2021-01-14 04:46:19

A new study has found that tap water for several cities in China’s Yangtze River Basin contains excessive levels of “persistent organic pollutants” linked to myriad health problems including cancer, raising concerns about the safety of local drinking water.

Zigong, Lianyungang, and Shanghai all had “extremely high” concentrations of perfluoroalkyl and polyfluoroalkyl substances (PFASs), including perfluorooctanoic acid (PFOA), in their water supply, according to the paper, which was published Tuesday in the peer-reviewed scientific journal Environmental Sciences Europe.

PFASs are human-made chemicals found in a variety of industries including textile, leather, and paper manufacturing. Sometimes called “forever chemicals,” they can remain in an environment — such as a stream or the human body — for many years without degrading, and are associated with health risks such as immune deficiency and cancer.

“East China and the Southwest regions posed a relatively higher risk to the Chinese population and some cities in the Yangtze River basin such as Zigong, Jiujiang, Lianyungang and a considerable share of other cities have exceeded the health-based guidelines issued by EU and US agencies,” said the study, which collected 526 tap water samples from 66 cities across China.

However, the research team, led by Huang Jun, an associate professor at China’s elite Tsinghua University, said further study is needed of the possible health effects from long-term exposure to the chemicals in question.

The study found that at one in five cities evaluated — affecting nearly 100 million people — was exposed to PFAS concentrations above 20 nanograms per liter, the so-called maximum contaminant level in the U.S. state of Vermont. Meanwhile, more than 40% of the cities studied, representing a total population of 192.6 million, exceeded PFAS notification levels set by California in September 2019.

Zigong in the southwestern Sichuan province, along with Lianyungang and Changshu in the eastern Jiangsu province, had the highest PFAS concentrations, according to the study.

Currently, China has neither a routine monitoring system for PFASs in the water supply nor a guideline for acceptable levels. There is also no national standard for PFASs in wastewater.

The study mapped the risk distribution associated with PFAS-contaminated tap water and found that high exposure is most concentrated in East China, where many fluorochemical plants and PFAS-using industries are located. Many such industries moved to areas with fewer operational hurdles after Western countries tightened their environmental regulations.

The PFOA intake of 11 cities — Zigong, Jiujiang, Lianyungang, Foshan, Suzhou, Wuxi, Haining, Changshu, Shijiazhuang, Zibo, and Shanghai — exceeds 3 nanograms per kilogram of body weight per day, exceeding standards set by the European Food Safety Authority and the Agency for Toxic Substances and Disease Registry in the U.S.

In 2010, a study by researchers with the Chinese Center for Disease Control and Prevention found high concentrations of PFOA in the breast milk of new mothers in Shanghai.

PFOA and perfluorooctanesulfonic acid (PFOS) are classified as persistent organic pollutants under the Stockholm Convention, an international environmental treaty effective since 2004. As a signatory to the convention, China restricted both chemicals in compliance with its conditions, said Wang Yawei, a researcher at the Research Center for Eco-Environmental Sciences under the Chinese Academy of Sciences.

In 2008, China classified PFOA as “highly polluting with high environmental risk,” and in 2011 called for PFOA and PFOS to be replaced with less harmful chemicals. Ultimately, the country in 2014 banned the production and application of PFOS without an official exemption. However, a lack of substitutes has hampered phasing out the chemicals.

“In the long run, if the convention limits (the use of such chemicals), there will be restrictions at the national level,” Wang told Sixth Tone. “However, for now, there is still a market (for them), so the government has to be concerned with finding alternatives for the substances. This requires a process and involves many parties, government departments, and enterprises.”

Editor: Bibek Bhandari.

(Header image: Viewfly/People Visual)