Environmental campaigners on Wednesday accused suppliers to major clothing brands including Adidas and Nike of poisoning China's major rivers with hazardous chemicals linked to hormonal problems.
Greenpeace said eight samples of wastewater discharge from two factories in the Yangtze and Pearl River deltas, identified as suppliers for the brands, contained "a cocktail of hazardous chemicals".
The Yangtze -- China's longest river -- and the Pearl River Delta serve as a source of drinking water for about 67 million people, including those in Hong Kong, according to Greenpeace.
"Our tests of the wastewater found toxic chemicals that have no place in our natural environment," Greenpeace campaigner Vivien Yau told a news conference in Hong Kong.
"We are calling on trendsetting brands that have major influence on their supply chains, such as Adidas, Nike and Li Ning to take the lead."
Li Ning is a popular Chinese sportswear brand.
"These brands have the ability and responsibility to work with their suppliers to provide products that do not irrevocably damage the environment and public health," added Yau.
Adidas offices in Hong Kong and Beijing could not be reached for comment by AFP while Nike disputed the environmental group's claims.
"To the best of our knowledge we are not contributing to pollution of the Yangtze Delta through our factory partners," Nike said in a statement to AFP, denying the use of the chemicals claimed by Greenpeace.
The Greenpeace report said laboratory testing found the wastewater samples contained nonylphenols and perfluorinated chemicals, which are used to make materials stain and stick resistant, among other uses.
The chemicals, which are restricted in European countries, could move up the food chain through fish and other marine life which have consumed the contaminated water, Greenpeace said.
It said the chemicals could disrupt the hormone balance in humans even at low levels.
"We are not focusing on just the two companies identified in the report. We are saying this is just the tip of the entire iceberg," Greenpeace campaign manager Gloria Chang told AFP, urging Beijing to speed up regulatory reforms.