Manistee Lake Association
Home	Picture Gallery	News Archive	Board Members	MLA Members Section

December 10, 2001 REPORT ON THE QUALITY OF MANISTEE LAKE WATER

In alternate years since 1995 students from the AuSable Institute have performed water quality studies on Manistee Lake.

In alternate years since 1995 students from the AuSable Institute have performed water quality studies on Manistee Lake. These studies recognized that the lake was in “good condition for a lake of its morphological features. Continued monitoring is important as a shallow lake can change quickly when placed in a stress situation. The lake must be protected from any further nutrient addition in the form of pollution from lawn fertilizers and septic fields” The 1998 report showed that the milfoil problem was severe and gaining with each successive year. Suggestions were made in ways to limit nutrients entering the lake and methods to eliminative the milfoil. Thus, the MLA was revived and actions were taken to control the milfoil that appears to be working. The 1999 and 2001 reports have raised additional issues of lake pollution. Thus, this is the first in a series of comparative data analyses to illustrate the possible decline in the quality of Manistee lake water. In this analysis we will look at fecal coliform contamination of lake water. As you review these analyses please bear in mind that the tests were performed by different students at different times using different methods of assaying and counting bacteria in lake water and do not constitute confirmed data. Rather, these data provides information on the water quality of Manistee Lake. It also illustrates a basis for concern regarding changes in water quality for as well as motivation to seek expert help in performing the analysis to confirm the students’ findings. The presence of bacteria in lake water is not unexpected since they are important to the decomposition process, which contributes to the overall quality of lake water. However, public health officials have been aware that the presence of fecal coliforms in drinking, river and lake waters is not natural and a cause for concern. These bacteria are found in the stomachs and intestinal tracts of warm-blooded mammals (humans, dogs, cats, cattle, etc.). If found in river, lake, drinking waters, etc their presence indicate fecal contamination. Since the fecal-oral route is a major route of infection in a variety of infectious diseases public health requirements have been set on the total numbers of these bacteria that are allowable per volume of water for various waters. For example no coliforms (total and fecal) are permitted in drinking water; less than 200 fecal coliforms per 100 mL of water for total body contact (swimming or bathing) and less than 1000 fecal coliforms for partial body contact (boating).   NOTE: The sites around the lake at which the water samples were taken (approximately 3 feet from shore in all cases) are illustrated on the map of Manistee lake (appended).   Table I Samples taken August 1999   Lake site Fecal coliforms (per 100 mL) Total colifoms (per 100 mL) Percent fecal coliforms (per 100 mL)   1 0 66 0 2 0 1650 0 3 33 1848 1.8 4 99 5544 1.8 5 66 3168 2.0 6 0 1221 0 7 33 3036 1.1 8 0 3234 0 9 33 1848 1.8 10 0 561 0 11 33 858 3.8   Table II Samples taken August 2001   Lake site Fecal coliforms (per 100 mL) Total coliforms Percent fecal coliforms (per 100mL)   1 233 233 0 2 200 200 0 3 133 5727 2.3 4 166 11088 0.3 5 133 2897 4.5 6 400 766 52.2 7 67 1699 3.9 8 500 766 65.3 9 ? ?699 ? 10 0 2498 0 11 0 3630 0 12 200 7620 2.6 13 0 1499 0 14 5761 15418 37.4 15 33 ? 100 16 0 1798 0 17 0 1232 0 18 233 899 25.9   The majority of coliform test sites in years 1999 and 2001 are not in the same areas. However, there are 5 sites that are relatively close to each other in both of the years. These are shown below for comparative purposes.   Table III Comparable Coliform test sites   1999   2001 Site FC TC %FC   Site FC TC %FC 1 0 66 0   2 200 200 0 5 66 3168 2.0   15 33 33 100 4 99 5544 1.8   10 0 2498 0 11 33 858 3.8   6 400 766 52.2 9 33 1848 1.8   17 0 232 0 FC=Number of fecal coliforms         TC=number of total coliforms   The data in the above table show that two sites had an increase in the numbers of fecal coliforms in 2001 and in 1999 no coliforms were present. Some interesting trends can be noted that illustrates fecal contamination may be at work in Manistee lake. In 1999 the numbers of fecal coliforms in all survey sites were below 200 which allows water contact. In the 2001 survey the number of sites that showed numbers of coliforms at 200 and above increased to seven. In the comparable site analysis two sites showed fecal coliform numbers at 200 and above. However the total number of coliforms in all sites in the 2001 survey also increased significantly. This illustrates that these studies are just preliminary and should not be interpreted as conclusive but rather should be viewed as a reason for concern that our lake is showing increased contamination. We must take immediate steps to confirm these results with professional analysis and if confirmed take quick action to reduce the contamination before even the slightest contact with lake water will be considered a serious problem.   Donald C.Thomas Secretary, Manistee Lake Association

Story submitted by:     Donald Thomas

News Archive