|Harbor Sampling Update|
August 28 - September 1, 2000
By Dr. David I. Taylor
Environmental Quality Department
MWRA Sewerage Division
Bacteria counts were generally low. Counts of fecal coliform bacteria met the state swimming standard at all 11 stations monitored in the Harbor. The state swimming standard is 200 colonies per 100 milliliters.
Enterococcus counts exceeded the state guideline at 3 stations, all off Deer Island. At these stations, counts ranged from 155 to 6,860 colonies per 100 milliliters. The guideline for Enterococcus is 33 colonies per 100 milliliters.
Dissolved oxygen levels met the state water quality standard at all Harbor stations. Concentrations in the bottom-waters ranged from 5.8 milligram per liter to 8.0 milligram per liter, well above the standard of 5 milligram per liter.Water clarity was as in previous weeks, 1 m to 2 m in the shallow bays (Dorchester, Quincy and Winthrop bays), and 2 m to 3 m in the Outer Harbor. Water-color in the Harbor was turbid green.
Wildlife. Schools of small pelagic fish were seen in the Outer Harbor off Deer Island. They also continue to be seen along the edges of the Harbor. Comb jellies were again seen in the Outer Harbor this week. Their numbers this year appear to be lower than last year, perhaps because of the lower Harbor salinities this wet summer.
Bacteria counts were low over most of the Charles River. At only 2 of the 11 stations did fecal coliform counts exceed the state swimming standard. The two stations, which were located in the uppermost Charles, had counts of 240 and 325 colonies per 100 milliliters.
Very low dissolved oxygen levels were observed at the lower most 5 stations. At these stations, concentrations in the bottom waters ranged from 1.9 to 3.8 milligram per liter on Aug 29, and from 0.4 to 5.2 milligram per liter on Aug 30.
Water clarity in the Charles was poor, and approximately 1.0 m at most stations. Water- color was turbid brown. Our sampling crew reported small oil slicks (possibly from boating activity) on the water surface at two stations.
Wildlife observed by the crew included Canada geese, domestic geese, Great Blue Herons, and turtles. The turtles sunning on the banks of the Charles tend to be larger than the turtles in the Mystic.