CFS announces First HK Total Diet Study findings on Polybrominated Diphenyl Ethers

The dietary exposure of the local population to Polybrominated Diphenyl Ethers (PBDEs) was low, indicating that it was unlikely to be a significant health concern, according to the third report of the First Hong Kong Total Diet Study released by the Centre for Food Safety (CFS) today (April 25).

Announcing details of the study report, a spokesman for CFS said, "PBDEs are a group of industrial chemicals extensively used in plastics, polyurethane foam, and textiles as flame retardants. These chemical substances persist in the environment, including the air, water, soil and food, for a long period of time, have strong tendency towards bioaccumulation and are potentially toxic to humans. There are three common commercial PBDE products, namely PentaBDE, OctaBDE and DecaBDE.

"The sources of PBDEs exposure for humans include indoor air, house dust and food. PBDEs are fat soluble and accumulate in the fatty tissues of both humans and animals. They are generally found in higher concentration in fatty foods, such as some meats, fish, dairy products and fats and oils."

The spokesman added that animal studies found that PBDEs could cause liver enlargement; affect brain, reproductive organs and neurobehavioural development; and disrupt thyroid hormone levels. However, the majority of tests indicated that PBDEs did not damage genetic materials in cells.

The Joint Food and Agriculture Organization (FAO)/World Health Organization (WHO) Expert Committee on Food Additives (JECFA) estimated that the dietary exposure of the general population to PBDEs was approximately 4 nanogrammes per kilogramme of body weight per day (ng/kg bw/day). This level of dietary intake of PBDEs was far lower than the level at which no adverse effects would occur in rodents.

"In assessing the dietary exposure of the local population to PBDEs, the report revealed that the dietary exposure to PBDEs for average and high consumers in the population, respectively, were 1.34 ng/kg bw/day and 2.9 ng/kg bw/day. Both were below JECFA's estimated dietary exposure of the general population to PBDEs (i.e. 4 ng/kg bw/day), and were not likely to be a significant health concern," the spokesman said.

A total of 142 composite samples, comprising 71 different food items(mainly foods of animal origin and their products and oil foods) were analysed in the study. All of the samples were found to contain PBDEs.

Among all the food groups, the main dietary source of PBDEs was "fish and seafood and their products" which contributed to 27.3% of the total exposure, followed by "meat, poultry and game and their products" (20.7%), "cereals and their products" (15.9%), and "fats and oils" (15.9%).

In terms of food items, salted egg was found to contain the highest level (mean: 4.56 ng/g), followed by vegetable oil (mean: 1.96 ng/g) and yellow croaker (mean: 1.63 ng/g). According to the risk assessment results, the intake of PBDEs upon normal consumption of these three kinds of food items does not pose a health concern.

"The findings of the current study indicated that the dietary exposure of the local population to PBDEs was unlikely to be a significant health concern. Nevertheless, PentaBDE and OctaBDE are fat soluble and have a strong tendency to accumulate in body fat. To reduce the dietary exposure to PBDEs, the public is advised to reduce fat consumption, for example, the public can trim fat from meat and meat products, consume low-fat products, as well as prepare food with a lesser amount of fats and oils.

"The public is advised to maintain a balanced diet so as to avoid excessive exposure to chemical contaminants from a small range of food items," he said.

The First Hong Kong Total Diet Study was launched in March 2010 and scheduled for completion in 2014. The first two reports on dioxins and dioxin-like polychlorinated biphenyls (PCBs) and inorganic arsenic were released earlier.

The Study aims to estimate the dietary exposure of the general population and various population subgroups to a range of substances, including contaminants and nutrients, and thus assess any associated health risks. It focuses on the total diet of the population rather than individual foods.

A total of 150 food items were chosen for the study according to the food consumption patterns of the Hong Kong population. They are being used for testing the levels of over 130 substances, including pesticide residues, persistent organic pollutants, metallic contaminants, mycotoxins, macro nutrients and elements. By combining the test results with food consumption data, the dietary exposure of the population to the selected substances can then be estimated.

The study report on PBDEs is available on the CFS' webpage at www.cfs.gov.hk. Results concerning other substances will be released in phases.

Ends/Wednesday, April 25, 2012
Issued at HKT 15:31