In 2007, MassDEP prepared an emerging contaminant screening process to identify contaminants that the agency needs to maintain an awareness of and/or actively address. This process was designed to help ensure that MassDEP would be aware of unregulated contaminants or contaminants that are not adequately regulated and would be prepared to take steps as necessary to protect public health and the environment. MassDEP's preliminary list of emerging contaminants is developed from database scans and based upon the knowledge of workgroup members and stakeholders regarding the presence of contaminants and potential exposure pathways, including awareness of high visibility issues. 

The first step in the screening process considered the following criteria:

  • Use of professional judgment regarding the importance of the contaminant issue;
  • Current and timely work on the contaminant by the U.S. Environmental Protection Agency (EPA) and/or other states to ensure MassDEP is not duplicating efforts;
  • Whether MassDEP or other agencies have or are working on a standard or guideline for the contaminant based on the most current scientific information; and
  • Consideration of MassDEP's jurisdiction and authorities to address the issue.

This screening process led to a Watch List of contaminants or contaminants that MassDEP would need to maintain an awareness of, because these chemicals are likely to be in the Massachusetts environment and more information is needed on them to determine if follow up action is warranted.

Step 2 of the screening process was to identify priority contaminants of which a subset would be nominated for the MassDEP Commissioner's consideration for agency action. This screening of the Watch List considered the availability of existing science on the contaminant, certainty in the science and a consideration of strategies that could be used to address each contaminant, including tangible outcomes. Higher priority was given to cross-media contaminants.

When the Emerging Contaminant Workgroup convened in 2013, it recognized that some of the emerging contaminants that were identified using the 2007 process are still emerging contaminants that MassDEP continues to work on in 2013 and most likely beyond. In addition, the Workgroup discussed that newly identified emerging contaminants could also be selected using different sources of information such as following:

  • The Toxics Use Reduction Act;
  • EPA's Unregulated Contaminant Monitoring Rule, in particular monitoring results for the occurrence studies of unregulated contaminants in Massachusetts public drinking water supplies;
  • Hazardous waste site sampling results and findings of unregulated contaminants at Massachusetts sites;
  • Field observations and reports on unregulated contaminants in the Massachusetts environment, such as algae blooms (and concern for cyanotoxins) in public drinking water supplies.

Using these relevant sources of information along with the first and second step screening processes described above has led to the identification of additional emerging contaminants and an updated 2013 Emerging Contaminant Priority List.

Emerging Contaminant List & Screening

Emerging Contaminant Screening Process Diagram


Preliminary List ~ 80 Contaminants

Based on:

  • Database scans
  • Knowledge of workgroup & stakeholders on the presence of the environmental contaminant & exposure pathways
  • High urgency and visibility issue

Screening Process: Step 1

Contaminant is screened out when:

  • It is not considered to be generally important;
  • Others (EPA, states) are addressing the issue adequately;
  • An existing MassDEP standard or guideline exists;
  • Jurisdictional issues

Result: Watch List ~ 30 Contaminants

Screening Process: Step 2


  • Certainty in science
  • Tangible outcomes
  • Cross-media contaminant

Result: Priority Emerging Contaminants ~ 10, of which 4 are nominated for short-term action.