Determination of Lead, Cadmium and Aluminium Leached from Cooking Utensils

Abstract

       The analysis of lead, cadmium and aluminium, which is leached from cooking utensils, was performed by heating with a 4% v/v acetic acid solution at boiling temperature for 2 hours. The leached solutions were quantitation analyzed for lead and cadmium by Flame-AAS and GF-AAS for aluminium. The results of method validation showed that the linearity of calibration ranges correlated between absorbance and the concentration of lead, cadmium and aluminium at a range of 0-3.00, 0-0.8 and 0-0.200 mg/L, with correlation coefficients (r) of 0.9999, 0.9993 and 0.9995, respectively. There were linear relationships between added and discovered amounts of these metals at the working range. The limits of detection (LOD) of lead, cadmium and aluminium were 0.05, 0.001 and 0.004 mg/L, respectively. Further, the limits of quantitation (LOQ) were 0.1, 0.01 and 0.010 mg/L, respectively. Accuracy and precision were studied as %recovery of spiked samples and %RSD under repeatability conditions. The recoveries for 3 levels of lead, cadmium and aluminium were 92-99%, 101-103% and 98-108%, respectively. The %RSD of the levels was 5.5-7.5, 2.3-3.3 and 2.8-5.9, respectively. Using these methods, a total of 32 cooking utensil distributions were analyzed. The results showed that 56% of samples were leached lead at a level <0.1-3.35 mg/L and 16% of samples were leached cadmium at a level <0.10-0.10 mg/L. None of the samples leached lead or cadmium over the legal limit as set forth by the Notification of Public Health No. 92 (B.E. 2528). All samples showed the presence of aluminium in the leaching solution at an average level of 232 mg/L. According to Thai law, there are no specified legal limitations for aluminium content in utensils. However, aluminium is regarded as a neurotoxin agent due to it accumulation in the brain, bones and liver. JECFA (1989) established a PTWI at 7 mg/kg of body weight for total intake. In order to protect consumers from aluminium intake, related organizations should establish limitations for aluminium leaching. As a result, storage of acidic foods with these cooking utensils is not recommended.