Investigating the extent of PFAS contamination in the Upper Danube Basin across environmental compartments

Liue al. En i onmen al Sciences Eu ope (2025) 37:99 h ps://doi.o g/10.1186/s12302-025-01141-6 RESEARCH Open Access © The Au ho (s) 2025, co ec ed publica ion 2025. Open Access This a icle is licensed unde a C ea i e Commons A ibu ion 4.0 In e na ional License, which pe mi s use, sha ing, adap a ion, dis ibu ion and ep oduc ion in any medium o o ma , as long as you gi e app op ia e c edi o he o iginal au ho (s) and he sou ce, p o ide a link o he C ea i e Commons licence, and indica e i changes we e made. The images o o he hi d pa y ma e ial in his a icle a e included in he a icle’s C ea i e Commons licence, unless indica ed o he wise in a c edi line o he ma e ial. I ma e ial is no included in he a icle’s C ea i e Commons licence and you in ended use is no pe mi ed by s a u o y egula ion o exceeds he pe mi ed use, you will need o ob ain pe mission di ec ly om he copy igh holde . To iew a copy o his licence, isi h p:// c ea i eco mmons. o g/ licen ses/ by/4. 0/. En i onmen al Sciences Eu ope In es iga ing heex en o PFAS con amina ion in heUppe Danube Basin ac ossen i onmen al compa men s Meiqi Liu1*, E nis Sa ace ic1, Thomas J. Oudega2,3, Ali A. A. Obeid2,3, Zsuzsanna Nagy‑Ko ács4, Balázs László4, S e en Ki laus1, O a ia Zoboli1, Jö g K ampe1, Julia De x2,3 and Ma hias Zessne 1,3 Abs ac Backg ound Pe ‑ and poly luo oalkyl subs ances (PFAS) a e eme ging o ganic pollu an s widely de ec ed in en i on‑ men al sys ems, posing isks o human heal h and he ecosys em. Despi e inc easing e o s o moni o PFAS in i e sys ems, knowledge gaps emain ega ding sou ces and emissions ia di e en pa hways. This s udy in es iga es PFAS con amina ion ac oss mul iple en i onmen al compa men s in he Uppe Danube Basin, including su ace wa e , g oundwa e , was ewa e , land ill leacha e, su ace uno , and a mosphe ic deposi ion. The p ima y objec i es a e o assess he ex en o PFAS con amina ion, iden i y key emission sou ces and anspo pa hways, and e alua e associa ed isks in e ms o he po en ial exceedance o cu en and p oposed en i onmen al egula o y h esholds in he Eu opean Union. Resul s The indings e eal a widesp ead p esence o PFAS, wi h PFOA, PFOS and sho ‑chain compounds being p edominan . The Alz Ri e and Gendo chemical pa k eme ge as ho spo s wi h a ‑ eaching e ec s downs eam, con ibu ing signi ican ly o di use legacy con amina ion o PFOA and being a signi ican sou ce o wo indus ial PFOA subs i u es, ADONA and GenX. Was ewa e ea men plan s, old municipal land ills, and si es wi h a his o y o i e‑ igh ing oam applica ion a e iden i ied as key pa hways o sou ces o legacy pollu ion, exhibi ing highe concen a ions compa ed o he o he ma ices. No ably, no signi ican emo al is obse ed when compa ing in lu‑ en and e luen samples om con en ional WWTPs. The s udy u he demons a es ha g oundwa e is ulne able o con amina ion om poin sou ces and o in il a ion om i e s, wi h bank il a ion p o ing la gely ine ec i e in p e en ing PFAS con amina ion. Conclusions The s udy unde sco es he necessi y o sou ce and pa hway con ol measu es o mi iga e PFAS pollu‑ ion, he implemen a ion o ad anced ea men echnologies o sa egua d d inking wa e and su ace wa e quali y, and a ge ed emedia ion o legacy soil and g oundwa e con amina ion. Addi ionally, s ong use egula ions should be explo ed o minimize ongoing emissions. The mul i‑compa men moni o ing p o es o be a c ucial app oach o unde ‑ s and he complexi y o PFAS dis ibu ion a he ca chmen scale. Compa a i e analysis and isk assessmen highligh chal‑ lenging si ua ions o wa e managemen , o e ing an indispensable basis o emission modeling as a nex s ep o quan i‑ a i e assessmen o he ele ance o di e en sou ces and pa hways o su ace wa e pollu ion. Keywo ds Wa e pollu ion, Eme ging con aminan s, Ca chmen moni o ing, Sou ce iden i ica ion, Wa e shed managemen , Wa e F amewo k Di ec i e, D inking Wa e Di ec i e, En i onmen al Quali y S anda ds *Co espondence: Meiqi Liu [email p o ec ed] Full lis o au ho in o ma ion is a ailable a he end o he a icle Page 2 o 20 Liue al. En i onmen al Sciences Eu ope (2025) 37:99 Backg ound Pe - and poly luo oalkyl subs ances (PFAS) ha e gained inc easing a en ion a he wo ldwide le el in ecen yea s, as a g owing numbe o s udies ha e e ealed links be ween hese syn he ic chemicals and ad e se e ec s on human heal h [97, 116]. Once p oduced, PFAS a e dis- ibu ed and accumula ed in he en i onmen , leading o human exposu e h ough pa hways such as d inking wa e , ood, ae osols, and indoo dus [26, 107, 119, 123, 128, 135]. PFAS ha e been used in a wide ange o indus ial and household applica ions since he 1950 s due o hei desi able p ope ies such as chemical s abili y, hyd o- phobici y, oleophobici y, and he abili y o lowe su ace ension [14, 41]. Howe e , mos PFAS a e ei he en i on- men ally and mic obiologically non-deg adable o ul i- ma ely ans o med in o e minal p oduc s ha a e s ill PFAS [23, 127]. Ex ensi e s udies ha e ound posi i e associa ions be ween PFAS exposu e and immuno oxic, neu o-de elopmen al oxici y, hy oid and kidney diso - de s, ho monal e ec s, ca cinogenic po ency, in e ili y, and cance s [98, 111, 119]. PFAS can en e en i onmen al media h oughou hei li e cycle, esul ing in a con inuous exchange o an e e inc easing amoun o PFAS be ween he en i onmen al compa men s [5]. Su ace wa e s, in pa icula , se e as condui s o he anspo and accumula ion o PFAS [103]. Unde s anding he a e and anspo o PFAS h ough di e en ou es o su ace wa e is c ucial o iden i ying emission sou ces and pa hways, as well as de eloping e ec i e managemen s a egies o con ol pollu ion and p o ec public heal h [63]. Su ace wa e con amina ion occu s h ough bo h he poin sou ce and di use pa hways [63]. In u al and non-indus ial ca chmen s, di use inpu s can be signi ican due o we and d y a mosphe ic deposi- ion [84, 99]. PFAS can so b o pa icula e ma e in ae osols, allowing a mosphe ic anspo o e long dis- ances [35]. PFAS deposi ed on soils can each g ound- wa e and su ace wa e du ing p ecipi a ion e en s, and PFAS ha e been widely de ec ed in uno wa e samples [22, 57, 133]. In addi ion, u ban s o m wa e can con ain no only PFAS accumula ed on sealed su - aces h ough a mosphe ic deposi ion, bu also PFAS washed-ou om a ious ma e ials applied in he buil en i onmen [9]. Majo pollu ion pa hways o iden i ia- ble emission poin s include ce ain indus ial acili ies, was ewa e ea men plan s (WWTPs) and he use o sludge gene a ed om PFAS-con amina ed WWTPs, he applica ion o aqueous ilm- o ming oam (AFFF) o i e igh ing- ela ed ac i i ies, and land ills [8, 16, 41, 85, 100]. In e ac ions be ween su ace wa e and g oundwa e can anspo PFAS om poin sou ces o g oundwa e and con ibu e o u he di use con ami- na ion [12, 49, 109]. In addi ion, he i e i sel can also di usely a ec g oundwa e quali y [72]. Despi e inc easing e o s o documen he con amina- ion o PFAS in i e s, a sys ema ic unde s anding o he ela i e con ibu ions o di e en en i onmen al pa h- ways emains lacking. Mul i-compa men moni o ing can p o ide he necessa y in o ma ion basis o a mo e comp ehensi e unde s anding o PFAS sou ces, a e, and anspo wi hin aqua ic sys ems [55]. Among he di e en en i onmen al compa men s, bank- il a ed wa e ep esen s a c i ical bu unde ex- plo ed one. As a sus ainable and cos -e ec i e d inking wa e supply me hod, i e bank il a ion is widely used ac oss Eu ope, pa icula ly in ci ies such as Be lin and Budapes [78, 86], as well as in de eloping egions [53, 106]. Howe e , li le is known abou he le els o PFAS con amina ion and anspo mechanisms wi hin he wa e ha lows h ough he i e bank, aising con- ce ns abou i s e ec i eness in emo ing hese pe sis en pollu an s. Simila ly, while nume ous s udies ha e in es iga ed PFAS con amina ion in was ewa e in Eu ope, ela i ely ew ha e sys ema ically examined bo h he in luen and e luen . Such in es iga ions a e essen ial o e alua e he emo al e iciencies o PFAS and o unde s and he sou ce o PFAS con amina ion om he p o ile o in lu- en samples [61]. The Uppe Danube Basin (UDB) p esen s an impo an case o unde s anding PFAS con amina ion on a la ge ca chmen scale. This egion has been he ocus o mic o- pollu an moni o ing [7, 73, 74], p o iding oppo uni ies o in eg a e ex e nal da a se s in o a ha monized assess- men o con amina ion p o iles. Howe e , p e ious s ud- ies ha e ocused mainly on a limi ed subse o PFAS, such as PFOA, PFOS, and sho -chain pe luo oalkyl acids (PFAA). Recen non- a ge and suspec sc eening s udies ha e e ealed a b oade spec um o PFAS in he Danube [88, 124], highligh ing he need o expanded a ge ed analysis o enhance ou unde s anding o hei occu - ence and dis ibu ion in he egion. Gi en he ex ensi e p esence o PFAS and hei di e se pa hways in o aqua ic sys ems [102, 103], egula o y e o s ha e been implemen ed o con ol hei en i on- men al impac . The S ockholm Con en ion on Pe sis- en O ganic Pollu an s [117], he US Na ional P ima y D inking Wa e Regula ion [125], and he Eu opean Union (EU) D inking Wa e Di ec i e(DWD) [33] ha e es ablished guidelines o limi PFAS pollu ion. Mo e ecen ly, wi hin he EU, a d a e sion o En i onmen- al Quali y S anda ds (EQS) [30] has p oposed upda ed egula o y limi s o PFAS in su ace and g oundwa e . Assessing PFAS con amina ion le els in he Danube in Page 3 o 20 Liue al. En i onmen al Sciences Eu ope (2025) 37:99 he con ex o hese e ol ing s anda ds would p o ide aluable insigh s o wa e managemen . To add ess knowledge gaps, a comp ehensi e moni- o ing campaign was conduc ed in he UDB, a ge ing 31 indi idual PFAS in mul iple en i onmen al compa - men s, including a mosphe ic deposi ion, su ace wa e , g oundwa e , su ace uno , land ill leacha e, and was e- wa e . Speci ic e o s we e made o collec samples om he Danube and i s bank- il e ed wa e in wo ci ies, as well as in luen and e luen om he same WWTPs. Fu he mo e, addi ional ex e nal PFAS moni o ing da a om coun ies wi hin he basin we e in eg a ed in o a ha monized da abase [71], p o iding a basis o a mo e comp ehensi e assessmen o PFAS concen a ions and dis ibu ion. By adop ing a holis ic app oach o mul i-compa men moni o ing, his s udy p o ides he i s comp ehensi e assessmen s o PFAS con amina ion in a la ge pa o he Danube egion. I o e s insigh s in o PFAS anspo ia di e en pa hways, iden i ies key emission sou ces and con amina ion ho spo s, e alua es he e icacy o a- di ional emo al mechanisms, and assesses he isks o exceedance o cu en and p oposed egula o y h esh- olds. These indings ad ance an in eg a ed unde s and- ing o PFAS dynamics a he ca chmen le el, and o e a ans e able app oach ha can suppo mic opollu an moni o ing and managemen e o s in o he ca chmen s beyond he Danube. Me hods S udy a ea desc ip ion The Danube is Eu ope’s second la ges i e , p o iding esou ces o nume ous human ac i i ies along i s cou se. This s udy ocuses on he UDB, which spans app oxi- ma ely 186,059 km 2 and ex ends o Budapes , Hunga y. The egion is home o o e 27.5 million inhabi an s in i e majo coun ies: Ge many, Aus ia, Czech Republic, Slo akia, and Hunga y. Figu e1 illus a es he loca ion o he UDB in ela ion o he en i e Danube basin in a global con ex . Sampling A comp ehensi e moni o ing campaign was conduc ed be ween 2021 and 2023 wi hin he UDB, a ge ing a i- ous en i onmen al compa men s, including i e wa e , g oundwa e , was ewa e , land ill leacha e, su ace uno and a mosphe ic deposi ion. Ri e wa e g ab samples we e collec ed unde base low condi ions in nine main ibu a ies o he Danube. Along he Danube, Vienna and Budapes we e selec ed as ep esen a i e si es, whe e base low samples and g oundwa e samples we e aken bimon hly. G oundwa- e samples we e collec ed om nea by bank- il a ion si es, as bank il a ion se es as p ima y and backup d inking wa e sou ces in Budapes [86] and Vienna [20], espec i ely. In addi ion, depending on he numbe o high- low e en s and he easibili y o sampling on si e, one o h ee high- low samples we e also collec ed a su - ace wa e si es. Mo e de ails on sampling a bank- il a- ion si es and ela ed analyzes a e a ailable in [93]. Fo was ewa e , weekly composi e samples we e aken a se en municipal was ewa e ea men plan s and ou indus ial was ewa e ea men plan s, om bo h in low and ou low poin s. A ou legacy municipal land ills— emnan s o o me was e disposal p ac ices no longe allowed unde cu en EU egula ions—samples o lea- cha e o g oundwa e di ec ly benea h he land ill we e collec ed. Su ace uno samples om unsealed soil we e collec ed du ing p ecipi a ion e en s om h ee si es ep esen ing ag icul u al, o es , and pas u e land uses. Composi e a mosphe ic bulk deposi ion samples we e collec ed a h ee si es o e h ee pe iods o 4 mon hs. All sampling ac i i ies ollowed he ecommenda ions o mul iple PFAS sampling guide documen s [17, 81]. The samples we e collec ed and s o ed in 1-l high-densi y polye hylene (HDPE) bo les. A e collec ion, he sam- ples we e anspo ed o he labo a o y in 48 h unde cooled condi ions (0–10 ◦ C) and s o ed a 6 ◦ C upon a i al. De ailed in o ma ion on sampling si es is a ail- able in he concen a ion da abase [71]. Chemical analysis andquali y con ol Fo quali y con ol, a leas one labo a o y blank sample and one ield blank sample was p epa ed o each en i- onmen al ma ix. To p e en c oss-con amina ion, all sampling ma e ials and equipmen ha e been ho oughly cleaned be o e use. The a ge ed analysis o hese com- pounds was pe o mance by liquid ch oma og aphy an- dem mass spec ome y (LC–MS/MS), ollowing EPA me hod 1633 [126]. The sample p epa a ion included concen a ion s eps using ei he au oma ed inline solid- phase ex ac ion (SPE) o manual SPE, depending on he sample ma ix, o ensu e he highes analy ical accu acy. Du ing labo a o y p ocessing, ex ac ed in e nal s and- a ds we e added du ing he SPE s ep o e alua e eco - e y a es, while non-ex ac ed in e nal s anda ds we e included o es ablish he ini ial calib a ion and ensu e he p ecision du ing LC–MS analysis. Fo sample injec ion, a PAL RTC sample was used. Sepa a ion was achie ed using an Agilen 1290 In ini y II HPLC pump, coupled wi h a Sciex Q ap 6500+ mass spec ome e equipped wi h an elec osp ay ioniza ion sou ce (EIS). A Phenomenex Luna Omega 3 µm PS C18 (100 × 3.0 mm, 100 Å) analy ical column was main ained a 40 ◦ C, wi h an injec ion olume o 40 µL. Fu he - mo e, a Phenomenex Luna C18 (50 × 3 mm, 110 Å) delay Page 4 o 20 Liue al. En i onmen al Sciences Eu ope (2025) 37:99 column was ins alled. Ch oma og aphic sepa a ion was pe o med using a mobile bina y g adien phase, and he g adien condi ions a e p o ided in Tables1. The ESI o he mass spec ome e ope a ed in nega i e ion mode, using mul iple eac ion moni o ing o he a ge compo- nen s lis ed in Table1. The limi o quan i ica ion (LOQ) o each subs ance was de e mined by di ec injec ion, ollowing he DIN 32645 guideline [25]. De ailed LOQ alues a e p o ided in Tables2. The alidi y o he LC–MS/MS analysis esul s has been ini ially e i ied in e nally by he da a managemen eam. Ques ionable esul s ha e unde gone epea ed analysis be o e being s o ed in he designa ed PFAS da abase. Addi ional da a collec ion Based on he moni o ing esul s collec ed du ing ou sampling campaign, we ha e u he expanded he da a- se by inco po a ing PFAS concen a ion da a om o he su eys, co e ing he s udy a ea as comp ehensi ely as possible. Se e al moni o ing campaigns ha e been conduc ed in he Danube egion, such as he EU P o- jec ”DHm3c” [59] and he Join Danube Su ey 4 [52], which p o ide aluable da a ha enhanced he em- po al esolu ion a some sampling si es, and ex ended spa ial co e age beyond he scope o ou own cam- paign. Fu he mo e, some na ional-le el s udies ex en- si ely ocuses on speci ic en i onmen al compa men s, con ibu ing subs an ial addi ional da a, o example, g oundwa e measu emen s om he Aus ian Na ional G oundwa e Moni o ing Campaign [15] and was ewa e measu emen s om Ge many [92]. In addi ion, ce ain da a a e no publicly a ailable bu ob ainable h ough di ec eques s o local en i onmen al minis ies. In gen- e al, hese e o s ha e led o subs an ial inc eases in he olume o concen a ion da a, imp o emen in spa ial and empo al co e age, and inc eased eliabili y o he Fig. 1 Map o he s udy a ea—Uppe Danube ( ed bounda y), i s ela i e posi ion o he whole Danube Basin (black bounda y) and in he wo ld (small map uppe igh co ne ). Danube and i s majo ibu a ies a e ou lined in blue; adminis a i e egions o majo coun ies in he Uppe Danube a e shaded in di e en colo s; majo la ge ci ies in he s udy a ea a e shown in ed poin s and labeled wi h names Page 5 o 20 Liue al. En i onmen al Sciences Eu ope (2025) 37:99 esul s, which helps p o ide a mo e comple e pic u e o PFAS con amina ion pa e ns ac oss he UDB. To sys ema ically manage and s o e he collec ed da a, we ha e cons uc ed a ha monized da abase [71], which is used o p esen he esul s in his s udy. This comp e- hensi e da abase is publicly a ailable and will p o ide suppo o u u e s udies and analysis in he UDB. I no only includes essen ial measu emen s in o ma ion, such as sample ma ices, concen a ion alues, uni s and LOQ, bu also p o ides ex ensi e me ada a, such as sampling si e coo dina es, sampling ype, sampling echniques, he labo a o y conduc ing he chemical analysis, and analy ical me hods applied. De ails on da a sou ces, en i- onmen al ma ices and he numbe o measu emen s included in he da abase a e p o ided in Supplemen a y Ma e ial 2. S a is ical analysis Concen a ion da a collec ed om he da abase a e i s classi ied in o di e en ypes based on en i onmen al compa men s and speci ic cha ac e is ics. Da a collec ed om he Danube ibu a ies a e u - he classi ied o assess he impac o was ewa e . The Table 1 O e iew o he PFAS compounds in es iga ed in his s udy Columns a e also gi en o indica e whe he he compound has been included in he lis s o calcula ing PFAS sum om he D inking Wa e Di ec i e (DWD, 2020) [33] and he p oposed En i onmen al Quali y S anda ds (EQS, 2022) [30]. Fo compounds included in he p oposed EQS (2022), ela i e po ency ac o s (RPFs) as PFOA- equi alen s a e gi en Classi ica ions o PFAS g oup is acco ding o he EPA Me hod 1633 [126] Subs ance CAS numbe PFAS g oup In DWD (2020) In p oposed EQS (2022) RPF PFBA 375‑22‑4 Pe luo oalkyl ca boxylic acids (PFCA) Yes Yes 0.05 PFPeA 2706‑90‑3 Pe luo oalkyl ca boxylic acids (PFCA) Yes Yes 0.03 PFHxA 307‑24‑4 Pe luo oalkyl ca boxylic acids (PFCA) Yes Yes 0.01 PFHpA 375‑85‑9 Pe luo oalkyl ca boxylic acids (PFCA) Yes Yes 0.505 PFOA 335‑67‑1 Pe luo oalkyl ca boxylic acids (PFCA) Yes Yes 1 PFNA 375‑95‑1 Pe luo oalkyl ca boxylic acids (PFCA) Yes Yes 10 PFDA 335‑76‑2 Pe luo oalkyl ca boxylic acids (PFCA) Yes Yes 7 PFUdA 2058‑94‑8 Pe luo oalkyl ca boxylic acids (PFCA) Yes Yes 4 PFDoDA 307‑55‑1 Pe luo oalkyl ca boxylic acids (PFCA) Yes Yes 3 PFT DA 72629‑94‑8 Pe luo oalkyl ca boxylic acids (PFCA) Yes Yes 1.7 PFTeDA 376‑06‑7 Pe luo oalkyl ca boxylic acids (PFCA) No Yes 0.3 PFBS 375‑73‑5 Pe luo oalkyl sul onic acids (PFSA) Yes Yes 0.001 PFPeS 2706‑91‑4 Pe luo oalkyl sul onic acids (PFSA) Yes Yes 0.3005 PFHxS 355‑46‑4 Pe luo oalkyl sul onic acids (PFSA) Yes Yes 0.6 PFHpS 375‑92‑8 Pe luo oalkyl sul onic acids (PFSA) Yes Yes 1.3 PFOS 1763‑23‑1 Pe luo oalkyl sul onic acids (PFSA) Yes Yes 2 PFNS 68259‑12‑1 Pe luo oalkyl sul onic acids (PFSA) Yes No – PFDS 335‑77‑3 Pe luo oalkyl sul onic acids (PFSA) Yes Yes 2 GenX 13252‑13‑6 Pe ‑ and Poly luo oe he ca boxylic acids (PFECA) No Yes 0.06 ADONA 919005‑14‑4 Pe ‑ and Poly luo oe he ca boxylic acids (PFECA) No Yes 0.03 4:2 FTS 757124‑72‑4 Fluo o elome sul onic acids (FTS) No No – 6:2 FTS 27619‑97‑2 Fluo o elome sul onic acids (FTS) No No – 8:2 FTS 39108‑34‑4 Fluo o elome sul onic acids (FTS) No No – PFOSA 754‑91‑6 Pe luo ooc ane sul onamides (FOSA) No No – N‑MeFOSA 31506‑32‑8 Pe luo ooc ane sul onamides (FOSA) No Yes 0.02 N‑E FOSA 4151‑50‑2 Pe luo ooc ane sul onamides (FOSA) No No – N‑MeFOSAA 2355‑31‑9 Pe luo ooc ane sul onamidoace ic acids (FOSAA) No No – N‑E FOSAA 2991‑50‑6 Pe luo ooc ane sul onamidoace ic acids (FOSAA) No No – 9Cl‑PF3ONS 73606‑19‑6 E he sul onic acids (ESA) No No – 11Cl‑PF3OUdS 763051‑92‑9 E he sul onic acids (ESA) No No – N‑MeFOSE 24448‑09‑7 Pe luo ooc ane sul onamide e hanols (FOSE) No No – N‑E FOSE 1691‑99‑2 Pe luo ooc ane sul onamide e hanols (FOSE) No No – Page 6 o 20 Liue al. En i onmen al Sciences Eu ope (2025) 37:99 a e age annual i e discha ge alues (2015–2021) we e calcula ed using da a om o icial hyd ological gauges. Simila ly, he a e age annual discha ge o ea ed munici- pal was ewa e du ing he same pe iod was ob ained by agg ega ing da a om he U ban Was ewa e T ea - men Di ec i e (UWWTD) Wa e base [31] a he ca ch- men le el using QGIS so wa e [104]. The p opo ion o municipal was ewa e ea men e luen in i e wa e a each sampling si e was hen calcula ed as he a io o annual e luen discha ge o annual i e discha ge. Based on hese esul s, he ibu a y si es a e classi ied in o h ee g oups, wi h he sha e o e luen in i e wa e below 1%, be ween 1% and 3% and abo e 3%. Al hough he da abase includes comp ehensi e PFAS measu emen s om Danube samples along he en i e i e s e ch up o Budapes , conside ing he a ying cha ac e is ics o Danube a di e en sec ions, a selec i e subse is employed o u he analysis and isualiza ions. Speci ically, only samples om Vienna and Budapes a e included in his ocused da ase . This app oach excludes da a om ups eam o a known ho spo egion ( he Alz i e ) in he UDB, he eby minimizing po en ial con- ounding in luences. Addi ionally, as bo h su ace wa e and bank- il e ed g oundwa e we e sampled in pa allel a Vienna and Budapes , his selec ion imp o es he com- pa abili y o esul s be ween compa men s. G oundwa e da a a e ca ego ized in o h ee g oups. Sampling poin s loca ed wi hin 5 km o a eas whe e AFFF was po en ially applied o nea legacy municipal land ills a e classi ied as po en ially impac ed by ho spo con amina ion, espec i ely. All o he sampling poin s a e classi ied as g oundwa e wi hou known in luences om ho spo . PFAS occu ence is isualized using hea maps, dis- playing de ec ion equencies ac oss di e en sample ypes. Boxplo s a e employed o illus a e concen a ion dis ibu ions, whe e he box dimensions ep esen he in e qua ile ange (IQR), spanning om he i s o he hi d qua ile. A line inside he box indica es he median alue, while whiske s ex end o he la ges o smalles alues wi hin 1.5 imes he IQR om he qua iles. Val- ues beyond he whiske s a e conside ed ou lie s and a e shown as indi idual poin s [131]. Fo some PFAS concen a ion boxplo s, he eg es- sion on o de s a is ics (ROS) me hod is applied [67]. This semipa ame ic app oach assumes a log-no mal dis ibu ion o en i onmen al concen a ion da a and impu es censo ed alues acco dingly [47, 48]. I is impo an o no e ha hese es ima es a e used solely o s a is ical analysis and do no ep esen ue meas- u ed alues. In addi ion, he a iabili y and unce ain y o he es ima ed alues may inc ease as he p opo ion o censo ed measu emen s inc eases. In his s udy, i he censo ed alues exceed 80% o ewe han h ee al- ues a e de ec ed abo e LOQ o a speci ic subs ance/ ype combina ion, a subs i u ion me hod is applied, eplacing measu emen s below he LOQ wi h hal he LOQ alue. Consequen ly, boxplo s may display boxes based on a ying hal -LOQ alues. I a single LOQ domina es he da ase , his may appea as a line a hal i s alue, while “ou lie s” in he plo may ep e- sen ei he hal -LOQ alues om less common LOQs, o ac ual measu emen s abo e LOQ. Ca e ul e alua- ion is necessa y when in e p e ing hese esul s, and i is ecommended o always conside he accompanying in o ma ion on he pe cen age o measu emen s abo e LOQ o each subs ance ha gi en in he boxplo s. Ne e heless, he combina ion o ROS and subs i u ion me hods is adop ed as i ensu es he mos unbiased and obus way o es ima e summa y s a is ics. Boxplo s ha e also been used o isualize he le els o he PFAS sum pa ame e s. The sums o he compounds o PFAS a e calcula ed acco ding o he EU D inking Wa e Di ec i e (DWD, 2020/2184) [33], which conside s he sum o 20 PFAS, and he p oposed En i onmen al Qual- i y S anda d Di ec i e (EQS, 2022) [30], which conside s he sum o 24 PFAS adjus ed o PFOA equi alen oxici y le els, espec i ely. I is impo an o no e ha only 17 o he 20 PFAS lis ed in DWD (2020) and 20 o he 24 PFAS lis ed in he p oposed EQS (2022) a e wi hin he scope o his s udy (Table1), and no all samples con ain measu e- men s o all lis ed PFAS. To a oid excessi e omissions, only samples ha con ain a leas 10 o he subs ances appea ing on bo h lis s a e included. Addi ionally, all alues below LOQ a e ea ed as ze o, as equi ed by egula ions, al hough his does no imply he absence o non-quan i iable concen a ions. To acili a e isualiza- ion on a loga i hmic scale, alues o he sum pa ame e s equal o ze o a e adjus ed o 0.0001 ng/l. This eplace- men ep esen s he minimum po en ial ue alue, cal- cula ed as he p oduc o he lowes LOQ and he lowes RPF among he PFAS compounds om he d a ed EQS. The e o e, he es ima es in he boxplo s ep esen he minimum likelihood o exceeding he h eshold le els. Due o he p opo ion o censo ed da a and he likeli- hood o non-no mal dis ibu ions, nonpa ame ic s a- is ical es s a e used o assess concen a ion di e ences be ween en i onmen al compa men s and sample ypes. The Wilcoxon signed ank es [130] is applied o pai - wise compa isons, while he K uskal–Wallis es [62] is used o mul i-g oup compa isons. I in ag oup di e - ences a e de ec ed, Dunn’s es [27] is pe o med o pos hoc pai wise analysis. The signi icance le el (p- alue) o all s a is ical es s is se a 0.05. All da a analyses we e pe o med wi h he s a is ical so wa e R ( 4.1.0)[105]. The ollowing R packages we e Page 7 o 20 Liue al. En i onmen al Sciences Eu ope (2025) 37:99 used o da a p ocessing: he odbc package [50] o da a- base impo , he idy e se collec ion [129] and he ggsci package [134] o da a manipula ion and isualiza ion, he NADA package [66] o he implemen a ion o he ROS me hod and he FSA package [94] o he Dunn es . Resul s anddiscussion PFAS occu ence A leas one PFAS compound lis ed in Table1 is p esen in 60% o all samples ( e e ed as ‘sample-le el de ec ion’ below). The PFCA and PFSA a e he mos equen ly de ec ed compound g oups, wi h sample-le el de ec- ions o 50% and 46%, espec i ely. This is ollowed by he FTS (11%) g oup. The de ec ion a es o he emain- ing g oups encompassed by his s udy a e all below 10%. Among indi idual compounds, PFOA exhibi s he high- es sample-le el de ec ion a e (40%), while o PFOS he le el is 33%. Excep o hese wo long-chain compounds, sho -chain compounds a e p edominan , comp ising PFBA (38%), PFBS (37%), PFHxA (36%), PFPeA (29%), PFHpA (27%) and PFHxS (23%). This obse a ion is consis en wi h global indings [85, 90, 101], and can be a ibu ed o he widesp ead dis i- bu ion and applica ion o hese sho -chain PFCA and PFSA compounds in he indus ial and comme cial ac i - i ies. Fu he mo e, hey a e he deg ada ion p oduc s o o he PFAS p ecu so compounds, and a e pe sis en in he en i onmen . In con as , he p esence o he o he subs ances is de ec ed in less han 20% o he samples. Speci ically, N-E FOSAA and N-E FOSE a e no de ec ed in any o he samples. As hese wo compounds ha e only limi ed ields o applica ion and a e epo ed wi h- ou con empo a y usage [41], i is possible ha bo h sub- s ances a e no p esen in he wa e en i onmen o UDB. Howe e , he de ec ion a es can a y signi ican ly by en i onmen al ma ix, as shown in o he c oss-com- pa men s udies om Eu ope [4] and he Uni ed S a es [46]. In ou s udy, among all leacha e and su ace uno samples, he a e wi h a leas one PFAS being de ec ed is 100%, ollowed by samples o was ewa e (98%), su ace wa e (83%), a mosphe ic deposi ion (73%) and g ound- wa e (50%). Figu e2 u he illus a es he a iabili y o dominan PFAS ac oss di e en sample ypes. The hea map p e- sen s measu emen -le el de ec ion o each subs ance- ype combina ion, which e e s o he de ec ion a e o measu emen s abo e LOQ o a speci ic compound, wi h nume ical da a p o ided in Supplemen a y Ma e- ials 3. Fo example, g oundwa e samples po en ially impac ed by AFFF applica ions o land ills ha e signi i- can ly highe de ec ions o many PFAS compounds com- pa ed o g oundwa e sample wi hou known sou ce o con amina ion. This could be explained by he ans e o PFAS om con amina ed lands o he g oundwa e [13, 19, 49]. To summa ize, he esul s o PFAS occu ences demon- s a e he widesp ead p esence o PFAS con amina ion, wi h no iceable di e ences obse ed ac oss en i onmen- al compa men s. Fu he mo e, a ia ions in de ec ions ac oss di e en ypes wi hin he same compa men s e eal he ela ionships be ween poin -sou ce emissions and con amina ion deg ees, as su ace wa e samples collec ed om ho spo egions o g oundwa e samples impac ed by con amina ed lands show clea ly highe de ec ions han o he s. PFAS spa ial dis ibu ion Su ace wa e Figu es3 and 4 illus a e he concen a ion dis ibu ions o commonly de ec ed PFAS in su ace wa e samples. The analysis includes he Alz Ri e , an indi ec ibu a y o he Danube ia he Inn, he main Danube a Vienna and Budapes , and o he Danube ibu a ies, which a e classi ied based on he p opo ion o ea ed was ewa e discha ges ela i e o hei o al annual i e discha ge. The Alz Ri e exhibi s a dis inc con amina ion pa - e n compa ed o o he su ace wa e g oups, pa icu- la ly o PFCAs and PFECAs. No only he de ec ions o hese compounds in Alz a e 100% o close o i , bu also hei concen a ions a e much highe , anging om hun- d eds o e en housands o nanog ams pe li e . Dunn’s es s con i m he obse a ion (Tables3), e ealing ha o selec ed PFCAs concen a ions in he Alz a e signi i- can ly highe han all he o he su ace wa e g oups. Fo PFECAs, he di e ences be ween he Alz and o he ib- u a y g oups a e signi ican , bu no o he Danube. Fo PFSAs, Alz does no exhibi highe concen a ions han he o he g oups. In con as , he le el o PFHxS is sig- ni ican ly lowe in he Alz compa ed o o he ibu a ies. The Gendo indus ial pa k is a ecognized con ami- na ion ho spo wi hin he Alz ca chmen . This a ea hos s se e al acili ies o he p oduc ion o plas ic and PFAS, some wi h a his o y o luo opolyme p oduc ion da ing back o he 1960s [29]. Repo s om he Ba a ian S a e O ice o he En i onmen indica e ex ensi e con amina- ion by PFOA in soils and g oundwa e o e an a ea o app oxima ely 230 km 2 nea Gendo [6, 13]. Acco ding o he local en i onmen al au ho i y [6], PFOA concen- a ions in he Alz Ri e we e epo ed a 5000–8000 ng/L in 2006, dec easing o below he LOQ o 20 ng/L by 2016. Howe e , ou esul s wi h samples collec ed om 2019 o 2023 show ha PFOA concen a ions in he Alz downs eam ange om 14 o 220 ng/L. This is simila o he indings o Joe ss e al. [54], who measu ed PFOA le - els a h ee si es downs eam o Gendo along he Alz in Page 8 o 20 Liue al. En i onmen al Sciences Eu ope (2025) 37:99 2018, epo ing concen a ions om 20 ng/L o 180 ng/L. Al hough PFOA p oduc ion a his si e was phased ou in 2008 [6], bo h ou s udy and Joe ss e al. [54] highligh he pe sis ence o legacy PFOA emissions om con ami- na ion in he su ounding soil and g oundwa e . Fo o he compounds, ou s udy obse es simila le - els o PFCA, PFSA and FTS compa ed o Joe ss e al. [54] in he Alz. Howe e , o GenX, ou measu ed mean concen a ion (38 ng/L) is much lowe han he p e i- ously epo ed 2600 ng/L. ADONA concen a ions ha e dec eased om a mean le el o 2100 ng/L o 1501 ng/L, s ill emaining a high le els. As eplacemen compounds o PFOA, ADONA and GenX ha e been de ec ed in su - ace wa e s in China, Eu ope, and No h Ame ica [96]. I is o pa icula in e es ha wi hin he UDB, he p esence o hese wo compounds is ound o be almos exclusi ely con ined o he Alz and he Danube sec ion downs eam o Alz. This inding p o ides s ong e idence ha he Gendo chemical pa k is a majo sou ce o hese speci ic PFAS con aminan s. P e ious s udies on PFAS con amina ion in he Dan- ube epo a e age PFOS concen a ions o 7 ng/L (2010) [73], 5.9 ng/L (2017) [74], and app oxima ely 2.1 ng/L (2023) [7], while ou s udy de ec s an a e age le el o 1.8 ng/L. Fo PFOA, his o ical a e age concen a- ions in he Danube a e 16.4 ng/L (2007) [79], 20 ng/L (2010) [73], 4.9 ng/L (2017)[74], and 2.8 ng/L (2023) [7], whe eas ou s udy inds an a e age le el o 2.3 ng/L. In gene al, a dec easing end is obse ed in PFOS and PFOA concen a ions a e hei g adual phase-ou and egula o y es ic ions, consis en wi h obse a ions in No h Ame ica [102]. Howe e , he pe sis ence o legacy con amina ion emains an issue due o he p o- longed use o PFOS-con aining p oduc s, he deg ada- ion and ans o ma ion o p ecu so compounds [68, 89], and he long en i onmen al esidence ime o long- chain PFAS [45]. Ou indings ela ed o he Gendo si e highligh how such ac o s con inue o con ibu e o con amina ion in he Danube. PFCA PFSA PFECA FTS FOSA FOSAA ESA FOSE PFBA PFPeA PFHxA PFHpA PFOA PFNA PFDA PFUdA PFDoDA PFT DA PFTeDA PFBS PFPeS PFHxS PFHpS PFOS PFNS PFDS GenX ADONA 4:2 FTS 6:2 FTS 8:2 FTS PFOSA N-MeFOSA N-E FOSA N-MeFOSAA N-E FOSAA 9Cl-PF3ONS 11Cl-PF3OUd S N-MeFOSE N-E FOSE Indus ial E luen Indus ial In luen Municipal E luen Municipal In luen Su ace Runo Land ill Leacha e G oundwa e Po en ially Impac ed by Land ills G oundwa e Po en ially Impac ed by AFFF Applica ions G oundwa e Wi hou Known Sou ce o Con amina ion Danube Bank- il e ed Wa e (Vienna and Budapes ) Main Danube (Vienna and Budapes ) T ibu a y Alz Danube T ibu a y A mosphe ic Deposi ion De ec ed Ra e (%) 020406080 100 Fig. 2 Hea map showing he measu emen ‑le el de ec ion a es o each PFAS subs ance–sample ype combina ions analyzed in his s udy. The X‑axis lis s he subs ance name, while he Y‑axis shows he sample ype. Da ke shades indica e highe de ec ions, as shown by he g adien colo ba om ligh ‑g ay o black (0–100%). The LOQ alues o each compound a e p o ided in Table s2 Page 9 o 20 Liue al. En i onmen al Sciences Eu ope (2025) 37:99 27 (100%), 38 (100%) 27 (100%), 38 (97%) 27 (100%), 38 (89%) 27 (96%), 38 (97%) 27 (100%), 38 (97%) 23 (43%), 38 (89%) 24 (29%), 38 (100%) 27 (81%), 38 (97%) 8 (100%), 38 (95%) 8 (100%), 38 (95%) 8 (12%), 38 (50%) 0.1 1 10 100 1000 10000 PFBA PFPeA PFHxA PFHpAPFOAPFBS PFHxS PFOS GenX ADONA6:2 FTS Concen a ion (ng/L) Sample Type T ibu a y Alz Main Danube (Vienna and Budapes ) LOQs Range Fig. 3 PFAS concen a ions on a loga i hmic scale o samples om Danube mains eam (Vienna and Budapes ) and i e Alz. Box in ed dashed ou line ep esen s he ange o LOQ alues among measu emen s; o di e en compounds, sample sizes and de ec ion abo e he LOQ (%) o each ype a e lis ed on op o he g aph, in a sequence o hei appea ance on he g aph. Values below LOQ a e semi‑quan i a i e 104 (23%), 587 (35%), 532 (48%) 110 (19%), 599 (15%), 546 (26%) 110 (25%), 598 (25%), 531 (39%) 110 (8%), 600 (8%), 546 (14%) 109 (15%), 605 (28%), 560 (34%) 110 (7%), 601 (16%), 546 (28%) 110 (14%), 601 (9%), 546 (22%) 110 (43%), 612 (60%), 564 (73%) 65 (0%), 118 (15%), 118 (2%) 65 (0%), 118 (36%), 118 (8%) 25 (24%), 60 (10%), 86 (33%) 0.1 1 10 100 1000 10000 PFBA PFPeA PFHxA PFHpAPFOAPFBS PFHxS PFOS GenX ADONA6:2 FTS Concen a ion (ng/L) LOQs Range Sample Type T ibu a y wi h Was ewa e Discha ge <1% T ibu a y wi h Was ewa e Discha ge 1-3% T ibu a y wi h Was ewa e Discha ge > 3% Fig. 4 PFAS concen a ions on a loga i hmic scale o samples om Danube ibu a ies classi ied in o h ee g oups acco ding o he p opo ion o was ewa e dilu ion. Box in ed dashed ou line ep esen s he ange o LOQ alues among measu emen s. Fo di e en compounds, sample sizes and de ec ion abo e he LOQ (%) o each ype a e lis ed on op o he g aph, in a sequence o hei appea ance on he g aph. Values below LOQ a e semi‑quan i a i e Page 16 o 20 Liue al. En i onmen al Sciences Eu ope (2025) 37:99 a e pa icula ly aluable o quan i ying and compa ing emissions h ough mul iple pa hways, especially di use emissions, which a e o en unde ep esen ed in compa - men -speci ic assessmen s. The compa a i e analysis highligh s key a eas ha equi e enhanced moni o ing e o s and u he e eals a iabili y in isk le els be ween en i onmen al compa men s, p o iding c ucial in o ma ion o p io - i ize esou ce alloca ion o mee en i onmen al quali y a ge s. Al hough his s udy ocuses on he UDB, PFAS con amina ion is a global conce n. The insigh s gained on he dis ibu ion o PFAS in ou s udy can con ibu e o a be e unde s anding o he pa e ns o con amina- ion, wi h implica ions o wa e managemen s a e- gies in o he i e sys ems acing simila challenges. Abb e ia ions 4:2 FTS 4:2 Fluo o elome sul onic acid 6:2 FTS 6:2 Fluo o elome sul onic acid 8:2 FTS 8:2 Fluo o elome sul onic acid AFFF Aqueous ilm‑ o ming oam ADONA 4,8‑Dioxa‑3H‑pe luo ononanoic acid DWD D inking Wa e Di ec i e EU Eu opean Union EIS Elec osp ay ioniza ion sou ce EQS En i onmen al Quali y S anda ds ESA E he sul onic acids FOSE Pe luo ooc ane sul onamide e hanols FOSA Pe luo ooc ane sul onamides FOSAA Pe luo ooc ane sul onamidoace ic acids FTCA Fluo o elome ca boxylic acids FTS Fluo o elome sul onic acids GenX Pe luo o‑2‑me hyl‑3‑oxahexanoic acid IQR In e qua ile ange LC–MS/MS Liquid ch oma og aphy– andem mass spec ome y LOQ Limi o quan i ica ion N‑E FOSA N‑E hylpe luo ooc ane sul onamide N‑E FOSAA 2‑(N‑E hylpe luo ooc anesul onamido)ace ic acid N‑E FOSE N‑E hyl‑N‑(2‑hyd oxye hyl)pe luo ooc anesul onamide N‑MeFOSA N‑Me hylpe luo ooc anesul onamide N‑MeFOSAA 2‑(N‑Me hylpe luo ooc anesul onamido)ace ic acid N‑MeFOSE N‑Me hyl‑N‑(2‑hyd oxye hyl)pe luo ooc anesul onamide PFAA Pe luo oalkyl acids PFBA Pe luo obu anoic acid PFBS Pe luo obu anesul onic acid PFCA Pe luo oalkyl ca boxylic acids PFDA Pe luo odecanoic acid PFDS Pe luo odecanesul onic acid PFHxA Pe luo ohexanoic acid PFHxS Pe luo ohexanesul onic acid PFHpA Pe luo ohep anoic acid PFHpS Pe luo ohep anesul onic acid PFOA Pe luo ooc anoic acid PFNA Pe luo ononanoic acid PFOS Pe luo ooc anesul onic acid PFPeA Pe luo open anoic acid PFPeS Pe luo open anesul onic acid PFT DA Pe luo o idecanoic acid PFTeDA Pe luo o e adecanoic acid PFUdA Pe luo oundecanoic acid PFOSA Pe luo ooc anesul onamide ROS Reg ession on o de s a is ics SPE Solid‑phase ex ac ion UDB Uppe Danube Basin WFD Wa e F amewo k Di ec i e WWTP Was ewa e ea men plan Supplemen a y In o ma ion The online e sion con ains supplemen a y ma e ial a ailable a h ps:// doi. o g/ 10. 1186/ s12302‑ 025‑ 01141‑6. Supplemen a y ma e ial 1. Supplemen a y ma e ial 2. Supplemen a y ma e ial 3. Acknowledgemen s Open access unding p o ided by TU Wien (TUW). The au ho s hank he wa e chemis y labo a o y o he TU Wien, especially he eam membe s Zd a ka Sa ace ic and Nedim Saho ic, o hei assis ance wi h he chemi‑ cal analysis. In addi ion, we acknowledge he con ibu ions o Elsa Ede and Se e in Os en, o hei assis ance du ing he sampling campaign. Au ho con ibu ions M.L.: da a cu a ion, o mal analysis, isualiza ion, w i ing—o iginal d a ; E.S.: me hodology, in es iga ion, w i ing— e iew and edi ing; T.J.O.: in es iga ion, esou ces; A.A.A.O.: in es iga ion, esou ces, w i ing— e iew and edi ing; Z.NK.: esou ces; B.L.: esou ces; S.K.: alida ion, w i ing— e iew and edi ing; O.Z.: alida ion, w i ing— e iew and edi ing; J.K.: w i ing— e iew and edi ing; J.D.: concep ualiza ion, me hodology, alida ion, w i ing— e iew and edi ing, supe ision, unding acquisi ion; M.Z.: concep ualiza ion, me hodology, alida‑ ion, w i ing— e iew and edi ing, supe ision, unding acquisi ion. Funding Open access unding p o ided by TU Wien (TUW). The esea ch leading o hese esul s has been suppo ed by he PROMISCES p ojec , unded by he Eu opean Union H2020 P og amme (H2020/2014‑2020) unde g an ag ee‑ men n ◦ 101036449. A ailabili y o da a and ma e ials The da ase gene a ed and analyzed du ing he cu en s udy is a ailable in he eposi o y [Pe - and Poly luo oalkyl Subs ance (PFAS) Concen a ions in he Uppe Danube Ca chmen : In eg a ed da a se om he H2020 P ojec PROMISCES—Case S udy 2],h ps:// doi. o g/ 10. 5281/ zenodo. 14027 087[71]. The R code suppo ing he da a analysis and compu a ional en i onmen al se up o he cu en s udy is a ailable in he Gi lab p ojec , [h ps:// gi lab. uwien. ac. a / meiqi. liu/ p omi sces_ cs2_ moni o ing]. Decla a ions E hics app o al and consen o pa icipa e No applicable. Consen o publica ion No applicable. Compe ing in e es s The au ho s decla e ha hey ha e no con lic o in e es . Au ho de ails 1 Ins i u e o Wa e Quali y and Resou ce Managemen , TU Wien, Vienna, Aus‑ ia. 2 Ins i u e o Hyd aulic Enginee ing and Wa e Resou ces Managemen , TU Wien, Vienna, Aus ia. 3 In e uni e si y Coope a ion Cen e Wa e and Heal h, ICC Wa e and Heal hh p://www.wa e andheal h.a . 4 Budapes Wa e wo ks L d., BUWW , Budapes , Hunga y. Recei ed: 2 Ap il 2025 Accep ed: 27 May 2025 Published: 15 June 2025 Re e ences 1. Acke man G un eld D, Gilbe D, Hou J e al (2024) Unde es ima ed bu den o pe ‑ and poly luo oalkyl subs ances in global su ace wa e s Page 17 o 20 Liue al. En i onmen al Sciences Eu ope (2025) 37:99 and g oundwa e s. Na Geosci 17(4):340–346. h ps:// doi. o g/ 10. 1038/ s41561‑ 024‑ 01402‑8 2. Ah ens L, Shoeib M, Ha ne T e al (2011) Was ewa e ea men plan and land ills as sou ces o poly luo oalkyl compounds o he a mos‑ phe e. En i on Sci Technol 45(19):8098–8105. h ps:// doi. o g/ 10. 1021/ es103 6173 3. Albe gamo V, Schollée JE, Schymanski EL e al (2019) Non a ge sc een‑ ing e eals ime ends o pola mic opollu an s in a i e bank il a ion sys em. En i on Sci Technol 53(13):7584–7594. h ps:// doi. o g/ 10. 1021/ acs. es . 9b017 50 4. Alygizakis NA, Besselink H, Paulus GK e al (2019) Cha ac e iza ion o was ewa e e luen s in he Danube Ri e Basin wi h chemical sc een‑ ing, in i o bioassays and an ibio ic esis an genes analysis. En i on In 127:420–429. h ps:// doi. o g/ 10. 1016/j. en in . 2019. 03. 060 5. Bǎlan SA, Meng Q (2021) PFAS in consume p oduc s: exposu es and egula o y app oaches. Fo e e chemicals: en i onmen al, economic, and social equi y conce ns wi h PFAS in he en i onmen , i s , edi ion. En i onmen al and occupa ional heal h se ies. CRC P ess, Boca Ra on, pp 51–87 6. Baye isches Landesam ü Umwel (2023) PFOA‑P oblema ik im Raum Gendo ‑ L U Baye n. h ps:// www. l u. baye n. de/ al la s en/ p oa_ gendo / index. h m. Accessed 08 Ma ch 2025 7. Beggs C, Mackie R, V ana B e al (2023) Es ima ion o pe ‑ and poly‑ luo oalkyl subs ances mass loads in he Danube Ri e using passi e sampling. Sci To al En i on 892:164458. h ps:// doi. o g/ 10. 1016/j. sci o en . 2023. 164458 8. Benskin JP, Li B, Ikonomou MG e al (2012) Pe ‑ and Poly luo oalkyl sub‑ s ances in land ill leacha e: pa e ns, ime ends, and sou ces. En i on Sci Technol 46(21):11532–11540. h ps:// doi. o g/ 10. 1021/ es302 471n 9. Bečano á J, Melymuk L, Voj a V e al (2016) Sc eening o pe luo oalkyl acids in consume p oduc s, building ma e ials and was es. Chemos‑ phe e 164:322–329. h ps:// doi. o g/ 10. 1016/j. chemo sphe e. 2016. 08. 112 10. Boi eux V, Dauchy X, Bach C e al (2017) Concen a ions and pa e ns o pe luo oalkyl and poly luo oalkyl subs ances in a i e and h ee d inking wa e ea men plan s nea and a om a majo p oduc ion sou ce. Sci To al En i on 583:393–400. h ps:// doi. o g/ 10. 1016/j. sci o en . 2017. 01. 079 11. B ase RA, Mullin EJ, Spink DC (2021) Legacy and eme ging pe ‑ and poly luo oalkyl subs ances: analy ical echniques, en i onmen al a e, and heal h e ec s. In J Mol Sci 22(3):995. h ps:// doi. o g/ 10. 3390/ ijms2 20309 95 12. B ielmann H, Döbe l G, Weiß S e al (2023) PFAS in Ös e eichs G und‑ wasse : Ve b ei ung. Ös e eichische Wasse ‑ und Ab allwi scha , Bew‑ e ung und Rolle on Al s ando en als po enzielle Quellen. h ps:// doi. o g/ 10. 1007/ s00506‑ 023‑ 00976‑8 13. B unn H, A nold G, Kö ne W e al (2023) PFAS: Fo e e chemicals— pe sis en , bioaccumula i e and mobile. Re iewing he s a us and he need o hei phase ou and emedia ion o con amina ed si es. En i on Sci Eu 35(1):20. h ps:// doi. o g/ 10. 1186/ s12302‑ 023‑ 00721‑8 14. Buck RC, F anklin J, Be ge U e al (2011) Pe luo oalkyl and poly luo o‑ alkyl subs ances in he en i onmen : e minology, classi ica ion, and o igins. In eg En i on Assess Manag 7(4):513–541. h ps:// doi. o g/ 10. 1002/ ieam. 258 15. Bundesminis e ü Land‑ und Fo s wi scha , Klima‑ und Umwel s‑ chu z, Regionen und Wasse wi scha (N.D.) Gewässe zus and‑ sübe wachungs e o dnung – GZÜV. h ps:// in o. bml. g . a / hemen/ wasse / wasse ‑ oes e eich/ wasse ech _ na io nal/ planu ng/ GZUEV. h ml. Accessed 25 Ma ch 2025 16. Busch J, Ah ens L, S u m R e al (2010) Poly luo oalkyl compounds in land ill leacha es. En i on Pollu 158(5):1467–1471. h ps:// doi. o g/ 10. 1016/j. en pol. 2009. 12. 031 17. Cali o nia S a e Wa e Quali y Con ol Boa d (2020) Pe ‑ and poly luo o‑ alkyl subs ances (PFAS) sampling guidelines o non‑d inking wa e . h ps:// www. wa e boa ds. ca. go / p as/ docs/ sep _ 2020_ p as_ sampl ing_ guide lines. pd . Accessed 08 Ma ch 2025 18. Capozzi SL, Leang AL, Rodenbu g LA e al (2023) PFAS in municipal land ill leacha e: occu ence, ans o ma ion, and sou ces. Chemos‑ phe e 334:138924. h ps:// doi. o g/ 10. 1016/j. chemo sphe e. 2023. 138924 19. Chen Y, Zhang H, Liu Y e al (2023) E alua ion o pe ‑ and poly luo o‑ alkyl subs ances (PFAS) in leacha e, gas condensa e, s o mwa e and g oundwa e a land ills. Chemosphe e 318:137903. h ps:// doi. o g/ 10. 1016/j. chemo sphe e. 2023. 137903 20. Ci y o Vienna (2006) Gene al wa e quali y in Vienna. h ps:// www. wien. g . a / engli sh/ en i onmen / wa e supply/ quali y/ quali y‑ gene al. h ml. Accessed 08 Ma ch 2025 21. Cla a M, Scha S, Weiss S e al (2008) Emissions o pe luo ina ed alkyla ed subs ances (PFAS) om poin sou ces–iden i ica ion o el‑ e an b anches. Wa e Sci Technol 58(1):59–66. h ps:// doi. o g/ 10. 2166/ ws . 2008. 641 22. Codling G, Yuan H, Jones PD e al (2020) Me als and PFAS in s o m‑ wa e and su ace uno in a semi‑a id Canadian ci y subjec o la ge a ia ions in empe a u e among seasons. En i on Sci Pollu Res 27(15):18232–18241. h ps:// doi. o g/ 10. 1007/ s11356‑ 020‑ 08070‑2 23. Cousins IT, DeWi JC, Glüge J e al (2020) The high pe sis ence o PFAS is su icien o hei managemen as a chemical class. En i on Sci P ocesses Impac s 22(12):2307–2312. h ps:// doi. o g/ 10. 1039/ D0EM0 0355G 24. Cu ell M, No hby N, Ne he way P (2024) Examining changes in g oundwa e PFAS con amina ion om legacy land ills o e a h ee‑ yea pe iod a Aus alia’s la ges u ban enewal si e. Chemosphe e 352:141345. h ps:// doi. o g/ 10. 1016/j. chemo sphe e. 2024. 141345 25. Deu sches Ins i u ü No mung (2008) DIN 32645:2008‑11, Chemis‑ che Analy ik‑ Nachweis‑, E assungs‑ und Bes immungsg enze un e Wiede holbedingungen_‑ Beg i e, Ve ah en, Auswe ung. h ps:// doi. o g/ 10. 31030/ 14654 13 26. Domingo JL, Nadal M (2019) Human exposu e o pe ‑ and poly luo o‑ alkyl subs ances (PFAS) h ough d inking wa e : a e iew o he ecen scien i ic li e a u e. En i on Res 177:108648. h ps:// doi. o g/ 10. 1016/j. en es. 2019. 108648 27. Dunne CW (1964) New ables o mul iple compa isons wi h a con ol. Biome ics 20(3):482–491. h ps:// doi. o g/ 10. 2307/ 25284 90 28. E iksson U, Haglund P, Kä man A (2017) Con ibu ion o p ecu so com‑ pounds o he elease o pe ‑ and poly luo oalkyl subs ances (PFASs) om was e wa e ea men plan s (WWTPs). J En i on Sci 61:80–90. h ps:// doi. o g/ 10. 1016/j. jes. 2017. 05. 004 29. ERM GmbH (2018) De ailun e suchung de PFOA‑ Belas ungen in Boden und G undwasse im Be eich Gendo . Abschlussbe ich Be ich N . 9, Dyneon GmbH, Bu gki chen. h ps://www.in ase .gendo .de/‑/ media/In e ne /chemiepa k_gendo _de/Downloads/Nachba scha / PFOA/20181212_Abschlussbe ich %20DU_PFOA_Gendo _Tex ‑ eil_ %20WEB.ashx?la=de‑DE. Accessed 12 May 2025 30. Eu opean Commission (2022) P oposal o a di ec i e amending he wa e amewo k di ec i e, he g oundwa e di ec i e and he En i‑ onmen al Quali y S anda ds di ec i e. h ps:// en i onmen . ec. eu opa. eu/ publi ca io ns/ p opo sal‑ amend ing‑ wa e ‑ di ec i es_ en. Accessed 08 Ma ch 2025 31. Eu opean En i onmen al Agency (2024) Wa e base ‑ UWWTD: Dis‑ cha ge poin s. h ps:// www. eea. eu opa. eu/ en/ da ah ub/ da ah ubi em‑ iew/ 21874 828‑ a7a‑ 4e7e‑ 8a0a‑ 52ec7 d92 9 9 . Accessed 08 Ma ch 2025 32. Eu opean Union (2013) Di ec i e 2013/39/EU o he Eu opean Pa lia‑ men and o he Council o 12 Augus 2013 amending di ec i es 2000/60/EC and 2008/105/EC as ega ds p io i y subs ances in he ield o wa e policy (Tex wi h EEA ele ance). h p:// da a. eu opa. eu/ eli/ di / 2013/ 39/ oj/ eng. Accessed 08 Ma ch 2025 33. Eu opean Union (2020) Di ec i e (EU) 2020/2184 o he Eu opean Pa liamen and o he Council o 16 Decembe 2020 on he quali y o wa e in ended o human consump ion ( ecas ) (Tex wi h EEA ele ance). h p:// da a. eu opa. eu/ eli/ di / 2020/ 2184/ oj/ eng. Accessed 08 Ma ch 2025 34. Eu opean Union (2024) Di ec i e (EU) 2024/3019 o he Eu opean Pa liamen and o he Council o 27 No embe 2024 conce ning u ban was ewa e ea men ( ecas ) (Tex wi h EEA ele ance). h p:// da a. eu opa. eu/ eli/ di / 2024/ 3019/ oj/ eng. Accessed 08 Ma ch 2025 35. Faus JA (2023) PFAS on a mosphe ic ae osol pa icles: a e iew. En i on Sci P ocess Impac s 25(2):133–150. h ps:// doi. o g/ 10. 1039/ D2EM0 0002D 36. Fiedle S, P is e G, Sch amm KW (2010) Poly‑ and pe luo ina ed compounds in household consume p oduc s. Toxicol En i on Chem 92(10):1801–1811. h ps:// doi. o g/ 10. 1080/ 02772 248. 2010. 491482 37. Gallen C, Eaglesham G, D age D e al (2018) A mass es ima e o pe luo oalkyl subs ance (PFAS) elease om Aus alian was ewa e Page 18 o 20 Liue al. En i onmen al Sciences Eu ope (2025) 37:99 ea men plan s. Chemosphe e 208:975–983. h ps:// doi. o g/ 10. 1016/j. chemo sphe e. 2018. 06. 024 38. Gao Y, Liang Y, Gao K e al (2019) Le els, spa ial dis ibu ion and isome p o iles o pe luo oalkyl acids in soil, g oundwa e and ap wa e a ound a manu ac o y in China. Chemosphe e 227:305–314. h ps:// doi. o g/ 10. 1016/j. chemo sphe e. 2019. 04. 027 39. Gebbink WA, an Asseldonk L, an Leeuwen SP (2017) P esence o eme ging pe ‑ and poly luo oalkyl subs ances (PFASs) in i e and d inking wa e nea a luo ochemical p oduc ion plan in he Ne he ‑ lands. En i on Sci Technol 51(19):11057–11065. h ps:// doi. o g/ 10. 1021/ acs. es . 7b024 88 40. Glo e CM, Quiñones O, Dickenson ERV (2018) Remo al o pe luo o‑ alkyl and poly luo oalkyl subs ances in po able euse sys ems. Wa e Res 144:454–461. h ps:// doi. o g/ 10. 1016/j. wa es. 2018. 07. 018 41. Glüge J, Sche inge M, Cousins IT e al (2020) An o e iew o he uses o pe ‑ and poly luo oalkyl subs ances (PFAS). En i on Sci P ocess Impac s 22(12):2345–2373. h ps:// doi. o g/ 10. 1039/ D0EM0 0291G 42. Gobelius L, Hedlund J, Dü ig W e al (2018) Pe ‑ and poly luo oalkyl subs ances in Swedish g oundwa e and su ace wa e : implica ions o En i onmen al Quali y S anda ds and d inking wa e guidelines. En i on Sci Technol 52(7):4340–4349. h ps:// doi. o g/ 10. 1021/ acs. es . 7b057 18 43. Gobelius L, Glims ed L, Olsson J e al (2023) Mass low o pe ‑ and poly luo oalkyl subs ances (PFAS) in a Swedish municipal was ewa e ne wo k and was ewa e ea men plan . Chemosphe e 336:139182. h ps:// doi. o g/ 10. 1016/j. chemo sphe e. 2023. 139182 44. Golo ko O, Ö n S, Sö engå d M e al (2021) Occu ence and emo al o chemicals o eme ging conce n in was ewa e ea men plan s and hei impac on ecei ing wa e sys ems. Sci To al En i on 754:142122. h ps:// doi. o g/ 10. 1016/j. sci o en . 2020. 142122 45. Hamid H, Li LY, G ace JR (2018) Re iew o he a e and ans o ma ion o pe ‑ and poly luo oalkyl subs ances (PFASs) in land ills. En i on Pollu 235:74–84. h ps:// doi. o g/ 10. 1016/j. en pol. 2017. 12. 030 46. Helme RW, Ree es DM, Cassidy DP (2022) Pe ‑ and poly luo ina ed alkyl subs ances (PFAS) cycling wi hin Michigan: con amina ed si es, land ills and was ewa e ea men plan s. Wa e Res 210:117983. h ps:// doi. o g/ 10. 1016/j. wa es. 2021. 117983 47. Helsel DR (2006) Fab ica ing da a: How subs i u ing alues o nonde‑ ec s can uin esul s, and wha can be done abou i . Chemosphe e 65(11):2434–2439. h ps:// doi. o g/ 10. 1016/j. chemo sphe e. 2006. 04. 051 48. Helsel DR (2012) S a is ics o censo ed en i onmen al da a using Mini ab and R, 2nd edn. Wiley Se ies in S a is ics in P ac ice. Wiley, Hoboken 49. Hepbu n E, Madden C, Szabo D e al (2019) Con amina ion o g ound‑ wa e wi h pe ‑ and poly luo oalkyl subs ances (PFAS) om legacy land‑ ills in an u ban e‑de elopmen p ecinc . En i on Pollu 248:101–113. h ps:// doi. o g/ 10. 1016/j. en pol. 2019. 02. 018 50. Hes e J, Wickham H, Gjoneski O, e al (2024) Odbc: Connec o ODBC compa ible da abases (using he DBI In e ace). h ps:// c an. ‑ p oje c . o g/ web/ packa ges/ odbc/ index. h ml. Accessed 08 Ma ch 2025 51. Hu XC, And ews DQ, Linds om AB e al (2016) De ec ion o poly‑ and pe luo oalkyl subs ances (PFASs) in U.S. d inking wa e linked o indus ial si es, mili a y i e aining a eas, and was ewa e ea men plan s. En i on Sci Technol Le 3(10):344–350. h ps:// doi. o g/ 10. 1021/ acs. es le . 6b002 60 52. ICPDR (2021) Join Danube Su ey 4: Scien i ic epo . Tech. ep., In e ‑ na ional Commission o he P o ec ion o he Danube Ri e . h ps:// www. icpd . o g/ si es/ de au l / iles/ nodes/ docum en s/ jds4_ scien i ic_ epo _ 20mb. pd 53. Indwa SP, Ghosh NC (2018) Ri e bank il a ion as a sus ainable solu‑ ion o d inking wa e quali y and quan i y p oblems in Ha idwa , U a‑ akhand. In: Singh VP, Yada S, Yada a RN (eds) G oundwa e . Sp inge , Singapo e, pp 179–193. h ps:// doi. o g/ 10. 1007/ 978‑ 981‑ 10‑ 5789‑2_ 14 54. Joe ss H, Sch amm TR, Sun L e al (2020) Pe ‑ and poly luo oalkyl subs ances in Chinese and Ge man i e wa e ‑ Poin sou ce‑ and coun y‑speci ic inge p in s including unknown p ecu so s. En i on Pollu 267:115567. h ps:// doi. o g/ 10. 1016/j. en pol. 2020. 115567 55. Ka dos MK, Clemen A, Jolánkai Z e al (2024) De elopmen and es ing o an e icien mic opollu an moni o ing s a egy ac oss a la ge wa e ‑ shed. Sci To al En i on 948:174760. h ps:// doi. o g/ 10. 1016/j. sci o en . 2024. 174760 56. Kim J, Xin X, Mamo BT e al (2022) Occu ence and a e o ul asho ‑ chain and o he pe ‑ and poly luo oalkyl subs ances (PFAS) in was ewa‑ e ea men plan s. ACS ES &T Wa e 2(8):1380–1390. h ps:// doi. o g/ 10. 1021/ acses wa e . 2c001 35 57. Kim Y, Pike KA, G ay R e al (2023) Non‑ a ge ed iden i ica ion and semi‑ quan i a ion o eme ging pe ‑ and poly luo oalkyl subs ances (PFAS) in US ainwa e . En i on Sci P ocess Impac s 25(11):1771–1787. h ps:// doi. o g/ 10. 1039/ D2EM0 0349J 58. Ki laus S, Cla a M, an Gils J e al (2022) Coupling a pa hway‑o ien ed app oach wi h ailo ‑made moni o ing as key o well‑pe o ming egionalized modelling o PFAS emissions and i e concen a ions. Sci To al En i on 849:157764. h ps:// doi. o g/ 10. 1016/j. sci o en . 2022. 157764 59. Ki laus S, Ka dos MK, Dudás KM e al (2024) A ha monized Danube basin‑wide mul i‑compa men concen a ion da abase o suppo in en o ies o mic opollu an emissions o su ace wa e s. En i on Sci Eu 36(1):1–21. h ps:// doi. o g/ 10. 1186/ s12302‑ 024‑ 00862‑4 60. Ko ho M, Mülle J, Jü ling H e al (2015) Pe luo oalkyl and poly‑ luo oalkyl subs ances in consume p oduc s. En i on Sci Pollu Res 22(19):14546–14559. h ps:// doi. o g/ 10. 1007/ s11356‑ 015‑ 4202‑7 61. K lo ic N, Sa ace ic E, De x J e al (2024) A sou ce‑based amewo k o es ima e he annual load o PFAS in municipal was ewa e . Sci To al En i on 920:170997. h ps:// doi. o g/ 10. 1016/j. sci o en . 2024. 170997 62. K uskal WH, Wallis WA (1952) Use o anks in one‑c i e ion a iance analysis. J Am S a Assoc 47(260):583–621. h ps:// doi. o g/ 10. 1080/ 01621 459. 1952. 10483 441 63. Ku wadka S, Dane J, Kanel SR e al (2022) Pe ‑ and poly luo oalkyl subs ances in wa e and was ewa e : a c i ical e iew o hei global occu ence and dis ibu ion. Sci To al En i on 809:151003. h ps:// doi. o g/ 10. 1016/j. sci o en . 2021. 151003 64. Lang JR, All ed BM, Field JA e al (2017) Na ional es ima e o pe ‑ and poly luo oalkyl subs ance (PFAS) elease o U.S. municipal land ill leacha e. En i on Sci Technol 51(4):2197–2205. h ps:// doi. o g/ 10. 1021/ acs. es . 6b050 05 65. Langbe g HA, A p HPH, Cas o G e al (2024) Recycling o pape , ca d‑ boa d and i s PFAS in No way. J Haza d Ma e Le 5:100096. h ps:// doi. o g/ 10. 1016/j. hazl. 2023. 100096 66. Lee L (2020) NADA: Nonde ec s and da a analysis o en i onmen al da a. h ps:// c an. ‑ p oje c . o g/ web/ packa ges/ NADA/ index. h ml. Accessed 08 Ma ch 2025 67. Lee L, Helsel D (2005) S a is ical analysis o wa e ‑quali y da a con ain‑ ing mul iple de ec ion limi s: S‑language so wa e o eg ession on o de s a is ics. Compu . Geosci. 31(10):1241–1248. h ps:// doi. o g/ 10. 1016/j. cageo. 2005. 03. 012 68. Lenka SP, Kah M, Padhye LP (2022) Occu ence and a e o poly‑ and pe luo oalkyl subs ances (PFAS) in u ban wa e s o New Zealand. J Haz‑ a d Ma e 428:128257. h ps:// doi. o g/ 10. 1016/j. jhazm a . 2022. 128257 69. Li B, Li LY, G ace JR (2015) Adso p ion and hyd aulic conduc i i y o land ill‑leacha e pe luo ina ed compounds in ben oni e ba ie mix‑ u es. J En i on Manage 156:236–243. h ps:// doi. o g/ 10. 1016/j. jen m an. 2015. 04. 003 70. Li J, Xi B, Zhu G e al (2023) A c i ical e iew o he occu ence, a e and ea men o pe ‑ and poly luo oalkyl subs ances (PFASs) in land ills. En i on Res 218:114980. h ps:// doi. o g/ 10. 1016/j. en es. 2022. 114980 71. Liu M (2024) Pe ‑ and poly luo oalkyl subs ances (PFAS) concen a ions in he uppe danube ca chmen : in eg a ed da ase om H2020 p ojec PROMISCES ‑ case s udy 2. h ps:// doi. o g/ 10. 5281/ zenodo. 14027 087. Accessed 08 Ma ch 2025 72. Liu Y, Ma L, Yang Q e al (2018) Occu ence and spa ial dis ibu ion o pe luo ina ed compounds in g oundwa e ecei ing eclaimed wa e h ough i e bank in il a ion. Chemosphe e 211:1203–1211. h ps:// doi. o g/ 10. 1016/j. chemo sphe e. 2018. 08. 028 73. Loos R, Loco o G, Con ini S (2010) Occu ence o pola o ganic con‑ aminan s in he dissol ed wa e phase o he Danube Ri e and i s majo ibu a ies using SPE‑LC‑MS2 analysis. Wa e Res 44(7):2325–2335. h ps:// doi. o g/ 10. 1016/j. wa es. 2009. 12. 035 74. Loos R, Ta azzi S, Ma iani G e al (2017) Analysis o eme ging o ganic con aminan s in wa e , ish and suspended pa icula e ma e (SPM) in he Join Danube Su ey using solid‑phase ex ac ion ollowed by UHPLC‑MS‑MS and GC‑MS analysis. Sci To al En i on 607–608:1201– 1212. h ps:// doi. o g/ 10. 1016/j. sci o en . 2017. 07. 039 Page 19 o 20 Liue al. En i onmen al Sciences Eu ope (2025) 37:99 75. Lu J, Lu H, Liang D e al (2023) A e iew o he occu ence, moni‑ o ing, and emo al echnologies o he emedia ion o pe ‑ and poly luo oalkyl subs ances (PFAS) om land ill leacha e. Chemosphe e 332:138824. h ps:// doi. o g/ 10. 1016/j. chemo sphe e. 2023. 138824 76. Maeng SK, Ameda E, Sha ma SK e al (2010) O ganic mic opollu an emo al om was ewa e e luen ‑impac ed d inking wa e sou ces du ing bank il a ion and a i icial echa ge. Wa e Res 44(14):4003– 4014. h ps:// doi. o g/ 10. 1016/j. wa es. 2010. 03. 035 77. Masone JR, Kolpin DW, Cozza elli IM e al (2020) Land ill leacha e con‑ ibu es pe ‑/poly‑ luo oalkyl subs ances (PFAS) and pha maceu icals o municipal was ewa e . En i on Sci Wa e Res Technol 6(5):1300–1311. h ps:// doi. o g/ 10. 1039/ D0EW0 0045K 78. Massmann G, Knappe A, Rich e D e al (2004) In es iga ing he in lu‑ ence o ea ed sewage on g oundwa e and su ace wa e using was ewa e indica o s in Be lin, Ge many. Ac a hyd ochimica e hyd o‑ biologica 32(4–5):336–350. h ps:// doi. o g/ 10. 1002/ aheh. 20040 0543 79. McLachlan MS, Holms öm KE, Re h M e al (2007) Ri e ine discha ge o pe luo ina ed ca boxyla es om he Eu opean con inen . En i on Sci Technol 41(21):7260–7265. h ps:// doi. o g/ 10. 1021/ es071 471p 80. McMahon PB, Tok ano AK, Bex ield LM e al (2022) Pe luo oalkyl and poly luo oalkyl subs ances in g oundwa e used as a sou ce o d inking wa e in he eas e n Uni ed S a es. En i on Sci Technol 56(4):2279–2288. h ps:// doi. o g/ 10. 1021/ acs. es . 1c047 95 81. Michigan PFAS Ac ion Response Team (2018) PFAS sampling guidance. h ps:// www. michi gan. go / p as espon se/ in es iga ions/ sampl ing‑ guida nce. Accessed 08 Ma ch 2025 82. Mo okeng NN, Madikizela LM, Tiggelman I e al (2024) De e mina ion o pe ‑ and poly luo oalkyl compounds in pape ecycling g ades using ul a‑high‑pe o mance liquid ch oma og aphy‑high‑ esolu ion mass spec ome y. En i on Sci Pollu Res 31(20):30126–30136. h ps:// doi. o g/ 10. 1007/ s11356‑ 024‑ 33250‑9 83. Mone a BG, Feo ML, To e M e al (2023) Occu ence o pe ‑ and poly luo ina ed alkyl subs ances in was ewa e ea men plan s in No he n I aly. Sci To al En i on 894:165089. h ps:// doi. o g/ 10. 1016/j. sci o en . 2023. 165089 84. Mülle CE, Spiess N, Ge ecke AC e al (2011) Quan i ying di use and poin inpu s o pe luo oalkyl acids in a nonindus ial i e ca chmen . En i on Sci Technol 45(23):9901–9909. h ps:// doi. o g/ 10. 1021/ es202 140e 85. Munoz G, Gi audel JL, Bo a F e al (2015) Spa ial dis ibu ion and pa i ioning beha io o selec ed poly‑ and pe luo oalkyl subs ances in eshwa e ecosys ems: A F ench na ionwide su ey. Sci To al En i on 517:48–56. h ps:// doi. o g/ 10. 1016/j. sci o en . 2015. 02. 043 86. Nagy‑Ko ács Z, László B, Flei E e al (2018) Beha io o o ganic mic o‑ pollu an s du ing i e bank il a ion in Budapes , Hunga y. Wa e 10(12):1861. h ps:// doi. o g/ 10. 3390/ w1012 1861 87. Ng C, Cousins IT, DeWi JC e al (2021) Add essing u gen ques ions o PFAS in he 21s cen u y. En i on Sci Technol 55(19):12755–12765. h ps:// doi. o g/ 10. 1021/ acs. es . 1c033 86 88. Ng K, Alygizakis N, And oulakakis A e al (2022) Ta ge and suspec sc eening o 4777 pe ‑ and poly luo oalkyl subs ances (PFAS) in i e wa e , was ewa e , g oundwa e and bio a samples in he Danube Ri e Basin. J Haza d Ma e 436:129276. h ps:// doi. o g/ 10. 1016/j. jhazm a . 2022. 129276 89. Nguyen HT, Kase zon SL, Thai PK e al (2019) Tempo al ends o pe ‑ and poly luo oalkyl subs ances (PFAS) in he in luen o wo o he la g‑ es was ewa e ea men plan s in Aus alia. Eme ging Con aminan s 5:211–218. h ps:// doi. o g/ 10. 1016/j. emcon. 2019. 05. 006 90. Nguyen MA, Wibe g K, Ribeli E e al (2017) Spa ial dis ibu ion and sou ce acing o pe ‑ and poly luo oalkyl subs ances (PFASs) in su ace wa e in no he n Eu ope. En i on Pollu 220:1438–1446. h ps:// doi. o g/ 10. 1016/j. en pol. 2016. 10. 089 91. Nguyen VT, Reinha d M, Ka ina GYH (2011) Occu ence and sou ce cha ac e iza ion o pe luo ochemicals in an u ban wa e shed. Chem‑ osphe e 82(9):1277–1285. h ps:// doi. o g/ 10. 1016/j. chemo sphe e. 2010. 12. 030 92. Nickel JP, Sache F, Fuchs S (2021) Da ase o mic opollu an concen a‑ ions and s anda d wa e quali y pa ame e s in was ewa e ea men plan s, combined sewe o e lows, and s o mwa e ou alls in Ge many. h ps:// doi. o g/ 10. 35097/ 449 93. Obeid AAA, Oudega TJ, Zoboli O e al (2023) The occu ence and pe sis ence o PFAS a i e bank il a ion si es in he Uppe Danube Basin. Oes e Wasse Ab allwi sch 75(9–10):515–527. h ps:// doi. o g/ 10. 1007/ s00506‑ 023‑ 00974‑w 94. Ogle DH, Doll JC, Wheele AP, e al (2025) FSA: simple ishe ies s ock assessmen me hods. h ps:// c an. ‑ p oje c . o g/ web/ packa ges/ FSA/ index. h ml. Accessed 08 Ma ch 2025 95. Pan CG, Liu YS, Ying GG (2016) Pe luo oalkyl subs ances (PFASs) in was ewa e ea men plan s and d inking wa e ea men plan s: emo al e iciency and exposu e isk. Wa e Res 106:562–570. h ps:// doi. o g/ 10. 1016/j. wa es. 2016. 10. 045 96. Pan Y, Zhang H, Cui Q e al (2018) Wo ldwide dis ibu ion o no el pe luo oe he ca boxylic and sul onic acids in su ace wa e . En i on Sci Technol 52(14):7621–7629. h ps:// doi. o g/ 10. 1021/ acs. es . 8b008 29 97. Panie i E, Ba alic K, Djukic‑Cosic D e al (2022) PFAS molecules: a majo conce n o he human heal h and he en i onmen . Toxics 10(2):44. h ps:// doi. o g/ 10. 3390/ oxic s1002 0044 98. Pasecnaja E, Ba ke ics V, Zacs D (2022) Occu ence o selec ed pe ‑ and poly luo ina ed alkyl subs ances (PFASs) in ood a ailable on he Eu o‑ pean ma ke ‑ A e iew on le els and human exposu e assessmen . Chemosphe e 287:132378. h ps:// doi. o g/ 10. 1016/j. chemo sphe e. 2021. 132378 99. P o enhaue D, Selle s E, Olson M e al (2022) PFAS concen a ions and deposi ion in p ecipi a ion: an in ensi e 5‑mon h s udy a na ional a mosphe ic deposi ion p og am ‑ na ional ends si es (NADP‑NTN) ac oss Wisconsin, USA. A mos En i on 291:119368. h ps:// doi. o g/ 10. 1016/j. a mos en . 2022. 119368 100. Phong Vo HN, Ngo HH, Guo W e al (2020) Poly‑and pe luo oalkyl subs ances in wa e and was ewa e : a comp ehensi e e iew om sou ces o emedia ion. J Wa e P ocess Eng 36:101393. h ps:// doi. o g/ 10. 1016/j. jwpe. 2020. 101393 101. Pigno i E, Casas G, Llo ca M e al (2017) Seasonal a ia ions in he occu ence o pe luo oalkyl subs ances in wa e , sedimen and ish samples om Eb o Del a (Ca alonia, Spain). Sci To al En i on 607–608:933–943. h ps:// doi. o g/ 10. 1016/j. sci o en . 2017. 07. 025 102. Podde A, Sadmani AA, Reinha D e al (2021) Pe and poly‑ luo oalkyl subs ances (PFAS) as a con aminan o eme ging conce n in su ace wa e : a ansbounda y e iew o hei occu ences and oxici y e ec s. J Haza d Ma e 419:126361. h ps:// doi. o g/ 10. 1016/j. jhazm a . 2021. 126361 103. P e o P, Po cel‑Rod iguez E, Ma ino D e al (2021) Pe ‑ and poly luo o‑ alkyl subs ances (PFAS) o possible conce n in he aqua ic en i onmen . Publica ions O ice o he Eu opean Union, Luxembou g 104. QGIS.o g (2025) QGIS geog aphic in o ma ion sys em. QGIS Associa ion. h ps:// www. qgis. o g/. Accessed 08 Ma ch 2025 105. R Co e Team (2025) R: The R p ojec o s a is ical compu ing. h ps:// www. ‑ p oje c . o g/. Accessed 08 Ma ch 2025 106. Ray C, G ischek T, Hubbs S, e al (2008) Ri e bank il a ion o d inking wa e supply. In: Encyclopedia o hyd ological sciences. Wiley. h ps:// doi. o g/ 10. 1002/ 04708 48944. hsa305 107. Rich e o á D, Go a s E, Fábelo á L e al (2023) PFAS le els and de e ‑ minan s o a iabili y in exposu e in Eu opean eenage s: esul s om he HBM4EU aligned s udies (2014–2021). In J Hyg En i on Heal h 247:114057. h ps:// doi. o g/ 10. 1016/j. ijheh. 2022. 114057 108. Saha B, A eia M, Tolayma T e al (2024) The unique dis ibu ion pa e n o PFAS in land ill o ganics. J Haza d Ma e 479:135678. h ps:// doi. o g/ 10. 1016/j. jhazm a . 2024. 135678 109. Sal a o e D, Mok K, Ga e KK e al (2022) P esump i e con amina ion: a new app oach o PFAS con amina ion based on likely sou ces. En i‑ on Sci Technol Le 9(11):983–990. h ps:// doi. o g/ 10. 1021/ acs. es le . 2c005 02 110. Schae e CE, Hoope JL, S om LE e al (2023) Occu ence o quan i ia‑ ble and semi‑quan i iable poly‑ and pe luo oalkyl subs ances in uni ed s a es was ewa e ea men plan s. Wa e Res 233:119724. h ps:// doi. o g/ 10. 1016/j. wa es. 2023. 119724 111. Schepens MAA, e Biesebeek JD, Ha mann J, e al (2023) Risk assess‑ men o exposu e o PFAS h ough ood and d inking wa e in he Ne he lands. Tech. ep., Rijksins i uu oo Volksgezondheid en Milieu RIVM. h ps:// doi. o g/ 10. 21945/ RIVM‑ 2023‑ 0011 112. Sha ma BM, Bha a GK, Tayal S e al (2016) Pe luo oalkyl subs ances (PFAS) in i e and g ound/d inking wa e o he Ganges Ri e basin: Page 20 o 20 Liue al. En i onmen al Sciences Eu ope (2025) 37:99 emissions and implica ions o human exposu e. En i on Pollu 208:704–713. h ps:// doi. o g/ 10. 1016/j. en pol. 2015. 10. 050 113. Shi Y, Ves e g en R, Xu L e al (2015) Cha ac e izing di ec emissions o pe luo oalkyl subs ances om ongoing luo opolyme p oduc ion sou ces: a spa ial end s udy o Xiaoqing Ri e , China. En i on Pollu 206:104–112. h ps:// doi. o g/ 10. 1016/j. en pol. 2015. 06. 035 114. Sil e M, Phelps W, Masa ik K e al (2023) P e alence and sou ce acing o PFAS in shallow g oundwa e used o d inking wa e in Wisconsin, USA. En i on Sci Technol 57(45):17415–17426. h ps:// doi. o g/ 10. 1021/ acs. es . 3c028 26 115. Sims JL, S oski KM, Kim S e al (2022) Global occu ence and p obabilis‑ ic en i onmen al heal h haza d assessmen o pe ‑ and poly luo oalkyl subs ances (PFASs) in g oundwa e and su ace wa e s. Sci To al En i on 816:151535. h ps:// doi. o g/ 10. 1016/j. sci o en . 2021. 151535 116. Sonne C, Jenssen BM, Rinklebe J e al (2023) EU need o p o ec i s en i onmen om oxic pe ‑ and poly luo oalkyl subs ances. Sci To al En i on 876:162770. h ps:// doi. o g/ 10. 1016/j. sci o en . 2023. 162770 117. S ockholm Con en ion (2024) S ockholm Con en ion on pe sis en o ganic pollu an s (POPs). h ps:// chm. pops. in / Imple men a ion/ Indus ial POPs/ PFAS/ O e iew/ abid/ 5221/ De au l . aspx. Accessed 08 Ma ch 2025 118. Sun S, Liang M, Fan D e al (2024) Occu ence and p o iles o pe ‑ luo oalkyl subs ances in was ewa e s o chemical indus ial pa ks and ecei ing i e wa e s: Implica ions o he en i onmen al impac o was ewa e discha ge. Sci To al En i on 945:173993. h ps:// doi. o g/ 10. 1016/j. sci o en . 2024. 173993 119. Sunde land EM, Hu XC, Dassuncao C e al (2019) A e iew o he pa h‑ ways o human exposu e o poly‑ and pe luo oalkyl subs ances (PFASs) and p esen unde s anding o heal h e ec s. J Exposu e Sci En i on Epidemiol 29(2):131–147. h ps:// doi. o g/ 10. 1038/ s41370‑ 018‑ 0094‑1 120. Tang J, Zhang Y, Sun J e al (2019) Occu ence and cha ac e is ics o pe luo oalkyl subs ances (PFASs) in elec opla ing indus ial was ewa‑ e . Wa e Sci Technol 79(4):731–740. h ps:// doi. o g/ 10. 2166/ ws . 2019. 092 121. Ta asoli E, Luek JL, Malley JP e al (2021) Dis ibu ion and a e o pe ‑ and poly luo oalkyl subs ances (PFAS) in was ewa e ea men acili ies. En i on Sci P ocess Impac s 23(6):903–913. h ps:// doi. o g/ 10. 1039/ D1EM0 0032B 122. Tolayma T, Robey N, K ause M e al (2023) A c i ical e iew o pe ‑ luo oalkyl and poly luo oalkyl subs ances (PFAS) land ill disposal in he Uni ed S a es. Sci To al En i on 905:167185. h ps:// doi. o g/ 10. 1016/j. sci o en . 2023. 167185 123. Uhl M, Schoe e s G, Go a s E e al (2023) PFASs: Wha can we lea n om he Eu opean Human Biomoni o ing Ini ia i e HBM4EU. In J Hyg En i on Heal h 250:114168. h ps:// doi. o g/ 10. 1016/j. ijheh. 2023. 114168 124. Ul ich H, Mache ius A, Kunkel U e al (2024) No el PFAS‑speci ic moni‑ o ing app oach o highly impac ed su ace wa e s. Chemosphe e 349:140893. h ps:// doi. o g/ 10. 1016/j. chemo sphe e. 2023. 140893 125. Uni ed S a es En i onmen al P o ec ion Agency (2024) Final PFAS na ional p ima y d inking wa e egula ion. h ps:// www. epa. go / sys‑ em/ iles/ docum en s/ 2024‑ 04/ d ink ing‑ wa e ‑ u ili ies‑ and‑ p o e ssion als‑ echn ical‑ o e iew‑ o ‑ p as‑ npdw . pd . Accessed 08 Ma ch 2025 126. Uni ed S a es En i onmen al P o ec ion Agency (2024) Me hod 1633 analysis o pe ‑ and poly luo oalkyl subs ances (PFAS) in aqueous, solid, biosolids, and issue samples by LC‑MS/MS. h ps:// www. epa. go / sys em/ iles/ docum en s/ 2024‑ 01/ me hod‑ 1633‑ inal‑ o ‑ web‑ pos i ng. pd . Accessed 08 Ma ch 2025 127. Wacke LP (2024) E olu iona y obs acles and no C ‑ F bond s eng h make PFAS pe sis en . Mic ob Bio echnol 17(4):e14463. h ps:// doi. o g/ 10. 1111/ 1751‑ 7915. 14463 128. Wang B, Yao Y, Wang Y e al (2022) Pe ‑ and poly luo oalkyl subs ances in ou doo and indoo dus om Mainland China: con ibu ions o unknown p ecu so s and implica ions o human exposu e. En i on Sci Technol 56(10):6036–6045. h ps:// doi. o g/ 10. 1021/ acs. es . 0c082 42 129. Wickham H, RS udio (2023) Tidy e se: easily ins all and load he ’Tidy e se’. h ps:// c an. ‑ p oje c . o g/ web/ packa ges/ idy e se/ index. h ml. Accessed 08 Ma ch 2025 130. Wilcoxon F (1945) Indi idual compa isons by anking me hods. Biome ‑ ics Bull. 1(6):80–83. h ps:// doi. o g/ 10. 2307/ 30019 68 131. Williamson DF, Pa ke RA, Kend ick JS (1989) The box plo : a simple isual me hod o in e p e da a. Ann In e n Med 110(11):916–921. h ps:// doi. o g/ 10. 7326/ 0003‑ 4819‑ 110‑ 11‑ 916 132. Xiao F, Halbach TR, Simcik MF e al (2012) Inpu cha ac e iza ion o pe luo oalkyl subs ances in was ewa e ea men plan s: sou ce disc imina ion by explo a o y da a analysis. Wa e Res 46(9):3101–3109. h ps:// doi. o g/ 10. 1016/j. wa es. 2012. 03. 027 133. Xiao F, Simcik MF, Gulli e JS (2012) Pe luo oalkyl acids in u ban s o mwa e uno : in luence o land use. Wa e Res 46(20):6601–6608. h ps:// doi. o g/ 10. 1016/j. wa es. 2011. 11. 029 134. Xiao N, Cook J, Jégousse C, e al (2024) ggsci: Scien i ic jou nal and Sci‑ Fi hemed colo pale es o ’ggplo 2’. h ps:// c an. ‑ p oje c . o g/ web/ packa ges/ ggsci/ index. h ml. Accessed 08 Ma ch 2025 135. Yao Y, Chang S, Sun H e al (2016) Neu al and ionic pe ‑ and poly luo o‑ alkyl subs ances (PFASs) in a mosphe ic and d y deposi ion samples o e a sou ce egion (Tianjin, China). En i on Pollu 212:449–456. h ps:// doi. o g/ 10. 1016/j. en pol. 2016. 02. 023 Publishe ’s No e Sp inge Na u e emains neu al wi h ega d o ju isdic ional claims in pub‑ lished maps and ins i u ional a ilia ions.