Report of
the Water Quality Committee
July 8,
2010
In an effort to improve water quality, and particularly
water clarity, and reduce the amount of algae, we have learned some things, but
still have much further to go.
1.
With aid from the U of Maine laboratory in Orono, we had them analyze for the pesticides normally used
on blueberries—Velpar, Terbacil,
and Propiconazole. They found no (at one location), or only
traces (at two locations), of Velpar, barely above
the limit of detection. Even assuming
that a person consumed all of their water from the pond (unwise!) the margin of
safety would be huge—approximately a million.
2. We sampled at the shoreline from six
locations shown on the map. It appears
we should in the future add a seventh location, the deepest area in the pond. That is the area of greatest concern because
that is where the “dead zone” is located, the deeper level where there is no
dissolved oxygen.
This is the only location used by the DEP when analyzing the lake, and
may often be the only location we will use in the future.
3.a. Nitrate and phosphorus are below the limits
of detection by the methods we used. These were good quality analysis kits from
a reputable manufacturer and recommended for this purpose. Both levels however, and especially that of
phosphorus, even though not detectable by these methods, are apparently still
high enough to permit algal growth.
b. Our next step in analysis will be to
look for a more sensitive kit for phosphorus,
(and its cost) and to explore with two water quality labs the cost of one
analysis for phosphorus.
c. Because a common source of
phosphorus contamination is run-off from dirt and gravel roads, we will be
checking road conditions around the pond, and perhaps doing sampling for
phosphorus from those locations.
4.
We sampled for detergent at all locations and found
none detectable by a method sensitive to at least 0.1 parts per million.
5.
We will need to borrow or improvise a kit for
sampling dissolved oxygen and temperature at various depths from the deepest
part of the pond. State analyses over
the years have shown a dead zone (totally lacking in oxygen) in the deepest
part. This is the result of decay of
algae and other plant life on the bottom.
We will also look into borrowing, or (only with approval) buying, a more
expensive, but far more convenient means for measuring dissolved oxygen.
6.
We will be contacting the state and several
commercial laboratories to determine the cost of running microbiological
samples.
7.
We will use the Secchi disk
method for measuring water clarity at the deepest point, and report on the
results.
8.
We will be contacting a person knowledgeable about
water quality issues in
Brian Friedmann, Dick Hall, Joe
Jordan, Dana Shaw