The proposed rules are related to three other sets of rules currently in progress:
Rule package DG-15-19 is proposing to establish groundwater standards for several compounds including PFOS and PFOA for the protection of human health.
Rule package DG-24-19 is proposing drinking water maximum contaminant levels (MCLs) for PFOS & PFOA.
Rule package WA-07-20 is proposing to regulate class B firefighting foams containing PFAS.
Rule package WY-23-13 is proposing revisions to ch. NR102, Wis. Adm. Code, in order to add text regarding waterbody assessments and biological thresholds, which are topics unrelated to this rule but may affect numbering for this rule package. With regard to existing regulations, these proposed rules relate to surface water quality standards and the WPDES permit program. Related rules include chs. NR 102, 104, 105, and 106 Wis. Adm. Code, which contain Wisconsin’s surface water quality standards and their application, and chs. NR 200 to 299, Wis. Adm. Code., which contain requirements for the WPDES permit program. Chapter 283, Wis. Stats., contains the statutory authority and requirements for the WPDES permit program. 5. Plain Language Analysis:
Poly- and perfluoroalkyl substances (PFAS) are human-made, organic compounds that have been manufactured for use in non-stick coatings, waterproof fabrics, firefighting foams, food packaging, and many other applications since the 1940s. PFAS are highly resistant to degradation and have been detected globally in water, sediment, and wildlife. This global distribution is of concern as PFAS have documented toxicity to animals and because epidemiological studies have suggested probable links to several human health effects. In Wisconsin, PFAS have been detected in drinking and surface water near sources of industrial use or manufacture and near spill locations. Perfluorooctane sulfonate (PFOS) has been found in fish tissue resulting in the issuance of special fish consumption advisories for some surface waters in the state.
The proposed rules include a water quality standard for two types of PFAS: PFOS and perfluorooctanoic acid (PFOA). Under the Clean Water Act, surface water quality standards can include criteria that are either numeric or narrative. Wisconsin’s existing Administrative Codes contain both numeric and narrative criteria for toxic substances:
- Chapter NR 105, Wis. Adm. Code, contains specific numeric criteria for numerous toxic pollutants as well as formulas for calculating numeric criteria for toxics that do not yet have promulgated criteria. - Section NR 102.04(d), Wis. Adm. Code, contains Wisconsin’s narrative criteria for toxics. This existing rule states that substances in concentrations or combinations which are toxic or harmful to humans shall not be present in amounts found to be of public health significance [emphasis added], nor shall substances be present in amounts which are acutely harmful to animal, plant or aquatic life. - The proposed PFOS and PFOA standard interprets Wisconsin’s existing narrative criterion with numeric thresholds, created under s. NR 105.04(4m) and s. NR 102.04, Wis. Adm. Code. The proposed rule defines levels of public health significance for the two types of PFAS based on preventing adverse effects from contact with or ingestion of surface waters of the state, or from ingestion of fish taken from waters of the state. - For PFOS, the proposed level of public health significance is 8 ng/L for all waters except those that cannot naturally support fish and do not have downstream waters that support fish.
- For PFOA, the proposed level of public health significance is 20 ng/L in waters classified as public water supplies under ch. NR 104, and 95 ng/L for other surface waters. Related to the proposed PFOS and PFOA standard, the proposed rule also includes assessment protocols that clarify when a surface water that contains levels of PFOS or PFOA above the public health significance threshold levels in the narrative standard should be listed on the state’s impaired waters list.
Additionally, this rule includes revisions to ch. NR 106, Wis. Adm. Code, that address WPDES permit implementation procedures for the new PFOS and PFOA standard. With regard to permit implementation of the narrative criteria, DNR is proposing source reduction as a first step toward reducing levels of PFOS and PFOA in the effluent rather than requiring treatment up front because source reduction is the most cost effective approach to reducing or eliminating PFOS and PFOA in wastewater discharges and it avoids the generation of contaminated carbon filters from treatment systems which will contain higher levels of PFOA and PFOS that will have to be disposed of in a safe manner. The proposed rule establishes WPDES permit requirements for PFOS and PFOA discharges to surface waters of the state, in ch. NR 106 – Subchapter VIII, Wis Adm. Code, including: the determination of the need for a PFAS Minimization Plan based on data generation in a reissued permit, a general schedule for PFAS Minimization Plan permit implementation procedures, and PFAS Minimization Plan requirements. The proposed permit requirements include standard PFOS and PFOA sampling frequencies for categories of permitted dischargers. If the department does not believe that PFOS or PFOA is present in a permittee’s discharge, sampling may be waived. Based on the effluent data collected, the proposed rule establishes procedures for determining whether a permitted facility’s discharge contains PFOS or PFOA at levels that have the reasonable potential to cause or contribute to an exceedance of the PFOS or PFOA standard. For permitted facilities that have the reasonable potential to exceed the PFOS or PFOA standard, the proposed rule requires that the permittee develop and implement a PFAS Minimization Plan in accordance with the timelines in the rule and WPDES permit schedule. The permittee must also continue sampling for PFOS and PFOA. It is expected that for nearly all WPDES permitted facilities with discharges to surface waters as well as industrial facilities that discharge wastewater to publicly owned treatment plants, source reduction actions outlined in minimization plans will reduce PFOS and PFOA discharges to levels that are below the public health thresholds in standard. Because past pollutant minimization plans for other similar pollutants such as mercury have been shown to result in a 43% percent (median) reduction in effluent concentrations and based on relatively low initial concentrations of PFOS and PFOA observed in permittees’ effluents, the department predicts that only a couple of industrial facilities (indirect dischargers) in the state will eventually have to install treatment to comply with the PFOS and PFOA standard. In these cases, the proposed rule allows a compliance schedule for installation of treatment technology.
In the event treatment becomes necessary for a WPDES permit holder, pursuant to s. 283.15, Wis. Stats., the permitted facility may apply for an economic variance if installation of treatment technology will cause substantial and widespread adverse social and economic impacts in the area where the permittee is located. Finally, this rule adds specifications for the preservation and holding times of aqueous, biosolids (sludge), and tissue samples that will be analyzed for PFAS in ch. NR 219, Wis. Adm. Code. 6. Summary of, and Comparison with, Existing or Proposed Federal Statutes and Regulations:
Federal statutes and regulations direct states to establish and periodically review water quality standards. State adoption of water quality standards and revisions to standards require EPA approval pursuant to 40 CFR 131.20 and 131.21. - 33 USC s. 1313(c) (section 303(c) of the Clean Water Act) requires that states periodically review and modify or adopt, if necessary, water quality standards. This requirement applies to all surface waters in the state.
- 33 USC s. 1314(a) (section 304 of the Clean Water Act) requires that EPA develop and publish criteria for water quality for all waters for uses such as aquatic life, public health protection, and recreation.
- 40 CFR s. 130.3 defines water quality standards as setting water quality goals for a waterbody that will protect its designated uses (such as protection of fish, wildlife, recreation, and public health and welfare). Criteria will be set to protect those uses. - 40 CFR s. 131.4 specifies that states are responsible for reviewing, establishing and revising their own water quality standards. - 40 CFR ss. 131.10 and 11 require states to develop water quality standards including uses and criteria to protect the uses. 40 CFR s. 131.11 (b) states that the criteria must be based on federal guidance, federal guidance modified to reflect site-specific criteria, or other scientifically defensible methods. - 40 CFR s. 131.11 specifies that criteria must protect the designated uses and that criteria must be based on sound scientific rationale and must contain sufficient parameters or constituents to protect the designated use. Furthermore, states must review water quality data and information on discharges to identify specific water bodies where toxic pollutants may be adversely affecting water quality or the attainment of the designated use or where the levels of toxic pollutants are at a level to warrant concern, and must adopt criteria for such toxic pollutants applicable to the water body sufficient to protect the designated use. - 40 CFR 131.20 requires states to periodically review water quality standards. - 40 CFR 132 and Appendices contain requirements for developing water quality standards in the Great Lakes System as well as implementation procedures for the standards and National Pollutant - Discharge Elimination System (NPDES) permitting requirements for point source discharges to the Great Lakes System. - 40 CFR 123.25 lists the federal regulations in 40 CFR 122 and 124 that states must follow in the administration of the NPDES permit program. State rules must be at least as stringent as these federal requirements. EPA has neither promulgated specific water quality standards for PFAS nor proposed criteria under s.304(a) of the Clean Water Act. EPA typically relies on states to take the initiative and develop water quality standards because states have varying types of fish and aquatic life species and varying types of waterbodies within, and adjacent to, their borders. Occasionally, EPA will specifically direct states to promulgate water quality standards or promulgate procedures for deriving criteria for pollutants in advance of state efforts, and then require that states adopt water quality standards for the pollutant that are at least as stringent as EPA’s procedure or standard. EPA has not expressly directed states to develop water quality standards for PFAS at this time, although states do not need EPA approval to begin developing water quality standards and have the discretion to develop water quality criteria for any pollutant.
The method of calculating numeric criteria in s. NR 105, Wis. Adm. Code, reflects such procedures established by EPA for Great Lakes states. As part of this rulemaking effort, the department also conducted preliminary calculations of numeric criteria using the procedures outlined ch. NR 105, Wis. Adm. Code. At this time, however, the department selected the approach outlined above to develop public health significance thresholds under ch. NR 102, Wis. Adm. Code. This approach was selected because PFOS public health significance levels are more closely correlated with the issuance of fish consumption advisories than the ch. NR 105, Wis. Adm. Code, numeric criteria would have been. Furthermore, codifying a method for developing PFAS minimization plans will reduce the administrative burden and permitting timelines that would have been associated with processing a large volume of variance requests expected as a result of the criteria developed using the procedures outlined ch. NR 105, Wis. Adm. Code. The department believes that public health significance thresholds combined with PFAS minimization plans will result in more timely reductions in levels of PFOS, PFOA and all other parameters regulated in WPDES permits, as permittees exceeding the proposed public significance thresholds will begin PFAS minimization plans immediately upon permit reissuance rather than after a prolonged variance application and review process and potential litigation. The department expects that the selected approach will be effective at reducing sources of PFOS and PFOA in areas of the state where PFOS or PFOA concentrations in wastewater are elevated.
7. If Held, Summary of Comments Received During Preliminary Comment Period and at Public Hearing on the Statement of Scope:
The department received written comments related to WY-23-19 from 49 entities during the preliminary comment period, and oral comments from 5 speakers during the public hearing on the statement of scope. Of the comments received, 38 entities expressed support of the proposed rules, 8 expressed opposition to the proposed rules, and the opinions of the remaining 8 were mixed. Those expressing mixed opinions voiced general support for the rulemaking effort but noted concerns about the cost of implementation, the desire to regulate PFAS as a class rather than compound by compound, technical issues with the toxicity values developed by the Department of Health Services, and regulation of PFAS at the source rather than at POTWs.
8. Comparison with Similar Rules in Adjacent States:
The administrative codes of adjacent states contain narrative criteria for the protection of surface waters, although none of the adjacent states’ narrative criteria are specific to PFOS or PFOA. The narrative criteria of Illinois, Iowa, and Michigan specifically prohibit concentrations of toxic substances in surface waters in amounts that will adversely affect human health or public health. Minnesota’s narrative criteria prohibits discharge of wastes in such quantities that will cause pollution as defined by law.
Code citations for these narrative criteria are as follows:
- Illinois: Ill. Admin. Code tit. 35, § 302.210: “Other Toxic Substances. Waters of the State shall be free from any substances or combination of substances in concentrations toxic or harmful to human health, or to animal, plant or aquatic life. Individual chemical substances or parameters for which numeric standards are specified in the Subpart are not subject to this Section.” - Iowa: IAC § 567.61.3(2)(d): “General water quality criteria. The following criteria are applicable to all surface waters including general use and designated use waters, at all places and at all times for the uses described in 61.3(1) ‘a.’ … ‘d.’ Such waters shall be free from substances attributable to wastewater discharges or agricultural practices in concentrations or combinations which are acutely toxic to human, animal, or plant life.”
- Michigan: R 323.1057, Mich. Admin. Code: “Rule 51. (1) Toxic substances shall not be present in the surface waters of the state at levels that are or may become injurious to the public health, safety, or welfare, plant and animal life, or the designated uses of the waters. As a minimum level of protection, toxic substances shall not exceed the water quality values specified in, or developed pursuant to, the provisions of subrules (2) to (4) of this rule or conditions set forth by the provisions of subrule (6) of this rule. A variance to these values may be granted consistent with the provisions of R 323.1103.”
- Minnesota: Minn. Stat. 7050.0210-13: “Pollution prohibited. No sewage, industrial waste, or other wastes shall be discharged from either a point or a nonpoint source into the waters of the state in such quantity or in such manner alone or in combination with other substances as to cause pollution as defined by law. In any case where the waters of the state into which sewage, industrial waste, or other waste effluents discharge are assigned different standards than the waters of the state into which the receiving waters flow, the standards applicable to the waters into which the sewage, industrial waste, or other wastes discharged shall be supplemented by the following: The quality of any waters of the state receiving sewage, industrial waste, or other waste effluents shall be such that no violation of the standards of any waters of the state in any other class shall occur by reason of the discharge of the sewage, industrial waste, or other waste effluents.”
Two adjacent states – Michigan and Minnesota – have released numeric water quality values for PFOS, or PFOS and PFOA. Both states developed their values according to the procedures outlined in 40 CFR 132, but each state used different inputs which resulted in different numeric values. Similarly, Wisconsin selected a different methodology and different inputs, as described in Section 9 below, and thus the proposed thresholds are different. Further, Minnesota released site-specific criteria (SSC) for PFOS rather than implementing the criteria statewide. Michigan has calculated statewide values as Wisconsin is proposing to do. Wisconsin chose not to pursue the development of SSC for this rulemaking effort. Over the past several years, the department has endeavored to collect data on the occurrence of PFAS across the state, and this data indicates the possibility of human exposure to PFOA and PFOS via surface waters or fish taken from surface waters in areas throughout the state. With statewide criteria the department seeks to provide protection for citizens’ use of all waters. Additionally, Minnesota’s code includes provisions for developing SSCs without rulemaking, but Wisconsin’s does not. Thus, there would be no administrative time saved or expedited human health protections gained by developing SSCs compared to statewide criteria. Wisconsin’s proposed threshold of 8 ng/L for PFOS is more stringent than Michigan’s value of 11 ng/L and, compared to Minnesota’s PFOS criterion in waters where it applies, less stringent than Minnesota’s criterion of 0.05 ng/L. Wisconsin’s proposed thresholds of 20 ng/L and 95 ng/L for PFOA in public drinking water supply waters and non-public drinking supply waters, respectively, are more stringent than Michigan’s values of 420 and 12,000 ng/L for PFOA in drinking and non-drinking waters, respectively.
Additional information on each adjacent state’s approach to developing their values is provided below:
- In 2020, the Minnesota Pollution Control Agency (MPCA) released SSC for PFOS in surface waters and fish tissue for Lake Elmo and two connected waterbodies, Bde Maka Ska and Mississippi River Pool 2. These SSC are not promulgated standards but were developed according to the procedures outlined in 40 CFR 132 pursuant to Minnesota’s statutory provisions. Minnesota’s administrative code provides the flexibility to implement SSCs without going through rulemaking. The value for fish tissue is 0.37 ng PFOS/g and the value for water that supports the fish tissue criterion is 0.05 ng PFOS/L. MPCA’s SSC incorporated the Minnesota Department of Health’s toxicity value, which was derived using a model that focuses on the protection of infants and women of childbearing age (WCBA). Accordingly, MPCA’s SSC derivation also included WCBA-specific body weights and fish consumption and drinking water intake rates. When asked for input from Minnesota on implementation, Minnesota officials responded that they implement their SSC for PFOS in a handful of waterbodies in the Minneapolis-St. Paul metro area – both in the East Metro cleanup area and in other parts. For the most part, PFOS criteria were developed in order to provide appropriate cleanup values for the East Metro and for an area of Minneapolis that has been impacted by a chrome plater. Limitations based on the numeric PFOS SSC described above have not yet been applied in NPDES permits. In 2007, MPCA and STS Consultants, LTD., developed SSC for PFOA and PFOS for Bde Maka Ska and Mississippi River Pool 2. Minnesota has had limited permit implementation of the 2007 criteria; to date, there is only one wastewater plant that has PFAS limits based on these criteria. See: https://www.pca.state.mn.us/waste/water-quality-criteria-development-pfas for more information. - Michigan Department of Environmental Quality (now called the Department of Environment, Great Lakes, and Energy; EGLE) released statewide water quality values for PFOS in 2014 and PFOA in 2011. The process for calculating surface water quality values, outlined in 40 CFR 132, is promulgated in Michigan’s administrative code R. 323.1057. However, values resulting from this process are not promulgated and appear in “Rule 57 Water Quality Values Spreadsheets” available at https://www.michigan.gov/egle/0,9429,7-135-3313_3681_3686_3728-11383--,00.html. Michigan’s PFOS and PFOA values apply to surface waters statewide. Concentrations of PFOS may not exceed 11 and 12 ng/L in drinking and non-drinking waters, respectively. Concentrations of PFOA may not exceed 420 and 12,000 ng/L in drinking and non-drinking waters, respectively. Michigan EGLE’s surface water quality values incorporate toxicity values based on data from studies where cynomolgus monkeys were exposed to PFOS or PFOA for 182 days (Butenhoff et al. 2002; Seacat et al. 2002). Derivation of both values also included adult body weights and fish consumption and drinking water rates. Michigan implements surface water values for PFOS and PFOA through various water quality programs. Michigan is carrying out an Industrial Pretreatment Program PFAS Initiative, a Municipal NPDES Permitting Strategy, and an Industrial Direct and Industrial Storm Water Discharge Compliance Strategy for monitoring and addressing PFOS and PFOA in regulated discharges. Under the Municipal NPDES Permitting Strategy, municipal permits issued/re-issued after October 1, 2021 will include effluent limits for PFOS/PFOA if applicable. In addition, after July 1, 2021, Michigan will require sampling of biosolids prior to land application as part of a biosolids Interim Strategy. Michigan supports these programs through ambient surface water and fish tissue monitoring.
Iowa and Illinois have not promulgated water quality criteria for any PFAS compounds.
9. Summary of Factual Data and Analytical Methodologies Used and How Any Related Findings Support the Regulatory Approach Chosen:
A detailed description of the procedures used to calculate these definitions of public health significance under the narrative criteria can be found in the Technical Support Document for this rule.
PFOA: Water ingestion is the exposure pathway of most concern for PFOA (i.e., it doesn’t bioaccumulate to high concentrations in fish). Thus, public health significance was based on the likelihood that, and degree to which, surface waters could be ingested.
- To determine which pathway or pathways by which people might be exposed to PFOA, the department reviewed several datasets of samples analyzed for PFAS, including: 1) paired surface water and fish tissue samples collected throughout Wisconsin and Minnesota between 2006 and 2020, 2) fish tissue samples collected as part of Wisconsin’s fish contaminant monitoring program between 2006 and 2020, and 3) surface water samples collected as part of long term trends (LTT) monitoring in Wisconsin in 2020.
- In the paired fish and water dataset, PFOA was detected in surface water samples from over 80% of the waterways, but was detected in only 2% of fish tissue samples. Those fish samples that contained PFOA came from 8 waterways and there were no PFOA detects in samples of fish taken from waterways where PFOA was undetected in the water itself. The pattern of PFOA being detected in most water samples, but few fish tissue samples, was mirrored in the fish contaminants and LTT datasets. Less than 4% of the fish contaminant samples contained detectable levels of PFOA (in contrast, over 85% of these fish samples contained detectable levels of PFOS). In the LTT dataset, PFOA was detected in over 80% of waterways. These data demonstrate that PFOA is unlikely to bioaccumulate in fish tissue and suggest that while there is widespread risk of exposure to PFOA via ingestion of surface waters, exposure via consumption of fish tissue is unlikely to provide a substantive contribution to overall body burdens of PFOA.
- Therefore, for those waters currently used as public water supplies, the level of public health significance was defined as the level already defined by the Departments of Health Services and Natural Resources for the purposes of drinking water protection. Details about the data and methods used to develop this level can be found in the Scientific Support Document for PFOA Groundwater Standards at: dnr.wi.gov/topic/Contaminants/documents/pfas/PFOAScientificSupport.pdf. - For waters not currently used as public water supplies, the department adjusted the formula used to develop the PFOA drinking water protection value to reflect the incidental water consumption rate that occurs during recreation. To determine this incidental ingestion rate, the department followed an approach used in EPA’s 2019 Recommended Human Health Recreational Ambient Water Quality Criteria or Swimming Advisories for Microcystins and Cylindrospermopsin. Briefly, this approach calculated the amount of water that people ingested during swimming activities and combined that with the number of hours that people spend recreating each day in order to generate a daily incidental ingestion rate. In order to assess the risk of PFOA exposure to children during recreation in surface waters and as per EPA’s 2000 Human Health Methodology, the department used the 90th percentile of exposure for the 6 to 10 years old age group to derive the level of public health significance for PFOA in non-public water supply waters.
PFOS: Fish ingestion is the exposure pathway of most concern for PFOS (i.e., it can build up to high levels in fish even when there is a small amount in the water column). For this reason, there are established PFOS thresholds corresponding to recommended fish consumption frequencies which are designed to reduce risks from exposure to PFOS while still receiving the benefits of fish consumption. Thus, public health significance was defined as the maximum PFOS concentration in a surface water that is expected to avoid issuance of a 1 meal per month PFOS-based fish consumption advisory for any species taken from that surface water. In other words, the proposed definition of public health significance aims to ensure that levels of PFOS in fish will be such that people can consume fish at a frequency of up to one meal per week (32 grams/day) without exceeding EPA’s non-cancer toxicity RfD of 2 x 10-5 mg/kg-day.
