An Assessment of Some Toxic , Essential Elements and Natural Radioactivity , in Most Common Fish Consumed in Jeddah-Saudi Arabia

This study has been carried out to determine the concentrations mg/Kg of the toxic elements (Al, Hg, Cd, Pb, U, Th, and As) and essential elements (K, Sn, Ca, Ni, Cu, Fe, Co, and Mn) using inductively coupled plasma optical emission spectrometer, and the radionuclides concentration levels of (238U, 226Ra, 232Th, 40K and 137Cs) using a high purity germanium spectrophotometer in ten of the most common fish samples collected from local store in Jeddah city, Saudi Arabia during 2014. The results showed that, 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 by FAO/WHO, 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), then this increase is to be of concern for fish consumer. The measured concentrations in (Bq/Kg) dry weight of natural radionuclides 238U, 226Ra, 232Th, 40K and fallout 137Cs in fish samples were calculated. The results show that the activities in fish samples were of no risk to public health. The total average annual effective dose μSv/y due to intake of 238U, 226Ra, 232Th and 40K from the ingestion of the fish samples were estimated to be 6.07 for infants (≤5 Y), 22.88 and 45.03 for children (5 10 Y and 10 15 Y) and 56.26 for adults (≥17 y), which are lower than the allowed value (1 mSv). The contribution of 137Cs is nearly negligible. This study could be useful as a baseline data for toxic, essential metals, and radiation, exposure. Corresponding author. S. H. Q. Hamidalddin, J. H. AlZahrani


Introduction
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 [1].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 [2].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 [3].Small fish become enriched with the accumulated substances in polluted aquatic systems.So, it can be used for pollution indicator and environmental changes study [4].On the other hand, naturally occurring radionuclides Uranium ( 238 U), Radium ( 226 Ra), Thorium ( 232 Th), and potassium ( 40 K) and the artificial radionuclides such as 137 Cs 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 [5].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, 210 Po is alpha-emitting radionuclides and gives (90%) of the natural radiation dose received by most marine organisms and the artificial 137 Cs has great abundant in the environment [6].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) [7].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 238 U, 226 Ra, 232 Th and 40 K and the artificial radionuclide 137 Cs 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.

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.

Instrumentation
Half (0.5) gm of the fish samples were analyzed by Inductively coupled plasma optical emission spectrometry 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 [8] [9]: It is the ratio of the estimated metal dose (EDI mg/Kg of body weight per day) and the reference dose (R f D mg/kg/day).If HI > 1.0, then the EDI of a particular metal exceeds the R f D, pointing out that there is a potential risk associated with that metal.
The estimated daily intake (EDI) was determined using the following equation [10] [11]: where: C metal 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 [12], 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 92.57keV were used to calculate 238 U average concentration and the photon energies of 351.87 keV of 214 Pb and 609.31 and 1120.27keV of 214 Bi were used to find the average concentration of 226 Ra (since there is a secular radioactivity equilibrium between 226 Ra progenies).The average concentration of 232 Th, which it is in a secular radioactivity equilibrium with its short half-life daughters, was determined using the gamma lines of 228 Ac (338.32,911.16, and 968.97 keV) and of 208 Tl (583.10 keV).The analysis of 40 K and 137 Cs 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 [13]: 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 [14]: 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) [7], 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 .

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.

Toxic elements:
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 [15].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 [16].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).
Essential element 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.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 [17].
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 [18].Therefore these fishes are healthy for consumption.

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 [12].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  [12].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) [19], 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.

Gamma Spectroscopy: Activity Concentration
The measured concentrations in (Bq/Kg) dry weight of natural radionuclides 238 U, 226 Ra, 232 Th and 40 K in ten samples of fish collected from the local markets in Jeddah-Saudi Arabia are listed in Table 5. 238 U concentrations in Bq/kg dry weight were from LDL to 2.69, for 226 Ra concentrations in Bq/kg dry weight ranged from 0.75 to 2.70, 232 Th concentrations in Bq/kg dry weight were from 0.64 to 2.67, whereas 40 K and the artificial radionuclide 137 Cs 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.Also the results showed that, the activity of the ratio 238 U/ 226 Ra ranged from 0.91 to 2.31, The highest 238 U/ 226 Ra 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 238 U due to the extraction of uranium from the water or from the accumulation of uranium on gill surfaces. 226Ra/ 232 Th ratios indicate that in fish samples (1,3,9,10) 226 Ra was in excess to 232 Th, 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 137 Cs 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 137 Cs activity for foodstuffs is 1000 Bq/kg [27].So, there is no hazard to public health from the 137 Cs activity in fish samples in the present study.

Table 1 .
Information of fish collected from the local markets in Jeddah-Saudi Arabia.
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 238 U, 226 Ra, 232 Th, 137 Cs, and 40 K respectively.

Table 3 .
Average Concentrations (mg/Kg), R f Ds 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.

Table 6
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.Table7shows 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 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 238 U, 226 Ra, 232 Th and 40 K from the fish products. [28]].

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.