Are there any times of the year when your site’s water source has a stronger concentration of nitrates? Speculate why this may be the case.
Consider the following excerpt from an article "High Nitrate Levels Plague 60 Iowa Cities, Data Show". In July, 2015, the Des Moines Register reported the following:
Identifying the sources
The EPA says nitrate threats can come from several sources, including farm fertilizer runoff, septic system leaks and movement of naturally occurring nitrates in the soil. Des Moines Water Works has blamed farming for the high nitrate levels that it has paid more than $1 million since 2013 to treat.
Across the state, many communities get below the federal cap by blending water from several underground wells or river collectors with differing nitrate levels. Still, that might not be enough for some towns, which could be forced to invest millions of dollars in new equipment or wells to ensure drinking water is safe.
The nitrates solution
Weather can play a large role in nitrate levels, along with land use, drainage, soil types and other factors. Farm groups have argued that reducing nitrate levels is extremely complex and will require increased conservation efforts from most of the state's nearly 90,000 farmers.
Cutting nitrate and phosphorus levels is expected to be costly, an estimated $1.2 billion annually over five decades. Conservation practices include building wetlands, bioreactors and saturated buffers and expanding cover crop usage.
You can read the rest of the article here: http://www.desmoinesregister.com/story/money/agriculture/2015/07/04/high-nitrates-iowa-cities/29720695/
To get a better sense of your site’s nitrate levels over the course of the year, you will be creating a chart with the date on the horizontal axis and nitrate level on the vertical axis.
Step 1: Select the complete range of the two columns of dates and their corresponding nitrate levels.
Step 2: Insert -> Chart. Choose a chart that you think best represents the data.
Step 3: Right click on your chart, and add a title.
Step 4: Right click on your chart. Under “Axis,” click on the horizontal and vertical axis titles, and then rename them to something more appropriate.
