الفهرس 
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Abstract
Heavy metals may contaminate in different food types causing serious health hazards such as symptoms of chronic toxicity, injury of kidney, renal failure and liver damage. Exposure to metals during growth and development can result in acute and long-term effects on the health of the children. As their bodies are developing and because they generally consume more food on a per body weight basis than adults, children are at particular risk of illness from exposure to chemical hazards in foods. Moreover, developing organs and tissues are more susceptible to the toxic effects of certain chemicals.
Therefore, the aim of this study was to develop of analytical method for determination of some essential and toxic elements in baby food and then carrying out monitoring of investigated elements in the baby food samples collected from the different pharmacies and markets in Giza, Egypt, also detect of concentrations levels of some essential and toxic elements in the homemade baby food samples and also study the effect of processing on the levels of the investigated elements in some herbal baby drinks. Finally carrying out risk assessment on the babies as the dietary exposure to such chemical contaminants through estimated their dietary intake relative to the acceptable daily intakes.
The results obtained can be summarized as following:
5.1. Validation of analytical method for determination of some essential and toxic elements in some baby food samples by using inductively coupled plasma
Microwave digestion method was especially recommended for determination of lead (Pb), cadmium (Cd), antimony (Sb), copper (Cu), iron (Fe), zinc (Zn), chromium (Cr), manganese (Mn), tin (Sn), cobalt (Co) and nickel (Ni) in baby food samples by using inductively coupled plasma optical emission spectrophotometer (ICP-OES). The method performance was tested on different baby food samples at basic and confirmatory wavelengths of tested elements. The basic wavelengths were selected according to the highest sensitivity, lowest relative standard deviations, no spectral interference and have sharp peaks. The basic wavelengths were found to be (205.56, 230.786, 238.204, 227.02, 202.548, 189.927, 257.61, 327.393, 214.44, 206.836 and 220.353 nm) for Cr, Co, Fe, Ni, Zn, Sn, Mn, Cu, Cd, Sb and Pb respectively. At these basic wavelengths and under optimize conditions the average recoveries of Zn, Fe, Cr, Mn, Sn, Pb, Cd, Cu, Sb, Co and Ni at different levels varied between 78 and 118 % with coefficient of variation expressed as relative standard deviation ranged from 1.81% to 16.83%. The limits of detection were found to be 0.01, 0.001, 0.009, 0.206, 0.09, 0.044, 0.145, 0.061, 0.055, 0.098 and 0.249 mg/kg for Pb, Cd, Sb, Fe, Zn, Cr, Mn, Sn, Co, Ni and Cu respectively by using calculated standard deviations (S”) 0.0034, 0.0003, 0.0029, 0.0687, 0.0301, 0.0148, 0.0483, 0.0204, 0.0183, 0.0326 and 0.083mg/kg for Pb, Cd, Sb, Fe, Zn, Cr, Mn, Sn, Co, Ni and Cu respectively. The practical limits of quantification were found to be 0.2, 0.2, 0.4, 1, 1, 1, 1, 1, 1, 1 and 1 mg/kg for Pb, Cd, Sb, Fe, Zn, Cr, Mn, Sn, Co, Ni and Cu respectively with coefficient of variation expressed as relative standard deviation for Pb, Cd, Sb, Fe, Zn, Cr, Mn, Sn, Co, Ni and Cu were 12.41%, 7.69%, 6.29%, 10.86%, 16.83%, 7.48%, 3.84%, 6.62%, 4.3%, 8.09% and 9.43 % respectively . The linear range found to be from 1 up to 0.1ug/l for Pb, Cd and Sb, while from 0.05 up to 6 mg/l for Fe, Zn, Cr, Mn, Sn, Co, Ni and Cu and correlation coefficients of the linear calibration curves were greater than 0.995. The method linearity was checked to be linear from limit of quantification 1 mg/kg, 2, 5 and 10 mg/kg for Cr, Co, Fe, Ni, Zn, Cu, Mn and Sn, from 0.4, 0.8 and 1.6 mg/kg for Sb, while checked from 0.2, 0.4, 0.8 and 1.6 mg/kg for Pb and Cd. The repeatability expressed as relative standard deviation of Pb, Cd, Sb, Fe, Zn, Cr, Mn, Sn, Co, Ni and Cu were 6.77%, 4.52%, 5.75%, 8.97%, 6.65%, 5.93%, 5.68%, 5.91%, 5.16%, 6.19% and 6.78 % respectively. The reproducibility of this method was carried out at different types of sample matrixes like fresh (mix vegetables), fatty food (fish) and dry (wheat with milk powder). Pooled reproducibility was estimated by pooling the variances of the three reproducibility of different matrix. The pooled reproducibility expressed as pooled relative standard deviation of Pb, Cd, Sb, Fe, Zn, Cr, Mn, Sn, Co, Ni and Cu were 3.69%, 4.08%, 3.41%, 6.23%, 4.76%, 2.28%, 2.21%, 2.9%, 2.41%, 2.69% and 3.3% respectively, while the measurement uncertainty expressed as expanded uncertainty in terms of pooled relative standard deviation at 95% confidence level for all elements were 21.44%, 21.74%, 21.24 % , 23.76%, 22.34%, 20.60 %, 20.57 %, 20.93 %, 20.66 %, 20.82 % and 21.23% for Pb, Cd, Sb, Fe, Zn, Cr, Mn, Sn, Co, Ni and Cu respectively.
5.2. Monitoring of validated elements in baby food samples
The results indicated that all tested samples were free from any detectable amount of (Pb) and (Sb) while all tested samples were recorded detectable amount of (Fe) and (Mn), 99.35% from the samples were recorded detectable amount of (Zn), 87.01% from the samples were recorded detectable amount of (Cu), 81.17% from the samples were detectable amount of (Cd), 46.1% from the samples were recorded detectable amount of (Sn), 22.73% from the samples were recorded detectable amount of (Ni), 7.79% from the samples were recorded mean concentrations of (Co) and 1.3% from the samples were recorded detectable amount of (Cr). The maximum detectable concentration of Zn, Mn, Cd and Cu were found in infant milk formulae samples (167.5, 7.11, 0.017 and 8.79 mg/kg) respectively, while the maximum detectable amount of Fe was found in baby cereals samples 163.90 mg/kg. All tested canned samples were recorded detectable amount of (Sn) but less than limit of quantification, on the other hand the mean concentrations of Fe and Mn in canned samples were higher than its concentrations in homemade samples, while the mean concentration of Zn in canned samples was lower than its concentrations in homemade samples.
5.3. Studying the effect of processing on the levels of the investigated elements in some herbal baby drinks
The results showed that all processed herbal drinks were free from any detectable amount of Pb, Cd, Sb, Cr, Sn, Co and Cu, while 7, 5, 5 and 2 samples were recorded detectable amount of Mn, Fe, Zn and Ni but all concentrations were less than limits of quantifications.
5.4. Estimation of dietary intakes and risk assessment
The results showed that all estimated weekly intakes were lower than acceptable provisional tolerable weekly intakes of tested elements. At mean concentration the estimated exposure ranged from 0.0003% of the APTWI for (Sn) element to 0.0343% of the APTWI for (Cd) element, while at maximum concentration the estimated exposure ranged from 0.0003% of the APTWI for (Sn) element to 0.1026 % of the APTWI for (Zn) element.