PFAS in drinking water and fish - risk management

One glass of water

The National Food Agency (NFA) has recommendations on risk management measures for drinking water contaminated with poly- and perfluorinated alkyl substances (PFAS).

The recommendations are addressed to drinking water producers, to local authorities, and to consumers that have private wells or are consumers of locally caught fish.

The aim of the measures is to reduce the exposure of consumers to PFAS from contaminated drinking wa-ter and fish and to minimize long-term intake of PFAS.

Pollution after fire-fighting training with highly fluorinated firefighting foams has in some cases led to high concentrations of many different PFAS in ground water and in private wells. The NFA's recommendations on risk management measures are based on what was known about the presence of these substances in drinking water up until 2016.

New information has been published about the occurrence and toxicity of different PFAS in aquatic environments both in Sweden and abroad, which might affect the recommendations in the future.

In summary, the recommendations include monitoring of eleven different PFAS in drinking water (PFAS11). The toxicity of most of the PFAS is not well known, but to maintain large safety margins against possible health risks, all substances included in PFAS11 are regarded to be as toxic as perfluorooctanesulfonate (PFOS).

Case by case risk management discussions with the NFA might be necessary when high concentrations of PFAS are observed. In terms of consumption of fish, recommendations are limited to perfluorooctanesulfonate (PFOS).

The following apply to drinking water:

  • PFAS should not be present in drinking water.
  • Long-term intake of drinking water with high concentrations of PFAS might reduce safety margins to levels suspected of causing health risks.
  • To maintain high safety margins, the total of PFAS11 in the drinking water should be below 90 nanograms/liter.

Monitoring of drinking water

If a drinking water supply is, or is suspected to be, contaminated by PFAS, the concentrations in the drinking water should be monitored.

Analyze drinking water for the PFAS listed in the table below. Monitor the drinking water regularly over time and under different conditions in order to identify possible contaminant sources, PFAS composition, seasonal variation, and possible trends.

The PFAS pattern in drinking water might provide information about the origin of the contamination. Even areas not initially suspected to be affected might at a later stage need to be monitored due to the properties and mobilities of the substances in the soil.

A risk assessment of the observed PFAS concentrations in the drinking water should be made by comparing the concentrations with the action levels specified below.

Suitable PFAS to analyze in drinking water

1 Perfluorobutanesulfonate (PFBS)
2 Perfluorohexanesulfonate (PFHxS)
3 Perfluorooctanesulfonate (PFOS)
4  6:2 Fluorotelomer sulfonate (6:2 FTS)
5  Perfluorobutanoate (PFBA)
 6  Perfluoropentanoate (PFPeA)
 7  Perfluorohexanoate (PFHxA)
 8  Perfluoroheptanoate (PFHpA)
 9  Perfluorooctanoate (PFOA)
 10  Perfluorononanoate (PFNA)
 11  Perfluorodecanoate (PFDA)

 

Action levels

There are currently no legally binding maximum limits for PFAS in drinking water. According to § 7 in the Drinking Water Ordinance (Livsmedelsverkets föreskrifter (2001:30) om dricksvatten), drinking water shall not contain substances in such concentrations that they might pose a risk to human health. The NFA has therefore established an action level for PFAS.

The action level is intended for drinking water producers, health authorities, and owners of private wells as a guide when determining if PFAS concentrations in the drinking water are so high that they might pose a health risk and therefore should be reduced or that consumers must be advised not to drink the water until such concentrations are reduced.

Risk assessment of PFAS in drinking water

Calculate the total concentration of PFAS in the drinking water in each sample as the sum of all PFAS in the table above. Results that are reported as "less than" (<) should not be included in the summation. If other PFAS than those in the table above significantly affect the total concentration, the NFA should be contacted for recommendations on risk management measures.

The limit of quantitation (LOQ) for individual PFAS should be in the range of 1–10 nanograms/liter.

Compare the total PFAS concentration with the action level of 90 nanograms/liter. Also compare the total PFAS concentration with the health-based guideline value (based on the TDI (Tolerable Daily Intake) for PFOS), which is 900 nanograms/liter.

Recommendations on risk management for drinking water

- covered by the Drinking Water Ordinance (Livsmedelsverkets föreskrifter (2001:30) om dricksvatten)

If PFAS are discovered in the drinking water at concentrations below the action level, i.e. PFAS11 is below 90 nanograms/liter

The long-term goal should be to minimize PFAS exposure from drinking water. This is justi-fied by the fact that there are other sources of PFAS exposure than drinking water, for ex-ample, freshwater fish. Moreover, some PFAS accumulate in the body during long-term ex-posure. Finally, the toxicity of PFAS might be reassessed in the future, which could lead to the TDI being lowered.

If the action level is exceeded in drinking water, i.e. PFAS11 is above 90 nanograms/liter

  • Take action as soon as possible so that PFAS in drinking water are reduced to concentra-tions as low as practically possible below the action level.
  • Monitor PFAS in the raw water if the drinking water comes from surface water. Inform the local health authority if the PFAS concentration in the raw water exceeds the action level for drinking water. This is justified because it might require additional risk management for the consumption of fish (see below).
  • Contact the industry organization Swedish Water and Wastewater Association for more information on measures to reduce the concentration of PFAS in the waterworks.

If the health-based guideline value (TDI) is exceeded in the drinking water, i.e. PFAS11 is above 900 nanograms/liter

  • Avoid drinking the water or preparing food with the water until the concentration is lowered.
  • Contact the NFA for further recommendations on risk management.

Recommendations for the local health authority when risk managing PFAS-contaminated fish

  • Monitor the concentration of PFOS in fish species and sizes that are consumed if contami-nation of PFAS is suspected in waters used for recreational or commercial fishing.
  • If high concentrations of PFOS are observed in edible fish, consider issuing dietary advice on consumption limits or introducing bans on fishing. The PFOS concentrations in fish mus-cle that might evoke considerations about dietary advice are presented in scenario calcula-tions performed by the NFA, see this document:
    Scenario calculations of PFOS intake from the consumption of PFOS-contaminated fish (only in Swedish).

Recommendations if you have a private well

If your water supply comes from your own private well or private waterworks, you are re-sponsible for the quality of the drinking water and for keeping the well in good condition. That means, for example, that you are responsible for the monitoring of the drinking water quality.

Long-term consumption of drinking water with high concentrations of PFAS reduces safety margins to levels suspected of causing health risks. Therefore, it is important to check that the drinking water from your well does not have high concentrations of these substances. Contact your local health authority, or the municipality, to find out if you live in an area that might be contaminated with PFAS.

The municipality can also help with information on how to analyze the content of PFAS in your drinking water.

Actions at different concentrations of PFAS

The NFA recommends the following actions depending on the concentration of PFAS in your drinking water:

  • If the drinking water contains 0–90 nanograms PFAS/liter:
    No specific action is needed. You can continue to drink the water.
  •  If the drinking water contains more than 90-900 nanograms PFAS/liter: 
    You can continue to drink the water, but you should ensure that the concentration is lowered as much as possible as soon as possible.
  • If the drinking water contains more than 900 nanograms PFAS/liter:
    Avoid drinking the water or preparing food with the water until the concentration has been lowered to  <900 nanograms/liter.

If the drinking water in your well contains more than 90 nanograms PFAS/liter, seek advice at your local health authority and consult companies that provide technological solutions for treating the water

Reviewed 2018-08-28