By FRANK CARINI/ecoRI News staff
Bacterial contamination from enterococci, rod-shaped bacteria found in the human intestine and a good indicator of the presence of human waste, and fecal coliform are swimming around in much of Rhode Island’s fresh water.
This contamination from human waste — via failing septic systems and cesspools, overrun wastewater treatment facilities and malfunctioning sewer infrastructure — animal waste and other sources has impaired 57 waters in Rhode Island, rendering them unable to meet federal water quality standards.
Fecal coliform and enterococci levels are used as indicators of the presence of fecal material — human or animal — in drinking and recreational waters. Both indicate the possible presence of disease-causing bacteria and viruses. Such pathogens may pose health risks to people swimming or fishing in one of these impaired water bodies
Infections caused by pathogen-contaminated waters include gastrointestinal, respiratory, eye, ear, nose, throat and skin diseases, according to the Environmental Protection Agency (EPA).
Escherichia coli — E. coli — is another species of fecal coliform bacteria that is specific to fecal material from humans and warm-blooded animals, and may also be used as an indicator of pathogenic bacteria in fresh waters. (See: Moswansicut Stream, Scituate).
In fact, each gram of human feces contains about 12 billion bacteria that may include pathogenic bacteria, such as salmonella, according to the EPA.
Besides possibly impacting public health, such contamination can degrade aquatic ecosystems and could result in the closure of shellfish beds, beaches and/or drinking water supplies, according to the state Department of Environmental Protection (DEM).
To help address the problem, the DEM is drafting the Rhode Island Statewide Bacteria Total Maximum Daily Load (TMDL) — an enforceable document that will establish the allowable bacterial contributions for Rhode Island’s surface waters, provide documentation of impairment and specify the actions needed to reduce this contamination.
The DEM held two public presentations about the document last month, and officials hope to have the final draft approved by the EPA later this year.
The goal of this TMDL, according to DEM officials, is the “attainment of water quality standards.” It will establish both the regulatory requirements and recommendations for municipalities and other stakeholders to address pollutant sources contributing to the impairment through a community-based approach. These impaired waters will need to be continuously monitored and assessed.
Studies in marine and fresh waters indicate that enterococci are one of the surest bacterial indicators of water quality, which isn’t good news for the Rhode Island ponds, rivers, brooks and streams listed in the document. Of the 57 impaired waters cited in the TMDL, 48 have been impaired by the presence of enterococci.
In water bodies, both marine and fresh, the acceptable level of enterococci contamination is low. Suitable levels for enterococci in fresh water, from a single sample reading, should be between 61 and 151 colony-forming units (cfu) per 100 milliliters of water, according to the EPA. The Rhode Island standard is the low end of that range, and readings can fluctuate depending on many variables.
For example, Bailey’s Brook in Middletown, which is on the DEM list of impaired fresh waters and is a tributary to a public drinking water supply, has produced cfu readings as high as 9,804 (Sept. 15, 2007) and as low as 5 (Oct. 28, 2006) during the past five years.
Bailey’s Brook, however, isn’t the only freshwater body in Middletown giving state and local officials fits. The Town Council recently ordered a watershed assessment of the Maidford River and Paradise Brook, both of which are on the DEM’s list of impaired waters.
According to the DEM’s draft report, enterococci, fecal coliform and other potentially harmful bacteria may enter surface waters because of:
A malfunctioning wastewater treatment plant. In Rhode Island, in addition to the 19 major and two minor municipal wastewater treatment plants, there are three major and three minor industrial wastewater treatment plants that have the potential to discharge untreated or partially treated wastewater.
Development. Stormwater runoff is water from rain or snowmelt that flows over impervious surfaces, such as roofs, asphalt and concrete, isn’t absorbed into the ground and thus isn’t naturally filtered. As this runoff moves, it picks up and carries away natural and anthropogenic pollutants and eventually deposits them into surface waters.
Thirty-two percent of the Bailey’s Brook watershed, for instance, is covered with impervious surfaces and 68 percent of it is developed, according to the DEM.
In developed areas, stormwater is typically channeled into storm drains, discharging via outfalls to wetlands and surface waters — i.e., the five outfall pipes that discharge into Scarborough Beach. Stormwater runoff is one of the leading sources of impairment to the nation’s waters.
Sanitary sewer overflows. These discharges of untreated wastewater from sewer systems are caused by clogged or cracked sewer pipes, by excess infiltration and inflow, by undersized piping and/or by equipment failure.
Illicit discharges to stormwater systems. Examples of illicit discharges commonly seen in urban communities in Rhode Island include direct discharges, such as sanitary wastewater pipes connected from a home to a storm drain, and indirect illicit discharges, such as a damaged sanitary sewer line that is leaking wastewater into a cracked storm sewer line.
Boats. They have the potential to discharge harmful bacteria in sewage from installed toilets and greywater — drainage from sinks, showers and laundry. Sewage and greywater illegally discharged from boats can contain pathogens, nutrients and chemical products that can lead to water quality violations.
Onsite wastewater treatment systems. When properly installed, operated and maintained, such systems — i.e., septic systems — effectively reduce bacteria concentrations in sewage. However, poor maintenance, overloading, improper design and/or construction and age can result in system failure and the release of bacteria and other pollutants into surface waters.
Waterfowl, wildlife and pets. Fecal matter from wildlife can be a significant source of bacteria in some watersheds, especially when human activities, such as the feeding of wildlife and habitat modification, result in the congregation of wildlife. Concentrations of geese, gulls, and ducks are of particular concern because they often deposit their waste directly into surface waters. In fact, it is illegal to feed waterfowl.
Pet waste also can be a significant contributor. For example, each dog is estimated to produce 200 grams of feces daily, and pet feces can contain up to 23 million fecal coliform colonies per gram. If pet waste isn’t properly disposed, these bacteria can be washed off the land and transported to surface waters by stormwater runoff.
Agriculture. Agricultural land includes dairy farming, raising livestock and poultry, growing crops, and keeping horses and other animals for pleasure and/or profit. Activities and facilities associated with agricultural land use can be sources of bacteria impairment. Communities, farmers, horse owners and others who confine animals are largely responsible for mitigating bacteria pollution. Direct deposition of fecal matter from farm animals standing or swimming in surface waters, and the runoff of farm animal waste are considered the primary mechanisms for agricultural bacteria pollution in surface waters.
Other impaired fresh waters could be added to the list in the future, according to DEM officials.