Market basket survey for some heavy metals in Egyptian fruits and vegetables

Abstract

A market basket survey was carried out with the aim to assess the levels of lead (Pb), cadmium (Cd), copper (Cu) and zinc (Zn) in various fruits and vegetables sold in Egyptian markets. Atomic absorption spectrometry was used to estimate and evaluate the levels of these metals. The results of this survey showed that the average concentrations detected were ranged from 0.01 to 0.87, 0.01 to 0.15, 0.83 to 18.3 and 1.36 to 20.9 mg/kg for Pb, Cd, Cu and Zn, respectively. The highest mean levels of Pb, Cd, Cu and Zn were detected in strawberries, cucumber, date and spinach, respectively. The levels of the metals compare with those reported for similar fruits and vegetables from some other parts of the world. The daily intakes of Pb, Cd, Cu and Zn through fruits and vegetables have also been estimated. They are found to be below the recommended tolerable levels proposed by [Joint FAO/WHO Expert Committee on Food Additives 1999. Summary and conclusions. In: 53rd Meeting, Rome, June 1–10, 1999] and may not constitute a health hazards for consumers.

Introduction

Food safety is a major public concern worldwide. During the last decades, the increasing demand of food safety has stimulated research regarding the risk associated with consumption of foodstuffs contaminated by pesticides, heavy metals and/or toxins (D’Mello, 2003).

Heavy metals are among the major contaminants of food supply and may considered the most important problem to our environment (Zaidi et al., 2005). Such problem is getting more serious all over the world especially in developing countries. Heavy metals, in general, are not biodegradable, have long biological half-lives and have the potential for accumulation in the different body organs leading to unwanted side effects (Jarup, 2003, Sathawara et al., 2004).

Lead and cadmium 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, especially with cardiovascular, kidney, nervous as well as bone diseases (WHO, 1992, WHO, 1995, Steenland and Boffetta, 2000, Jarup, 2003). In addition, they are also implicated in causing carcinogenesis, mutagenesis and teratogenesis (IARC, 1993, Pitot and Dragan, 1996). Other metals such as copper and zinc are essential for important biochemical and physiological functions and necessary for maintaining health throughout life. Zinc deficiency results in a variety of immunological defects whereas copper deficiency is characterized by anaemia, neutropenia and skeletal abnormalities (Prentice, 1993, ATSDR, 1994, Linder and Azam, 1996).

Heavy metal contamination may be occurred due to irrigation with contaminated water, the addition of fertilizers and metal-based pesticides, industrial emissions, transportation, harvesting process, storage and/or sale.

Human beings are encouraged to consume more vegetables and fruits, which are a good source of vitamins, minerals, fibers and also beneficial to their health. However, these plants contain both essential and toxic metals over a wide range of concentrations. It is well known that plants take up metals by absorbing them from contaminated soils as well as from deposits on parts of the plants exposed to the air from polluted environments (Khairiah et al., 2004, Chojnacha et al., 2005). The publicity regarding the high level of heavy metals in the environment has created a certain apprehension and fear in the public as to the presence of heavy metal residues in their daily food. The public is confused and alarmed about their food safety.

Keeping in view of the potential toxicity, persistent nature and cumulative behavior as well as the consumption of vegetables and fruits, there is necessary to test and analyze these food items to ensure that the levels of these contaminants meet the agreed international requirements. Regular survey and monitoring programmes of heavy metal contents in foodstuffs have been carried out for decades in most developed countries (Jorhem and Sundstroem, 1993, Pennington et al., 1995a, Pennington et al., 1995b, Milacic and Kralj, 2003, Saracoglu et al., 2004). But, in developing countries such as Egypt, limited data are available on heavy metals, in canned orange juice (Mesallam, 1987), in medicinal plants (Abou-Arab et al., 1999), in meat (Abou-Arab, 2001) and in leafy vegetables and some aromatic medicinal plants (Dogheim et al., 2004). This study therefore presents data on the level of heavy metals (lead, cadmium, copper and zinc) in selected fruits and vegetables sold in the local markets of Egypt. The study is also dealing with the daily intake of these metals through consumption of fruits and vegetables.