Water Quality Monitoring

Water Quality: 

Water sampling in 2010 was accomplished by Roger Williams, Sandy Williams, Panos Pitsas, and Chet Hurd with help from VLAP Coordinator, Sara Steiner.   We sampled in June, July and August and plan to do the same in 2011.


As it turns out the best way to test for mercury is testing fish from the lake.  We brought a few small mouth bass to the VLAP lab in Concord at the end of the summer.  Fish & Game had also submitted some Silver Lake fish for mercury testing.  The mercury readings were low and these fish would be considered safe for consumption. See results:

April 12, 2011

Volunteer monitors, along with the U.S. Environmental Protection Agency, the New Hampshire Department of Fish and Game, and the New Hampshire Department of Environmental Services (DES) have played a significant part in collecting fish throughout the state for mercury analyses.  DES now processes the fish specimens and provides the data to make some very important decisions that have serious implications to both human and animal populations.  The purpose of this effort is two-fold:  To better characterize the levels of mercury that are accumulating in the fish that live in our state’s waterbodies, and to develop fish consumption advisories to protect human health.

DES is now able to report the mercury results from twelve fish submitted from Silver Lake, Harrisville during 2010.

Collection Date Fish Type Length (cm) Weight (grams) Mercury (ppm)
08-Aug-10 Small Mouth Bass 23.5 135 0.1386
08-Aug-10 Small Mouth Bass 20.5 90 0.128
08-Aug-10 Small Mouth Bass 20.5 99 0.1171
08-Aug-10 Small Mouth Bass 16 50 0.0859
08-Aug-10 Small Mouth Bass 23.5 145 0.129
08-Aug-10 Small Mouth Bass 24 150 0.1731
08-Aug-10 Small Mouth Bass 24 168 0.1348
01-Jul-10 Small Mouth Bass 22.5 142 0.1231
01-Jul-10 Small Mouth Bass 25 174 0.1379
01-Jul-10 Small Mouth Bass 23 119 0.2724


In general, small and large mouth bass, eastern chain pickerel, and yellow perch tend to have higher mercury levels.  Trout in general tend to have lower mercury levels because they are raised in fish hatcheries and later released into water bodies.  Landlocked salmon also tend to have low levels (however, this is based on limited information).  It is recommended to avoid consuming small/large mouth bass, eastern chain pickerel and yellow perch greater than 12 inches in length.

DES recommends the following mercury level ranges as guidance:

 Mercury Levels (ppm)*             Guidance Category*

< 0.6                                         Safe to consume

0.61 – 0.99                                Caution

> 1.0                                         Red Flag

*Note these recommended ranges and categories are not officially established as such, but were developed as a relative guidance forNew Hampshire.

There are several areas of the state where we have limited fish mercury data.DES, along with New Hampshire Fish and Game and volunteer monitors provide the majority of fish analyzed for mercury.  We encourage continued monitoring of fish mercury levels inSilverLake.  I have attached an information sheet describing the proper fish collection procedure.

Thank you for interest in the mercury in fish program!

Jody Connor                                                 Sara Steiner

LimnologyCenterDirector           VLAP Coordinator