A range of harmful chemicals known to disrupt hormones, have been found in wild fish along China’s Yangtze River, in a study done by environmental group Greenpeace.

Researchers tested two commonly eaten fish—carp and catfish—in four cities along the upper, middle and lower sections of the river.

Almost all of the fish contained alkyphenols, used in things like detergents and textile manufacturing. Researchers also detected perflourinated compounds, like PFOS, which are used in plastic products and grease-repellent coating.

A toxics campaigner for Greenpeace China, Yixiu Wu told Radio Free Asia these chemicals pose long-term threats to the environment.

[Yixiu Wu, Toxics Campaigner for Greenpeace China]:

“On the one hand, these chemicals are largely used in production. On the other hand, and very importantly, they are very difficult to break down in the environment, and can be carried around the world. They can be absorbed by carriers, and will not be broken down for example in waste water management.”

Alkyphenols like nonylphenol (NP) and octylphenol (OP) are known to disrupt hormones, and can alter sexual development in some species. PFOS have been associated with changing thyroid function and decreasing sperm count in humans.

Wu says the use of these dangerous chemicals has decreased around the world, but that’s not the case in China.

[Yixiu Wu, Toxics Campaigner for Greenpeace China]:
“PFOS, NP and OP have become heavily monitored chemicals in many countries, and their use are restricted or banned altogether. But in China, we don’t have any monitoring or regulation of these chemicals, so their presence has been on the rise.”

After the study was published, Chinese state-run media issued several reports with expert opinions saying the levels of chemicals detected are not high enough to harm humans.

Wu says authorities should focus on regulating the use and disposal for these harmful toxins, instead of dispelling public concern.

The Yangtze River is China’s longest river, providing water to 400 million people and 186 cities. It’s also home to almost half of the country’s chemical enterprises.