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Scientists from the Maryland Department of the Environment descended upon an Anne Arundel County neighborhood in search of clues. We knocked on doors and put dye into plumbing systems. We walked an industrial area and found failing septic holding tanks. One scientest descended into a manhole, looking for ways that bacteria might be fouling the nearby creek.
When the Furnace Creek Sanitary Survey was complete, seven possible violations of environmental law were referred to local authorities for further investigation.
The field study, which took place over a few weeks in January and early February, is the latest bit of detective work designed to uncover the causes of longstanding bacterial pollution in Furnace Creek. The Northern Anne Arundel County creek was also among the areas described in a report last summer on sources of contamination in area waterways.
Water samples, originally collected by the Anne Arundel County Health Department for beach monitoring, characterized the impairment and documented the non-attainment of required bacteria standards. A joint effort between Salisbury University and MDE employed MDE’s Bacteria Source Tracking (BST) protocol to identify the sources of contamination. This protocol uses antibiotic resistance analysis to determine the source(s) of bacteria. The BST study, which occurred between December 2007 and November 2008, concluded that the profile of bacterial contamination is most likely 33 percent from human sources, 29 percent from pets, and 38 percent from wildlife. As a result, the Maryland General Assembly requested a thorough study because “human sources” pose the greatest health risk and can be reduced.
MDE’s Shoreline Survey Program was asked to identify and document potential human sources of bacteria pollution in the immediate drainage basin surrounding Furnace Creek. The Program primarily determines pollution sources that have the potential to adversely affect the surrounding water quality of shellfish harvesting waters. A team of inspectors, who visit approximately 1,500 properties each year to determine pollution sources, addressed the human sources such as the public sewer system (infrastructure and pumping stations), onsite waste disposal systems (septics), and the residential population.
A review of the sewer system overflow history identified two overflow events from the Hammerlee pumping station during the time the BST work was being conducted. One overflow occurred on the same day a BST water sample was being collected. Both incidents may have contributed to the human signature that was identified in the bacteria population of these samples, but they are not likely to be the primary or ongoing source of human bacteria throughout the year.
The MDE team even asked that a manhole cover be removed to allow a look at underground pipes near the creek. No sign was found of any leak that could have contributed to the bacteria near a monitoring station in the waterway.
The majority of the onsite waste disposal (or septic) systems were functioning properly. The field teams attempted to inspect 40 properties and ultimately injected dye into toilets (a dye tracer test) to determine if the system was properly controlling pollution on 28 of those systems. Three properties refused access while nine others were not home (including weekend attempts). Two residential properties and four commercial properties were possible sources of bacterial pollution. Two of these were well-removed from Furnace Creek and therefore highly unlikely to have affected the water quality.
The investigators confirmed that a houseboat in the creek was occupied, but attempts to inspect were denied. If the waste generated on this boat had not been handled properly, it would constitute a perpetual human signature source and confirmed contribution to the creek’s impairment.
During these investigations, the field teams thoroughly documented all potential sources of bacterial contamination. Two homeless camps were discovered in a heavily forested section of the creek. Each site had a quantity of trash strewn about and, although these were not “occupied” at the time of the survey, this type of activity could be a source of bacteria to the water body.
The team also surveyed several commercial properties just outside the mouth of Furnace Creek. Some were found with failing septic systems or holding tanks. One was seen to have sanitary piping going into the ground. The field team was asked to make an appointment for an inspection - and when they returned they found the piping had been removed. Because of the distance of the commercial properties from Furnace Creek, it is questionable whether the human signature seen in water samples from the monitoring station could be attributable to these sources.
All documentation was forwarded to the appropriate agencies for follow-up enforcement and corrective action. Bacteria Source Tracking helped identify the major categories of contamination in Furnace Creek and, in conjunction with intensive field work identifying those pollution sources, a positive step was taken to reduce public health concerns while improving the water quality of the creek.
A postscript: The Department of Natural Resources reported that the houseboat sank not long after MDE sought access thereby eliminating a suspected significant contributor of bacterial contamination to the creek. Enforcement action is still pending.
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