Wisconsin Legislature: 002 - CR 21-101 Rule Text

Wisconsin state drinking water maximum contaminant levels (MCLs) have been established, in ch. NR 809, Wis. Adm. Code, for: glyphosate, at 700 micrograms per liter (ug/L), Escherichia coli (E. coli) bacteria, at 0 bacteria present in a drinking water sample, trichloroethylene (TCE), at 5 ug/L, and tetrachloroethylene (PCE), at 5 ug/L. Secondary Standards, established for aesthetic quality, have been promulgated in ch. NR 809, Wis. Adm. Code, for aluminum at 50 to 200 ug/L. Note that concentration in ug/L is equivalent to parts per billion (ppb).

5. Plain Language Analysis:

Chapter 160, Wis. Stat., is Wisconsin’s Groundwater Standards Protection law. This chapter requires the department to develop numerical groundwater quality standards, consisting of enforcement standards and preventive action limits. Chapter NR 140, Wis. Adm. Code, establishes groundwater standards. These proposed amendments to ch. NR 140, Wis. Adm. Code, would add new state groundwater quality standards for 17 substances and revise existing standards for another 8 substances. In accordance with s. 160.07, Wis. Stat., amendments to ch. NR 140, Wis. Adm. Code, groundwater quality standards for substances of public health concern are based on recommendations from DHS. DHS’s recommendations are available at: https://www.dhs.wisconsin.gov/water/gws-cycle10.htm. The technical analysis supporting each of the recommendations can be found by clicking on the substance.

The proposed rule for new and revised groundwater quality standards are grouped into five categories: Per- and Polyfluoroalkyl Substances (PFAS), Volatile Organic Compounds (VOCs), Metals/Metalloids, Agricultural Chemicals, and Bacteria. PFAS includes new public health related groundwater standards for perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). VOCs includes revised public health related groundwater standards for: trichloroethylene (TCE), tetrachloroethylene (PCE), 1,4-dioxane, and 1,2,3-trichloropropane (1,2,3-TCP). Metals/Metalloids includes new public health related groundwater standards for hexavalent chromium and strontium, and revised public health related groundwater standards for: aluminum, boron, molybdenum, and cobalt. Agricultural Chemicals includes new public health related groundwater standards for: thiamethoxam, imidacloprid, clothianidin, isoxaflutole plus isoxaflutole DKN degradate, isoxaflutole BA degradate, thiencarbazone-methyl, glyphosate, glyphosate aminomethylphosphonic acid (AMPA) degradate, and sulfentrazone, and revised public health related groundwater standards for Dacthal that would include the Dacthal Tetrachloroterephthalic Acid (TPA) and Monomethyl tetrachloroterephthalic acid (MTP) degradates. Bacteria includes new public health related groundwater standards for Escherichia coli (E. coli) bacteria.

Minor revisions, to clarify rule language and update rule reference information, are also proposed to ch. NR 140. These revisions include:

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Revising order of Antimony and Anthracene in s. NR 140.10, Table 1 to correct their alphabetical order in the table.

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Removing, in s. NR 140.20, Table 3, the indicator parameter for ammonia nitrogen. Health standards were established for ammonia (as N), in s. NR 140.10, Table 1, as part of the "Cycle 9" revisions to ch. NR 140.

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Making needed additions and revisions to ch. NR 140 Appendix I to Table 1 substance names, Chemical Abstracts Service (CAS) registry numbers, and common synonyms.

6. Summary of, and Comparison with, Existing or Proposed Federal Statutes and Regulations:

The U.S. Environmental Protection Agency (EPA) establishes health-based drinking water maximum contaminant levels (MCLs), cancer risk levels, and health advisories (HAs) that are used to assess the quality of groundwater drinking water supplies. Federal drinking water MCLs are established based on scientific risk assessments and, in some cases, economic and technological considerations. Cancer risk levels are established as the concentration of a chemical in drinking water that corresponds to a specific excess estimated lifetime cancer risk. Federal lifetime health advisories (LHAs) are developed based on an established health risk acceptable daily intake (ADI) level or reference dose (RfD). An ADI or RfD is the daily oral exposure to a chemical that is likely to be without an appreciable risk over a lifetime.

The proposed amendments to ch. NR 140, Wis. Adm. Code, adds new or revised state numeric groundwater quality standards for: PFAS including perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA); VOCs including trichloroethylene (TCE), tetrachloroethylene (PCE), 1,4-dioxane, and 1,2,3-trichloropropane (1,2,3-TCP); metals/metalloids including hexavalent chromium, strontium, aluminum, boron, molybdenum, and cobalt; agricultural chemicals including thiamethoxam, imidacloprid, clothianidin, isoxaflutole plus isoxaflutole DKN degradate, isoxaflutole BA degradate, thiencarbazone-methyl, glyphosate, glyphosate aminomethylphosphonic acid (AMPA) degradate, sulfentrazone, Dacthal including the Dacthal Tetrachloroterephthalic Acid (TPA) and Monomethyl tetrachloroterephthalic acid (MTP) degradates; and bacteria including Escherichia coli (E. coli) bacteria.

Federal drinking water MCLs have been established for: glyphosate (700 ug/L), Escherichia coli (E. coli) bacteria (0 bacteria present), trichloroethylene (TCE) (5 ug/L) and tetrachloroethylene (PCE) (5 ug/L). EPA cancer slope factors have been established that can be used to determine 1 in 1,000,000 drinking water cancer risk levels. EPA cancer slope factors have been established for: hexavalent chromium [EPA OPP = 0.791 (mg/kg-day)-1, EPA IRIS draft = 0.5 (mg/kg-day)-1], isoxaflutole [0.0114 (mg/kg-day)-1], 1,2,3-trichloropropane (1,2,3-TCP) [30 (mg/kg-d)-1] and 1,4-dioxane [0.01 (mg/kg-d)-1]. EPA LHAs have been established for: strontium (4,000 ug/L), the sum of Dacthal and its degradates (MTP and TPA) (70 ug/L), perfluorooctanoic acid (PFOA) (70 ng/L), perfluorooctane sulfonate (PFOS) (70 ng/L), boron (6,000 ug/L), molybdenum (40 ug/L) and 1,4-dioxane (200 ug/L).

RfDs have been established by EPA for: hexavalent chromium (0.003 mg/kg/day), thiamethoxam (0.012 mg/kg/day), imidacloprid (0.057 mg/kg/day), clothianidin (0.098 mg/kg/day), isoxaflutole (0.02 mg/kg/day), thiencarbazone-methyl (1.17 mg/kg/day), sulfentrazone (0.14 mg/kg/day), 1,2,3-trichloropropane (1,2,3-TCP) (0.004 mg/kg/day) and 1,4-dioxane (0.03 mg/kg/day).

In October 2021, EPA issued a strategic roadmap for PFAS. EPA describes PFAS as an urgent public health and environmental issue that requires increased and sustained action by every level of government – federal, Tribal, state, and local. EPA’s roadmap describes actions EPA plans to take to reduce PFAS in the environment. However, these actions do not include establishing numeric standards for PFAS in groundwater, which is exclusively a state responsibility in Wisconsin.

7. If Held, Summary of Comments Received During Preliminary Comment Period

and at Public Hearing on the Statement of Scope:

A preliminary public hearing on Statement of Scope SS 090-19, related to revisions to ch. NR 140, was held on Nov. 12, 2019. Comments on the proposed scope were accepted through Nov. 19, 2019. A significant number of comments were received in support of the proposed scope for ch. NR 140 rulemaking. Comments were also received expressing concerns that the proposed scope did not list the specific substances that would be included in the proposed ch. NR 140 rulemaking effort and was therefore too broad. Those comments suggested that the list of the specific substances for which DHS provided groundwater standard recommendations should be added to the rulemaking scope.

Comments received in support of the proposed scope statement for ch. NR 140 rulemaking primarily focused on potential state groundwater quality standards for PFAS. Comments noted that there are health effects associated with exposure to PFAS compounds and that rules and standards were needed to protect Wisconsin water resources and drinking water supplies. Comments suggested that established groundwater standards for PFAS would provide regulatory certainty to responsible parties for cleanup and remediation at contamination sites. Comments were also received suggesting that, as PFAS are often detected in the environment as a complex mixture of different PFAS compounds, they should be regulated as a "class," or group of chemicals with a similar chemical composition and mechanism of toxicity.

The department provided the DHS with a list of substances, designated the "Cycle 10" list, and requested that DHS review toxicologic information on these substances and, if appropriate, provide recommendations for health-based groundwater quality standards for the substances. Comments on the scope pointed out that the specific substances on the "Cycle 10" list, that DHS provided groundwater standard recommendations for, including two PFAS compounds, were not listed in the scope statement. Comments suggested that this lack of specificity and detail made the scope too broad and potentially noncompliant with state law, and that therefore, the scope should be rejected by the Natural Resources Board and sent back to the department to have the list of the specific substances, for which DHS provided recommendations, added to it. Comments were also received related to the specific scientific studies and methods used by DHS to develop their health-based groundwater standard recommendations.

8. Comparison with Similar Rules in Adjacent States:

The states adjacent to Wisconsin – Minnesota, Michigan, Illinois and Iowa – use groundwater protection values/levels/standards in their regulation of practices and activities that might impact the quality of groundwater. Minnesota, Michigan, and Illinois have promulgated individual state groundwater protection standards. Iowa uses established federal standards (federal drinking water MCLs, LHAs and established cancer risk levels) as its state groundwater protection standards.

Groundwater protection quality values/levels/standards are usually developed based on health risk assessments. States are often required to follow state-specific health risk assessment methodology when establishing groundwater protection quality standards. States may use state-specific health risk assessments, factors and methodology in calculating and developing their groundwater protection standards. This use of different health risk assessment factors and methodologies has led to the establishment of different state groundwater protection values/levels/standards for the same substance. For example, the health-based groundwater protection level for strontium used by the states surrounding Wisconsin varies by state. The level established in Minnesota is 3,000 micrograms per liter (ug/L), the level established in Michigan is 4,600 ug/L, Illinois has not established a strontium groundwater protection level, and Iowa uses the federal lifetime health advisory level of 4,000 ug/L as its strontium groundwater protection level.

The state of Minnesota has established state groundwater protection "Health Risk Limits" (HRLs) under Minnesota Statutes Section 103H.201. The state of Minnesota has established HRLs for: hexavalent chromium (100 ug/L), thiamethoxam (200 ug/L), clothianidin (200 ug/L), PFOA (35 nanograms per liter or ng/L), TCE (0.4 ug/L), PCE (5 ug/L), 1,2,3-TCP (7 ug/L) and 1,4-dioxane (100 ug/L). The Minnesota Department of Health has also calculated "Health Based Values" (HBVs) for some groundwater contaminants. Minnesota HBVs are not standards that have been promulgated by rule but are calculated concentrations that may be used as advisory levels by Minnesota state groundwater and environmental protection programs. Minnesota has established HBVs for: imidacloprid (3 ug/L), glyphosate (500 ug/L), glyphosate AMPA (1,000 ug/L) degradate and PFOS (20 ng/L). The Minnesota Department of Health also issues Risk Assessment Advice (RAA) levels for some groundwater contaminants. Minnesota Department of Health RAAs are advisory concentrations developed to assist Minnesota agencies in evaluating potential health risks to humans from exposures to a chemical. Generally, RAAs contain greater uncertainty than HRLs and HBVs because the information available to develop them is more limited. The state of Minnesota has established RAAs for: strontium (3,000 ug/L) and boron (500 ug/L).

The state of Michigan has established state groundwater protection quality standards. Michigan "Drinking Water Criteria and Risk Based Screening Levels” (RBSLs) are Michigan state groundwater protection standards authorized in accordance with Michigan's Natural Resources and Environmental Protection Act, 1994 PA 451 (NREPA). Michigan has established a Drinking Water Criteria/RBSL for: hexavalent chromium (100 ug/L), strontium (4,600 ug/L), glyphosate (700 ug/L), PFOA + PFOS (70 ng/L), TCE (5 ug/L), PCE (5 ug/L), 1,2,3-TCP (42 ug/L) and 1,4-dioxane (7.2 ug/L).

The state of Illinois has established state groundwater quality standards for "potable resource groundwater." Illinois Groundwater Quality Standards are state groundwater protection standards promulgated in 35 Ill. Adm. Code 620, environmental protection regulations. Illinois state "Groundwater Quality Standards for Class I: Potable Resource Groundwater" have been established for: TCE (5 ug/L), PCE (5 ug/L), boron (2,000 ug/L) and 1,4-dioxane (7.7 ug/L).

The state of Iowa has not established specific state groundwater protection standards. In accordance with Iowa Environmental Protection Regulations 567 IAC Chapter 133, Iowa uses established federal EPA lifetime health advisory levels, "negligible risk levels" (NRLs) for carcinogens, the estimate of one additional cancer case per million people over a lifetime of exposure, and federal drinking water maximum contaminant levels (MCLs) as "Action Levels" in their regulation of practices and activities that may adversely impact groundwater quality. Federal lifetime health advisory levels have been established for: strontium (4,000 ug/L), the sum of Dacthal and its degradates (MTP and TPA) (70 ug/L), perfluorooctanoic acid (PFOA) (70 ng/L), perfluorooctane sulfonate (PFOS) (70 ng/L), boron (6,000 ug/L), molybdenum (40 ug/L) and 1,4-dioxane (200 ug/L). EPA cancer slope factors have been established that can be used to determine NRLs for carcinogens. EPA cancer slope factors have been established for: hexavalent chromium [EPA OPP = 0.791 (mg/kg-day)-1, EPA IRIS draft = 0.5 (mg/kg-day)-1], isoxaflutole [0.0114 (mg/kg-day)-1], 1,2,3-trichloropropane (1,2,3-TCP) [30 (mg/kg-d)-1] and 1,4-dioxane [0.01 (mg/kg-d)-1]. Federal drinking water MCLs have been established for: glyphosate (700 ug/L), Escherichia coli (E. coli) bacteria (0 bacteria present), trichloroethylene (TCE) (5 ug/L) and tetrachloroethylene (PCE) (5 ug/L).

9. Summary of Factual Data and Analytical Methodologies Used and How Any Related Findings Support the Regulatory Approach Chosen:

In accordance with s. 160.07, Wis. Stat., the department is required, for substances of public health concern, to propose rules establishing recommendations from DHS as state groundwater quality enforcement standards. In accordance with s. 160.15, Wis. Stat., the department is required to establish by rule a preventive action limit for each substance for which an enforcement standard is established.

To develop proposed groundwater standards, DHS follows the process described in ss. 160.09 to 160.17, Wis. Stat. This includes a review of federal numbers, state drinking water standards, and acceptable daily intake values from the EPA, research studies and a search of peer-reviewed scientific research. DHS then develops a scientific support document describing the findings of their review and basis for the recommended proposed groundwater standards. At the conclusion of its review, DHS provided the department, in a document titled, Recommended Public Health Groundwater Quality Standards, Scientific Support Documents for "Cycle 10" Substances, June 2019, its recommendations for groundwater quality standards for the protection of public health.

DHS recommended new standards for 17 substances: perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), hexavalent chromium, strontium, thiamethoxam, imidacloprid, clothianidin, isoxaflutole, isoxaflutole DKN degradate, isoxaflutole BA degradate, thiencarbazone-methyl, Dacthal TPA and MTP degradates, glyphosate, glyphosate aminomethylphosphonic acid (AMPA) degradate, sulfentrazone, and Escherichia coli (E. coli) bacteria.

DHS also provided recommendations for revisions to existing public health related state groundwater quality standards for 8 additional substances: trichloroethylene (TCE), tetrachloroethylene (PCE), 1,2,3-trichloropropane (1,2,3-TCP), 1,4-dioxane, aluminum, boron, molybdenum and cobalt.

The department is proposing rules establishing the DHS enforcement standard recommendations as ch. NR 140, Wis. Adm. Code, state groundwater quality enforcement standards. The department is also proposing rules establishing ch. NR 140, Wis. Adm. Code, state groundwater quality preventive action limits in accordance with s. 160.15(1), Wis. Stat.

10. Analysis and Supporting Documents Used to Determine the Effect on Small Business or in Preparation of an Economic Impact Report:

Chapter 160, Wis. Stat., and ch. NR 140, Wis. Adm. Code, do not create independent regulatory authority. The enforcement of state groundwater quality standards is done by state regulatory agencies through regulatory programs that incorporate groundwater protection. State regulatory agencies, in exercising their statutory authority and duties that are established elsewhere in the statutes and administrative rules, establish regulations that assure that regulated facilities and activities will not cause state groundwater quality standards to be exceeded.

After the department establishes groundwater standards in ch. NR 140, Wis. Adm. Code, each state regulatory agency is required to review its administrative rules and amend or create rules necessary to ensure that the activities, practices, and facilities regulated by the regulatory agency complies with the new standards. S. 160.19, Wis. Stat.

The department anticipates that rulemaking activity in other regulatory programs may significantly decrease the cost of this groundwater standards rule. The department is in the process of promulgating a permanent rule adding numeric thresholds for PFOS and PFOA to the surface water quality standards. The surface water quality standards proposed rule includes WPDES permit implementation procedures for source reduction and treatment of PFOS and PFOA in wastewater discharges. Many of the industries and facilities governed by surface water quality standards would also be subject to the changes in this groundwater proposed rule. If the surface water quality rule is promulgated, the department anticipates the implementation and compliance cost of the proposed groundwater rule will substantially decrease. The WPDES permit program may also propose rules amending how the WPDES permit program regulates the land application of biosolids that contain PFOA and PFOS.

Any reasonable estimate of the implementation and compliance costs of this rule will be altered by the statutorily require review and ongoing promulgation of regulatory program rules outside the scope and authority of this rule. To comply with the directive in s. 227.137, Wis. Stat., the department analyzed and is providing a detailed quantification of the economic impact of the proposed rule, including the implementation and compliance costs that are reasonably expected to be incurred by or passed along to the businesses, local governmental units, and individuals that may be affected by the proposed rule, based on the current administrative and statutory authority in the regulatory programs that rely on groundwater standards.

To the extent possible, the department estimates average annual costs incurred by other regulatory programs and rules is $3,284,171 in any year over a 5-year permitting cycle and $9,537,243 maximum over any two-year period. The table below summarizes the categories of costs incurred for compliance and implementation. The department does not anticipate costs to regulated entities from the addition of standards for metals/metaloids, agricultural chemicals, and bacteria (see sections 3, 4, and 5 of Attachment C to the EIA). A detailed assessment of the estimated compliance cost associated with this rule can be found in the EIA narrative document (Attachment C).

Estimated Average Compliance Cost Per Year