PFAS in Sludge – New Accredited Method

PFAS in sludge (or biosolids) originates from wastewater treatment plants where these persistent chemicals accumulate via sorption onto suspended solids. PFAS are commonly found in urban wastewater due to inputs from consumer products and industrial point sources (fire-fighting training sites, airports, production facilities etc). Conventional wastewater treatment does not effectively remove PFAS, resulting in their persistence in effluent and sludge. When such sludge is applied to agricultural land as fertilizer, PFAS can potentially leach into soil, water, and food crops, and may pose risks to environmental and human health. Studies have shown that PFAS can be absorbed by edible plants and bioaccumulate in animals consuming contaminated feed and thus facilitate entry into the food chain.   The extent of plant uptake varies depending on PFAS composition and concentration as well as plant species. Although biosolids are nutrient-rich and regulated, it has been debated if even low-level PFAS contamination may lead to environmental accumulation over time due to their chemical stability.

Over recent years, the number of regulations and recommendations concerning PFAS in sludge has increased significantly. In Sweden, “action limits” have been introduced within the sludge certification system REVAQ, corresponding to PFAS4 at 7.5 µg/kg DM and PFAS22 at 25 µg/kg DM. These groups are based on Danish criteria, where current guidelines specify 10 µg/kg DM for PFAS4 and 400 µg/kg DM for PFAS22—values that also apply to soil. However, a revision of these Danish limits may occur following a 2023 report suggesting updated thresholds of 15 µg/kg DM for PFAS4 and 50–100 µg/kg DM for PFAS22. In Norway, the revised Fertilizer Regulation has introduced a limit of 40 µg/kg DM for PFOS + PFOA.

Eurofins now offers a new accredited method for sludge analysis with industry-leading reporting limits (limits of quantification, LOQ) of 0.03–0.1 µg/kg DM for most compounds. Three analytical packages will be available: one aligned with PFAS22 according to REVAQ and Danish guidelines, and two extended packages covering PFAS28 and PFAS35, consistent with our offerings for water, soil, and sediments. The latter two packages also include PFAS4 and PFAS22. Additional PFAS compounds, such as diPAPs and FTCAs—currently gaining attention in sludge contexts—can be ordered separately. Please contact us for further details.

Sample preparation, including drying and milling, must be added (code SL797). For dewatered sludge, a minimum of 100 g of sample is required. The standard turnaround time (TAT) is 10 working days. More detailed information is available through our search engine (see below).

For questions regarding PFAS, our analytical advisory service is available through customer support at 010-490 8110 or via email at sh-analys.miljo.se@etn.eurofins.com.

Links:

Eurofins search engine: https://analyskatalog.eurofins.se/

REVAQ (in Swedish): https://www.svensktvatten.se/vara-sakomraden/avlopp-och-miljo/slamanvandning-och-revaq/

Norwegian fertilizer regulation (in Norwegian): https://lovdata.no/dokument/SF/forskrift/2025-01-29-116/KAPITTEL_1#%C2%A71

Mijøstyrelsen (Danish guidelines; in Danish): https://mst.dk/erhverv/sikker-kemi/kemikalier/graensevaerdier-og-kvalitetskriterier

Mijøstyrelsen (report cut-off values):

https://mst.dk/publikationer/2023/marts/derivation-of-cut-off-values-for-pfas-in-sewage-sludge