PADEP Proposes Classifying Manganese as Toxic Substance, Revising Water Quality Criteria

August 3, 2020

In the July 25, 2020, edition of Pennsylvania Bulletin, the Pennsylvania Department of Environmental Protection published its “Water Quality Standard for Manganese and Implementation” as the proposed revisions to water quality criteria for manganese as advanced by the Environmental Quality Board (EQB) last December.

Act 40 of 2017 directed the Department to present to the Environmental Quality Board regulations listing manganese as an exception in 25 Pa Code 96.3(d), with the intent to move the water quality criteria found in Chapter 93 (currently 1 mg/l) to the water intake instead of the facility’s discharge point. However, PADEP has resisted compliance with Act 40, instead proposing to classify manganese as a toxic substance.

The rulemaking package proposes to remove the current 1 mg/l Water Quality Standard in 25 PA Code § 93.7 and to add manganese to the list of toxic substances in 25 PA Code §93.8c, Table 5 at 300 ug/l or 0.3 mg/l on the basis of the potential for the ingestion of manganese to cause certain neurological effects.

Public water systems in Pennsylvania are currently required by 25 PA Code Chapter 109.202(b) to not exceed 0.05 mg/L of manganese in finished drinking water.

According to the National Institute of Health, manganese is an essential trace element and is involved in amino acid, cholesterol, glucose, and carbohydrate metabolism; reactive oxygen species scavenging; bone formation; reproduction; and immune response. The current Adequate Intake (AI) for manganese is 2.3 mg/day for adult males and 1.6–2.6 mg/day for adult females.

PADEP is requesting comments on two alternatives for the point of compliance: either at the intake of the first public water system downstream of the facility or in the surface water at a facility’s discharge point.

Comments on the proposed regulation are due by September 25, 2020. According to the eComment listing for the proposed rulemaking, virtual public hearings will be held on September 8 at 2:00 p.m., September 9 at 6:00 p.m. and September 10 at 2:00 p.m.

Submitting Comments to the PADEP

  • Via online comments (eComment) *preferred method*: If an acknowledgement of comments submitted online is not received by the sender within two business days, the comments should be re-sent to the EQB to ensure receipt.
  • Via email ( A subject heading of the proposed rulemaking and a name and address must be included with each transmission. If an acknowledgement of comments submitted via email is not received by the sender within two business days, the comments should be re-sent to the EQB to ensure receipt.
  • Via written comments: Mail your comments to Environmental Quality Board, P.O. Box 8477, Harrisburg, PA 17105-8477.

All comments must be received by the EQB on or before the close of the public comment period on September 25, 2020.

We’ll keep you updated on the status of this newly proposed criteria so that we can help you determine if your next project could be impacted. If you have any questions, please contact Scott Rasmussen (724-327-5200 or

About the Author

Scott Rasmussen

Scott is a Principal in our Environmental Engineering and Sciences Practice and works out of our Monroeville office. He has more than 37 years of experience in conducting and managing environmental assessment and compliance projects at mining, industrial, commercial, and residential properties.

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