Tests on seafood collected from Hong Kong supermarkets between June and early August this year by environmental group WWF revealed the presence of banned chemicals.

One sample contained more than double the international food safety limit for a potential carcinogen.

The results follow WWF-Hong Kong’s second annual supermarket seafood procurement policy scorecard, covering the territory’s nine major supermarket groups.

WWF was particularly scathing in its criticism of A.S. Watson, CR Vanguard and Kai Bo, saying they had "taken minimal actions to improve their seafood sustainability."