Illinois EPA Notifies Dupo Water System of PFOS Detection

January 14, 2026 K im Biggs, Il linois EP A FOR IMMEDIA TE RELEASE 217 -558- 1536 kim.bigg s @illinois.gov Illinois EP A Noti fies Village of Dupo and Co nnected W ater Systems of Right- to -Know Requirements T rig ger ed by Recent Sampling PF AS Chemical Det ected in Grou ndwat er; System Owner s/Oper ators, Priva te W ell Owners, and all Re sidents ar e Encour aged to be Pr oactive in Reducing PF AS Exposur e Springfield – The Illinois Environmental Pr otection Agency (Illinois EP A) is notif ying the owners and oper ators o f the Dupo Community W ater System (CWS) that there has been a detection of perfluoroocta nesulf oni c acid (PFOS), a P er - and P olyfluoroalkyl Subs tances (PF AS) compound, in the most r ecent water sampling requir ed by the U. S. Environm ental Protection Agency (U. S. EP A) under the Fifth Unr egulated Contaminant Monitoring Rule (UCMR 5). The s ampl e identified PFOS at 4.5 parts per trillion (ppt), which is above the f ederal Maximum Co ntaminant Level (MCL) and the Illinois Class I ground water qu ality standard of 4 ppt. The Illinois EP A is also not if ying owners and oper ator s of two sys tems, Columbia CWS and Pr airie du P ont P u blic W ater District, which can obtain wa ter from the Dupo CWS through an emergency connection. The Illinois Envir onmental Protect ion Act requir es the o wners or oper ators of CWSs to notif y their customer s when groundwater cont a mination poses a t hrea t of e xposure to the public above the Clas s I ground water qu ality standards. Notific ation may be made b y mail, email, post card, t ext mes sage, or telephone within fiv e business day s of offici al receipt of the Il linois EP A ’ s notice. Within seven days of sending the notices, the owners or oper ators of the CWS must pr ovide the Illinois EP A with written pr oof that the notice s have been sent. “Right- to -Know laws were dev eloped to ensure the public is informed when contam ination poses a t hreat of e xposur e, ” said Illino is EP A Acting Directo r James Jennings. “While this notic e applies to specific locatio ns, Il linois EP A encour ages al l residents to tak e steps to reduce e xposure to PFAS compounds. ” PF AS are a gr oup of sever al thousand human-made chemicals that are manuf actured f or their oil and water -r esistant properties. Since the 1940s, PF AS have been used in a wide r ange of consumer pr oducts, industri al proces ses, and in s ome fire-fighting foams (cal led aqueous film-forming foam or AFFF). This has re sulted in PF AS being released int o the air, water, and soil. PF AS do not easily br eak down under na tural - mor e -

Right to Kno w/D upo/2 conditions and ar e of ten ref erred to as “for ever chemic als. ” Attached are copies of the P ublic Health Notices being pro vided to the CWSs, which includes inf ormation on potential health effects, home water filter tr eatment options, and ways to m inimize PFAS e xposure fr om other sourc es. Illinois has been among t he most pr oactive sta tes in the country in developing and implementing PF AS health standar ds and groundwater qu ality standards, in or der to prot e ct its re s idents. Il linois EP A has iss ued PF AS Health Advisories to pr ovide guidance to local officials and CWS oper ator s in protecting the health of wa ter consumers, and calculate s health based guidance lev els (HBGLs) which r epresent the concentr ations in drinking water a t whi ch no adver se health effects ar e expected to occur. In 2025, Illinois adopted g roundwater quality standar ds for six PF AS, based o n the most r ecent scientific informa tion available. Those inc lude perfluoro octanoic acid (PFO A), PFOS, he xafluoroprop yle ne oxide dimer acid, also kno wn as GenX (HFPO-DA), perfluor ohexanesulf onic acid (PFHxS), pefluorononanoic acid (PFNA), and perfluorobutane sulfonic acid (PFBS). U. S. EP A r ecently set MCLs, which are feder al drinking wa ter standar d s, f or certain PF AS, r equiring CWSs to sample for and com ply with the feder a l MCLs for PF AS by April 2029. All residents may be at risk from PFAS exposure. PFAS are stable, persistent chemicals and will bioaccumulate in blood and organs over time. Current scientific literature indicates that people are primarily exposed to PFAS through the ingestion of food and water, including: • ingestion of contaminated food and water, including food packaged in containers or wrappers containing PFAS. • hand - to -mouth contact with products treated with PFAS (such as carpets and textiles) or products that contain PFAS (such as paints, and cosmetics). • incidental ingestion of household dust. CWSs, private well owners, and residents are encouraged to be proactive in addr es sing potential PFAS contamination, not only in drinking water, but through the o ther common routes of exposure. Ways to reduce exposure include: • Choose stainless steel, cast iron, or non-stick cookware that does not contain PFAS. • Avoid water repellents on clothing. • Use personal care products without “PTFE” or “Fluoro” ingredients. • Use water filters designed to remove PFAS (NSF/ANSI 53 or 58 standards). In addition, the Illinois Department of Public Health (IDPH) encourages private well owners near the impacted water systems to test their water for PFAS or consider installing treatment, such as activated carbon filters, on drinking water faucets. "When elevated levels of contaminants are found in drinking water supplies, it is important for nearby private well owners to take appropriate precautions," said IDPH Director Dr. Sameer Vohra. "IDPH's Division of Environmental Health is available to assist private well owners in finding an accredited laboratory and evaluating test results." - mor e -

Right to Kno w/D upo/3 Priva te wel l owner s wh o have health-r elated questions or requir e technical assis tance can contact ID PH by phone at (217) 782-5830 or by email at dph. t ox@Il linois.gov. The notice provided to CWS will be posted on the Illinois EPA website at: https://epa.illinois.gov/topics/drinking-water/public-water-users/notices.html. More information regarding PFAS, including health effects and additional ways to reduce exposure, is available on the Illinois EPA PFAS webpage at https://epa.illinois.gov/topics/water-quality/pfas.html. Additional information can be found on the Agency for Toxic Substances and Disease Registry website at: https://www.atsdr.cdc.gov/pfas/. The IDPH provides additional information on PFAS in drinking water at: https://dph.illinois.gov/topics-services/environmental-health-protection/private-wa ter/fact-sheets/pfas- drinking-water.html. ### Attachment: P ublic Health Notices

PU B LIC H EAL TH NO TICE – IMPOR T ANT INF ORMA TION ABOUT YO U R DRINKING W AT E R Why Yo u ’ r e Receiving This Notice P erfluorooctanesulfonic acid (PFOS), a P e r - a nd P olyflu oroalkyl Substances (PF AS) compound, has bee n de tected in t he Dup o Community W at er System at a level that e xceeds the groundwa ter quality standard established by the State of Illinois. This notic e is requir ed by law under the Illinois Environmental Prot ecti on Act and the G roundwater Pr otection Act. The inf ormatio n is summariz ed below: • PFAS Compou nd: PFO S • Detect ed Level: 4.5 part s per trillion • Illinois Standard: 4 parts per tril lion What A re PF AS? P FA S a re human - ma de chem icals used since the 19 40s. Beca use they repel oil a nd water and re sist heat, they ar e c omm only found in products such as non - stick coo kwar e, foo d packaging, waterproo f clothin g, stain - re s ista nt furni ture, and firefight ing foam. P FA S po llute water through spills, leak s, and disposa l of products. They a re ofte n call ed “for ever chemicals ” because they remain i n the e nvironment for decades. Health Risks L ong - t e r m ex p os u re t o P FAS may incr ease the risk o f: • Ferti lity pr oblems and high blood pres sure during pregnancy • Development al im pac ts in c hild ren • Certai n cancer s, including ki dney, prosta te, and t esti cu la r • A w eak ened immun e sy st em • Disrupt ion to key hormonal systems, such as thyroid functio n, reproductive hormo nes, stress response, an d metabolic regu lation

Exposure does not guarant ee health prob lems. Ris k depends on the PF AS level and how l ong you’ve b een exposed. Consult your hea lthcare provid er for health concern s. Reducing PF AS in Y our Drin king W ater Boiling water does not remove PF AS, but certain water filter s can reduce or remove them. With many filters on the market, it’ s important to c hoose one that is specifically certified to remove or reduce PF AS. F ilters vary by type, br an d, an d installati on meth od — such as pitcher filter s, fau c et - mounted units, or whole - hom e syst ems. Belo w are types of filters shown to effectively red uce or remov e PFAS levels: • Cha rc o al (Granul ar A ctivated Carbo n or G AC) – traps chemicals as water flows through • Reverse Os mosis (RO) S ys tem s – filters out pollutants using a thin m embr ane • Ion Exchange Resins – t iny beads that a ttr act and hold con tami na nts Check for Certifica tion Use filters that meet National Sani tation Foundation/ A meri can National Sta ndards Instit ute (NSF / ANS I) stan dards, speci fically NSF / A NSI 53 (for r educi ng health - rel ated co ntam in ants, including P F AS) or NSF / ANS I 5 8 (for reverse osm osis systems). Y ou ca n verify certifica tion at: https://info.ns f.or g/Ce rt ified/ dwtu/. Be sur e to replace filters as directed by the manufacturer; f ailure to do so can increase PF AS exposure. Question s? Conta ct Jef f Guy, Illi nois EPA Office o f Communit y Relations: 📞📞 (217) 785 - 872 4 󹵸 󹵹 󹵺 󹵻 󹵼 󹵾 󹵽 Jeff.G uy@il linoi s.g ov Learn More Scan the QR co de below to visit the Illino is EPA PFAS information p age: https://epa.i llinoi s.gov /topic s/wate r - quali ty/ pfas.ht ml

PU B LIC H EAL TH NO TICE – IMPOR T ANT INF ORMA TION ABOUT YO U R DRINKING W AT E R Why Yo u ’ r e Receiving This Notice P er fluorooctanesulfonic acid (PFOS), a Per - and Polyfluoroalkyl Substances (PF AS) compoun d, has bee n detected in the Du po Community W ater System (C WS) at a le vel that e xceeds the groundwater quality standa rd established by the State of Illinois. This system ser ves as an emergency connection to the Col umbia CWS. Alth ough this eme rgency connection is not use d during no rmal ope r ati ons, it is autho rized for use if other d rinking wate r sources become unavailable. This noti ce is required by law under the Illin ois Environmental Protection Act and the Groundwater Protection Act. The information i s summarized below: • PF AS Compound: PFO S • Detect ed Level: 4.5 parts per t rillion • Illinois St andard: 4 parts per trillion What A re PF AS? PF AS are human - made chemicals used since t he 1940s. Bec ause t hey repel oil and wa te r and resist heat, they are commonly found in products such as non - stick cookware, food pack aging, waterproof clothing, stain - resistant furni ture, an d firefighting foam. P FA S pollute water throu gh spi lls, lea ks, a nd dis posal of products. They a re often called “forever chemicals ” because they rem ai n in the environm ent for decades. Health Risks L ong - ter m exp osure to P FA S may increas e t he risk of: • Fer tili ty problems and high blood pres sur e duri ng pregn ancy • Dev elopm ental impacts i n c hi ld re n • Ce rtain c ance rs, includi ng kid ne y, p rostate, and test icular • A w ea ke ned imm une sy stem • Disruption to key hormonal systems, suc h as thyroid function, reproduc tive hormones, stress respons e, and me tabolic re gulation

Exposu re does not gua rante e health problems. Ris k depe nds on the PFA S leve l and how lon g you’ve been e xposed. Cons ult your healthc are provide r for health c once rns. Reducing PF AS in Y our Drin king W ater Boiling water does no t remove PF AS, but certai n water filters can reduce or remove them. With many filters on the m arket, it’ s importa nt to ch oose one that is spe cifically cer tified to remove or red uce PF AS. Fi l te rs vary by type, br and, an d in stallation method — su ch as pitcher filte rs, fau c e t - mounte d units, or whole - home systems. Below ar e types of fil ters shown to effectively red uce or r e move PF AS level s: • Charcoal (Granular Acti vated Carbon or GAC) – t r aps chemicals as water flows t h rou gh • Rev erse O smosis (R O) Sys tems – filters out pollutants usi ng a thin memb r ane • Ion Ex change Resins – tiny beads that attract and hold contaminants Check for Certifica tion Use filters that meet Natio nal Sanitati on Foundation/ A merican Natio nal Sta ndards Institute (NSF / AN SI) standards, specifically NS F / ANS I 53 (for reducing health - re lated contamina nts, including PF A S) or NSF /ANSI 58 (for rever se osmosis systems). Y ou can verif y certification at: https://info.nsf.or g/Certified/ dw tu/. Be sure to r ep lace filters as di rected by the manufacturer; f ailure to do so can in crease PFAS e xp osure. Question s? Contact Jef f Guy, Illinois EPA Offi ce of Commu nity Re lations: 📞📞 (217) 78 5 - 8724 󹵸 󹵹 󹵺 󹵻 󹵼 󹵾 󹵽 Jeff.Guy@illinois. gov Learn More Scan the QR code bel ow to visit th e Illinoi s EPA PFAS informa tion p age: https://epa.i llinois.gov/topics/water - quality/pf as.html

PU B LIC H EAL TH NO TICE – IMPOR T ANT INF ORMA TION ABOUT YO U R DRINKING W AT E R Why Yo u ’ r e Receiving This Notice P er fluorooctanesulfonic acid (PFOS), a Per - and Polyfluoroalkyl Substances (PF AS) compoun d, has bee n detected in the Du po Community W ater System at a level th at ex ce eds the groundwater quality standard establis hed by the State of Illin ois. This system ser ves as an emergency connecti on to the Pr airie Du P ont Public W ater D istrict. Although t his eme rgency connection i s not used during no rmal ope ra ti ons, it is autho rized for use if other d rinking water sources become unavailable. This noti ce is required by law under the Illin ois Environmental Protection Act and the Groundwater Protection Act. The information i s summarized below: • PF AS Compound: PFO S • Detect ed Level: 4.5 parts per t rillion • Illinois St andard: 4 parts per trillion What A re PF AS? PF AS are human - made chemicals used since t he 1940s. Bec ause t hey repel oil and wa te r and resist heat, they are commonly found in products such as non - stick cookware, food pack aging, waterproof clothing, stain - resistant furni ture, an d firefighting foam. P FA S pollute water throu gh spi lls, lea ks, a nd dis posal of products. They a re often called “forever chemicals ” because they rem ai n in the environm ent for decades. Health Risks L ong - ter m exp osure to P FA S may increas e t he risk of: • Fer tili ty problems and high blood pres sur e duri ng pregn ancy • Dev elopm ental impacts i n c hi ld re n • Ce rtain c ance rs, includi ng kid ne y, p rostate, and test icular • A w ea ke ned imm une sy stem • Disruption to key hormonal systems, suc h as thyroid function, reproduc tive hormones, stress respons e, and me tabolic re gulation

Exposu re does not gua rante e health problems. Ris k depe nds on the PFA S leve l and how lon g you’ve been e xposed. Cons ult your healthc are provide r for health c once rns. Reducing PF AS in Y our Drin king W ater Boiling water does no t remove PF AS, but certai n water filters can reduce or remove them. With many filters on the m arket, it’ s importa nt to ch oose one that is spe cifically cer tified to remove or red uce PF AS. Fi l te rs vary by type, br and, an d in stallation method — su ch as pitcher filte rs, fau c e t - mounte d units, or whole - home systems. Below ar e types of fil ters shown to effectively red uce or r e move PF AS level s: • Charcoal (Granular Acti vated Carbon or GAC) – t r aps chemicals as water flows t h rou gh • Rev erse O smosis (R O) Sys tems – filters out pollutants usi ng a thin memb r ane • Ion Ex change Resins – tiny beads that attract and hold contaminants Check for Certifica tion Use filters that meet Natio nal Sanitati on Foundation/ A merican Natio nal Sta ndards Institute (NSF / AN SI) standards, specifically NS F / ANS I 53 (for reducing health - re lated contamina nts, including PF A S) or NSF /ANSI 58 (for rever se osmosis systems). Y ou can verif y certification at: https://info.nsf.or g/Certified/ dw tu/. Be sure to r ep lace filters as di rected by the manufacturer; f ailure to do so can in crease PFAS e xp osure. Question s? Contact Jef f Guy, Illinois EPA Offi ce of Commu nity Re lations: 📞📞 (217) 78 5 - 8724 󹵸 󹵹 󹵺 󹵻 󹵼 󹵾 󹵽 Jeff.Guy@illinois. gov Learn More Scan the QR code bel ow to visit th e Illinoi s EPA PFAS informa tion p age: https://epa.i llinois.gov/topics/water - quality/pf as.html