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Technical Memorandum: Review of MWRA Water Quality Monitoring Results to Address Potential for Harmful Effects of the Deer Island Discharge on Threatened and Endangered Species in Massachusetts Bay
Citation:
Hagy, Jim, Tim Gleason, A. Oczkowski, A. Tatters, AND Y. Wan. Technical Memorandum: Review of MWRA Water Quality Monitoring Results to Address Potential for Harmful Effects of the Deer Island Discharge on Threatened and Endangered Species in Massachusetts Bay. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-22/063, 2022.
Impact/Purpose:
To assist US EPA Region 1 in addressing questions and concerns related to reissuance of the administratively continued NPDES discharge permit for MWRA’s Deer Island water treatment facility, EPA Region 1 requested that a review team from EPA’s Office of Research and Development evaluate the data and analyses included in recent MWRA water column monitoring reports. The charge to the team was to evaluate how these data and analyses address the potential for the discharge to cause environmental effects that could harm North Atlantic right whales (Eubalaena glacialis) or other threatened and endangered species that utilize habitats in Massachusetts Bay. This document is the result of the the review team's discussions and deliberations and will be delivered to EPA Region 1, which will determine how the document may be used to support their permitting activities related to the Deer Island discharge. At the discretion of EPA Region 1, the document may be released to the public as a component of information considered by EPA to support decision making.
Description:
To assist US EPA Region 1 in addressing questions and concerns related to reissuance of the administratively continued NPDES discharge permit for MWRA’s Deer Island water treatment facility, EPA Region 1 requested that a review team from EPA’s Office of Research and Development evaluate the data and analyses included in recent MWRA water column monitoring reports. The charge to the team was to evaluate how these data and analyses address the potential for the discharge to cause environmental effects that could harm North Atlantic right whales (Eubalaena glacialis) or other threatened and endangered species that utilize habitats in Massachusetts Bay. The key conclusions reached by the review team are as follows: The MWRA reports do not show evidence that the discharge is currently harmful to North Atlantic right whales (Eubalaena glacialis) or that it is likely to cause harm in the future. However, these data also do not provide evidence for the opposite, namely that such an impact is not already occurring or that it would be unlikely in the future. These data and additional evidence documenting related biological changes across the Gulf of Maine suggest that Massachusetts Bay is experiencing a shift in biological and oceanographic regimes. The regime shift increases the scientific uncertainty regarding the role of the discharge in supporting HABs in Massachusetts Bay and resulting effects of HABs on the marine food web, including whales. The MWRA water column monitoring results document biological changes both near the discharge and across Massachusetts Bay principally characterized by seasonal increases in the abundance of several harmful algal bloom (HAB) species including the dinoflagellates Alexandrium catenella since 2005 and Karenia mikimotoi since 2017. Although there is little evidence that HABs are harming whales in New England, North Atlantic right whales in New England are currently exposed to saxitoxin and domoic acid, HAB toxins that elsewhere in the world have harmed and killed whales and other marine mammals, seabirds, and marine fisheries. Ship strikes and entanglement in fishing gear are the main anthropogenic cause of mortality of North Atlantic right whales. However, marine HABs currently present a relatively unpredictable, increasing, and potentially serious threat to North Atlantic right whales. Therefore, a cautious approach is warranted that includes continued monitoring of ecological changes near the outfall and in the surrounding areas of Massachusetts and Cape Cod Bays. Monitoring should be adjusted to focus on the most pertinent environmental concerns and their potential relationship to the discharge, while reducing effort to monitor issues that have been resolved significantly via decades of monitoring.