ESTIMATION OF LEAD AND CADMIUM LEVELS IN FLESH OF SOME IMPORTED SALTED CANNED FISH

ESTIMATION OF LEAD AND CADMIUM LEVELS IN FLESH OF SOME IMPORTED SALTED CANNED FISH

NAHED M. ABDELAZIZ^* and Z.M. ZAKY^**

^*Department of Food Hygiene, Fac. of Vet. Med., Sohag Univerisity, Sohag, Egypt.

^** Department of Forensic Medicine and Toxicology Fac. of Vet. Med., Assiut Univerisity, Assiut, Egypt.

Email:  nahedvet2012@yahoo.com                                                        Assiut University web-site: www.aun.edu.eg

INTRODUCTION

Fish is widely consumed in many parts of the world by humans because it has high protein content, low saturated fat and also contains omega fatty acids known to support good health (US EPA, 2004). It have been found to be good indicators of heavy metal contamination in aquatic systems (Burger et al., 2002).

Canned fishes in particular are well eaten in the developed world it is convenient and affordable for most working families (NOAA, 2002).

Fish may be contaminated by toxic elements during fish growth, transportation, and storage. Contamination may also occur during production, handling and canning process. Information on the metal content in canned fish is important to ensure that the fish consumed is safe for human consumption. The estimated weekly intakes of these metals by adults consuming different species of canned fish are also evaluated for possible human health risks (Ikem and Egiebor (2005).

Heavy metals are potential environmental contaminants with the capability of causing human health problems if present to excess in the food. They are given special attention throughout the world due to their toxic effects even at very low concentrations (Das, 1990). Several cases of human disease, disorders, malfunction and malformation of organs due to metal toxicity have been reported (Jarup, 2003).

Lead is a heavy metal that accumulates in the body and affects different systems and organs such as central and peripheral neural system, gastrointestinal tract, muscles, kidneys and hematopoietic system Ciobanu et al. (2012). Short-term exposure to high levels of lead can cause brain damage, paralysis (lead palsy), anemia and gastrointestinal symptoms. Longer-term exposure can cause damage to the kidneys, reproductive and immune systems in addition to effects on the nervous system (Rose et al., 2001).

Cadmium and lead are among the most abundant heavy metals and are particularly toxic. The excessive content of these metals in food is associated with etiology of a number of diseases (WHO, 1992, 1995).

International Agency for Research on Cancer (IARC) classified cadmium and lead as human carcinogen (IARC, 1993; Steenland and Boffetta, 2000).

Cadmium exposure induces bone damage, osteoporosis, and renal tubular dysfunction that leads to renal failure in long term (Ciobanu et al., 2012) and Engström et al. (2012), It is also associated with several cancers (Satarug, 2012) and Sawada et al. (2012).

The present study was carried out to determine the current levels of total lead and cadmium in the muscle tissue of canned salted fish samples, imported from different countries and compare with the guidelines set down by FAO/WHO (1992) and EOSQC (1993).

MATERIALS and METHODS

Sampling

A total of forty five imported salted canned fish (15 each of Sardine Salmon, and Anchovies) were collected from different markets in Sohag city, Egypt that divided according geographical areas of production during 2014 (G1, G2, G3).

Lead and cadmium were determined by using ZEEnit 700P Atomic Absorption Spectrophotometer with Graphite furnace (AASG) (Atomic Absorption Spectrophotometer model AnalytikjenaAG, USA) in the Central Laboratory of the Faculty of Veterinary Medicine, Assiut University, Egypt. 0.5 g was weighed into a set of digestion tubes. 10 ml of nitric acid was mixed into the sample vessels. Mixture of content of the digestion tubes were then digested by Microwave at a temperature of 60º C for 30 min. The digestion was cooling to room temperature and diluted with ultra-pure water to make a volume of 25 ml, put in clean glass vials and kept till analysis.

The combined stock standard (Pb and Cd (1000 ppm each) was prepared from reference standards and stored in the refrigerator until use. The method of calibration curve was used for calibration and quantification of the AAS to its effective position. The working standards were first determined to create the standard curve; this was followed by the measurement of the unknown analyses. The atomic absorption spectrophotometer was adjusted to specific wavelength corresponding to each of the metals to be measured.

Statistical Analysis

Statistical analysis was performed using SPSS 13.0 for Windows. Analysis of Variance (ANOVA) was used and statistical significance was set at P<0.05. Duncan Multiple Range Test was used to separate differences in treatment means.

RESULTS

Table 1: Mean lead levels ±SE in muscle of Sardine, Salmon, and Anchovies from Thailand (G1), Morocco (G2) and Spain (G3) and number of samples tested in each group (No).

Figure (1) lead concentration (ppm) in tested (sardine, salmon and anchovies) samples

Letters on bars (a, b, c) denote the significant differences among groups (P<0.05).

Table 2: Mean values ±SE of cadmium levels in muscle of Sardine

Salmon, and Anchovies from Thailand (G1), Morocco (G2), and Spain (G3) and number samples tested in each group (No).

Figure (2) Cadmium concentrations (ppm) in fish species; Sardine, Salmon and Anchovies samples.

NS means non-significant differences.

DISCUSSION

The average values of lead in G1, G2 and G3 in sardine showed were 2.495±0.013, 2.320±0.010, 0.271±0.047 ppm respectively which higher than (0.1 ppm) that recommended by EOSQC (1993)  while G3 had lower lead level than the limit of (0.5 ppm) that reported by FAO/WHO (1992). These result are similar to result recorded by Rafael (1975), 0.13-2.15 ppm in Spanish sardine, Olga Marta et al.(1991) recorded the levels of lead as 0.29-0.72 ppm in Costa Rica, also as Ashraf et al. (2006) 0.84 ±0.46 ppm in Saudi Arabia and Tarley et al. (2001), 0.77-2.15 ppm in Brazil.

Lead levels in salmon were 0.298±0.158, 0.452±0.127 and 0.275±0.132 ppm in G1, G2, and G3 respectively. These levels are higher than the permissible limit recorded by EOSQC (1993) and lower than that recorded by FAO/WHO. (1992). Ashraf et al. (2006) recorded a same level value of lead in salmon (0.31±0.11) ppm in Saudi Arabia.

In anchovies the lead levels were 6.939±2.370, 2.060±0.061, 2.691±0.473 ppm in G1, G2, and G3, respectively. These values are higher than the limits recommended by EOSQC (1993) and FAO/WHO (1992). Similar result were obtained with Türkmen    et al. (2008) ( 0.87±0.40 ppm in samples collected from Black sea and Tüzen (2009) 0.30 ± 0.02 ppm in Turkey but the result recorded by Gilmartin and Revelante (1974) from Adriatic sea  were lower than our result >0.01.

The mean values of cadmium in sardine were 0.063±0.011, 0.098±0.025 and 0.066±0.021 ppm, while in salmon were 0.037±0.009, 0.053±0.010 and 0.061±0.020 ppm, in anchovies were 1.007±0.093, 0.464±0.055 and 1.908±0.540 ppm, in G1, G2 and G3, respectively. In all samples the cadmium levels are lower than (0.1 ppm) that recommended by EOSQC (1993) and also lower than (0.5 ppm) that recommended by FAO/WHO (1992) except the third group in anchovies was higher than the permissible limits.

A similar results of cadmium levels in sardine were reported by Suppin et al. (2005) in Austria was (0.012 ppm), Olga Marta et al. (1991) in Costa Rica (0.06-0.16 ppm), Ashraf et al. (2006) in Saudi Arabia (0.18 ±0.19 ppm) and Gilmartin and Revelante (1974) from Black sea recorded lower levels than our result >0.01.

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