Now health researchers want to know whether PFAS made you sick.
The Australian National University wants Katherine residents to complete a survey to help it discover whether disease rates are higher here compared with other communities.
The more than 600 Katherine residents who took a blood test will automatically receive an invitation to take part in the study.
Similar studies are being launched today at Williamtown and Oakey.
The Federal Government has funded the ANU to check more than 600 blood tests taken from Katherine and today's survey launch is part of that check.
Initial results of blood testing found at least some Katherine residents with high concentrations of PFAS in their blood.
The results of the ANU's study is not expected until next year.
The NT Health Department has already released the results of a desktop cancer check for Katherine.
NT chief medical officer Dr Hugh Heggie said the research showed no evidence of cancer clusters in the Katherine region.
Dr Heggie said Katherine's cancer statistics were even lower on average than the rest of the NT.
Australia's chief medical officer, Professor Brendan Murphy, last year said a positive blood test for PFAS contaminants would not indicate, by itself, any harm to a person's health.
"Blood levels are not predictive of health problems in individuals. There is no consistent evidence of PFAS resulting in specific health impacts therefore levels considered higher than the Australian general population may have no impact on the individual," the federal Health Department said.
There is no practical treatment available to lower levels of PFAS in people, the department advises.
The chemicals last for a long time in the human body.
Despite this advice, the ANU says Katherine residents have been potentially exposed to PFAS through the use of contaminated water including bore water on their properties, and eating locally grown foods.
The ANU is conducting the PFAS Health Study, which investigates whether disease rates are higher in Katherine compared with other communities.
The study is also investigating if high PFAS levels are linked to specific exposure pathways or specific health outcomes.
ANU researchers are urging people who live in these communities, especially those that participated in the blood testing , to participate in the latest study.
"Over 2500 people have had blood tests for PFAS in these communities and we are calling on those people to complete this survey," said ANU principal investigator Professor Martyn Kirk.
"This survey is very important because it will give a more complete picture of PFAS exposure to residents of these areas and policy makers.
"We need to combine information gathered from this survey with the blood test results to really understand how people have been exposed and the possible outcomes.
"We want to find clear answers about the health effects of PFAS exposure."
Katherine residents will receive an invitation to participate in the 30-minute survey if they had their blood tested through the Voluntary Blood Testing Program.
People who did not participate in the Voluntary Blood Testing Program but would still like to fill in a survey can contact the study team at firstname.lastname@example.org or 1800 430 903.
"We are looking at whether PFAS is linked to different diseases and the levels of stress in these communities," said Professor Kirk.
"Internationally, there is a need for more research into the health effects of PFAS and this study is an important step towards this."
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