Wisconsin Administrative Code › Department of Natural Resources › NR 100-199 - Environmental Protection General › Chapter NR 140 - Groundwater Quality › Subchapter III - Evaluation and Response Procedures › Section NR 140.24 - Responses when a preventive action limit is attained or exceeded

Current through June 24, 2024
(1)
				  NOTIFICATION AND ASSESSMENT. If the concentration of a substance, including
				  indicator parameters, in groundwater attains or exceeds a preventive action
				  limit at a point of standards application as described in s. NR 140.22 (2):
(a) The owner or operator of the facility,
				  practice or activity shall notify the department in writing when monitoring
				  data is submitted that a preventive action limit has been attained or exceeded
				  in accordance with any deadlines in applicable statutes, rules, permits or plan
				  approvals. Where no deadlines are imposed, the owner or operator shall notify
				  the department as soon as practical after the results are received. When the
				  results of any private well sampling attain or exceed a preventive action
				  limit, the owner or operator of the facility, practice or activity shall notify
				  the department within 10 days after the results are received. The notification
				  shall provide a preliminary analysis of the cause and significance of the
				  concentration.
Note:
Section
					 292.11(2) (a),
					 Stats., requires that the department be notified immediately of hazardous
					 substance discharges.
Note:
See s. NR 140.27.
(b) Upon receipt of the notice under par.
				  (a), the department shall evaluate the information and, if further information
				  is required to make the assessment under par. (c), direct the owner or operator
				  to prepare and submit a report by a specified deadline. The report shall assess
				  the cause and significance of the increased concentration based on a
				  consideration of the factors identified in par. (c) and shall propose a
				  response to meet the objectives of sub. (2).
(c) The department shall assess the cause and
				  significance of the concentration of the substance in determining the
				  appropriate response to meet the objectives of sub. (2). In addition to all
				  other relevant information, the department shall consider the information
				  submitted under par. (b) and the following factors where applicable:
1. Background water quality.
a. The department shall compare background
				  water quality data and monitoring data from wells downgradient of the facility,
				  practice or activity to determine if downgradient water quality is adversely
				  affected. If the background water quality at a facility, practice or activity
				  is not known or is inadequately defined, the department may require additional
				  sampling of existing wells, or installation and sampling of additional wells,
				  or both.
b. Except for substances
				  which are carcinogenic, teratogenic or mutagenic in humans, before requiring a
				  response at a site where the background concentration of a substance is
				  determined to be equal to or greater than the preventive action limit, the
				  department shall determine that the proposed remedial action will protect or
				  substantially improve groundwater quality notwithstanding the background
				  concentrations of naturally occurring substances.
2. Reliability of sampling data. As part of
				  its review of the quality of the sampling data, the department shall evaluate
				  the sampling procedures, precision and accuracy of the analytical test, size of
				  the data set, and the quality control and quality assurance procedures used. If
				  there is insufficient information to evaluate the reliability of the sampling
				  data, the department may require additional samples or other changes in the
				  monitoring program at the facility, practice or activity.
3. Public health, welfare and environmental
				  effects of the substance. The department shall consider the public health,
				  welfare and environmental effects of the substance, including but not limited
				  to its mobility in the subsurface, environmental fate, the risks considered
				  when the standard was adopted and whether it is carcinogenic, mutagenic,
				  teratogenic or has interactive effects with other substances.
4. Probability that a preventive action limit
				  or an enforcement standard may be attained or exceeded outside the design
				  management zone. In evaluating the probability that a preventive action limit
				  or an enforcement standard may be attained or exceeded outside the design
				  management zone, the department shall consider, at a minimum, geologic
				  conditions, groundwater flow rate and direction, contaminant mobility in the
				  subsurface and environmental fate.
5. Performance of the facility, practice or
				  activity. The department shall consider whether the facility, practice or
				  activity is performing as designed in accordance with the design requirements
				  in s. NR 140.22 (1). The department shall consider the type, age and size of
				  the facility, practice or activity; the type of design, if applicable; the
				  operational history; and other factors related to performance of the facility,
				  practice or activity as appropriate.
6. Location of the monitoring point. The
				  department shall consider the location of the monitoring point in relation to
				  the facility, practice or activity and the design management zone in assessing
				  the appropriate response.
7. Other
				  known or suspected sources of the substance in the area. If other known or
				  suspected sources are present in the vicinity of a facility, practice or
				  activity of concern, the department shall evaluate the probability of
				  contributions from other sources of the substance. The department shall
				  consider, at a minimum, the number, size, type and age of nearby sources; the
				  groundwater flow patterns; and the substances involved.
8. Hydrogeologic conditions. The department
				  shall consider the geologic and groundwater conditions, including but not
				  limited to the nature, thickness and permeability of the unconsolidated
				  materials; the nature and permeability of bedrock; the depth to the water
				  table; groundwater flow gradients, both vertical and horizontal; the position
				  of the facility, practice or activity within the groundwater flow system; and
				  the present and potential groundwater use in the vicinity of the facility,
				  practice or activity at which an exceedance occurs. If there is insufficient
				  hydrogeologic information, the department may require additional
				  information.
9. Extent of
				  groundwater contamination. The department shall consider the current and
				  anticipated future extent of groundwater contamination in 3 dimensions. If
				  water supplies are affected or threatened, the department shall evaluate the
				  existing effects and potential risks of the substance on the potable water
				  supplies. If the extent of contamination is not known, the department may
				  require further documentation of the extent of contamination.
10. Alternate responses. The department shall
				  evaluate alternate responses, including consideration of the technical and
				  economic feasibility of alternate responses from Table 5 or 6 or both, the
				  practicality of stopping the further release of the substance and the risks and
				  benefits of continued operation of the facility, practice or activity and the
				  ability of a response to meet other applicable environmental protection
				  laws.