Assessment Of Pesticide Residues And Heavy Metals As Well As Investigation Of Household Methods For Pesticide Residue Elimination From Imported Date Fruits In Malaysian Market
Toxic pollutants are a major environmental concern that has put human health at risk. Pesticides and heavy metals are at the top of the list of environmental toxins posing a threat to nature. Developing and validating methods for extracting and analyzing residual environmental pollutants such as pes...
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| Summary: | Toxic pollutants are a major environmental concern that has put human health at risk. Pesticides and heavy metals are at the top of the list of environmental toxins posing a threat to nature. Developing and validating methods for extracting and analyzing residual environmental pollutants such as pesticides and heavy metals in vegetables and fruits has become of great interest to ensure that the level of pollutants in them is within the permissible limits to protect the health of consumers. The acetate buffered QuEChERS (AOAC) was successfully modified and optimized for date fruit matrix extraction and pesticide residue analysis using Minitab 17.0 software and the Plackett-Burman (P-B) screening design programme. The modified method demonstrated high recovery and low matrix effect (less than 20) for the three pesticides tested, two organophosphorus (dimethoate and chlorpyrifos) and one carbamate (carbendazim). The modified method outperformed the original unbuffered method in terms of pesticide recoveries. High-performance liquid chromatography equipped with diode array detector (HPLC-DAD) method was developed and optimized for simultaneous determination of the examined pesticides in date fruit samples extracted by modified acetate buffered QuEChERS methodology. The method was validated by determining the following analytical and statistical parameters: the linearity, limit of detection limit (LOD), limit of quantification (LOQ) and accuracy of the method. The recovery (%) was found to be between 101-104.2 %. Among the examined 20 samples, dimethoate was detected in 13 samples (65%) and ranged between 0.01059 - 0.053 mg/kg of fresh weight. Carbendazim was detected in all examined twenty samples (100 %) and ranged between 0.01485 - 0.3207 mg/kg of fresh weight. Chlorpyrifos was detected in 12 samples (60 %) and ranged between 0.0324 - 1.543 mg/kg of fresh weight. The health risk assessment of the examined pesticides was calculated based on the mean concentration in each individual date fruit sample. Though the residues in most samples exceed the European Commission MRLs, there was no health risk associated with any of the studied pesticides as no samples exceeded the acceptable health hazard index (HHI) limit (<1) for adults or children. The efficiency of some wash treatments on the removal of pesticide residues from the date fruits was investigated and optimized. The methods included washing by either tap water, detergent solution and three concentration levels of either, NaCl, acetic acid, H2O2 or KMnO4. (1 %, 2 %, and 3 % v/v) in two efferent temperature levels, 25°C and 37°C. The concentration of pesticides decreased dramatically as contact time, temperature and concentration in the fruits treated with different wash solutions. The effect of washing on date fruit’s nutrition value were studied and optimized. All treatments resulted in a negative effect on nutrition value. The decrease in nutrition value increased gradually by increasing contact time, temperature and washing solution concentration. A method for digestion and determination of eight heavy metals in date fruits flesh and in the adhered dust was developed and optimized using GFAAS spectrophotometer. The mean concentrations of heavy metals in date flesh are similar to global values and appeared to be descending in order: Fe> Al> Cu>As>Ni> Pb> Sn> Cd. The risk assessment calculated from the means of heavy metals concentration in samples showed that hazard quotients (HQs) are less than 1 for all the examined heavy metals which indicated that the consumption of these dates does not cause health risks for the consumers. The effect of water washing on various heavy metals deposited on date fruits was investigated. Washing for around 90 seconds at room temperature greatly reduced heavy metal levels in all samples. The washing effect on heavy metals removal rates ranged from 0.95 % to 34.78 %. |
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