Drinking water in several cities and regions in China contains high levels of perfluoroalkyl and polifluoroalkyls (PFASs), according to a study published in Environmental Sciences Europe. The findings of a team of researchers at Tsinghua University, Beijing, China, indicate that the removal of these chemicals from drinking water in cities and regions in China is urgently needed and that PFAS released from industries and other sources, better control and need reduction.
PFASs are a group of chemicals used to make coatings and products that are resistant to heat, oil, stains and grease, such as clothing, adhesives, food packaging and heat-resistant non-stick cooking surface. It is very durable and the general prevalence of PFASs in the environment and related exposure and adverse health effects such as impaired lipid metabolism, thyroid hormone levels and the immune system shown in animals have received more attention in recent years. However, PFASs are not regularly monitored in drinking water in many parts of the world, including China.
To better understand the current status of PFAS contamination and the potential for human exposure, the researchers provided evidence from 30 available research studies on PFASs in Chinese drinking water, including 526 drinking water samples in 66 cities in China with a total population of approximately 452 million, revise. .
Dr Jun Huang, the corresponding author, said: “Although several PFASs are particularly perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), have been phased out in North America and Europe since 2002, and some Asian countries, especially China, continue to produce these chemicals. As a result, there is a potential risk of PFAS-related soil and surface water pollution being released into the environment. This raises concerns about the presence of PFASs in drinking water, direct exposure to humans and potential toxic effects. ‘
The authors found that populations in eastern China and the southwestern regions have a relatively higher risk due to exposure to PFAS, compared to other regions. Some cities in the Yangtze River basin, such as Zigong, Jiujiang and Lianyungang, have exceeded the health-based guidelines issued by EU and US agencies.
Zigong (502.9 ng / L), Lianyungang (332.6 ng / L), Changshu (122.4 ng / L), Chengdu (119.4 ng / L), Wuxi (93.6 ng / L) and Hangzhou (74.1 ng / L) was the city with the highest PFAS concentrations in drinking water.
Dr Huang said: ‘The total concentrations of PFOS and PFOA in these cities are far more than the non-enforceable health advice of 70 ng / L published in 2016 by the US Environmental Protection Agency. Individual U.S. states have set maximum levels of pollution. which is even stricter than federal guidelines, such as Vermont, which in 2019 set a maximum pollution level of 20 ng / L for five PFASs (PFOA, PFOS, PFHxS, PFHpA and PFNA, separately or combined). “
The authors also found that the drinking water in more than 40% of the cities studied exceeded the notification levels of 5.1 ng / L for PFOA and 6.5 ng / L for PFOS, issued by the US state of California in 2019. Exposure to this PFOA and PFOS is associated with adverse health outcomes, including increased incidence of testicular and renal cancer, decreased fertility and fertility, immunosuppression, and thyroid disorders in animal studies.
The authors suggest that the high levels of PFASs in some cities and regions studied in China are mainly due to intensive industrial activities, specifically fluoropolymer (PTFE) production and a high population density in those regions.
The authors also investigated the potential daily exposure to PFASs via drinking water for the Chinese population, using the mean and maximum concentrations of PFOA and PFOS previously considered a health care provision.
The authors found that compared to a standard proposed in 2018 by the US Agency for Toxic Substances and Diseases (ATSDR) of an acceptable intake of 3 ng / kg per single day, the PFOA intake for the Chinese population is more than 3 ng / kg per single day in Zigong, Jiujiang, Lianyungang, Foshan, Suzhou, Wuxi, Haining, Changshu, Shijiazhuang, Zibo and Shanghai. These levels are also higher than the new acceptable weekly intake of 4.4 ng / kg for the sum of PFOA, PFOS, PFHxS and PFNA, established by the European Food Safety Authority (EFSA) in 2020. The authors also found that the risk of PFAS intake is higher for infants due to their relatively higher water consumption.
Dr Huang said: “While there are currently no guidelines for PFASs in drinking water in China, a Chinese health adviser first suggested values of 85 ng / L for PFOA and 47 ng / L for PFOS in China. Our results indicate “that PFASs in drinking water in some Chinese cities have exceeded these levels, and that most cities have strictly exceeded international guideline levels, so further monitoring as well as control and treatment measures are urgently needed.”
The authors warn that more research is needed to understand the potential health effects associated with long-term exposure in cities and regions with high levels of PFAS, especially in areas with PFAS-related manufacturing facilities. In addition, better monitoring of PFASs in drinking water is needed in remote areas to provide a complete overview of PFAS contamination in Chinese drinking water.
Reference: “Per- and polyfluoroalkyl substances (PFASs) in Chinese drinking water: risk assessment and geographical distribution” by Liu et al., January 11, 2021, Environmental Sciences Europe.
DOI: 10.1186 / s12302-020-00425-3
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