Environmental Testing of Ocean Water

MEL can test salt water, though we don't get a lot of call to do so, yet (we welcome your inquiries, aquaculture farmers!).  In the meantime, we include this page to inform you about the common types of ocean water testing that goes on in Maine.

The Maine Healthy Beaches Program monitors the water quality of about 60 beaches in Maine.  Their mission is to keep beach users safe from bacterial pollution. When a beach tests positive for certain bacteria, the Maine Healthy Beaches program gets the word out and posts closures. Their army of volunteers typically tests for temperature, salinity, and enterococcus bacteria on a weekly basis from Memorial Day to Labor Day (the peak recreation months of summer).

Government  regulation has done a lot to eliminate practices that used to pollute the water, such emptying sewage directly in to shoreland recreation zones, but the system is still susceptible to accidental discharges and inadvertent overflows after heavy rains and spring flooding are not uncommon.

The main barometer used to measure the bacterial cleanliness of salt water is a test for enterococci bacteria.  Enterococci is an indicator organism that points to the presence of even more unsavory companions, such as fecal coliform bacteria and other pathogens.  Enterococci are measured in colony-forming-units per 100mL of water.  A result higher than 104 cfu/100mL is considered high enough to trigger resampling or to post a temporary beach closure. Results of bacteria tests at your favorite swimming beaches are archived with the EPA (link below).

In Maine, the State Laboratory Certification body accepts the following methods for testing for enterococcus: SM9230, EPA1106, EPA600, EPA1600, and Idexx's Enterolert.  Method ASTMD5259, published in 2014, is not yet accepted in Maine.

The Future of Ocean Water Testing

In addition to the State's already established testing program for Red Tide and related biotoxins, the growth of salt-water aquaculture in Maine waters should bring with it increased testing for nitrogen and phosphorus pollution from dense communities of confined fish, even in areas where tides perform a cleansing function.


Maine Healthy Beaches:  http://www.mainehealthybeaches.org/

Maine Healthy Beaches "Bacteria Fact Sheet": http://www.mainehealthybeaches.org/documents/Bacteria_Fact_Sheet.pdf

Maine Center for Disease Control "Recreational Water Illness" (webpage): http://www.maine.gov/dhhs/mecdc/infectious-disease/epi/healthyswimming/index.shtml

State of Maine Shellfish Sanitation and Management webpage: https://www.maine.gov/dmr/shellfish-sanitation-management/index.html

Biotoxin Information: Maine Department of Marine Resources: https://www.maine.gov/dmr/shellfish-sanitation-management/programs/biotoxininfo.html#Testing

EPA Beaches (webpage): https://www.epa.gov/beaches

EPA Beach Advisory and Closing Online Notification (aka BEACON) Maps - zoom in to see recent results for salinity, enterococci and temperatures from beaches near you: https://watersgeo.epa.gov/beacon2/beacon.html

[INTERESTING READ - WHERE THE STANDARD CAME FROM:] Federal Register "Water Quality Standards for Coastal and Great Lakes Recreation Waters" (2004):  https://www.federalregister.gov/documents/2004/11/16/04-25303/water-quality-standards-for-coastal-and-great-lakes-recreation-waters

Gulf of Maine Research Institute (website) - this non-profit conducts local ocean monitoring work of all parts of the ecosystem: https://www.gmri.org/

Wikipedia, "Enterococcus": https://en.wikipedia.org/wiki/Enterococcus

Maine Healthy Beaches sign post.  Photo by Joe Shlabotnik.

Maine Healthy Beaches sign post. Photo by Joe Shlabotnik.