PURPOSE:

This study was part of an EPA grant to Cohasset High School’s Summer Institute Program to assist the Gulf Association with its water quality monitoring program. The Gulf Association members expressed concern about the fecal coliform level in the Gulf River. Therefore, students at CSCR conducted water quality tests monitoring the fecal coliform levels in the Gulf River.

INTRODUCTION:

Fecal coliform are bacteria found in the feces of warm-blooded animals and humans. The bacteria can enter bodies of water from discharged sewage, storm runoff, and directly from mammals and birds. By themselves, fecal coliform bacteria aren’t harmful. However, it is an indicator of pathogenic organisms present in the water. In high fecal coliform counts (over 200 colonies per 100 ml of water) the chance that pathogenic organisms are present is greater. Pathogenic organisms include bacteria, viruses, and parasites that cause disease. Pathogenic organisms may infect individuals who swim in waters with high fecal coliform counts.

For recreational waters such as the Gulf River, the Massachusetts Surface Water Quality Standard for Bacteria states that fecal coliform counts must be less than or equal to 200 colonies /100 ml. This "magic number" of 200 colonies per 100 ml of sample water is determined by calculated the geometric mean of a representative set of samples taken over a period of 30 days. Four or five samples within this 30-day period constitute a representative sample. Recreational waters that meet this standard are healthy waters for primary (swimming) and secondary (fishing and boating) recreation. (Mitchell and Stapp, 25). Due to this statement, a group of students at CSCR conducted a water quality test to check the safety of the Gulf River.

MATERIALS FOR FIELD WORK:

- Sterile sample containers
- Thermometer
- GPS (Global Positioning System)
- Cooler
- Ice packs
- Pipette
- Refractometer
- Distilled water
- Felt tip marker
- Paper towel

FIELD PROCEDURE:

1. Once the site of sampling is reached, label the container with the site and date.
2. Fully submerge the container at least six inches.
3. Open the container (still submerged) and wait until it is completely filled. Be sure not to take it out of the water until the cap is tightly screwed back on. It is imperative that the sample is in no contact with the air.
4. Place the sample in a cooler and surround it with ice packs until testing. Samples should be maintained at 4 degrees Celsius.
5. Take the temperature at the site.
6. Note the tide.
7. Make observations of the weather over the past day or so.
8. To take a salinity reading, place a drop of distilled water on the Refractometer. If it is calibrated the instrument should read zero. If it isn’t calibrated take a screwdriver and slightly turn the knob at the top of the device until it reads zero. Once calibrated, place a drop of sample water on the lens of the refractometer and record salinity. Find the coordinates of longitude and latitude of the sight using the GPS. Record latitude and longitude.

LAB MATERIALS:

- ‘Fisherbrand’ FinnPippette
- ‘Millipore’ Filtration System
- Filter beaker
- Stopper
- Filter paper
- Clamps
- ‘Precision Scientific’ Incubator bath
- Tweezers
- Isopropyl alcohol
- Nutrient Broth
- Matches
- Distilled Water

LAB PROCEDURE:

1. Before running the filtration system, place a piece of filter paper on the stopper. Be sure the plastic on each side is peeled off without being touched with anything but sterile tweezers. You can quickly sterilize the tweezers by dipping them in isopropyl alcohol and putting them in the flame of a match.
2. Next, clamp together the filter beaker on top of the stopper.
3. Then pour 100ml of sample water into it and run the system. After all the water has gone through flush some distilled water through the system.
4. After that you should do a dilution. Take the FinnPippette (model #J64136) and set it to 10ml. Insert a new cartridge into the device and fill it with water. Pour it into the filtration system. This is 10ml of water so add 90Ml of distilled water into the filtration system and turn it on.
5. Put one tube of nutrient broth into each petri dish.
6. Using sterilized tweezers, carefully take off the filter paper, making sure to not let anything touch it. Place the filter paper into each dish. For each sample put its dilution and regular filter paper into separate petri dishes.
7. When all samples have been run through the filtration system double bag all of them and place them in the incubator.
8. The water in the incubator should be heated to 44.5 degrees Celsius. Leave the samples there for 24 hours.
9. Clean up the lab, including anything that needs to be sterilized. Put glassware into the autoclave and turn it on.
10. Return to the lab within 23-26 hours to take the samples out of the incubator for examination.
11. When a dish is opened there should be tiny blue dots present on the filter paper. These are bacteria colonies. Count the colonies on each dish and record the data.

ANALYSIS:

The main trend of the data seems to indicate that when the salinity values fall below 25 parts per thousand (ppt), then the fecal coliform counts are elevated.  When salinity values are 25 ppt or higher, the fecal coliform counts tend to fall between 50-150 colonies, which is within the acceptable range for swimming.  (The standard in Massachusetts for recreational waters is below 200 colonies for every 100 ml).

Our results seem to indicate that the tide is one variable related to changes in fecal coliform counts. The counts closest to the bridge (Shockman) at the mouth of the river have lower counts than Gannet Mushquashcut and Gannet Canoe that are farther up the river. However, to confirm these results, more testing will be required.

Chart 1: Shockman: (view chart)
The geometric mean of samples taken at the Shockman site was 69.17. This suggests that fecal coliform contamination is not a problem at this end of the Gulf River. There was only one count that was noted as TNTC, or too numerous to count. This sampling event was assigned the value of 201. Most of the counts under 200 seemed to have a salinity value of around 32 ppt, suggesting that ocean influences are significant at this site.

Chart 2: Hartshorne: (view chart)
The geometric mean of samples taken at the Hartshorne site was 80.60. Two times the counts were zero; only one time did we find a TNTC result. Similar to the Shockman site, the counts that were below 200 had a salinity value of around 30, again suggesting that tidal influences are strong at this section of the river.

Chart 3: Malley: (view chart)
The geometric mean of samples taken at the Malley site was 152.69. There were three times that the count was too numerous to count and two additional counts of 194 and 247. Although reasons why counts might be elevated at this site are still unknown to us at this time, we have noticed that the geometric mean of counts tends to be higher as one moves further away from the harbor.

Chart 4: Gannet Mushquashicut: (view chart)
The geometric mean of samples taken at the Musquashicut site was 138.98. There were four times that the count was too numerous too count. These TNTC results, however, were significantly higher than 200 while the salinity was much lower on those days suggesting that fresh water sources were more influential at this site.

Chart 5: Gannet Canoe: (view chart)
The geometric mean of samples taken at the Canoe Club site was 205.36. This exceeds the Massachusetts standard for safe use of recreational waters. Six samples were either noted as TNTC or counted at 354 and 342. Salinity values were low when tide was low at this site suggesting that fresh water influences are significant at this site. Furthermore, dissolved oxygen levels were lowest at this site providing further evidence that this site requires additional investigation.

CONCLUSION:

It appears that as one moves from the mouth of the Gulf River to its upper reaches fecal coliform counts tend move from below the acceptable standard to above that standard. (See Chart 6, "Overview of Geometric Mean of Key Sampling Sites.") Further investigation of this trend is needed.

RECOMMENDATIONS:

Recommendations for further testing center upon improved consistency in data collection. To meet this goal, new field data sheets have been created for use during each field sampling event. These new data sheets will allow for better notation of weather conditions, wildlife observations, time, water temperature, salinity, and GPS notations. This will make the data tables more useful for interpretation of the data. Better consistency in these areas would produce more accurate analysis.

In addition, as recommended by Dr. Oscar Pancorbo of the Massachusetts Department of Environmental Protection, enterococci testing will replace fecal coliform testing. New methodologies will ensure greater quality control and produce more "actionable" data.

WORKS CITED:

Massachusetts Department of Environmental Protection, Standard Operating Procedure for SM9222D, Division of Environmental Analysis, Senator William X. Wall Experiment Station 37 Shattuck Street Lawrence, MA 01843.

Mitchell, Mark K., Stapp, William B., Eleventh Edition Field Manual for Water Quality Monitoring An Environmental Education Program for Schools, Dubuque, Iowa 1997, Kendall/Hunt Publishing Company.

   The Summer Institute is a series of Cohasset Middle High School courses that use the outdoor environment as the primary classroom. CSCR is proud to partner with Cohasset Middle Senior High School as host of many of these courses.

   Established 5 years ago with a pilot research program in Little Harbor and a Maritime Studies course, the Summer Institute has grown into 6 courses involving dozens of students and 10 teachers. Summer Institute courses are built upon the premise that students learn best when actively engaged in learning activities. The courses are designed to expose students to a variety of topics through outdoor experiences that maximize use of New England's unique environment and history.

   Students enrolled in Summer Institute courses receive credit equal to course credit earned during the traditional school year and are, therefore, expected to successfully complete comparable academic work.

How to enroll in a Summer Institute course:

• Cohasset Middle High School students:
  complete the application form and give it directly to the teacher offering the course.
  
  
• All other students:
  print out and complete the application form and mail with appropriate payment (made payable to CSCR) to the following address:
  
  Attention: Summer Institute
  CSCR
  40 Parker Avenue
  Cohasset, Ma. 02025