BOSTON — In conjunction with the Charles River Watershed Association and the Mystic River Watershed Association, EPA is announcing water quality report card grades for calendar year 2012, according to a press release.

These report cards represent the 18th and seventh public reporting on bacterial water quality conditions for the Charles River and Mystic River Watershed, respectively, since kicking off collaborative efforts addressing water quality issues in these urban rivers, stated the release.

This year EPA announced a grade of “B+” for the lower Charles River. The grade is based on bacterial contamination found in analyzed samples collected by the Charles River Watershed over the past year at ten monitoring sites from the Watertown Dam to Boston Harbor.

The Mystic River Watershed received a great of “D” from EPA this year. The grade is based on bacterial contamination found in analyzed samples that were collected by volunteers over the past year at fifteen monitoring sites throughout the watershed.

Read the entire press release here.