E. Coli as Sole Indicator of Water Pollution Questioned

In Ireland, bacterial contamination of water is a national concern, with the Environmental Protection Agency reporting that over 25% of groundwater samples were contaminated with E. coli in the 2004 to 2006 period. E. coli is the most important indicator used in Ireland and its presence indicates water is unfit for human consumption. It has long been thought that E. coli can only survive for short periods of time in the environment, hence its almost universal use as an indicator of recent faecal contamination of waterways.

However, new research investigating pathogen survival in Irish soils conducted by Teagasc Johnstown Castle Environment Research Centre and NUI Galway has found that E. coli can become integrated into the indigenous microbial community in soils and survive for more than nine years, considerably longer than scientists initially thought.
"This has important implications for the indicator status of E. coli, suggesting that the presence of E. coli in surface or groundwaters may not be indicative of recent faecal contamination," explains researcher Fiona Brennan in TResearch, the Teagasc Research and Innovation magazine.
"It also suggests that E. coli persistence may be favoured in some soil types and these soils may represent a greater risk of bacterial leaching," she explains. Research conducted at Johnstown Castle has investigated bacterial transport in grassland soils both in situ at field sites and in field lysimeter (soil monolith) units.
In conjunction with NUI Galway, Teagasc researchers are now using proteomics to investigate the unique properties of E. coli that allow it to persist in the soil for such long periods. Initial findings have found that the environmentally persistent E. coli produce specialised proteins, including 'cold shock' and 'stress response' proteins, which may assist in the survival and growth of the organism at lower temperatures. E. coli's ability to survive for prolonged periods of time in soil may compromise its use as the sole indicator of faecal contamination of water.

Toward Long-range Beach Forecasts On Bacterial Contamination

Long-range forecasts of beach bacterial contamination are inching closer to reality because of a new water quality prediction method scheduled for publication in the July 15 issue of the ACS' Environmental Science & Technology, a semi-monthly journal.

"For the first time, this study showed that bacteria concentrations could be forecasted with reasonable accuracy, hastening the day when people will be able to better plan their beach holidays," the report says.
In the new study, Walter E. Frick and colleagues explain that decisions on whether beaches are safe for swimming, or should be closed due to fecal contamination, are based on testing the water for E. coli. However, existing tests take 24 hours to complete, providing a backward-only look at conditions the previous day. As a result, beaches may be closed unnecessarily when water quality has improved, or open when water quality has declined and disease-causing microorganisms are present.
Building on pioneering modeling studies in the Great Lakes by the U. S. Geological Survey (USGS) and others, the researchers developed "Virtual Beach," a broadly-applicable software tool for the development of models that predict concentrations of indicators of fecal contamination at beaches. Unique features of Virtual Beach are the ability to evaluate a dynamic modeling approach for using short-term data sets to rapidly develop reliable models, and the use of available weather and marine forecast variables to forecast E. coli levels 24 hours or more in advance.
Evaluations of Virtual Beach were accomplished using data collected by USGS, NOAA and other sources for Huntington Beach on Lake Erie in northeastern Ohio. During the 42-day study, models developed by Virtual Beach correctly forecasted 24 hours in advance eight instances when E. coli levels exceeded safety standards. These results exceeded the accuracy of traditional sampling methods and approximately matched the accuracy of nowcasting (real-time predictions), according to the researchers.
Journal reference:
Frick, Walter E., Ge, Zhongfu, and Zepp, Richard G. Nowcasting and Forecasting Concentrations of Biological Contaminants at Beaches: A Feasibility and Case Study. Environ. Sci. Technol., 42, 13, 4818-4824, 2008 DOI: 10.1021/es703185p
Adapted from materials provided by American Chemical Society, via EurekAlert!, a service of AAAS.

Experts say avoid Saginaw Bay muck Ecoli bacterial threat

Scientists and health officials are warning people to avoid muck along Saginaw Bay beaches, saying it contains bacteria levels more than three times the amount that make a beach off-limits to swimmers. Joan Rose, a Michigan State University water microbiologist, leads a science committee studying the dead algae. It has been washing up on the region's beaches in increasing amounts for the past six years.During a public meeting this week, Rose reported on two samples taken from a private beach at Port Austin in Huron County. She estimated a handful has up to 1,000 colonies of E. coli bacteria.The committee is advising residents to avoid the muck until more testing can be done and a standard developed for E. coli levels in dead algae."I think there is a risk just like there is with raw chicken in your house," she said, according to a Friday story in The Bay City Times.High levels of E. coli also have been found in muck tests paid for by residents in Hume Township near Caseville.Area residents have long complained about dirty goo oozing out of the Pinnebog River and into the Lake Huron bay. State officials have said it's mostly dead plant material and there likely are many sources.Some shoreline residents blame large livestock farms in the county, while the farmers point to failing septic systems along the waterfront.The science committee advised people who touch the muck to wash their hands thoroughly with soap and water.Other suggestions included keeping beaches clean of trash, using toilet facilities, using appropriate areas for diaper changing, cleaning up food debris and staying out of the water when ill, the Huron Daily Tribune reported.