investigation of trace elements in vegetables - Paas.com.pk

Pakistan Journal of Science (Vol. 61 No. 4 December, 2009)INVESTIGATION OF TRACE ELEMENTS IN VEGETABLESF. Deeba, Z. Iqbal, S. Rehman, A. Inayat and A. Habib *Applied Chemistry Research Center *Center for Environmental Protection Studies, PCSIR Laboratories Complex LahoreABSTRACT: Three vegetables tori (Luffa acutangula), kaddu (Cucurbita pepo) and brinjal(Solanum meongena) were collected from four different places. Vegetables collected from PCSIRcolony, Taj Bagh, Railway road and Mandi Singh Pura were represented by 1, 2, 3 and 4 respectively.The samples were digested with hydrochloric acid and perchloric acid. After filtration andsubsequently volume was made for analysis. Trace elements Fe, Zn, Mn, Cu and Cr were investigatedby atomic absorption spectrophotometer Maximum concentration of Fe, Cu, Zn, Mn and Cr wererecorded in Tori-1 (13 mg/kg), Tori-4 (0.49mg/kg), Kuddu-1 (4.5 mg/kg), Tori-3 (1.4 mg/kg) andBrin-2 (0.69 mg/kg) respectively. While minimum concentration for Fe, Cu, Zn, Mn, and Cr werefound in Kaddu-4 (3.24 mg/kg), Brin-2 (0.25 mg/kg), brin-2 (3.22 mg/kg), Kaddu-4 (0.72 mg/kg) andTori-2 (0.15 mg/kg) respectively.Key words: Vegetable, Trace elements, Atomic absorption spectrophotometer, Digestion, PerchloricacidINTRODUCTIONVegetables are staple part of human meal takenas food in raw or cooked forms. Over the past fewdecades, there has been a change in the focus ofnutritional, health concerns from malnutrition to widespread chronic shortages of micronutrients. Theirdeficiency may cause serious functional disorders(Anthony et al., 2007). Trace elements are inorganiccompounds, which are essentially required for normalmetabolism (Achterberg, 1994). These minerals arerequired in minute quantities (Kaplan et al., 1993). Theyhave tendency to accumulate in human vital organs overprolonged period of time leading to unwanted side effects(Sathawara et al., 2004). The excess and deficiency ofmicronutrients may produce undesirable effects. Excessof these nutrients in food are associated with number ofdiseases especially with cardiovascular, kidney, nervousas well as bone diseases (Steenland and Boffetta, 2000,lamp, 2003). The deficiency of trace metals also causediseases like impaired immune functions, gastrointestinaldistress, muscular pains etc (Paul et al., 1997).Therefore determination of metal content invegetables is important from view point of crop yield,food nutrition and health impacts. The requirement ofvegetables in our daily diet must be 300-350 gm perperson as these contain large quantities of Vitamins,Carbohydrates, essential amino acids and dietary fibers,which are required for normal functioning of human(WHO, 1998).Lead, copper, zinc and iron concentrate in thesoil and water and ultimately leads to the vegetables(Ghafoor and Manzoor, 2004). Metallic uptake has beenwidely investigated throughout the world. Metals usuallyenter the food chain from water to soil and then to plantroots (Chaney et al., 1998). Zinc and cadmium werefound in vegetables (Ansari and Kazi, 1999). Heavymetals in edible green vegetables grown along the sites ofrivers were estimated in Iran (Eslami et al., 2007).Factors affecting the uptake of heavy metals in vegetablesincludes nature of soil, application of fertilizers and waterirrigated (Anyanwa et al., 2004). Keeping in view of theimportance of the role of heavy metals play in definingthe nutritional status of human body, the present studywas initiated to investigate the level of heavy metals FeCr, Cd, Mn, Zn and Cu in vegetables. The level of abovecited metals were investigated by atomic absorptionmethod in three vegetables abundantly consumed by thelocal population.MATERIALS AND METHODSVegetables Tori (luffa acutangula), Kaddu(curcurbita pepo) and Brinjal (solanum meongena) werecollected from four different places. The numbers 1, 2, 3and 4 were assigned to vegetables collected from PCSIRcolony, Taj Bagh, railway workshop and Singh Puramandi, respectively (Table 1). Collection of vegetableswas carried out in the similar conditions i.e. same day andsame season. Samples were collected randomly andstored in polyethylene bags previously treated with 10%HNO 3. All samples were separately washed with distilledwater to eliminate air borne pollutants. Stakes and leaveswere separated from all samples and slices of vegetableswere made. These samples were air-dried on sheet of apaper to remove excess moisture. Then samples were195

Pakistan Journal of Science (Vol. 61 No. 4 December, 2009)dried in oven at 80°C for one hour. Precisely weighed (2g each) samples were ground in mortar and thensubjected to wet washing and digested with HNO 3:HCLO 4 in the ratio of 2:1.Table-1. Vegetables and their collection sites.Name Code given Collection locationLuffa Acutangula Tori1 PCSIR ColonyTori2Taj BaghTori3 Railway WorkshopTori4 Mandi Singh PuraCucurbita pepo Kaddu I PCSIR ColonyKuddu2 Taj BaghKuddu3 Railway WorkshopKuddu4 Mandi Singh PuraSolanummeongenaBrinl PCSIR ColonyBrin2Taj BaghBrin3 Railway WorkshopBrin4 Mandi Singh PuraAfter digestion samples were filtered with 0.45~m pore size cellulose nitrate membrane filter paper andvolume made up to 100 ml with distilled water. Thesamples were stored in airtight containers for elementalanalysis through atomic absorption spectrophotometer for(Eslami et al., 2007). Atomic absorptionspectrophotometer (Hitachi polarized Zeeman Atomicabsorption spectrophotometer) was used along-with sixstandard solutions (0.1-2.5 mg/I). . Flow rate of air andacetylene 17.0 l/min and 2.0 l/min were adjusted andanalysis was performed accordingly. Metal contents werecalculated by comparison with the standard curve ofrespective metals. Specific hollow cathode lamps wereused for each metal at their respective wavelength. Thedata thus collected were subjected to statistical analysisthrough ANOVA technique (Steel et al., 1997).RESULTS AND DISCUSSIONThe concentrations of Fe, Cu, Mn, Zn and Crwere observed in three vegetables collected from fourdifferent locations. The results (Table 2) showed thatmaximum concentration of Fe, Cu, Zn, Mn and Cr. wererecorded in Tori-l (13 mg/kg), Tori-4 (0.49mg/kg),Kuddu-l (4.5 mg/kg) Tori-3 (1.4 mg/kg) and Brin-2 (0.69mg/kg) respectively. While minimum concentration forFe, Cu, Zn, Mn, and Cr were found in Kaddu-4 (3.24mg/kg), Brin-2 (0.25 mg/kg), brin-2 (3.22 mg/kg),Kaddu-4 (0.72 mg/kg) and Tori-2 (0.15 mg/kg),respectively. Iron: Maximum concentration of iron wasfound in Tori 1 (13 mg/kg) followed by Kaddu 1 (6.31mg/kg) and Brin 1(5.5mg/kg). Iron act as catalyst in bodyand present in greater than any other trace element. Ironis the most abundantly found element in the human body,Table-2. Analysis of trace elements in Vegetables.SamplecodesTori 1Tori 2Tori 3Tori4Brin.1Brin.2Brin.3Brin.4Kaddu IKaddu 2Kaddu 3Kaddu 4FeMg/kg13.0 a± 0.5667.1 be±0.1417.8 b±0.4246.2 cd±0.5655.5 de±0.4244.3 f±0.8485.12 ef±0.0985.06 ef±0.0846.31 cd±0.4385.4 de±0.5654.13 fg±0.0983.248 g±0.169CuMg/kg0.46 a±0.0420.39 a±0.0280.40 a±0.0980.49 a±0.0560.39 a±0.0710.25 a±0.0710.3 a±0.0280.48 a±0.0560.46 a±0.0710.40 a±0.0140.36 a±0.0710.45 a±0.056ZnMg/kg3.88 abc±0.8482.6 de±0.7073.5 bed±0.1413.9 ab±0.4243.4 f±0.0283.22 bcde ±0.1692.31 e±0.0712.93 ede ±0.1134.5 a±0.5652.72 de±0.1472.71 de±0.1272.7 de±0.141MnMg/kg1.3 ab±0.1411.3 ab±0l.4 a±0.4241.3 ab±0.1411.3 ab±0.4241.12 ab±0.0561. 0 ab±1.2401.13 ab±0.0421. 04 ab±0.0561.1 ab±0.4240.96 ab±0.0710.72 b±0.098CrMg/kg0.35 b±0.0420.15 b±0.0560.36 b±0.0280.48 b±0.0980.65 b±0.0840.69 b±0.0710.60 b±0.1410.60 ab±1.4120.42 b±0.0560.38 b±0.0560.46 b±0.0140.51 b±0.071The means with the different superscripts in a columndiffer significantly (P≤ 0.05)according to estimate hemoglobin and myoglobincontains 57.6% and 8.9% iron respectively (Jacob et aI.,1974). National research council recommended the dailydietary allowance of iron for male is 10-12 mg and forfemale 15 mg and the recommended limit of iron was upto 30mg (Kaplan et aI., 1993). Our vegetables containiron content more as compared to Nigerian vegetables(Anthony et al., 2007) and less than Poland and Iranvegetables (Buszewski et aI., 2000 and Mohsen andSeilsepour, 2008).Zinc: The maximum concentration of zinc was found inKaddu 1 (4.5 mg/kg) and minimum was in Kaddu 4(2.7mg/kg) (Table- 2). Zinc is the second abundant tracemetal in the human body. Zinc is important for enzymaticaction. Normal body contains 1.4- 2.3 gm of zinc and itresent in all body cells. Recommended daily deity intakeof zinc is about 15 mg for adult male and 12 mg forfemale (Kaplan et aI., 1993). It was less than determinedin reddish root, spinach, green pepper and tomato thatcontain63.15, 297.40,61.36 and 46.20 ppm respectively(Mohsen and Seilsepour, 2008). It was also less than theNigerian and Iranian vegetables (Anthony et al., 2007196

Pakistan Journal of Science (Vol. 61 No. 4 December, 2009)and Eslami et al., 2007).Copper: The maximum concentration of copper metalwas found in Tori 4 (0.49 1 mg/kg), and Kadddu(0.46mg/kg) minimum was in Brin 2 0.25 mg/kg (Table2). Normal biological activities of amino acids andtyrosinase enzymes require copper as an essential tracemetal. Excessive intake of copper may cause haemolysis,hepatotoxic and nephlotoxic effects. The mean dailyintake of copper from UK total dietary studies (TDS) fellfrom 2.3 mg per person to less than 1.6 mg per person(Watson et aI., 1993), whereas according to an estimate1.5 -3.0 mg/day of dietary copper has been determine tobe safe and adequate for human consumption (Kaplan etal., 1993). This content was less than vegetables studiedin Indian which containl2.3 mg/kg (Lokeshwari andChandrappa, 2006). It was also less than Poland andIranian vegetables (Buszewski et al., 2000 and Mohsenand Seilsepour, 2008).Manganese: The maximum concentration of manganesewas found in Tori 3 (1.4 mg/kg), Brin 1 (1.3mg/kg) andKaddu 2 (1.lmg/kg). In mammals and poultry,Manganese is essential for normal growth, skeletalformation and for normal reproductive function. Theestimated safe and adequate daily dietary intake in adultsis 11 mg/day (Kaplan et al., 1993). This content was lessthan Iranian vegetables like reddish root 130mg/kg, dill37.51 mg/kg, coriander 43.95 mg/kg and tomato 14.93mg/kg (Mohsen and Seilsepour, 2008).Chromium: The maximum concentration of chromiumwas found in brin 2 (0.69 mg/kg), Kaddu 4 (0.51 mg / kg)and Tori 4 (0.48 mg/ kg) Table 2. Chromium is present inhuman tissues in variable concentration and its deficiencycharacterized by disturbance in glucose, lipid and proteinmetabolism (Underwood, 1971). The US Nationalacademy of sciences has recommended 50200 kg, whereas for UK total dietary study (TDS) copper intake limitfor chromium was 136 kg (Kaplan et. al., 1993).This content was greater in our vegetables ascompared to Iranian and Nigerian vegetables (Eslami etal., 2007 and Haliru et al., 2009). Similarly high level oftrace elements in the vegetables from Iran, Egypt andGreece were reported (Samarghandi et al., 2000,Dogheim et al., 2004, Karavoltsos et al., 2002)respectively. Variation in metal contents in the vegetablescan be related to the physical and chemical nature of thesoil and absorption capacity of plant (Sharma et al.,2007).Conclusion: This study concludes that heavy metalswere investigated in three vegetables collected from fourdifferent places. The amount of Fe, Cu, Zn, Cr werefound within acceptable limits, according torecommended dietary allowance by food and nutritionboard USA for one day and are safe for humanconsumption.REFERENCESAchterberg, C. How to put the food guide pyramid intopractice. J. Am. Diet Assoc. 94:1030-1038(1994).Ansari T. P and T. G. Kazi. Biocycling of trace and toxicelements in different vegetables from sludgesamples. Chern. Res. Commun., 9:51-56 (1999).Anthony, E., A. Wonegbe and U. Ikhuoria. Levels ofselected heavy metals in some Nigerianvegetables. Trends Appl. Sci. Res., 2: 76-79(2007).Anyanwu, E. C., E. J.E. Ijeoma, and M. A. Saleh. Bioavailableof lead concentration in vegetableplants grown in soil from a reclaimed industrialsite. Health Implication. Int. 1. Food Saf., 6:31-34 (2004).Chaney, R. L and E. H. Allen. Metal speciation theory,analysis and application. (Interaction amongelements affects trace elements transfer inagricultural and eItVironment food chain).Lewis publication Boca Raton, Fla, pp.219-254(1998).Dogheim, S. M., M. M. Ashraf, S. A. Gadalla, M. A.Khorshid and S. M. Fahmy. Pesticides andheavy metals levels in Egyptian leafy vegetablesand some aromatic medicinal plants. FoodAddit. Contam. 21 :323-330 (2004).Eslami, A., R. J. Khaniki, M. Nurani, M. Mehrasbi, M.Peyda and R. Azmi. Heavy metals in ediblegreen vegetables grown along the river sites ofthe rivers of Iran. J. BioI. Sci., 7:943-948(2007).Eaton. Methods for preparation of reagent grade water,Standard method for examination of water andwastewater, APHA, 20th Ed .pp 1 (1998).Friberg, L., G. F .Nordberg and B. Vepuk. Handbook onthe toxicity of Metals, Elsevier, North Holland,Bio medical press, Amsterdam. ( 1984)Ghafoor, A. and Q. Manzoor. Lead, copper iron, zincconcentration in vegetables irrigated with cityeffluents urbanized lands, 1. Indian Soc. SoilSci., 52: 114-117(2004).Haliru, M., V. O. Ajibola and E. B. Agbaji. Evaluation ofthe uptake and accumulation of metals by somecommonly irrigated vegetables in soils treatedwith different concentrations of these metals. J.Appl. Sci., I: 1-5 (2009).Jacob, A. Blood and is disorders, Weatherall 7 th Ed.Oxford Back well press, Oxford, Unitedkingdom, pp135. (1974).Jarup, L. Hazards of heavy metal contamination. Br.Med. Bull., 68:167182(2003 ).Kaplan, L. A., A. J Pesca and S. C. Kazmierczak. Theory,Analysis, Correlation in clinical Chemistry 4th197

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