Background
The Hoosic River has its headwaters in northern Berkshire County and runs through downtown North Adams before ultimately joining the Hudson River in Stillwater, NY. As with many other U.S. rivers, elevated levels of bacteria have been documented in much of the Hoosic River in Massachusetts, and this contamination poses a threat to human health. Over the past several years, the Massachusetts Department of Environmental Protection, the Berkshire Regional Planning Commission, and MCLA have been investigating water quality and point sources of bacterial pollution to this river.

During the summer of 2012, MCLA ENVI students Felipe Aedo and Richie Doucette collected and analyzed hundreds of samples of stream water from the Hoosic River and its tributaries in Massachusetts to identify remaining “hotspots” of bacterial contamination (defined as locations with > 500 colonies of E. coli per 100 mL water). Hotspots of bacterial contamination exhibit E. coli concentrations that are much higher than the water quality standard for the Hoosic River, which is 235 MPN colonies per 100 mL.

Bacterial contamination of surface water is generally measured using “indicator bacteria”, which are usually not harmful themselves, but rather “indicate” the likely presence of other pathogenic microorganisms. E. coli is one of these indicator bacteria; most strains are not harmful to human health, but these bacteria are present in animal guts along with other microorganisms that are harmful to people. Thus, high levels of E. coli suggest that other dangerous bacteria, viruses, and/or protozoa are probably present.

In lab this week, we will be collecting water samples from locations flagged by previous studies and partnering organizations as possible hotspots.

After collecting our water samples, we will begin the process of analyzing their E. coli concentrations, and then the following day we will return to the lab to complete the analyses and read our results.

Instructions
We will collect water samples, as well as a field blank, in sterile plastic containers (and we will wear gloves and properly handle this possibly polluted water). All samples will be stored on ice until they are brought back to the lab for processing.

In the lab, I will show you how to use the Colilert enzyme substrate test to determine E. coli concentration, as well as how to run dilutions. We will also discuss several quality control procedures.

Write-Up
All of the data collected at and up-gradient from the storm water outfall pipe adjacent to Domino’s Pizza on River St. is herePreview the document.

Please write a formal lab report for this activity following the formal lab write-up instructions.

Our research question is, “where might contamination be entering the storm system in North Adams?”

You should describe the location of this study and the methods we employed.