PFAS Health Study Component two: Blood serum study of PFAS exposure, related risk factors and biochemical markers of health December 2021

Abstract

Per- and polyfluoroalkyl substances (PFAS) are man-made chemicals that may be harmful to human health. The main goal of the Blood Serum Study was to see whether people who lived or worked in Australian communities affected by PFAS contamination had higher levels of PFAS in their blood. The three communities were Katherine in the Northern Territory (NT), Oakey in Queensland (Qld) and Williamtown in New South Wales (NSW)—the ‘exposed communities’. To do this, we compared blood levels of PFAS in people from the exposed communities to blood levels of PFAS in people in who lived in similar communities without environmental PFAS contamination. The three communities without contamination were Alice Springs in the NT, Dalby in Qld, and Kiama and Shellharbour in NSW—the ‘comparison communities’. From 2016 to 2020, people from the exposed and comparison communities provided a blood sample for PFAS testing and completed a questionnaire. A medical laboratory measured the levels of nine types of PFAS in blood. Only perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS) and perfluorooctanoic acid (PFOA) were detected in more than 80% of all blood samples. Average (geometric mean) PFAS levels of participants from the exposed communities were higher than participants from the comparison communities. Although, PFOA levels were similar in the exposed and comparison communities. Across the three exposed communities, the average PFAS levels in blood ranged from 4.9 to 6.6 nanograms per millilitre (ng/mL) for PFOS, from 2.9 to 3.7 ng/mL for PFHxS and from 1.3 to 1.8 ng/mL for PFOA. Across the three comparison communities, the PFAS levels in blood ranged from 2.5 to 3.3 ng/mL for PFOS, from 0.7 to 1.2 ng/mL for PFHxS and from 1.2 to 1.4 ng/mL for PFOA. PFOS and PFHxS were the main ingredients of the firefighting foams that contaminated the environment of the exposed communities. About half of participants from the exposed communities had high blood levels of PFHxS. About a third had high blood levels of PFOS. We investigated what may have led to participants who lived in the exposed communities having high levels of PFAS in their blood. We identified several risk factors for a person having a high blood level of PFOS or PFHxS in their blood, including consuming bore water or certain locally grown foods, living in an exposed community for a long period of time and exposure to firefighting foams in the workplace. Most participants from the exposed communities reported that they changed how much they used bore water or ate locally grown foods once they knew about the PFAS contamination. A medical laboratory also measured different chemicals related to health (biochemical markers) in blood samples, such as cholesterol, so we could see how they vary with PFAS levels in blood. Overall, there were few instances where higher PFAS levels were associated with higher or lower levels of biochemical markers. One example was that participants from Williamtown who had higher PFOS, PFHxS or PFOA levels in their blood also had a higher level of cholesterol in their blood. Higher levels of cholesterol in blood may lead to blockages in the coronary arteries, the blood vessels that carry oxygen into the heart muscle. Another example was for blood tests related to kidney function. Participants from Katherine and Williamtown who had higher PFAS levels in their blood also had higher levels of uric acid in their blood. All of these differences in biochemical markers were small and unlikely to lead to poor health. Further, higher PFAS levels in blood may not be the causes of the differences in biochemical markers but the consequences of them. For example, someone with poor kidney function may not be able to excrete PFAS from their body as easily as someone with normal kidney function, which may result in higher PFAS levels in blood. Blood levels of PFAS in the exposed communities were similar to those in some communities in the United States of America affected by environmental PFAS contamination from firefighting foams, but lower than in a community in Sweden. Consuming bore water or certain locally grown foods were risk factors for high levels of PFAS in blood. Changes in behaviour could limit people’s intake of PFAS and blood levels for most people will decline naturally over time