TDS and carbonic acid.

[Taliesin-DS]

I just went over the water quality report of my water supplier and checked the numbers.
It's tested at our local pumping station.
The conductivity is 23,8 mS/m wich i calculated is about 152 TDS.
In the list of dissolved stuff is says Waterstofcarbonaat 107 ppm (which is carbonic acid).
What i can find about this acid is that it gets picked up when you measure conductivity.
What i understand about this is according to these numbers, 107 out of 152 of my waters TDS is harmless co2, which leaves me with 45 TDS.
Am i right about that ?

Edit: typo in topic title, but can't edit it.

 

[herenorthere]

It isn't exactly right, but it's probably close enough. Each ion has a different effect on conductance and the conversion of conductance to dissolved solids estimate assumes a "typical" water chemistry. But that's a question for a geochemistry exam, not anything you need to worry about.

Does the report also list hardness or results for things like Ca, Na and Cl? Knowing those is more worthwhile than knowing a TDS number which was estimated from a conductance measurement.

 

[Taliesin-DS]

Ca 38.6
Na 11.4
Cloride 12
Sulfate 17
Total hardness in D 6

some other stuff in smaller amounts: (in microgram/liter)
K 1.2
Fe <0.01
Mn <0.005
Al <2
Sb <1
Ba 0
B <10
Cd <0.10
Cr 0.702
Cu <5
Hg <0.02
Pb <0.5
Ni 1.34
Se <1
Zn 0
Cyanide <2
Fluoride 0.05

NH4 <0.03
NO2 <0.01
NO3 9.5
C 21

pH 7.88
Temperature 10 c
The water comes from rainwater that falls on a big hill with a pine forest on top, it's a nature reserve.
After that the water seeps down through 100 meters of sand to the bottom of the hill were it's pumped up as tapwater.

Edit: at the other side of the same big hill theres a small peat bog with 2 species of dews and 1 ping species growing in the same water.

 

[herenorthere]

Assuming those are reported as ppm, they add up to 100+, but that isn't bad. The NO3 is almost to the US limit of 10 (which is widely violated in agricultural regions) and the Cr and Ni are surprisingly high. Are you in a mining/smelting area?

 

[Sig]

Too much nitrate would probably be one of the worst things in the water for cps, as that's a steady source of nitrogen.

 

[Taliesin-DS]

There hasn't been any mining here ever, there are the water is from used to be a dedicious forest in the middle ages.
The trees have been chopped down for wood, a lot of it was used for brick production further downstream.
After that the land dried out and became a big desert with sandstorms.
To stop that they planted lots of pines and nothing has happened there since.
10 to 20 miles from here there is some industry, a big paper factory wich has been shut down for years and an Akzo Nobel chemical factory, maybe that's the source of the nickel and chrome, but i wouldn't know
The big hill i was talking about is about 50 by 150 km and is made of sand deposited there in the last iceage.
There is virtually no industry or large towns on that hill itself.
Only a little agriculture, most of it is woods, and a large military area were they train with artillery.

 

[herenorthere]

I was just curious - the Cr and Ni re-awakened my dormant geology and geochemistry background. I think those amounts of Cr and Ni might be a concern in a public drinking water source here, but it would depend on the form of the Cr. A military area is a plausible source for just about any kind of contaminant and those levels aren't unheard of in nature.

As for whether such water is OK for CPs, it's probably fine for Neps but a little too "salty" for Sarrs, etc. I don't know if the NO3 is high enough to be a problem for plants not expecting it.

 

[Taliesin-DS]

A lot of ppl fertilize their cp's, doesn't that add a lot more NO3 then just 10ppm in water?

Edit:totally read the report wrong XD
Everything from Al to fluoride isnt in mg/l, but in microgram/liter...

 

[herenorthere]

That makes more sense. That amount of NO3, although dangerous for new baby humans, might have little effect even on plants like Sarrs that come from a low-NO3 environment. As for fertilizing CPs, people do lightly fertilize Neps and that's one of the reasons I think the water is fine for Neps.