Regulation Changes: Bacteria, Organic Carbon and Testing, Oh My!

March 23, 2021

By: Meredith Wheeler

The potential aggregate effect to aquatic lifeforms from all pollutants confined within a facility’s wastewater is tested by means of Whole Effluent Toxicity; it is part of the implementation of the Clean Water Act to monitor the discharge for toxic contaminants.

This testing is used by the National Pollutant Discharge Elimination System regulators to determine if a facility is in compliance with protocols. The EPA Region 1 is the regulating authority for all permits relating to Maine, New Hampshire, Massachusetts, Vermont, Connecticut and Rhode Island. The regulations and limits have been, and continue to be, updated which causes issues if applicants are not reviewing their permits closely. As of late, there have been two changes that have caused clients to erroneously label their required testing:

  • Up until roughly 2015, freshwater permits had language that stated

“The permittee shall conduct acute and chronic toxicity tests on effluent samples using two species, Daphnid (Ceriodaphnia dubia) and Fathead Minnow (Pimephales promelas) following the protocol in Attachment A.”

Recently the EPA regulators have reformed this language slightly by stating the following,

“The permittee shall conduct acute and chronic toxicity tests on effluent samples using two species, Daphnid (Ceriodaphnia dubia) and Fathead Minnow (Pimephales promelas) following the protocol in Attachment A and B.”

What Does This Mean and Why Does This Matter?

As you can see, if permittees weren’t closely analyzing wording, what separates these are the words “and B”. This breaks from the long-standing method of testing in which two pertinent endpoints (C-NOEC and LC-50) were obtained from the same assay, and instead necessitates permittees to have a separate assay for each endpoint. In addition to the very slight word shift in testing procedures, there are newer monitoring requirements. Of these (the most noteworthy) has been the addition of Dissolved Organic Carbon for freshwater dischargers, and an increase in Enterococcus testing and a new reporting limit for seacoast dischargers.

  • Required monitoring of ambient Dissolved Organic Carbon
    • In the past, as long as the discharged effluent was monitored and treated properly with slight adjustments if necessary and deemed non-toxic, it was safe to discharge the effluent into the respective receiving waters with minimal monitoring. The EPA and Region 1 became aware that metals, Aluminum in this case, is important to monitor for discharge purposes and its reasonable potential as it is non-essential to aquatic life and can be toxic in minor volumes. In this case, the Dissolved Organic Carbon analysis is crucial to calculate an Aluminum value.For example; Aluminum has the capability to decrease the ion-regulating (such as salt) function of fish gills via accumulation, which can cause mortality or affect growth and reproduction, therefore distressing the health and preservation of a population.

Isn’t Organic Carbon A Good Thing Though?

  • Yes! To an extent. If you’ve ever seen a water system that looks like it is muddy, or tea-colored, that’s because it’s high in organic carbon. The muddy appearance can block light that’s required by phototrophs to survive. By monitoring organic carbon, regulators also have the ability to target facilities that might be subjecting water systems to more organic material than it can handle. The concern here is that when organic carbon is in excess, more oxygen is consumed due to increase in the growth of microorganisms that require high oxygen demand. This causes acidification in systems that might already have a low buffering capacity.

By monitoring Dissolved Organic Carbon, regulators can track the health of water systems and laterally perform calculations based on additional water qualities (pH and Hardness) to create a, specifically Aluminum, reference limit that would lessen the reasonable potential impact on the environment.

  • Increase in Enterococcus testing and imposed reporting limits for the seacoast
    • Specific to the seacoast, Enterococcus bacteria testing is monitored for tidal waters utilized for swimming purposes. This is more related to public health monitoring for human interaction with potential harmful bacteria, however dischargers that contain high amounts of this bacteria can also impact organism health due to the potential infections that can result from overexposure. Therefore, by monitoring the effects, regulators can stay ahead in public outreach to determine if an area utilized for swimming purposes should become temporarily closed until the bacteria can be cleared.

Does This Have To Do With the Shellfish Program?

  • Nope! The Shellfish Program is primarily concerned with Fecal Coliform and coli, not as much with Enterococcus (although it is an additional indicator of contamination). These bacteria are related to sewage and/or feces of mammals and birds. These bacteria can survive in both freshwater and saltwater which can severely impact water qualities and be dangerous to human health and aquatic life. Enterococcus, for example, can affect the quality of life in fish and invertebrates when found at high levels. This might not be easily seen as it does not necessarily lead to acidification of a waterbody. Specifically, water systems that house shellfish can become impaired for human consumption if there are presence of fecal coliforms.

Overall, as regulators update the NPDES monitoring requirements, it is critical that applicants review their permits regularly and send it to the testing facility that is ensuring defendable data. These changes might mean that projects become more complex as supplementary testing is becoming required from an overall compliance perspective.

If you have questions about your permit or want to learn more about our services, start a conversation with us now.

Meredith Wheeler
Project Manager
Meredith brings over a half a decade of experience in project management, general laboratory and toxicology work in the National Pollutant Discharge Elimination Systems and currently works in our Hampton, NH lab. She is passionate about client interfacing and assisting in understanding permits. She holds a Bachelor’s degree in Biology from Roger Williams University and is usually seen both at work and outdoors with her rescue shepherd, Jameson.

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