'Minamata disease' was caused by eating fish which have high levels of:

Industrial and agricultural pollutants released into water bodies undergo biomagnification: heavy metals taken up by plankton and small aquatic organisms become progressively more concentrated at each higher level of the food chain, reaching toxic concentrations in the fish and shellfish that people eat.

From the 1930s to the 1960s, the Chisso Corporation discharged industrial wastewater containing methylmercury into Minamata Bay in Japan. This mercury bioaccumulated in local fish and shellfish, and residents who relied on this seafood as a dietary staple absorbed toxic levels of methylmercury, developing severe neurological damage — sensory numbness, loss of muscle coordination, impaired speech and vision, and in severe cases death — a condition now named Minamata disease after the bay where it was first identified.

• Arsenic contamination is tied to a separate chronic poisoning condition called arsenicosis, most notably from contaminated groundwater in regions such as parts of India and Bangladesh — a different metal, different source, and a different disease.

• Cadmium contamination is tied to its own well-documented Japanese pollution case — Itai-itai disease in Toyama Prefecture, caused by cadmium in irrigation water damaging bones and kidneys — again a distinct metal and a distinct disease from the Minamata Bay poisoning.

• Since each of these pollution disasters is linked to a single specific metal at a specific location, treating all three metals together as the cause of the Minamata Bay poisoning is incorrect.

The methylmercury discharged into Minamata Bay and bioaccumulated in the local seafood is therefore the toxic substance behind Minamata disease.