Elsevier

Food and Chemical Toxicology

Volume 49, Issue 12, December 2011, Pages 3081-3085
Food and Chemical Toxicology

Health risk assessment of eight heavy metals in nine varieties of edible vegetable oils consumed in China

https://doi.org/10.1016/j.fct.2011.09.019Get rights and content

Abstract

Eight heavy metals, namely Cu, Zn, Fe, Mn, Cd, Ni, Pb and As, in nine varieties of edible vegetable oils collected from China were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) and graphite furnace atomic absorption spectrometry (GF-AAS) after microwave digestion. The accuracy of procedure was confirmed by certified reference materials (GBW10018 and GBW08551). The relative standard deviations were found below 10%. The concentrations for copper, zinc, iron, manganese, nickel, lead and arsenic were observed in the range of 0.214–0.875, 0.742–2.56, 16.2–45.3, 0.113–0.556, 0.026–0.075, 0.009–0.018 and 0.009–0.019 μg g−1, respectively. Cadmium was found to be 2.64–8.43 μg/kg. In general, iron content was higher than other metals in the investigated edible vegetable oils. Comparing with safety intake levels for these heavy metals recommended by Institute of Medicine of the National Academies (IOM), US Environmental Protection Agency (US EPA) and Joint FAO/WHO Expert Committee on Food Additives (JECFA), the dietary intakes of the eight heavy metals from weekly consumption of 175 g of edible vegetable oils or daily consumption 25 g of edible vegetable oils for a 70 kg individual should pose no risk to human health.

Highlights

► This is the first time that the different varieties of edible vegetable oils were studied in China. ► The levels of cadmium, lead and arsenic were all higher than those in previous reports. ► Iron was found to be the dominant elemental ion as compared with other heavy metals in edible vegetable oils. ► The estimated intakes of Cu, Zn, Fe, Mn, Cd, Ni, Pb and As from the vegetable oils pose no risk to human health.

Introduction

Vegetable oils are widely used in cooking and alimentary, cosmetic, pharmaceutical and chemical industries (Dugo et al., 2004). Vegetable oils are beneficial and popular due to their cholesterol-lowering effect. In contrast to animal fats, which are predominantly saturated and hence do not react readily with other chemicals, especially oxygen, unsaturated vegetable oils are more reactive (Mendil et al., 2009).

The quality of edible oils regarding their freshness, storability and toxicity can be evaluated by the determination of several trace metals. Levels of trace metals like Cu, Zn, Fe, Mn and Ni are known to increase the rate of oil oxidation while other elements such as As, Cd and Pb are very important on account of their toxicity and metabolic role (Anthemidis et al., 2005). The presence of metals in vegetable oils depends on several factors. They might come from the soil, environment, genotype of the plant, fertilisers and/or metal-containing pesticides, introduced during the production process or by contamination from the metal processing equipment (Zeiner et al., 2005, Jamali et al., 2008).

Heavy metals can be classified as potentially toxic (arsenic, cadmium, lead, etc.), probably essential (vanadium, cobalt) and essential (copper, zinc, iron, manganese, etc.). Toxic elements can be very harmful even at low concentration when ingested over a long time period (Unak et al., 2007). The essential metals can also produce toxic effects when the metal intake is excessively elevated (Gopalani et al., 2007). It is necessary to assess the levels of heavy metals in edible vegetable oils and to report possible contamination that would represent a health hazard. A few researchers have made some progress on the determination of heavy metals in edible oils (Cindiric et al., 2007, Pehlivan et al., 2008, Mendil et al., 2009). Food consumption had been identified as the major pathway of human exposure to toxic metals, compared with other ways of exposure such as inhalation and dermal contact. US Environmental Protection Agency (US EPA), Joint FAO/WHO Expert Committee on Food Additives (JECFA) and Institute of Medicine of the National Academies (IOM) have provided guidelines on the intake of trace elements by humans. The IOM of the National Academies recommended the adequate intake (AI) and the tolerable upper intake level (UL) values for some essential elements (IOM, 2002, IOM, 2003; the JECFA recommended permissible tolerable weekly intakes (PTWIs) and acceptable daily intakes as guidelines for food additives and certain contaminants in foods (JECFA, 2003). Also, the US EPA provided reference dose (RfDo) values in μg/kg body wt/day for some elements (US EPA, 2007a).

China is one of the largest producers and consumers of edible vegetable oils in the world. In the year of 2010, the total edible vegetable oil consumption in China reached 24.75 million tons. However, there has been no report, to our knowledge, on the heavy metal levels in edible vegetable oils in China. The main objective of this study were to determine the concentrations of copper, zinc iron, manganese, cadmium, nickel, lead and arsenic in edible vegetable oils consumed in China and estimate the potential human health risks from weekly consumption of 175 g of edible vegetable oils or daily consumption 25 g of edible vegetable oils for a 70 kg individual.

Section snippets

Sample collection

Total 109 samples of edible vegetable oils (13 soybean oil, 12 corn oil, 14 peanut oil, 12 sesame oil, 11 rapeseed oil, 12 cottonseed oil, 12 olive oil, 11 blend oil and 12 sunflower oil samples) were purchased in Chinese supermarkets during 2009 and 2010. The most widely accepted and most frequently consumed several brands such as Kinlongyu, Fortune and Luhua were selected. The collected oil samples were packed in polyethylene bags and stored below −20 °C until analysis.

Reagents and apparatus

All reagents were of

Results and discussion

Detection limit values of elements as milligram per liter were found to be 0.018 for Cu, 0.010 for Zn, 0.016 for Fe, 0.020 for Mn, 0.09 for Cd, 0.35 for Ni, 0.18 for Pb and 0.17 for As in this study. The recovery values were nearly quantitative (⩾95%) for microwave digestion method. The relative standard deviations were less than 10% for all investigated elements. In order to validate the method for accuracy and precision, certified reference materials, namely chicken (GBW10018) and porcine

Conclusion

Eight heavy metals (Cu, Zn, Fe, Mn, Cd, Ni, Pb and As) in nine varieties of edible vegetable oils collected from China were determined by inductively coupled plasma atomic emission spectrometry and graphite furnace atomic absorption spectrometry after microwave digestion. To the best of our knowledge, this is the first time that the different varieties of edible vegetable oils in China were studied. The results suggested that significant differences existed in some element concentrations among

Conflict of Interest

The authors declare that there are no conflicts of interest.

Acknowledgement

The authors would like to thank the key science and technology project of Henan for its financial support [092101310300].

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