River Bacteria

State Standards for bacteria

Recreational use:

  • 200 colonies of fecal coliform bacteria /100ml for primary contact recreation
  • 1000 colonies of fecal coliform bacteria /100ml for secondary contact recreation

Swimming beaches:

  • geometric mean of 33 enterococcus bacteria or 126 E.coli bacteria per 100 ml of water (fresh water)
  • geometric mean standard of 35 enterococcus bacteria per 100 ml of water for five samples over 30 days and an instantaneous (single sample) standard of 104 enterococcus bacteria per 100 ml of water (salt water).

River Sampling

**For the Mass. Department of Environmental Protection-approved SOP, get the pdf file here

Equipment

  • Sterile High Density Polyethylene (HDPE) bottle, 250 ml
  • Pair of latex gloves
  • Rinse water and towel
  • Field data sheet
  • Cooler with ice and koolits
  • Zip-loc bag (1 gallon size)

Sampling Protocol

Wash hands before starting run - if you sample in an area that may have high fecal levels rinse hands before handling the next sample bottle

Be careful not to touch your hands to yourself before you have cleaned them in order to avoid coming into contact with pathogens. If you are sampling from waters known to be contaminated with sewage, wear latex gloves to protect yourself

Sample should be taken from representative, flowing water.

Carefully wade in to the stream, walking upstream and avoid to stir up bottom sediment. Wait for pre-disturbance (from wading in) conditions to return before taking sample.

Take a sample in mid-stream, or if not possible, from as far out from shore as is safe. Keep the bottle closed until just ready to sample. Do not rinse the bottle. Point the bottle opening upstream, into the current. If there is no current, create a current artificially by pushing bottle forward horizontally in a direction away from the hand. Be sure not to collect any sediment, and avoid collecting any water from the surface layer of the river as this is uncharacteristic of the water flowing through.

Replace the cap, leaving 1" of air space in the bottle. It is important to leave the air space so that the sample will constantly mix while transported.

On field sheet, record sample ID and check the "Bacteria" column.

Transporting the Sample

Place sample bottle in cooler with ice. If you cannot put ice directly in your cooler because you store other materials in there, use a zip-loc bag filled with ice. Put your sample in that zip-loc bag, zip it shut and place in cooler with frozen koolit.

Deliver to lab within 6 hours of collection.