Analysis of food contamination by lead, cadmium, mercury, copper and aluminum in Ningxia

Abstract

Objective To investigate the situation of food contamination by lead, cadmium, mercury, copper and aluminum in Ningxia Region. Methods Ten categories of food samples up to 712 copies including dairy, edible mushrooms, eggs, preserved egg, meat, organs, aquatic products, vegetables, grains and pasta from supermarkets of five administrative cities of Ningxia Autonomous Region were selected in 2010. The contents of lead, cadmium and mercury in food were detected in 646 samples of 9 categories of food, and copper content of the 30 meat samples were detected. Aluminum content in 66 samples of flour food was tested. According to the methods of national food safety standards (GB 5009.12-2010) and national food hygiene standards (GB/T 5009.13-2003, GB/T 5009.15-2003 and GB/T 5009.17-2003), lead, copper, cadmium and mercury in various foods were tested. Aluminum was determined using the method for determination of spectrophotometry. Results The detection rates of lead, cadmium, mercury in the nine categories of food were 52.8% (341/646), 62.1% (401/646), 51.7% (334/646); the detection rates of copper in the meat was 90.0% (27/30); the aluminum in flour food was 84.8% (56/66), respectively. Compared with the national standards, the eligible rates of lead, cadmium, mercury, copper and aluminum were 97.1% (627/646), 98.2% (539/549), 100.0% (646/646), 100.0% (30/30) and 75.8% (50/66), respectively. Food contaminated by lead and cadmium were mainly distributed in preserved egg [lead detection rate 9.5% (2/21)], organs [lead detection rate 6.7% (2/30), cadmium detection rate 30.0% (9/30)], vegetables [lead detection rate 9.9% (8/90)] and a small amount of food products [lead detection rate 4.7% (7/150)]. The levels of lead in fried flour food and fine dried noodles were higher [40.9% (9/22), 36.4% (4/11)]. Conclusions Food contamination by lead, cadmium, mercury and copper is not serious in Ningxia. The monitoring results of lead, cadmium, mercury and copper in food are satisfying in Ningxia. But there is aluminum contamination in flour food. It is important to do the risk evaluation of aluminum contamination in food as quickly as possible. Key words: Food safety; Heavy metal; Lead; Cadmium; Mercury; Copper; Aluminum