Received 28 February 2016; accepted 25 April 2016; published 28 April 2016
Fish is consumed in many countries because it has high protein supplies, essential amino acids, vitamin, and mineral content. Fish are exposed to chemicals such as heavy metals in polluted and contaminated waters. Heavy metals from the human activities and resources are continually sent out into aquatic ecosystems, they are serious health risks due to of their toxicity, long persistence, bio concentration in the food chain  . Toxic elements such as mercury, arsenic, cadmium, and lead, can cause mental and central nervous system damage. It is important to check and control heavy metal levels in seafood, because heavy metal ions can easily accumulate in fish more than other foodstuffs. Lakes, rivers, stream, and sea are polluted by chemical substances, paints, petroleum products, and industrial, domestic, and modern agriculture wastes in the form of particles, metal ions, and organic and inorganic compounds. The heavy metal ions accumulation in seafood, including fish, becomes high. Heavy metals in organs of fish, such as internal organs, kidneys, and spleen, can be transmitted to and accumulated in organs of human body by their consumption. Fish is one of the most important foods to be eaten for a healthy life, therefore, heavy metals in food chain make threats to human health  . At low concentrations, heavy metals are toxic to fish, while essential elements (Zn, Al, B, Ba, Cr, Fe, Mn, Ni, Sr, Cu and Co) become toxic at high concentrations  . Small fish become enriched with the accumulated substances in polluted aquatic systems. So, it can be used for pollution indicator and environmental changes study  . On the other hand, naturally occurring radionuclides Uranium (238U), Radium (226Ra), Thorium (232Th), and potassium (40K) and the artificial radionuclides such as 137Cs in the environment can be concentrated in and transferred along the food chains, damaging biological effects on populations and ecosystems may come from these ionizing radiation  . Great interests focus on the consumption of marine foodstuffs such as fish, seaweeds and manufactured products including radioactivity. The radiation dose received and accumulated in the body by marine fauna comes from the naturally occurring uranium series, 210Po is alpha-emitting radionuclides and gives (90%) of the natural radiation dose received by most marine organisms and the artificial 137Cs has great abundant in the environment  . Radioactive contamination of the Pacific Ocean after the Fukushima nuclear accident has raised public worry about seafood safety. 137Cs half-life is long and is found in the environment for a long time, so levels of cesium radiation and the consumption of contaminated fish are calculated, the results compare to International Commission on Radiological Protection annual dose limit (1 mSv to the public)  . In this study, ten samples were analyzed to calculate the concentrations (mg/Kg) of toxic elements (Al, Hg, Cd, Pb, U, Th, and As) and essential elements (K, Sn, Ca, Ni, Cu, Fe, Co, and Mn). Also, the concentrations in (Bq/Kg) dry weight of natural radionuclides 238U, 226Ra, 232Th and 40K and the artificial radionuclide 137Cs in the fish samples were measured. The total average annual effective dose due to intake of natural radionuclides from the ingestion of the fish samples were estimated for infants, children, and adults also, the estimated metal dose (EDI) values for daily average consumption and hazarded index (HI) in fish samples were calculated to determine and monitor the serious health risks due to the consumption of contaminated fish.
2. Materials and Methods
2.1. Collection and Preparation Samples
Ten samples were taken from the local markets in Jeddah―Saudi Arabia. The samples data of fish (i.e. Scientific Name, Common Name, Country of Origin, Type, Collection Time) are indicated in Table 1. The fish species were collected from random commercial market depending on the availability of the species for sale at April 2014. Samples obtained were cleaned, thawed on, cut to pieces and dried to constant weight at 110˚C. These samples were ground into powder and stored in polyethylene bags.
Half (0.5) gm of the fish samples were analyzed by Inductively coupled plasma optical emission spectrometry
Table 1. Information of fish collected from the local markets in Jeddah- Saudi Arabia.
(ICP-OES) (Perkin Elmer- Optima 8300 ICP-OES Spectrometer) to get the concentrations of toxic elements (Al, Hg, Cd, Pb, U, Th, and As) and essential elements (K, Sn, Ca, Ni, Cu, Fe, Co, and Mn) in fish samples. For radiometric analyses, each dried sample was weighed, put, and sealed in 640 cc polyethylene Marinelli beakers then stored for nearly 4 month under 27˚C to prevent the escape of Radon gas and to allow the attainment of radioactive secular equilibrium between 238U series and 232Th series. The radioactive nuclei concentrations in the samples were determined using High purity Germanium (HPGe) coaxial detector with relative efficiency of 25% and FWHM 2.0 keV at 1332 keV, of 60Co. To reduce gamma ray background (HPGe) Detector was surrounded by lead shielding Genie 2000 basic spectroscopic software was installed in the computer for data acquisition and analysis. The system was calibrated for energy and absolute efficiency. The lowest limits of detection (LDL) were calculated tobe0.311, 0.312, 0.34, 1.66, and 0.45 Bq/Kg for 238U, 226Ra,232Th, 137Cs, and 40K respectively. To collect the background count rates, an empty polyethylene Marinelli beaker was placed in the detection system. The measurements were done for a counting time of 82,800 sec.
1) Assessments of heavy metals hazard index (HI) in fish samples:
A hazard index (HI) may be used to describe the risk from metals intake through ingestion. The hazard index (HI) was calculated by using the equation below   :
It is the ratio of the estimated metal dose (EDI mg/Kg of body weight per day) and the reference dose (RfD mg/kg/day). If HI > 1.0, then the EDI of a particular metal exceeds the RfD, pointing out that there is a potential risk associated with that metal.
The estimated daily intake (EDI) was determined using the following equation   :
where: Cmetal is the metal concentration level of metals in fish; W represents the daily average consumption of fish is given as: 0.003, 0.025, and 0.068 kg/day for Infants, children and adults respectively  , m is the body weight of 10 kg for Infants, 30 kg for children and 70 kg for adults.
2) Activity concentrations:
The photon energies of63.29 and 92.57 keV were used to calculate 238U average concentration and the photon energies of 351.87 keV of 214Pb and 609.31 and 1120.27 keV of 214Bi were used to find the average concentration of 226Ra (since there is a secular radioactivity equilibrium between 226Ra progenies). The average concentration of 232Th, which it is in a secular radioactivity equilibrium with its short half-life daughters, was determined using the gamma lines of 228Ac (338.32, 911.16, and 968.97 keV) and of 208Tl (583.10 keV). The analysis of 40K and 137Cs concentrations was based on their peaks in the spectrum at energies 1460.80 and 661.66 keV respectively.
Determination of activity concentrations in Bq/kg dry weight was calculated using the flowing equation  :
where: C is the count per second of the net peak area of specific gamma ray energy. m is the mass of the samples in (kg). β is the transition probability of gamma-decay. ε is the detector absolute efficiency at the specific gamma-ray energy.
3) Annual effective dose:
Annual radionuclide intakes and effective doses for fish consumers age groups as (infant (≤5 Y), children (5 - 10 Y and 10 - 15 Y), and adults (≥17 Y)) were calculated using the equation  :
where: D is the effective dose by ingestion of the radionuclide (Sv/Y), A is the activity concentration of the radionuclides in the sample (Bq/kg), C is the internal dose conversion factor by ingestion of the radionuclides (Sv/Bq) which varies with both radioisotopes and the age of the individual were reported by (ICRP)  , R is the annual intake of fish (Kg/Y) which is calculated for different age groups of population. In our study the average mass of the fish consumed by the infants (age ≤ 5 y), children (age 5 - 10 y and 10 - 15 y) and adults (age from 17 y and above) were 1 kg/y, 5 kg/y, 10 kg/y and 25 kg/y, respectively .
3. Results and Discussion
3.1. Elements Concentrations Using Inductively Coupled Plasma Optical Emission ICP- OES) Spectrometry
Table 2 shows the corresponding concentrations of toxic and essential elements in mg/Kg of analyzed fish samples namely (Seagan, Bagha, Tilapia, Sardine, Herring, Catfish, Shrimp, Tuna) using inductively coupled plasma optical emission (ICP-OES) spectrometry.
Aluminum (Al) is a trace element in fish. The results obtained shows that Al concentrations were not detected (ND) in the fish samples from 1 to 8, samples 9 and 10 (Tuna) were lower than detection limits (LDL*).
Mercury (Hg) is a heavy element in fish, the existing of this element in food such as fish may cause risk on human health. Table 2 represents the Hg for all fish species were (ND).
Cadmium (Cd) highest concentrations mg/Kg were in fresh Seagan, frozen Tilapia, and fresh Sardine (0.015, 0.019, 0.022) respectively. On the other hand, the lowest Cd concentrations mg/kg were in frozen Herring, Shrimp, and canned Tuna (0.001, 0.002, 0.002, 0.03). For the rest of samples analyzed, cadmium concentrations were low or not detected.
Lead (Pb) is heavy element and can be found in fish directly from seawater and sediments and exists in the fish consumers’ tissues. It is harmful to human health at high concentrations, the allowed limit is 0.2 mg/kg  . In this study, Pb was not detection (ND), so there is no risk to fish consumers.
Uranium (U) is a radioactive metal, but Uranium's toxic hazard resides not only in its radiation effects but in its chemical effects  . Results show that highest U concentrations mg/kg were in fresh Bagha and Tilapia (3.086, 4.906, 5.075). For all samples, the concentrations mg/Kg ranged from 0.519 to 5.075.
Thorium (Th) is a naturally-occurring, radioactive metal. Since Thorium is found almost everywhere, all people absorb some through food, drinking water, and in air. Th concentrations of fish species ranged from ND to 0.032 mg/kg. The concentration in frozen Tilapia was LDL.
Arsenic (As) presents in fish consumed by human. It is a toxic and trace element and inorganic arsenic is found at very low concentrations in fish and other seafood products, some types of fish have high concentrations. In this work, values for As ranged from ND for canned Tuna to 0.752 mg/kg for fresh Sardine. All the samples analyzed were below the maximum allowed limit put by Brazilian legislation (1 mg/kg).
Potassium (K): All fish contain potassium. It is necessary for human health, but deficiency or increase in potassium intake is a risk for human, the recommended daily dietary intake of potassium (in Australia) for adults is 2.0 - 5.5 g). The lowest k concentration determined in fish species was found as 21.017 mg/kg in frozen shrimp and the highest 176.571 mg/kg in frozen Herring.
Table 2.The Corresponding Concentrations of elements in mg/Kg of Fish samples using ICP-OES spectrometry.
Tin (Sn) is an essential element in fish and becomes toxic when the tin migrate from the container to canned fish. In this work, the highest concentration of tin 3.651 and 3.548 mg/kg in fresh and frozen Tilapia, the lowest values 0.469 mg/kg in frozen Shrimp. The concentration values in mg/kg were 0.505 and 0.588 in canned Tuna.
Calcium (Ca) Calcium is an essential component of fish. The results indicated that, Ca concentrations values in mg/kg were high for fresh Tilapia 1130.70, fresh Bagha 1020.298, frozen Herring 829.987, frozen Tilapia 741.760, fresh Sardine 687.159, fresh Seagan 646.890, and frozen Shrimp 99.298 , while the lowest values in mg/kg 5.082, 7.674, and 11.431 for canned Tuna and Catfish respectively.
Nickel (Ni) is a trace element in fish. In this work, Ni has low values mg/kg in fresh samples. The concentrations of Ni in all the samples were far below the allowed limit 70 - 80 mg/kg  .
Copper (Cu) makes health hazard when it took in large amount exceeded the allowable limit by the World Health Organization and Food and Agriculture Organization, 30 mg/kg. Table 2 shows that the concentrations of copper in fish samples were not found.
Iron (Fe) is essential element to all living and the allowable limit by the National Health and Medical Research Council National for Food Standard is 8.76 μg/g. In this work, the highest concentrations in mg/k of iron were in Tilapia (8.380 sample 8 and 8.268 sample 3), these values are lower than the maximum allowed limits.
Cobalt (Co) is essential for red blood cell formation, the maintenance of nerve tissue, and useful for humans because it is part of vitamin B12. Rich dietary sources of cobalt include fish meal, but high levels of cobalt can cause lung and heart diseases. Cobalt concentrations in this work ranged from ND (fresh Sardine and frozen Herring) to 0.006 (frozen Tilapia) mg/kg. The results do not affect a risk to human.
Manganese (Mn) highest concentrations (1.030 and 1.026 mg/kg) were detected in fresh Tilapia and frozen Herring, while the minimum values (0.022 and 0.024) were found in canned Tuna. Based on the above results, it can therefore be concluded that elements bioaccumulation in the fish samples under study did not exceeds the allowed limits set for metals by  . Therefore these fishes are healthy for consumption.
3.2. Daily Intake of Metals and Hazard Index
The daily intakes (EDI) of the metals were calculated using the average concentrations of metals in the fish samples and the average consumption of fish per day for age groups infants, children, and adults as reported by  . The daily intakes (EDI) mg/kg body weight/day of toxic and essential elements were presented in Table 3. For Al, (EDI) was lower than limit (LDL), and Hg, Pb, and Cu, (EDI) were not found (ND). The daily intakes (EDI) mg/kg body weight/day for infants, children, and adults of Cd were 2.74E−06, 7.62E−06, and 8.88E−06, for U, (EDI) were 0.59E−03, 1.63E−03, and 1.90E−03, (EDI) of Th were 2.48E−05, 6.88E−05, 8.03E−05. As (EDI) 1.37E−04, 3.82E−04, and 4.45E−04. The daily intakes (EDI mg/kg body weight/day for infants, children, and adults of essential elements were (K: 3.40E−02, 9.44E−02, 11.01E−02), (Sn: 1.08E−06, 3.00E−06, 3.50E−06, (Ca: 1.56E−01, 4.32E−01, 5.03E−01), (Ni: 2.61E−05, 7.25E−05, 8.45E−05), (Fe: 0.96E−03, 2.66E−03, 3.10E−03), (Co: 1.08E−06, 3.00E−06, 3.50E−06), and (Mn 9.05E−05, 2.52E−04, 2.93E−04). These results are lower than the recommended values by  . Estimated hazard index (HI) in fish samples do not affect a threat to the human health, where the HIs of the considered metals were less than one (<1)  , except (HI) for Ca element with values 7.80, 21.60, and 25.15 mg/kg body weight/day, (for infants, children, and adults) were greater than one (>1), then this increase are to be of concern for fish consumer. The results were shown in Table 3.
Table 4 shows comparison between the concentrations (mg/Kg) of the toxic and the essential elements in the present study and the concentration values of the studies in other countries. The concentrations (mg/Kg) of the toxic and the essential elements in fish samples varied from one country to another due to the different types of fish and the environment in which these fish were lived as shown in these tables.
3.3. Gamma Spectroscopy: Activity Concentration
The measured concentrations in (Bq/Kg) dry weight of natural radionuclides 238U, 226Ra, 232Th and 40K in ten samples of fish collected from the local markets in Jeddah―Saudi Arabia are listed in Table 5. 238U concentrations in Bq/kg dry weight were from LDL to 2.69, for 226Ra concentrations in Bq/kg dry weight ranged from 0.75 to 2.70, 232Th concentrations in Bq/kg dry weight were from 0.64 to 2.67, whereas 40K and the artificial radionuclide 137Cs concentrations in Bq/kg dry weight existed in the range from 14.02 to 352.32 and from LDL to 1.44 respectively. The results showed that, the samples for fresh fish (1-4) and sample 5 for frozen fish have the highest radiation comparison with other samples, while the sample No. 10 (canned fish) has the lowest radiation.
Table 3. Average Concentrations (mg/Kg), RfDs mg/kg body weight/day, EDIs (mg/kg body weight/day) and HI of elements in fish due to ingestion of infants, Children, and Adults.
*  .
Also the results showed that, the activity of the ratio 238U/226Ra ranged from 0.91 to 2.31, The highest 238U/226Ra concentration (2.31 Bq/Kg) was in the fish samples from frozen Herring (Philippines), and in samples (2, 3, and 9), this meant that there was excess in 238U due to the extraction of uranium from the water or from the accumulation of uranium on gill surfaces. 226Ra/232Th ratios indicate that in fish samples (1, 3, 9, 10) 226Ra was in excess to 232Th, this is due to water interaction with samples. 137Cs was detectable in the fish samples except in sample 1 (fresh Seagan), the highest value of 137Cs content is in sample 5 (frozen herring) 1.44 Bq /kg and the lowest value is 0.63 Bq/kg in sample 7 (Shrimp). The allowed level of 137Cs activity for foodstuffs is 1000 Bq/kg  .
So, there is no hazard to public health from the 137Cs activity in fish samples in the present study.
3.4. The Annual Effective Dose (μSv/y) Estimation for Different Age Group
Table 6 represents the calculated age-dependent annual effective dose (μSv/y) due to intake contaminated fish with radiation. The annual effective dose (μSv/y) of 238U for Infants (≤5 y) ranged from 0.07 to 0.22 with an average 0.13, for children (5 - 10 y, 10 - 15 y) from 0.30 to 0.92 with average 0.55, and from 0.58 to1.8 with an average 1.09 respectively, for adults (≥17 y) from 1.74 to 5.38 with an average 3.25. The annual effective dose (μSv/y) of 226Ra for Infants (≤5 y) varied from 0.47 to 1.56 with an average 0.99, for children (5 - 10 y, 10 - 15 y) from 3.00 to 10.80 with average 6.39, and from 11.25 to 40.50 with an average 23.97 respectively, for adults (≥17 y) from 5.25 to 18.90 with an average 11.86. The annual effective dose (μSv/y) of 232Th for Infants (≤5 y) were from 0.29 to 0.39 with an average 0.58, for children (5 - 10 y, 10 - 15 y) from 1.22 to 3.87 with average 2.41, and from 2.10 to 6.68 with an average 4.16 respectively, for adults (≥17 y) from 4.83 to 15.35 with an average 9.56. The annual effective dose (μSv/y) of 40K for Infants (≤5 y) were from 0.29 to 7.40 with an average 4.37, for children (5 - 10 y, 10 - 15 y) from 0.91 to 22.90 with average 13.53, and from 1.07 to 26.78 with an average 15.82 respectively, for adults (≥17 y) from 2.17 to 54.61 with an average 32.26 (μSv/y). The total average annual effective dose (μSv/y) for all groups were 6.07, 22.88, 45.03, and 56.26 respectively. The results of the present work show that the lowest total average annual effective dose (μSv/y) value due to the radiation in fish was for infants, while the largest was for adults. This is due to the amount of fish consumed by each group.
Table 7 shows the comparison of the Average concentration Bq/Kg and the total average annual effective dose (μSv/y) values of this study and the values of similar studies. The highest concentration values for natural
Table 4.Comparison between the concentrations(mg/Kg) of the toxic and essential elements in the present work and the similar studies of other countrie.
Table 5. The specific radioactive concentrations in Bq/kg dry weight for fish samples.
Table 6. Annual effective dose (μ Sv/y) due to the intake of natural radionuclides of 238U, 226Ra, 232Th and 40K from the fish products.
*  .
Table 7. Describe the Average concentration Bq/Kg, the total average annual effective dose (μSv/y) values of this study and the values of similar studies.
radionuclides 238U, 226Ra, 232Th, 40K, and 137Cs were in Kainji lake Nigeria, while the lowest values were inHong Kong. The total average annual effective dose values were not found in the most of the studies.
This study has been carried out to analyze the concentrations mg/Kg, The daily intakes (EDI) mg/kg body weight/day, and hazarded indices (HIs) of some toxic and essential metals in ten fish samples. The concentrations of the elements (Al, Hg, Pb and Cu) in all fish samples were not detected or below the detection limit. The concentrations of metals (Cd, U, Th, As, K, Sn, Ca, Ni, Fe, Co, and Mn) were below the recommended limit by the international organizations. The estimated metal dose (EDI) values for daily average consumption were lower than the recommended values of FAO/WHO (2004), and hazard indices (HI) in fish samples were below safety levels for human consumption (HI < 1) except (HI) for Ca element with values were greater than one (>1), this increase in Ca element is to be of concern for fish consumer. Also, the natural radioactivity and fallout 137Cs levels (Bq/Kg) dry weight of gamma-emitters in ten fish samples were determined. The results show that the activity concentrations and the total average annual doses μSv/y (calculated for infants, children and for adults) received from the intake of 226Ra 232Th and 40K due to the ingestion of the fish were of no risk to public health. All these average doses are less than the annual dose limit of 1 mSv/y and the contribution of 137Cs is nearly negligible. In both techniques, the results were compared with the study results in other countries. The values were varied from one country to another due to the different types of fish, food habit, and the environment in which these fish were lived. On the basis of the results of this study, it appears that more specifications are needed for imported types of fish and the sources and the environment in which the fish were lived is to be of concern for researchers.
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