Signage warning of the risks of eating carp caught near the Bandiana Army base on the NSW-Victorian border should be installed and a PFAS groundwater plume managed, the Department of Defence has been told.

The delayed Human Health and Ecological Risk Assessment (HHERA), published two years after fish were caught for testing, has found "PFAS exposure risks are all low and acceptable for scenarios that currently occur in the investigation area".

But there are "potentially unacceptable" health risks involved with activities that consultants say are not currently happening.

PFAS exposure through the following ways were considered to be a low and acceptable risk to human health:

PFAS exposure through the following ways, thought to be not currently occurring in the area, present a potentially unacceptable risk to human health:

The town water supply continues to be monitored by North East Water and 108 samples have consistently reported levels of PFAS within drinking water guidelines.

But "the PFAS concentrations identified in the groundwater within the lower Jack in the Box Creek catchment, and within the Kiewa River catchment preclude the use of groundwater as potable water or stock watering. Management or mitigation should be considered".

In line with findings from the HHERA, a PFAS management area plan was also released this week.

The plan has stated within 12 months, warnings of the health risks associated with eating carp should be established, and groundwater and surface water studies started.

"Although widespread extraction of groundwater is not occurring within the catchments, PFAS impacts in some areas have precluded the use of groundwater for these purposes [drinking water and/or stock watering]," it states.

"Concentrations of PFAS in groundwater were above drinking water guidance values for the two groundwater wells installed in the lower Jack in the Box Creek catchment.

"The PFAS concentrations identified in the groundwater within the lower Jack in the Box Creek catchment and within the Kiewa River catchment preclude the use of groundwater for potable water, stock watering, and irrigation of poultry for the consumption of eggs.

"The HHERA has identified a potential unacceptable risk associated with the consumption of carp from the Unnamed Creek and a section of the Kiewa River. While the investigation has not identified this is as being a currently realised practice, Victorian agencies have advised that precautionary advise is required to notify stakeholders of the potential risk."

A carp caught from a waterbody in the Kiewa River floodplain on November 26, 2018, contained 17,000 micrograms per kilogram of PFAS - the trigger point for investigation according to food standards is 5.2 ug/kg.

Food Standards Australia New Zealand sets trigger points for analysing per- and poly-fluoroalkyl (PFAS) in foods to identify when further investigation of a food may be required.

FSANZ states "there is insufficient data to recommend a regulatory approach and set maximum limits" and that the man-made chemicals have been used in a wide range of products, including garments and textiles, fabric protection, furniture, and some types of fire-fighting foam.

"Scientific literature on the effects of these chemicals on people is inconclusive. However testing on animals has shown some effects at low doses."

FSANZ trigger points were exceeded in the Bandiana investigation area for 11 out of 24 fish samples; mostly carp, but one Murray Cod sample had a concentration of 5.7 ug/kg.

Consultants concluded that given the conservative nature of the guidelines, which assumes consumption of fish every day, "and the limitations on fishing the Murray cod", "the health risk from the consumption of Murray cod is considered to be low and acceptable".

Previous studies have shown carp may be more susceptible to PFAS contamination, in part due to their foraging habits on the river bed.

When the concentrations of PFAS in fish and yabbies caught were measured against ecological, rather than human health advice, 25 out of 33 samples were higher than guidelines.

The HHERA confirmed what had been published in the detailed site investigations; floodplains on private property were identified as an area of elevated risk for PFAS exposure.

The health risk from swimming there is "potentially unacceptable".

Consultants estimated that while the water exceeds recreational guidelines, a child could swim in water on the floodplain for 18 days each year "before reaching the limit of adopted acceptable risk".

For Jack in the Box Creek, a child could swim in the creek for 44 days per year safely.

The 2018 study found that for the Jack in the Box Creek and Kiewa River catchments "on-base source areas are continuing to contribute to the PFAS identified".

The PFAS management plan outlines that the current fire station on East Bandiana has been identified as a "significant source area".

The current fire station, constructed in 1993, is on East Bandiana and high concentrations of PFAS were detected in shallow groundwater.

"A groundwater plume has been identified extending to the east across the base, and off-base seepage samples have confirmed the groundwater is discharging to the surface water on the Kiewa River floodplain," the management plan states.

"The extend of the plume off-base is unknown.

"However, based on seepage water samples collected as part of the HHERA, it is evident that during selected times of the year groundwater is contributing to off-site surface water impacts on the Kiewa River floodplain."

The management plan has proposed a detailed groundwater remediation feasibility study be done to reduce migration, as well as a study of surface water.

Defence and the Victorian government will move to "implement administrative controls related to groundwater use in specific areas".

Defence has set up an online enquiry form for the community to ask questions.

There are 28 Defence sites around the country being investigated for PFAS and 24, which now includes Bandiana, have transitioned to the management phase.