A public meeting at Carney Hospital next week will detail the findings of a much-anticipated report on water quality in the Neponset River - and on whether two industrial dams, including the Baker Dam in Lower Mills, should be removed or altered.

The meeting, scheduled for 7 p.m. on Thursday, Dec. 13 in Carney's second floor Cushing Auditorium, will be the first public airing of a new report commissioned by the state's Riverways program, which has been studying the impact of the dams and a related problem: the existence of high levels of PCBs that are trapped in sediments behinds the dams and in river muck throughout the lower Neponset. Environmental activists have long called for the elimination of the dams to clear passage for native fish species, many of which spawn in the river. More recently, data suggesting that PCB contamination may be exacerbated by the defunct dams has raised new questions about whether the structures pose an even greater hazard to fish life or humans.

In a report published in the Nov. 15 edition of the Dorchester Reporter, experts familiar with the details of the new report indicated that the study will show that PCB remnants are traveling over the Baker dam in Lower Mills and into the Neponset River estuary at levels greater than anticipated, endangering certain marine life.

According to representatives of the Neponset River Watershed Association (NepRWA), preliminary results from testing done over the last year-and-a-half indicate that an average of 25 pounds of PCBs - otherwise known as Polychlorinated Biphenyls - are being released into the river and estuary each year from sediments caught behind the Baker Dam. A similar problem is also releasing PCBs into the river from the Tileston-Hollingsworth Dam in Hyde Park, site of a former paper mill. The chemical remnants, which are embedded in sediments that have built up behind the dam over many years, are typically released when storm events stir up the mud and muck that have trapped the pollutants.

NepRWA, which advocates for the dams' removal, have already begun recruiting activists from Dorchester and Mattapan civic associations to form a community advisory group that it plans to launch next year to further advocate for dam removal and remediation of the sediments.

In a related move, the Massachusetts Department of Environmental Protection (MassDEP) and the Department of Conservation and Recreation (DCR) will host a second meeting next week in Hyde Park to discuss plans to continue testing surface soils along the river for PCB deposits. That meeting will be held on Monday, Dec. 10 in the Menino Hall at the Hyde Park Library, 35 Hyde Park Ave. from 6 to 7:30 p.m.

The sampling project, set to begin this month, is aimed at assessing whether dredging projects conducted in the 1960s may have left PCB deposits along the shoreline. The project will focus on eight separate areas along the Neponset Riverway trail from the Baker Dam in Dorchester to the Neponset Valley Parkway in Readville. A small percentage of the testing, officials say, will be conducted on private property.

For more information on the Riverways meeting on Dec. 13, contact Gabrielle Stebbins at the state's Riverways office at 617-626-1571.