Question 11. Summarize your findings from the Water Quality Lab. Be sure to include your observations and the sources of each water-quality issue you investigated.

Nitrates can lower oxygen level in the water because of that the fish were killed and small fish could be poisoned.

Base on the data and the finding I conclude that Nitrates can lower oxygen level in the water and because of it, the fish were killed and also the small fish could be poisoned. I hope you are satisfied with my answer and feel free to ask for more clarification. Have a nice day