Macroinvertebrate Testing
Ideally, the macroinvertebrate testing sites would match the sites where the physical/chemical testing took place. However, some of those sites were not appropriate for macro testing due to inaccessibility or other factors. Two sites – O’Neil Woods and Granger Road at Crystal Lake – were accessible and appropriate, and were tested.
Ideally, the macroinvertebrate testing sites would match the sites where the physical/chemical testing took place. However, some of those sites were not appropriate for macro testing due to inaccessibility or other factors. Two sites – O’Neil Woods and Granger Road at Crystal Lake – were accessible and appropriate, and were tested.
The macroinvertebrates that were identified and quantified by the sampling fall into three groups according to their sensitivity to pollution, including silt and sand (sedimentation from water runoff): (1) sensitive; (2) somewhat sensitive; and (3) pollution tolerant. The more diversity of types of macroinvertebrates, especially in the first group (pollution sensitive), the better the water quality. This is quantified by first categorizing the macroinvertebrates by species, then counting the number found in each species. A letter code is assigned according to the count, e.g. A = 1 to 9; B = 10 to 99; and C = 100 or more. However, the number of each type species found in its specific species category is not taken into account in the final overall score for the sampling. That is, it does not matter whether the count was 8 or 88. It is the pollution sensitivity of the species and the number of types found that determine the final score.
