Road Salt Runoff - Impact on Macroinvertebrates and Water Quality
Macroinvertebrates are critical food resources for higher trophic level predators in freshwater food webs. Salt contamination due to road de-icing can often produce a dense saline layer just above the sediment–water interface potentially exposing benthic macroinvertebrates to high salt concentrations. Reported impacts on salinity increase on macroinvertebrate communities are varied. However, generally it is noted that some species may develop tolerance to higher salinity concentrations and that macroinvertebrates still act as good ecological indicator species in regard to water quality. This study explored the potential impacts road salt application may have on river chemistry and its macroinvertebrate community composition. Additionally, the potential of molecular method, environmental DNA (eDNA), was investigated by comparing the results from kick sampling to those of the eDNA. The results from the study did not show any significant differences between sites affected by road salt runoff and those not. Additionally, it was noted that the eDNA method identified wider variety of species than kick sampling and morphological identification. In water quality analysis showed sodium, copper and zinc showed a significant difference between sites affected by road salt runoff and those that were not. Additionally, conductivity that was used as a measure for salinity showed significant difference between affected and unaffected sites. Thus, it is concluded that within the scope of this study, the macroinvertebrate communities sampled do not seem to display a significant correlation between salinity changes and the species abundance.
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