Authorities in South Korea's capital are trying to untangle themselves from a slimy row: how many octopus heads is it safe to eat?

Octopus heads are a favourite dish on the peninsula - for their apparent aphrodisiac qualities.

In September, the Seoul city government enraged restaurateurs and the fishing industry when it announced octopus heads contained hazardous amounts of cadmium, a carcinogen that poisons the liver and kidneys.