Seeds of 8 apricot cultivars comprising of Kullabi, Tadmori, Ajjami, Lawzi, Wizri, Hamwi laqisi, Hamwi Shahmi, and Baladi were investigated. However, Kullabi, Tadmori, Ajjami, Lawzi, Wizri, Hamwi laqisi, Hamwi Shahmi, and Baladi are the common name of local Syrian cultivars belongPrunus armeniaca related to family Rosaceae. Apricot fruits (Prunus armeniaca) were purchased at local grocery store in Damascus the capital city of Syria. The fresh fruit samples were transported to the laboratory where the stones were removed and individual stones were hammered to obtain the seed kernel. The apricot seeds were visually inspected and defective seeds were discarded. Next, the non-edible parts was removed, and the kernels were oven dried at 70-80°C until they reached a constant weight. They were then grounded and sieved through an 80 mesh sieve to have their powder. Dry mass factor was calculated by drying the powder for 4 hours at 105^oC. The sample size, however, was considered reasonably well enough for the purpose of the study. The determinations were made in triplicate for each apricot cultivar seed samples.

First the short-lived nuclides were determined. Using a pneumatic rabbit system, approximately 200 mg from each sample was irradiated separately (but the standard reference material together with two comparators in order to calculate the neutron flux) for 60 seconds at a thermal neutron flux of 5×10¹¹ n.cm^-2s^-1 in inner irradiation site at Miniature Neutron Source Reactor (MNSR) Slowpoke Nuclear Research Reactor (is a low-energy) (tank-in-pool type, China). After 300-600 second decay time samples and standard reference material were measured on 75 mm from end cap of detector, comparators (Al-0.1% Au) were measured separately after 20 minutes decay time on 200 mm from end-cap of detector.

Second the other elements with longer half life times were determined. A maximum of 8 capsules filled with sample material (~200 mg), together with a two capsule filled with a certified reference material and four comparators were ordered in irradiation container. The samples were irradiated for 20 hours at a thermal neutron flux of about 5x10¹¹ n.cm^-2s^-1. To determine the elements with medium lived radio-nuclides, all samples were measured for 30-60 minutes after 5 to 10 days decay time after irradiation on 25 mm from the en-dcap detector. To determine the long lived radio-nuclides, the samples are measured again for 8 hours after about 3 weeks decay time after irradiation directly on the top of detector. Comparators (Al-0.1% Au) were measured separately after 5days decay time on 200 mm from end-cap of detector. After this third measurement, all 3 spectra of each sample are interpreted together by using k0-IAEA software.

Samples were measured by using gamma spectroscopy: HPGe detectors 25% relative efficiency, FWHM1.79 at 1.333 MeV, with Selina gammapls software version(1.02), the peak search, the energy gamma system were calibrated by using point source radioactive (such as : ¹⁵²Eu, ¹³⁷Cs, ⁶⁰Co, …etc). The results were controlled using Nist 1547 peach leaves and Nist 1515 Apple leaves as standard reference methods.

The overall concentrations of the trace elements in all seed samples of eight apricot cultivars grown in Syria are shown in Table 2 and Table 3. An overall average concentration of Zinc (Zn) (97.41 mg/kg), Iron (Fe) (70.01 mg/kg), Copper (Cu), (22.85 mg/kg), Aluminum (Al), (16.46 mg/kg), Manganese (Mn) (13.56 mg/kg), Rubidium (Rb) (7.84 mg/kg), Iodine (I) (5.21 mg/kg), Bromine (Br) (1.24 mg/kg), Cobalt (Co) (0.34 mg/kg), and Antimony (Sb) (0.02 mg/kg) were recorded in the apricot seed samples.

Trace elements are also called micro elements which are required in amounts less than 100 mg/day 7.

Zinc (Zn):

The trace element contents in these eight apricot varieties showed that Zn was the most abundant micro (trace) element, ranging from 84.52 mg/kg (Ajjami cultivar) to 112.80 mg/kg (Wizri cultivar). While concentration of Zn was below detection limit in Hamwi shahmi apricot seeds. Also, lower concentrations of Zn and Mn were recorded in apricot 6.

Zn is known to be involved in most metabolic pathways in humans, and Zn deficiency can lead to loss of appetite, growth retardation, skin changes, and immunological abnormalities. Zn reported as a coenzyme for over 200 enzymes involved in body immunity system 26. RDA for Zn (8 mg/day for adult women and 11 mg/day for adult men) appears sufficient to prevent deficiency in most individuals 37.

Iron (Fe):

The range of Fe in all studied apricot seed samples varies from 59.06 mg/kg (Baladi cultivar) to 78.98 mg/kg (Lawzi cultivar). The permissible limit Fe set by FAO/WHO in edible plants was 20 µg/g 38. According to USDA the daily recommended intake (RDA) of Fe is 8 mg for adult male and 18 mg for adult female 34. Fe is an important trace element and is a core of red blood cells. It's deficiency can cause anemia 3239.

Copper (Cu):

The lowest concentration of Cu that is 18.59 mg/kg (Hamwi laqisi cultivar) and maximum concentration estimated 27.86 mg/kg (Tadmori cultivar). The permissible limit of Cu set by FAO/WHO 40 in edible plants was 3.00 mg/kg 39. After comparison, element limit in the studied apricot seed samples with those proposed by FAO/WHO 40 it is found that all seed samples accumulate Fe and Cu above this limit. Cu is a constituent of enzymes like cytochrome c oxidase, amine oxidase, catalase, peroxidase, ascorbic acid oxidase, cytochrome oxidase, plasma monoamine oxidase, lactase, uricase, tyrosinase, cytosolic superoxidase dismutase etc 8.

Aluminum (Al):

Al is the most widespread metal on the Earth (8% of Earth crust), and nearly all foods contain small amount Al. The daily average intake of Al estimated vary from 2 to 10 mg/day 41. The range obtained from Al in this study was (13.06 mg/kg) (Baladi cultivar) to (19.81 mg/kg) (Hamwi leqissi). These values are higher than those reported in other research papers for a total of sixteen (16) cereals samples 5. There is concern because of the possibility of increased amounts of Al being deposited in the brain and implicated as interfering with a variety of cellular and metabolic processes 5.

Manganese (Mn):

The range of Mn in all studied apricot seed samples varies from 10.28 mg/kg (Kullabi cultivar) to 17.46 mg/kg (Wizri cultivar). Mn is a cofactor of hydrolase, decarboxylase, and transferase enzymes 7. Mn is a component of arginase and superoxide dismutase and plays a role as co-factor of certain enzymes 2037. The USDA has recommended an intake of Mn of 2.3 mg/day for adults male and 1.8 mg/day for female 34.

Rubidin ( Rb ):

The content of Rb in case of apricot seed was within 2.94 and 17.45 mg/kg for Kullabi and Hamwi leqissi, respectively. These values are lower than those reported in other research papers. According to Jibiri and Agomuo 42 Rb concentration in green beans, cassava, guinea corn and maize have been reported to be 85.5, 37.5, 41.7 and 20.7 mg/kg respectively.

Iodine (I):

The lowest concentration of I is 1.06 mg/kg (Hamwi shahmi cultivar) and maximum concentration estimated 30.67 mg/kg (Wizri cultivar). Iodine is a basic component of the thyroid hormones, thyroxine and mono-, di-, and tri-iodothyronine and it is stored in thyroid as thyroglobulin 7.

Bromine (Br):

The highest amount of Br was found in Ajjami cultivar seed (3.28 mg/kg) while the lowest amount of Br was found in seeds of Kullabi cultivar 0.55 mg/kg. Analysis of samples for Br show that concentration of Br in the Hamwi laqisi, Hamwi shahmi and Baladi cultivars were below detection limit.

Cobalt (Co):

The Co content of the studied apricot seeds varied from 0.18 mg/kg (Tadmori cultivar) to 0.67 mg/kg (Ajjami cultivar). The RDA for Co has been defined at around 300 micrograms 6. Cobalt is required in the haematopoiesis of red blood cells and in preventing anemia 43.

Antimony (Sb):

The concentration of Sb in apricot seeds was very low and ranged from 0.012 mg/kg (Hamwi shahmi) to 0.049 mg/kg (Kullabi).

Various investigators have addressed the levels of essential and non essential trace elements from various vegetables, fruits, spices, herpes and food items 154445. Mehari et al. 4 reported that among total of 49 food samples comprising of 16 fresh fruits, 17 fresh vegetables, 4 herbs, and 12 processed foods the highest concentrations of Fe, Pb, Zn, and Mg were found in apricot, moringa, yellow yam, American okra, and Chinese okra respectively. The concentration or quantity of trace elements in crop depend on the soil in which the crop is grown 4246. The content of elements was found to vary widely depending on different cultivars of apricot 27. The content of trace elements is one of the most essential aspects that influence the use of edible plant parts in human nutrition 30. The presence of trace elements in plants is affected by nutrients and agrochemical inputs 15. In general, minerals contents were determined vary widely depending on the different varieties, species, and locations of caper plants. The soil, fertilizers and other cultural factors affect the presence of minerals in seeds 21.

The non-essential (toxic) elements (Molybdenum (Mo), Chromium (Cr), Mercury (Hg)) concentration in seeds of 8 varieties of Syrian apricot are shown in Table 4. Analysis of samples for toxic elements show that the overall average concentration of Mo, Cr and Hg in all studied seed samples of apricot cultivars were 0.80 mg/kg, 0.27 mg/kg and 0.38 mg/kg respectively. As shown in Table 4, Mo was present in three of the eight samples (cultivar) analyzed at concentration of a low of 0.48 mg/kg (Kullabi), 0.67 mg/kg (Wizri) and 1.24 mg/kg (Hamwi shahmi) (Table 4).

Molybdenum (Mo) is a component of several metalloenzyme including xanthine oxidase, aldehyde oxidase, nitrate reductase, and hydrogenase 78. Chromium (Cr) was also present in two of the eight samples analyzed at concentration of a low of 0.20 mg/kg and 0.35 mg/kg in Wezri and Hamwi laqisi cultivars respectively. Most foodstuffs contain less than 0.1 mg Cr/kg 11. It is well accepted that Cr is essential for normal blood glucose and lipid metabolism and insulin- co adjuvant 32. Analysis of samples for Mercury (Hg) show that concentration of Hg in all studied seed of apricot cultivars were below detection limit in all the varieties except in Wezri cultivar (0.38 mg/kg). The permissible limit of Hg set by USDA in food was 1.5 mg/kg 47. Levels of Hg in most field crops are sufficiently low to cause little concern from a human health viewpoint 47. In this study also we found low levels of Mo, Cr and Hg concentration in apricot seeds of different apricot cultivars were lower than the permissible limits and therefore, do not represent a health risk. Some heavy metals are essential to maintain normal human body functions at trace amount. However, they may be dangerous or even toxic if present at higher concentrations 14. Keeping in mind the potential toxicity and persistent nature of toxic elements, and the frequent consumption of fruits, it is necessary to analyze these food items to ensure the levels of these contaminants meet agreed international requirements 11. Different reason may cause contamination of plant products with toxic elements. Using mineral fertilization, contaminated water, industrial emission and transportation, mining and processing metal ore are the main sources of toxic metal in agricultural system 48.