Bird populations across parts of a city's industrialised western suburbs have heightened levels of notorious PFAS in their systems - also known as forever chemicals.

The levels of these stubborn chemicals were 10 times higher in some birds than in a comparable study of birds in a rural area.

Rates were highest in young birds, having been passed the chemicals from their mothers and then as they left the nest to feed on insects, spiders, snails and worms.

The Macquarie University-led study released on Thursday, sampled invasive house sparrows from 16 locations in Melbourne's southwest, including around Williams Laverton Royal Australian Air Force base and the Qenos Chemical Plant in Altona.

The sites were already known to have heightened levels of PFAS, particularly the still-active air force base, which was the site of extensive firefighting training in the past.

The banned perfluorinated aqueous film forming foams - used to extinguish liquid fires - are the predominant source of PFAS in the environment globally.

In encouraging news, lead researcher Max Gillings said the results did not suggest forever chemicals were being extensively spread from these contaminated sites to the surrounding environment.

"The levels in the birds that we were finding weren't necessarily extreme, but they certainly were higher than what you would expect in a rural location, for example," he told AAP.

"Certainly this area of Melbourne has got a lot of potential industrial sources of PFAS contamination, and that's what's contributing to the elevated levels that we're seeing."

PFAS has been linked with developmental issues in birds, raising concerns given the highest levels of the chemicals were detected during the birds' early life stages.

"Some previous studies have shown definitely reproductive effects, so things like egg failures," Dr Gillings said.

"We don't really know the full implications of that for their health, especially over the long-term."

The reason exposure drops as the birds get older is that their diet changes from morethan 90 per cent invertebrates such as insects as nestling youngsters, to less than 10 per cent in adults, which feed mostly on grains.

However, when adults are breeding their diet switches back towards animal food sources to meet the energy demands of reproduction and rearing chicks.

"Similar trends in PFAS levels with age have been reported for a wide range of species, including humans and other mammals, and this seems to be linked to transfer from mother to offspring," Dr Gillings said.

"Our study adds more evidence confirming that PFAS pollution is a major issue throughout Australia, with impacts on communities and ecosystems alike."