Exposure assessment for the intake of PCDD/Fs and dioxin-like PCBs as well as PFAS through the consumption of different fish species

Note: the original source of this report is the BfR website - see BfR Opinion No 043/2023 issued 27 September 2023

Many fish and seafood are rich in vitamins and trace elements. However, they can also con-
tain undesirable substances that might accumulate in the fat. The German Federal Institute for
Risk Assessment (BfR) has calculated the amounts of such substances that consumers ingest
when eating one to three servings (150 g each) of fish per week. The substances under con-
sideration are divided into two groups:

1. Dioxins (PCDD/Fs) and dioxin-like (dl) PCBs are long-living contaminants that enter the en-
vironment through human activities (in the case of dioxins, also through forest fires or volcanic
eruptions).

2. Per- and polyfluoroalkyl substances (PFAS) are a group of organic fluorinated compounds
that originate from industrial processes and are found, inter alia, in impregnating agents, out-
door clothing, and fire-fighting foams.

The occurrence of these environmental contaminants can vary greatly from region to region.
This was taken into account in the calculations. Evaluations were made with regard to mean
and high levels for the different fish species. No data were available for seafood.

The highest mean levels of PCDD/F-PCBs are found in eels, sharks/curled strips of smoked
dogfish, and bream. The lowest levels are found in codfish and tuna. For PFAS, the highest
mean levels were detected in perch-like freshwater fish and eels, and the lowest levels in pol-
lock/Alaskan pollack, tuna, and pangas catfish. The occurrence data used come from various
programmes of the official food surveillance authorities. Even though suspect and follow-up
samples were excluded, no conclusion about the representativeness of the samples for the
entire German market can be made.

The determined intake levels were compared with the respective health-based guidance val-
ues of the European Food Safety Authority (EFSA). For both substance groups, the EFSA has
derived a tolerable weekly intake (TWI) at which no adverse health effects are to be expected.
For PCDD/F-PCBs, the TWI is 2 pg per kg body weight (bw) per week. This TWI is already ex-
ceeded with the consumption of one portion of fish per week for eels, curled strips of smoked
dogfish, bream, trout, herring fish, pike, and other fish with mean levels of dioxins and PCBs.
The lowest intakes of PCDD/F-PCBs were found for the consumption of codfish, tuna, and
rainbow trout.

For PFAS, the EFSA derived a TWI of 4.4 ng per kg bw per week. For some fish species for
which the present hypothetical exposure assessment was conducted, the TWI for the sum of
the four PFAS was exceeded already when one fish meal per week is assumed.

PCDD/F-PCBs and PFAS are undesirable in the food chain. In recent decades, legal regula-
tions have considerably reduced the amount of these substances released into the environ-
ment by humans. The intake of these via food has thus decreased considerably. Nevertheless,
reduction efforts should be continued. For PFAS, a restriction proposal was submitted to the
European Chemicals Agency (ECHA) in March 2023. This was prepared with the participation
of the BfR.

PCDD/F-PCBs are found mainly in fatty animal food products such as fatty fish. If consumers
limit the consumption of such foods, they can reduce the intake of these substances. However,
when considering fish consumption, the focus should not be only on the levels of contami-
nants, but also on the health benefits, which, among other things, result from the supply of vit-
amins, trace elements, and polyunsaturated fatty acids.