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Re: [APD] Re: tapwater NO3 survey
Yes, this confusing use of "Nitrate" to refer to something
else (i.e., nitrogen that is from nitrate) causes trouble.
You need to check what they mean unless you're reading an
actual official copy of the Water Quality Report.
--- Jim Seidman <js4 at seidman_net> wrote:
> >The city of Chicago report for 2002 reported 0.4ppm NO3.
> It was
> >reported as high as 1.8ppm back in '99.
> You are confusing NO3 with NO3-N. Actually, I think many
> people posting
> on this topic are making the same mistake. Most water
> quality reports
> give NO3-N, meaning the amount of nitrogen present as
> nitrate. The "ppm"
> measure is based on weight. NO3 weighs 4.4 times as much
> as just a
> nitrogen atom. So 4.4 ppm NO3 is only 1.0 ppm NO3-N,
> since in the latter
> case you're not counting the weight of the oxygen atoms.
> I happen to have the 2002 City of Chicago report in front
> of me. It
> reports 0.4 ppm "Nitrate (as nitrogen)", meaning NO3-N.
> This means that
> it's 1.8 ppm NO3.
> The nitrate levels (at least out of the Jardine
> filtration plant) have
> stayed in the 0.3-0.4 ppm NO3-N range for years. The
> information you saw
> for 1999 probably reported levels as NO3 rather than
> NO3-N for some
> Also, others have mentioned the MCL (and MCLG) of 10 ppm.
> This figure is
> 10 ppm NO3-N, thus 44 ppm NO3.
> - Jim
> Aquatic-Plants mailing list
> Aquatic-Plants at actwin_com
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