On July 23 of this year, a significant number of dead trout were found in the Huntley River. The subsequent investigation revealed that approximately 2000 fish died in the section of the river between route 2 and Gordon's Pond. The incident corresponded with exceptionally heavy rains the previous evening. During the investigation, samples of water, sediment and fish were collected for analyses. The focus of the investigation by the Department of Technology and Environment is not of a legal nature, and findings to date do not indicate wrong doing by any individual.
"Preliminary results suggest that several factors, all apparently related to run-off from the land may have played a role in the death of the fish" indicated George Somers, Head of the Groundwater Section. "Additional analyses of samples is continuing, and completion of the full investigation will take at least weeks, possibly months."
"Conclusions from autopsies of the fish appear to rule out infection or disease as the cause of death, and are consistent with suffocation or toxic stress. Any number of factors could account for these symptoms, and further analyses of fish samples may be conducted pending a fuller understanding of water quality results."
Results of initial analyses indicate that several pest control products were present in water and sediment samples, and there is also some indirect evidence that there may have been high ammonia levels in the water. One possible source of ammonia would be from the application of urea type fertilizers. Sufficiently high concentrations of either of these compounds could explain the death of the fish by suffocation or toxic stress. In addition, sediment loads were high, and cannot be ruled out as a contributing factor. Land wash from adjacent fields is the most likely pathway by which these contaminants would reach the river.
It is difficult to determine with certainty whether the concentration of these compounds, either individually or in combination, would have been lethal to fish, especially where the analytic results represent the conditions at the time of sampling, not at the time of the fish kill some hours earlier. Further work on water quality analyses is continuing.
Mr. Somers indicated "The Department is deeply concerned about these events, particularly with respect to their severity and regularity. This incident, and others like it over the past few years, highlight the pressing need for Government to work closely with stakeholders to address the issue of soil erosion and related impacts on the aquatic environment. Properly engineered buffer zones along water courses to prevent the concentrated discharge of run-off water and any associated contaminants will be an important strategy in reducing the likelihood of similar occurrences in the future."