Sampling Lake Michigan
April 24 2009 | Blue Water Task Force,
by Mara Dias
The following Q&A; with Matt discusses the highlights of the beach monitoring program.
Q - Tell us about the current water testing program, what is the overall objective?
M - We’re testing the water at the popular surf breaks on both sides of the Grand Haven channel. We’re looking for E. coli and Enterococcus because these bacteria are indicators of other pathogens that can make people sick. The Ottawa County Health Department does a great job of testing the beaches from Memorial Day to Labor Day but we tend to surf a lot more during the Spring, Fall, and Winter so we decided to take matters into our own hands and start our own testing program to make sure we aren’t surfing in contaminated water.
Q - What can you tell us that you have learned so far? (ie does temperature affect ecoli, turbulence, etc).
M - Well, so far, we can say that the water around Grand Haven has had pretty low bacteria counts, especially when the water is really cold. This has been a nice surprise since we really had no idea what we would find in the Fall, after the Health Dept. finishes their sampling for the year.
Q - Does the data collected so far confirm or deny your initial theories on water quality in GH?
M - Since the project focuses on ‘surf days,’ which also tend to be the rainy and nasty days with a lot of muddy runoff in the river, I expected to see more high bacteria counts than what we’ve found. Of course, this is good news for all of us who spend time in the water.
Q - Can we make any conclusions at this time based on the rain events last fall?
M - We’re going to continue testing while we still have funding but so far, we have no reason to think that the water is too polluted to surf. We’re blessed with a beautiful beach, a lot of Spring and Fall surf, and it appears that water quality is pretty good as well.
Q - What does the data mean?
M - To determine whether we are exposing ourselves to nasty ‘bugs’ (bacteria, viruses, etc.) associated with human waste when we’re surfing and kiteboarding at the Grand Haven and Ferrysburg breaks, we are testing for E. coli, and Enterococci. These particular bacteria are found in the digestive tracts of humans and, in fact, they generally don’t cause us any harm (it’s not the same strain of E. coli that makes us sick). However, when we find them in high numbers at the beach, it’s a pretty good indication that other nasty pathogens are present which could make us sick. We will be collecting water samples on most ‘surfable’ or ‘kiteable’ days from now until the ice sets in. We’ll pick it up again after the ice is gone in the spring. Sampling locations include the Grand Haven State Park and north of the pier on the Ferrysburg side.
The numbers that we will report are ‘Colony Forming Units’ (CFU) per 100 milliliters. You can think of this as the number of viable bacteria cells in a 100 milliliter sample. For E. coli, as long as the number stays below 300 CFU per 100 ml for a single day, there’s little cause for concern. For Enterococci, as long as the numbers stay below 104 CFU per 100 ml it’s safe to surf. Of course, these numbers are merely thresholds that the U.S. Environmental Protection Agency has established for recreational waters. This does not mean that at 275 E. coli CFU there’s no chance of getting sick or at 325 CFU you will contract every nasty ailment known to man. The number that we will report are geometric means (a type of average) of at least 3 separate samples collected in approximately 3 to 4 foot of water. We are also collecting additional data including water temperature, wave height, longshore current, weather conditions, and the number of people in the water.
This program was funded in part (roughly two-thirds) by a grant from the Norcross Wildlife Foundation and by you, the local surfers (roughly one-third). Pathogen monitoring has been contracted to the Annis Water Resources Institute of Grand Valley State University. For additional information, contact Matt Cooper (616-331-8790, firstname.lastname@example.org).