (µg/kg b.w/day) and hazard index estimation of imidacloprid in various food commodities

Commodity

Average concentration of imidacloprid in commodity(∑C) (µg/kg)

Mean annual intake of commodity per person (kg) (F)

No. of days in year(D)

Average weight of person(W)

ADI(µg/kg b.w/day)

EDI (µg/kg b.w/day)

Hazard index (%)

Fruits#

39

9.5

365

60

60

0.016

0.028

Vegetables#

125

23

365

60

60

0.131

0.218

Wheat*

10

52.8

365

60

60

0.024

0.040

Rice*

9

66

365

60

60

0.027

0.045

Pulses*

8

12

365

60

60

0.004

0.007

# NNMB survey 2005-2006, *NSSO, 1975-2000

4.4 DISCUSSION

Total 250 samples were analyzed. 50 samples each of fruits, fruit juices and baby foods, 70 samples of vegetables and 30 samples of cereals were analyzed for presence of imidacloprid residues. None of the samples of fruit juices and baby foods showed presence of imidacloprid. Similar results have been reported in studies of Turkey and Brazil which have showed absence of pesticides residues in fruit juices (Topuz et al., 2005, Furlani et al., 2011).However, the traces of pesticides in fruit based soft drinks of Spain have been also reported (García-Reyes et al ., 2008). Thus, these two food commodities may be free from imidacloprid because of their processing. However imidacloprid was detected in 38 samples comprising fruits, vegetables and cereals which is around 15.20% of total samples. In 22% samples of fruits, presence of imidacloprid was observed out of which 2% of samples were above to their respective MRL.

Level of imidacloprid in apple ranged from 0.02-0.26 mg/ kg, banana from ND-0.04 mg/ kg, orange from 0.019-0.13 mg/ kg and grapes from 0.04 - 0.78 mg/ kg (Table 4.2). Imidacloprid was not detected in any of the samples of pomegranate. However one sample of grape has shown the residue of imidacloprid above to MRL (0.50 mg/ kg). Although in 24% of vegetable samples imidacloprid was detected but only 5.71% have shown presence of imidacloprid above their respective MRL (Kapoor et al., 2013).

The presence of imidacloprid residues was in following order potato> cauliflower> cabbage> tomato > brinjal> capsicum> okra. 33% samples of cereals have shown presence of imidacloprid but only 3% of samples were above their respective MRL fixed by PFA (0.05 mg /kg). Imidacloprid residues have been also reported in vegetables and fruits samples of Palestine. In the study it was found that the imidacloprid concentration in some crops of Palestine was more than their MRLs (Daraghmeh et al., 2007). In several studies of Almeria, Spain, it was found that out of 200 samples of fruits and vegetables analyzed ,25-53% (average 21%) of samples showed presence of imidacloprid residues (Fernandez-Alba et al., 2000)

Many countries have legal directive to control level of pesticide residues in food through maximum residue limit (MRL) for protection of consumer’s health [(PFA (1954) & (WHO, 2003). The level of pesticides residues in food commodities are legislative to minimize exposure of consumer’s to unnecessary intake of pesticide and to ensure their careful use. From viewpoint of human health, it is essential to compare exposure estimates to determine toxicological criteria such as estimate daily intake (EDI)

Results of this study have been used to calculate EDI. The unit of EDI is microgram pesticides per kilogram body weight per day (µg/kg b.w/day). The EDI is a actual estimation of pesticide exposure calculated as per the international guidelines (WHO, 1997 and Osman et al., 2011) using following equation: EDI=∑C x F/D x W

where C is the average of imidacloprid concentration in each commodity (µg/kg); F is mean annual intake of food per person (Kg); D is number of days in a year i.e. 365 and W signifies the mean body weight of human body i.e.60 kg (Kapoor et al., 2013)

The annual intake per person as total of fruits, vegetables, wheat, rice, pulses is 9.5, 23, 52.8, 66, 12 kg/year respectively according to Indian survey performed in the years 1975-2000; 2005-2006 (NNMB,1979-2008 and NSSO,1975-2000). Average of imidacloprid in each food commodity, annual consumption of individual commodities per person, the estimated daily intake (EDI) and acceptable daily intakes (ADI) (µg/kg body weight/day) are compared in Table 4.3. ADI are also established by international organizations like FAO & WHO (FAO, 2002 & 2004). The EDIs have been calculated between 0.004 to 0.131 µg/kg body weight/day, while the hazard indices (EDI/ADI) ranged from 0.007 to 0.218 for the tested food samples.

Hence it is shown that lifetime consumption of commodities like vegetables, fruits, fruit juices, baby foods, wheat, rice and pulses may not cause health hazards for the population of Lucknow city, India (Darko and Akoto., 2008) since the hazard indices for imidacloprid residues were less than one. It has been reported in a study that common home processing removes significant amount of pesticides residues from vegetables (Nath and srivastava, 1990) (Kapoor et al., 2013)

Hence risk of health hazard because of imidacloprid residue in commodities like vegetables, fruits, fruit juices, baby foods, wheat, rice and pulses does not creates alarming situation and thus may not be of great concern. Monitoring of pesticides residues in food is priority objective of pesticide research to avoid possible risk to human health. Monitoring of pesticide residues is a key tool for ensuring compliance of good agriculture practices. Thus, periodical monitoring of pesticides residues in food is very important to provide guidance on the judicial use of pesticide in the interest of public health

CONCLUSION

The present study showed mild occurrence of imidacloprid residues in analyzed food commodities collected from Lucknow city, India. It is therefore indicated that life time consumption of vegetables, fruits, fruit juices, baby foods, wheat, rice and pulses may not exhibit health hazard for population of Lucknow city, India since the hazard indices for imidacloprid residues were less than one. Therefore the risk of health hazards due to imidacloprid residues in these food commodities may not be of great concern for population of Lucknow city, India.

Therefore, imidacloprid residues in these food commodities may not pose any health hazards to the population of Lucknow city, India. The findings of the study also suggest that periodical monitoring of imidacloprid residues should be carried out in other food commodities as well at national level to prevent and minimize health risks. Although our results indicate negligible risk associated with exposure of imidacloprid, special precautions should be taken to reduce total exposure to this chemical from various foods. A periodical monitoring of imidacloprid in other foods commodities like non-vegetarian diet are the recent need for consumers as well as authorities of food quality control (Kapoor et al., 2013).

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