In the Spotlight
Monitoring Program Documents
Harbor Remediation

Fifteen years ago, Boston Harbor was characterized as the most polluted harbor in the United States. A shallow marine estuary, the Harbor is a final receptacle of pollutants and excess nutrients from rivers and streams throughout eastern Massachusetts. The combination of decades of nonpoint source pollution from urban runoff and an antiquated sewage treatment system has resulted in serious water quality and human health concerns.

“Battelle, under this contract, is our best consultant yet.” —Dr.Michael Mickelson, Massachusetts Water Resources Authority

As part of a court-ordered plan to clean up the Harbor, the Massachusetts Water Resources Authority (MWRA) constructed the largest sewage treatment facility in the United States, including a new 9.5 mile ocean outfall brought online September 6, 2000. MWRA was required to develop and implement a monitoring program to document recovery of the Harbor and verify that discharge through the new offshore sewage outfall will not adversely impact Massachusetts Bay.

Under contract by MWRA, Battelle developed a multi-dimensional monitoring program that is the most comprehensive program of its kind in the nation. The program includes:

Water column studies. To address nutrient loading to Massachusetts Bay and possible changes to phytoplankton and the food web, Battelle completed baseline field, laboratory and modeling studies to evaluate the dynamics of nutrients and related parameters in the region. Post-discharge monitoring which began in September 2000 will determine impacts of the effluent release.

Fate and transport studies. Sediment samples are collected and analyzed for a suite of chemical contaminants, microbiological parameters and sewage tracers. Studies showing improvement of sediment quality near combined sewer overflows have also been completed. Results to date indicate that sediment quality in Boston Harbor is improving.

Sediment monitoring stations in Massachusetts and Cape Cod Bays were established to answer concerns that the Harbor’s problems would be transported into outlying waters.

Benthic response. Battelle is addressing concerns over the impact on the soft-bottom benthic community through a sampling program in both Boston Harbor and Massachusetts Bay. Annual sampling is conducted at eight stations in the Harbor and 27 stations in the Bay. In addition to conventional benthic community analysis, sediment-penetrating camera systems and video imagery are used to evaluate sediment conditions. The program also includes photographic and video surveys of hard-bottom communities found near the Bay outfall.

Fish and shellfish. Public health concerns related to consumption of fish and shellfish are being addressed through measurement of trace metal and contaminant organic chemical concentrations in winter flounder and lobster. Flounder health is examined through the histopathology of flounder liver collected from five locations in the harbor and bays. Battelle is also evaluating bioaccumulation of potential contaminants through caged mussels deployed each summer at key locations in the Boston Harbor/Massachusetts Bay system.

Pathogens and viruses. MWRA is also required to collect data to comply with shellfish-growing water regulations, and to assure that the operation of the outfall in Massachusetts Bay does not adversely affect shellfish-growing waters. Battelle conducted surveys to document sewage indicators such as fecal coliform and Enterococcus at specific locations in Massachusetts Bay to define baseline conditions. These data will be used to compare pre-discharge bacteria counts to bacteria counts after the outfall operation and evaluate the water quality of the “conditional” classified shellfish-growing waters surrounding the discharge point.

The monitoring program also includes an extensive effort to evaluate the presence and levels of a wide variety of human enteric virus pathogens. The studies are evaluating potential for hazards to public health due to anthropogenic viruses in Combined Sewer Overflow receiving water and wastewater treatment plant receiving water, including Boston Harbor, its tributary rivers, and Massachusetts Bay. Correlative data is being developed.

Special studies. Battelle has conducted several surveys in Boston Harbor and Massachusetts Bay using the Battelle Ocean Sampling System (BOSS) to characterize background water properties and to locate and track the sewage effluent and past sludge discharge plumes in the Harbor. The resultant data indicated that much of the sewage effluent previously discharged at the mouth of the Harbor was rapidly exported to the Bay. This information has proved critical to assessing the transport of sewage in the Harbor and is presently being used to guide modification of fate and transport models.

Plume Tracking. Battelle has designed an extensive plume tracking effort to be conducted in 2001 to determine the initial dilution characteristics of the outfall and to track the long-term location and mixing dynamics of the outfall plume. A tracer dye will be added to the effluent stream at Deer Island Treatment Plant over a period in mid summer of 2001 to maintain a constant concentration. The release at the diffuser will be sampled with a suite of sensors towed through the water providing high-resolution, in-situ measurements of the dye concentration, salinity, temperature, density, turbidity, dissolved oxygen, and chlorophyll. These data will be used to evaluate the initial dilution of the outfall and to verify that the NPDES permit dilution requirements are met.

In October 2000, MWRA awarded Battelle a one-year extension of its contract to support the Harbor Outfall Monitoring Program. For more information about Battelle’s monitoring capabilities, please contact Carlton D. Hunt (781) 952-5374, huntc@battelle.org.