Exposure Risk of PFASs in Major Foods in China, Including Dairy Products and Baby Foods

Per- and polyfluoroalkyl substances (PFASs) are a group of man-made chemicals that are manufactured and used in a variety of industries around the world (e.g. textiles, household products, fire-fighting, automotive, food processing, food packaging, construction, electronics).¹ Due to the multitude of uses, PFASs are now detected worldwide. Certain PFASs like perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are very persistent in the environment and can accumulate and stay in the human body (PFASs were detected in human blood, breast milk, etc.) for long periods of time, which will lead to adverse human health effects.² In 2020, the detection of PFASs in some food packages at fast food giants such as McDonald's and Burger King in the United States triggered heated discussion on Chinese social media. (Read more at ChemLinked news) 

Among all exposure pathways, diet is regarded as a major route, where these substances are most often found in drinking water, fish, fruit, egg and egg product.¹ Therefore, the study of the contamination level of PFASs in food has also become a serious topic both nationally and internationally. In this article, ChemLinked collects the study of PFASs in some major foods in China as below.

PFASs Exposure Risk in Seafood 

Researchers³ (Han Tongzhu et al.) in China determined the content of 14 PFASs in fishery organism from Jiaozhou Bay in China. The detection rate of PFOS is the highest (100%), followed by PFOA (95.7%), PFUnDA (93.6%), PFDA (80.9%), PFDoDA (57.4%), and PFNA (31.9%). The total concentration of PFASs in 14 species of fishery organisms ranged from 1.77 ng/g to 31.09 ng/g wet weight. PFOS, PFOA and PFUnDA were the dominant compounds among all the seafood, with the mean concentration of 4.77 ng/g, 0.85 ng/g and 0.68 ng/g, respectively.

• Dietary Risk Assessment

At present, there is no unified tolerable daily intake (TDI) established for PFAS chemicals. But some countries and international organizations have raised their proposals. For example, the European Food Safety Authority (EFSA) set the suggested value for PFOS at 150 ng/kg bw/day and PFOA at 1500 ng/kg bw/day in 2008. In April 2017, the Australian Government adopted TDI values for PFOS (20 ng/kg bw/day) and PFOA (160 ng/kg bw/day) based on an evaluation by Food Standards Australia New Zealand (FSANZ).⁴ On 25th May 2016, the U.S. Environmental Protection Agency released reference doses (RfDs) for PFOS and PFOA of 20 ng/kg/day.

Disclosed by Han’s paper in 2016⁵, the exposures of PFOA and PFOS of seafood from the coastal area of Jiaozhou Bay were 3.07 ng/kg/day and 13.18 ng/kg/day, respectively, less than the TDI proposed by the EFSA and the RfD by the EPA. However, since seafood is not the only food for the local citizens and the estimation of dairy intake is only an average value, the health risks of PFASs exposure and the excessive seafood intake still cannot be ignored, especially the PFOS in fish.

Estimated Daily Intake of PFOA and PFOS in Seafood in Jiaozhou Bay (ng/kg/d, ww)

Source: Distribution and potential sources of perfluoroalkyl substances (PFASs) in Jiaozhou bay

PFASs Exposure Risk in Milk 

From 2014 to 2015, Yu⁶ collected 660 milk samples from 31 provinces and municipalities and determined the contamination of 20 PFASs. The result shows the detection rate of PFOA (70.91%) is the highest, followed by PFOS (63.79%), PFHxA (47.58%), PFHxDA (45.15%), etc. Among all the detected PFASs, PFOS (0.126 μg/L) and PFOA (0.093 μg/L) have the highest average concentration. Moreover, the determination result is close to an analysis conducted by EFSA. In 2012, EFSA analyzed the PFAS determination data of over 2300 samples from 13 EU countries. It is found that PFPA, PFHxA, PFHpA, PFOA, PFNA, PFHxS, PFHpS and PFOS are the dominant PFASs in milk. The average concentration range of PFOA and PFOS is 0.0018-0.12 μg/L and 0.0007-0.11 μg/L, respectively. 

The Detection Rate, the Concentration Range and the Average Concentration of 20 PFASs in Milk, μg/L

Source: Investigation of Residual Levels And Residue Analysis on Perfluoroalkyl Substances in Milk 

• Dietary Risk Assessment

Providing the average body weight of residents is 60kg, who drink milk 0.3 L every day, then PFOS and PFOA exposures are 0.00063 μg/kg bw/d and 0.000465 μg/kg bw/d, respectively. Compared with the TDI value for PFOS (0.15 μg/kg bw/d) and PFOA (1.5 μg/kg bw/d) given by EFSA, the intake of milk will not pose an acute hazard to local residents.

PFASs Exposure Risk in Baby Food

• In Infant Formula

Yukiko Fujii et al.⁷ collected nine infant formula products (for infants under 12 months) from the retails stores in China and Japan and evaluated the perfluorinated carboxylic acids (PFCAs) levels. The study found PFOA, PFNA and PFDA were frequently detected in infant formula products from both Japan and China. 

The Concentration of PFACs in Infant Formula

Source: Investigation of Residual Levels and Residue Analysis on Perfluoroalkyl Substances in Milk

In 2016, Cao Min et al.⁸ randomly selected infant formula products from supermarkets in Beijing and determined the level of five PFAS chemicals. It is found PFOS, PFOA and PHHxA are the predominant compounds with detection rates of 18.3%, 16.7% and 15%. The average concentration levels of them are 0.0479, 0.0498 and 0.0851 μg/kg, respectively. Meanwhile, PFBA and PFBS are not detected in infant formula products. The total concentration range of the five chemicals is 0.0353~0.2828 μg/kg.

• In Complementary Food for Infants—Baby Rice Flour

Leng⁹ determined 12 PFAS chemicals in baby rice flour products and found PFOA was with the highest detection rate, the content level of which ranged from 0.07 to 0.11 μg/kg. PFOS was only found in several samples with a content of 0.16 μg/kg. The content of the other 10 PFSA chemicals (namely, PFB, PFBA, PFPA, PFBS, PFHxA, PFHpA, PHNA, PFDA, PFU-A and PFDoDA) were not detected.

• Dietary Risk Assessment

After conversion, although the exposure level of PFASs in baby food is below the TDI value for PFOS and PFOA given by EFSA, considering the metabolism capability of infants, etc., further studies are still needed.

PFASs Exposure Risk in Vegetable & Meat

Regarding the PFASs in other foods, a study¹⁰ conducted in Chengdu in 2016 shows that PFAS chemicals have widely existed in foods like rice, vegetable, egg, fish, pork and milk (milk products mainly from brands like Mengniu, Yili and New Hope). PFHxa, PFOA, PFNA and PFDS have been detected in every sample, followed by PFPeA, PFHpA, PFHxDA and PFOS with detection rates of 91%. Moreover, the concentration level of PFASs in animal-derived food is higher than that in plant-derived food. 

Based on the investigation of 150 households, researchers estimated the daily intake of each diet for Chengdu residents and gave the estimated daily intake of PFASs as listed below. The EDI of PFOS and PFOA are below the TDI given by EFSA, which will not bring acute damage to the human body.

Daily Intake of Each Diet for Chengdu Residents

 The Estimated Daily Intake of PFASs in Different Diets in Chengdu

 Source: Pollution Characteristics and Human Health Risk of Perfluoroalkyl Substance Exposure Through the Diet in Chengdu City

Supervision of PFASs in China and Prediction

At present, China only stipulates the use of PFAS in food contact materials and relevant requirements can be found in GB 4806.6-2016 Standard for Resins Used to Make Plastics in Contact with Foodstuffs, GB 9685-2016 Standard for Uses of Additives in Food Contact Materials and Articles, and GB 4806.10-2016 Standard for Paints and Coatings in Contact with Foodstuffs. 

In line with the further study of PFASs in the environment and organisms, the use of PFASs is expected to be under stricter supervision in worldwide. The author predicted China will control the PFASs level from their source first. In 2019, China’s Ministry of Ecology and Environment solicited public opinion on the feasibility of banning the production and use of PFOA.¹¹ Since the exposure level in foods, disclosed by the current researches, did not pose a hazard on people from the perspective of risk assessment, relevant regulations and standards will not be formed at this stage. The management and supervision of PFASs in food contact material will still be the major task.

Suggestions to Food Enterprises 

To enterprises, except for reducing the use of PFASs and finding the appropriate alternatives, here are several suggestions for reference.

1. Choose the appropriate test method to monitor the PFASs level in food and raw material like raw milk. In China, there is a GB standard (GB 5009.253-2016) formulating the determination method of PFOS and PFOA in animal-derived food.

2. Avoid processing foods with equipment that used PFASs.

3. Ask suppliers to stop the use of certain PFAS chemicals, etc.