Kelly-Ann UR, Are We There Yet?

     This week I was finally able to travel the length of the St. Johns River and test surface samples at five locations for total nitrate.  The day I chose to preform the transect was beautiful for field work.  Each location was at least partly sunny with a mild breeze.  I had started at the North part of the river, in Jacksonville, and traveled against the flow to take a total of five surface samples.  These samples were immediately placed in a cooler with ice packs. 

Taking a Surface Sample at Lake George

      Working on my own out in the field taught me to be adaptable.  I had originally decided that I wanted to take a sample one meter in at each site, however in two locations, Jacksonville and Sanford, I was only able to access the river via floating docks.  My GPS also proved to be better as a general guideline to the sites and could not always be trusted.  Twice it told me the park I was trying to get to was half way over a bridge.  I had gotten frustrated enough twice to pull over next to the river and take a sample instead of going in circles trying to find the exact site I had planned on.  

Testing for Nitrates

     Back in the lab I used method 10021 with a Hach DR/890 colorimeter to analyze the total nitrates in each sample.  The data surprised me, with nitrate levels much lower than I expected:

-Site one: 0.3 mg/L

-Site two: 0.1 mg/L

-Site three: 0.1 mg/L

-Site four: 0.1 mg/L

-Site five: 0.0 mg/L

The nitrates become more concentrated closer to mouth of the river, which was expected, however with the many possible anthropocentric sources of nitrates that I observed near several locations, I did think these concentrations would be higher.

     The last step to this project will be looking up what the acceptable levels of nitrate are for the St. Johns River, and what steps the St. Johns River Water Management District is taking to keep the river clear of excess nitrates.