[Study on the dietary intake level for indicator polychlorinated biphenyls in China]

To obtain representative data on levels of indicator polychlorinated biphenyls (PCBs) in foods consumed by the general population and to estimate the dietary intake of indicator PCBs in China.

The food samples were collected during the fifth China Total Diet Study (2009-2013). Based on the geographical location and dietary habits, China was divided into the south area and the north area, and 10 province regions from each area were chosen. In each province region, one urban site and two rural sites were selected to collect food samples. Considering the food consumption level and the PCBs contaminate rule, a total of 160 samples including meat, eggs, fish, milk, cereals, beans, potatoes and vegetables were selected. The concentration of 7 indicator PCBs in food were determined by stable isotope dilution gas chromatography-mass, and combined with food consumption to calculate the dietary intake of indicator PCBs.

The concentration of indicator PCBs in 8 categories of food were in the range of 0.8-1 300.1 pg/g. The levels of indicator PCBs were significantly higher in the aquatic products, averaging (307.8±302.4) pg/g, followed by eggs at (76.6±92.1) pg/g and meat at (63.0±54.9) pg/g. The daily dietary intake of indicator PCBs varied from province to province, ranging from 0.13 ng·kg(-1)·d(-1) to 3.58 ng·kg(-1)·d(-1), averaging (0.67±0.77) ng·kg(-1)·d(-1). Fujian had the highest level (3.58 ng·kg(-1)·d(-1)) , followed by Shanghai (1.48 ng·kg(-1)·d(-1)) and Zhejiang (1.09 ng·kg(-1)·d(-1)) . Compared with the minimum risk level (MRL) value (20 ng·kg(-1)·d(-1)) proposed by US Agency for Toxic Substances and Disease Registry, the highest dietary intake level was only 17.9% MRL, the average dietary intake level was 3.4%MRL. Aquatic products was still the major contributor to the dietary intake of indicator PCBs in China, 48% of average dietary intake level (0.32 ng·kg(-1)·d(-1)/0.67 ng·kg(-1)·d(-1)) .

The dietary intake of indicator PCBs in China was at a low level, and showing a declining trend.