BALTIMORE (April 28, 2004) – Water samples collected by the Maryland Department of the Environment (MDE) on Monday, April 26, 2004 show that bacteria levels in the Corsica River pose minimal public health risk.
Water samples were taken at three points upstream from where the Centreville wastewater treatment plant feeds into Gravel Run and four points downstream from the plant. They were tested for E. coli and Enterococci, which are more accurate indicators of the presence of illness-causing bacteria than fecal coliform.*
Water was tested for Enterococcus at points 0.8 miles, 2.7 miles, 4.5 miles and 5.5 miles downstream in the Corsica River. Bacteria levels ranged from less than 10 colony forming units (CFUs) per milliliter (mg/ml) to 31 CFU/ml. The standard for full-contact swimming is 104 CFU/ml or below.
While Enterococci levels in the Corsica River were low, water sampled along Gravel Run and Three Bridges Branch upstream from the plant showed high levels of both E. coli and Enterococcus. The source(s) of the bacteria could not be identified and may be attributable to any warm-blooded animals, including wildlife.
“Testing will continue for as long as necessary to ensure that the Centreville plant is operating safely,” said Kendl P. Philbrick, Maryland secretary of the environment. Philbrick said that MDE has been testing effluent from the plant daily since mid-April
Test results of effluent taken earlier in April and released last week showed fecal coliform, pH and dissolved oxygen at safe levels. A recurring problem with chlorine levels, which had fluctuated between high and acceptable levels, may have been solved when the plant operator repaired a faulty motor at the last stage of water treatment, where chlorine is neutralized.
The earlier tests showed that total suspended solids, biochemical oxygen demand and phosphorus were marginal or high, reinforcing the need for the new plant now under construction in Centreville. (Test of water samples shared by MDE and the plant operator, Miller Environmental, during the last two weeks have relatively similar results.)
For more than two months, the Environmental Crimes Unit of the Attorney General’s Office has been investigating allegations of an illegal bypass and non-reporting of significant sewage spills at the plant lodged by a former town employee. MDE compliance officers have been at the plant nearly daily since April 13. The plant had been operated by town employees, but at the beginning of April, Centreville hired Miller Environmental to operate the plant.
* Freshwater is tested for E. coli. Saltwater is tested for Enterococci.
Summary of Bacteriological Results for Samples Collected at Centerville, 4/26/2004 (.pdf)