Per- and polyfluoroalkyl substances (PFAS) are environmental contaminants that are potentially harmful to health. We examined if rates of selected cancers and causes of deaths were elevated in three Australian communities with local environmental contamination caused by firefighting foams containing PFAS. The affected Australian communities were Katherine in Northern Territory, Oakey in Queensland and Williamtown in New South Wales.
All residents identified in the Medicare Enrolment File (1983–2019)—a consumer directory for Australia’s universal healthcare—who ever lived in an exposure area (Katherine, Oakey and Williamtown), and a sample of those who ever lived in selected comparison areas, were linked to the Australian Cancer Database (1982–2017) and National Death Index (1980–2019). We estimated standardised incidence ratios (SIRs) for 23 cancer outcomes, four causes of death and three control outcomes, adjusting for sex, age and calendar time of diagnosis.
We observed higher rates of prostate cancer (SIR=1·76, 95 % confidence interval (CI) 1·36–2·24) in Katherine; laryngeal cancer (SIR=2·71, 95 % CI 1·30–4·98), kidney cancer (SIR=1·82, 95 % CI 1·04–2·96) and coronary heart disease (CHD) mortality (SIR=1·81, 95 % CI 1·46–2·33) in Oakey; and lung cancer (SIR=1·83, 95 % CI 1·39–2·38) and CHD mortality (SIR=1·22, 95 % CI 1·01–1·47) in Williamtown. We also saw elevated SIRs for control outcomes. SIRs for all other outcomes and overall cancer were similar across exposure and comparison areas.
There was limited evidence to support an association between living in a PFAS exposure area and risks of cancers or cause-specific deaths.
- • We studied 23 incident cancers and four causes of death in three PFAS exposure areas.
- • The study included everyone who had ever lived in an exposure area since 1984.
- • We sampled comparison groups from areas without known PFAS contamination.
- • Study participants were linked to national cancer and death registries.
- • There was limited evidence for increased risk of any cancer or cause-specific death.
Per- and polyfluoroalkyl substances (PFAS) are man-made chemicals that move through water and land. Their extensive use in household and industrial settings since the 1950s has led to global environmental contamination . PFAS are easily absorbed from the environment and distributed and retained in the human body . This has led to significant concerns for potential health effects, including cancer.
A particular source of environmental PFAS contamination is aqueous film forming foams (AFFF), used to extinguish liquid fuel fires in aviation settings. In Australia, AFFF products were used on Department of Defence bases for fire emergencies and training purposes, for several decades, starting in the 1970s. This has led to contamination of residential areas surrounding military bases, including Katherine in Northern Territory (NT), Williamtown in New South Wales (NSW) and Oakey in Queensland (Qld) . Since the early 2000s, use of these particular foams has been phased out. However, PFAS remain detectable in water sources and land near the military bases . The health effects of living in these communities is unknown.
The current epidemiological literature on human cancer in relation to PFAS is largely focussed on perfluorooctanoic acid (PFOA) and involves three types of populations: workers exposed in plants that use or produce PFAS (occupational exposure), communities living in areas with documented contamination of the local environment or drinking water supply (community exposure), and the general population (background exposure).
The International Agency for Research on Cancer (IARC) found limited evidence for the carcinogenicity of PFOA and classified PFOA as possibly carcinogenic to humans (Group 2B) . Largely based on two studies of community exposure in the mid-Ohio valley region of the USA from the C8 Health Project , the IARC considered the evidence for kidney and testicular cancer to be credible while two more recent reviews considered the association for these cancers to be ‘suggestive’ and ‘most likely causal’ . All assessments recognised that there were overlaps in cases between the two studies from the C8 Health Project and that estimates for testicular cancer were based on small numbers.
The particular AFFF used in Australia contained perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS) as the main active ingredients . The evidence for cancer and cause-specific mortality in populations exposed to PFAS contamination composed of PFOS and PFHxS is sparse. Recently, a Swedish study by Li et al. involving community exposure in such a context reported no evidence for an overall increased risk of cancer .
The aim of this study was to examine if incidence of cancers and cause-specific deaths in those who had lived in one of the three PFAS exposure areas in Australia was higher than in comparison areas without known contamination.