A study has found some trout in Rotorua contain so much mercury that people should limit how much they eat.
Scientists for the National Institute of Water & Atmospheric Research say the mercury comes from natural geothermal springs, but the problem may be exacerbated by runoff from farms.
Study head Ngaire Phillips says that even in the worst case scenario the chance of a person developing a chronic illness from mercury poisoning is one in a hundred thousand.
The Royal Forest and Bird Protection Society of New Zealand says the possible effects from farm runoff is yet another reason for people to work towards cleaner farming.
