Every Wednesday night during the winter, Derek Morrison of Rotorua throws several bunches of watercress into a pot of geothermally heated water and boils it for dinner.
The 76-year-old kaumatua says the plant, added to sweeten boiled meat and potatoes, is delicious and has been a staple foodfor local Maori for as long as he can remember.
Yesterday the Ohinemutu resident dismissed the results of a HortResearch study showing that watercress grown in geothermal-fed waters accumulated high concentrations of arsenic.
The study, by Dr Brett Robinson, suggested that people eating watercress grown in areas such as Rotorua, Taupo and parts of the Waikato River could be at higher risk of developing skin cancer, rashes or problems with their nervous systems.
But Mr Morrison said he had never heard of anyone suffering ill-health from eating local watercress and he had no intention of changing his diet.
"We've got a big family and we've been eating it all our lives ... I eat it at least once a week."
Fellow Ohinemutu resident Brett Bonnington yesterday remembered collecting watercress as a child from the stream behind his home and rubbished suggestions that there was any danger in eating it.
"In winter we have boil-ups two or three times a week and there's watercress all through it. We live on it."
A 1995 study by Environment Bay of Plenty also raised concerns over the level of arsenic and other chemicals in the Tarawera River, where large quantities of watercress grow.
It too found that arsenic levels in watercress breached recommended health guidelines and the fish contained higher levels of mercury because of the river's geothermal waters.
The regional council's environmental investigations manager, John McIntosh, said a follow-up study on the actual health effects of eating the watercress had never been done because no problem was apparent.
Bay of Plenty's medical officer of health, Dr Phil Shoemack, confirmed that there had been no reports of people falling ill, but said "it's certainly conceivable it could occur".
"Basically, harvesting watercress from an uncontrolled environment, people are taking a gamble."
Dr Shoemack said the development of any arsenic-related health problems would depend on how much watercress was eaten.
