# Cambridge tap water ICP-MS results



## Vsevolod Stakhov (27 Feb 2021)

Hello, I have recently received results for mass-spectography analysis of the Cambridge city tap water which includes some interesting meausures that are not usually listed in the official water company reports. 

ElementDimTap waterTap water tank (EI)50/50 RO/Tap tank (EI)50/50 Tank after 3x 50% changesLiug/l7,9​8​4,5​4,1​Beug/l< 0,03​< 0,03​32​< 0,03​*B*ug/l25​120​60​47​*Na*mg/l11​19​9,9​8,1​*Mg*mg/l4,2​10​11​7,7​Alug/l< 0,25​< 0,25​< 0,25​< 0,25​Siug/l-​-​-​-​Pug/l740​1160​1240​340​Smg/l-​-​-​-​Clmg/l24​30​14​15​*K*mg/l2,1​27​43​12​*Ca*mg/l110​110​52​52​Tiug/l0,17​0,4​0,53​0,2​Vug/l0,089​0,25​0,048​0,059​Crug/l0,25​0,7​0,17​0,096​*Mn*ug/l0,04​< 0,0125​0,13​0,024​*Fe*ug/l180​340​250​110​Coug/l0,16​0,82​0,57​0,21​Niug/l3​4​5,1​1,8​*Cu*ug/l21​14​16​11​*Zn*ug/l3,2​45​93​41​Gaug/l0,0064​13​11​0,0049​Geug/l0,08​0,2​0,18​61​Asug/l0,22​0,72​0,26​0,12​Seug/l0,63​0,42​< 0,2​< 0,2​Brug/l-​-​-​-​Rbug/l1,6​11​13​4,7​Srug/l430​450​180​190​Zrug/l< 0,05​0,12​< 0,05​< 0,05​Nbug/l0,0085​25​11​0,0048​*Mo*ug/l0,35​1,2​5,4​2,9​Agug/l0,047​0,14​0,064​0,0077​Cdug/l0,003​0,0043​0,0065​0,0032​Snug/l< 0,003​0,15​0,097​0,012​Sbug/l0,066​0,11​0,12​0,065​Teug/l0,0094​0,016​0,02​0,011​Iug/l2,5​0,32​0,3​0,83​Csug/l0,011​0,037​0,038​0,013​Baug/l61​50​12​14​Laug/l< 0,0005​< 0,0005​0,0014​< 0,0005​Ceug/l< 0,0005​0,0014​0,019​< 0,0005​Prug/l< 0,0005​0,0034​0,0079​< 0,0005​Ndug/l< 0,0025​< 0,0025​0,0059​< 0,0025​Smug/l0,00085​0,0069​0,011​0,0023​Euug/l0,0071​0,0079​0,0039​3​Gdug/l< 0,0005​0,0057​0,0083​0,0015​Dyug/l< 0,0005​0,0075​0,011​0,0014​Houg/l< 0,0005​0,0011​0,0019​< 0,0005​Erug/l< 0,0005​< 0,0005​0,0035​< 0,0005​Tmug/l< 0,0005​< 0,0005​0,0009​< 0,0005​Ybug/l< 0,0005​0,0068​0,013​0,0031​Hfug/l0.095​0,19​0,11​0,06​Taug/l0,0028​0,0046​0,0029​< 0,0025​Wug/l< 0,0025​0,0068​0,011​0,0062​Hgug/l< 0,025​< 0,025​< 0,025​< 0,025​Tlug/l0,01​0,0094​0,0097​0,0059​Pbug/l0,094​< 0,025​< 0,025​< 0,025​Thug/l0,017​0,067​0,029​0,0095​Uug/l0,42​0,013​0,03​0.033​

Interesting thing is the amount of Manganese: it clearly looks like a limiting factor for plants as it disappears quickly in the tanks despite of EI dosing. Zn and B seems to be accumulating slightly on the contrary. I'm also quite surprised to see that much Iron in the tap water, but MS catches also colloid Iron (e.g. from the tubes) that is not really solluble. Same is valid for Phosphorus: ICP-MS can even find organic Phosphorus in algae cells. They were not able to find quantities of Br, Si and S because of the technical issue. That analysis was done using Bruker Aurora M90 ICP-MS analyser.        

So our tap water is very poor in Magnesium (so I add it for all tanks), Potassium and Sodium. Manganese is definitely something I need to think about when mixing micro...


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## AverageWhiteBloke (27 Feb 2021)

Vsevolod Stakhov said:


> So our tap water is very poor in Magnesium (so I add it for all tanks),


I think @dw1305 has a map in here showing the geology in the UK. There aren't many places where Mg is coming out the tap. It has only started coming out of my tap lately according to the latest water report since they started blending the local reservoir water with an underground aquifer.


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## Zeus. (27 Feb 2021)

Vsevolod Stakhov said:


> I have recently received results for mass-spectography analysis of the Cambridge city tap water


Impressive.


Vsevolod Stakhov said:


> Interesting thing is the amount of Manganese:


Yes it does seem to be getting 'moped' up quickly by the plants with a weekly EI dose being about 0.1ppm Mn when using APFUK trace


Vsevolod Stakhov said:


> I'm also quite surprised to see that much Iron in the tap water



similar levels here in Yorkshire, however we do get a big 'swing' over the seasons



Vsevolod Stakhov said:


> So our tap water is very poor in Magnesium



about 5ppm Mg is about normal for most of UK.

I expected to see more K as well, water company's rarely report on K as there is no legal limit.


Vsevolod Stakhov said:


> Manganese is definitely something I need to think about when mixing micro...



Based on your report I would have to agree.

Can we send you some water samples for analysis


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## Vsevolod Stakhov (27 Feb 2021)

AverageWhiteBloke said:


> think @dw1305 has a map in here showing the geology in the UK. There aren't many places where Mg is coming out the tap.


Yes, I have read that. I wanted mostly to check potassium levels in tanks and in the tap as potassium test kits are rubbish (e.g. EL test kit has shown 20ppm K in RO water with TDS=2). But checking other elements were very useful and Mn/Fe results were even quite surprising to me.


Zeus. said:


> Yes it does seem to be getting 'moped' up quickly by the plants with a weekly EI dose being about 0.1ppm Mn when using APFUK trace


I've been adding 0.1ppm Fe daily tap water tank using APFUK mix. In 50/50 tank that micro dosing had caused heavy melting issues, so I had to dose it at 0.05ppm Fe level adding additional Fe from Seachem Iron. For now, I mix APFUK (0.05) with Chempack Iron (2% Fe, 3% Mn, 6% Mg) at 0.05ppm and add some more Fe Gluconate from Seachem Iron. And it seems to be good for L. Aromatica and does not cause melting. From ICP results, I suppose that the culprit of melting was Boron. 

As you see, Boron level is around 0.12ppm in the tap water tank. But that tank is malawi cichlid tank planted with very hardy plants (tonns of Vallisneria, Echinodorus, Cryptocorine etc), so that dosing has not caused any issues. Suprisingly tap water cichlid tank has almost no algae, even on glass, whilst 50/50 RO tank has constant issues with staghorn...


Zeus. said:


> Can we send you some water samples for analysis


I have done that by sending water samples to Moscow  The cost of each analysis was around 10£ and mail costs are around 3-4£ (for any number of samples). If that looks reasonable please PM me, so I can act as a water proxy  They do both fresh and seawater analysis (promising Br, S and Si being fixed 'soon').


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## Vsevolod Stakhov (27 Feb 2021)

And, erm, for some elements I've lost `0,0` in when copying table, e.g. Be or Ga - so when results in tap are like 0,013 and in aquarium like 13 means that `0,0` was missed out...


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## X3NiTH (27 Feb 2021)

Can I just say that’s a fairly comprehensive test! Super Interesting!


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## jaypeecee (27 Feb 2021)

Vsevolod Stakhov said:


> I'm also quite surprised to see that much Iron in the tap water...


Hi @Vsevolod Stakhov 

I'm going to take a thorough look through these figures later. But, the iron figure is very much in line with my water company's 2019 report. To be specific:

Min : 3.00 micrograms/l
Mean: 21.98 micrograms/l
Max: 217.30 micrograms/l

The PCV* for iron is 200 micrograms/l.

*PCV = Prescribed Concentration or Value

JPC


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## jaypeecee (27 Feb 2021)

Vsevolod Stakhov said:


> I have done that by sending water samples to Moscow  The cost of each analysis was around 10£ and mail costs are around 3-4£ (for any number of samples). If that looks reasonable please PM me, so I can act as a water proxy  They do both fresh and seawater analysis (promising Br, S and Si being fixed 'soon').


Hi @Vsevolod Stakhov

I'm _very_ interested - excited even! When you say "The cost of each analysis...", is that the cost of each water parameter?

JPC


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## Vsevolod Stakhov (27 Feb 2021)

jaypeecee said:


> I'm going to take a thorough look through these figures later. But, the iron figure is very much in line with my water company's 2019 report.


Yes, I was quite surprised as well. But ICP-MS shows elemental compounds, it does not show which specific chemical molecule contains that element. For example, JBL Fe test shows clear 0 for our tap water (but it shows stable chelates in fish tanks). So I can only assume that this Iron in tap water is in some insoluble compounds, e.g. rust (Fe(OH)3 + Fe2O3) or Ferrous Phosphate. The amount of P (714ug means 2.2ppm of PO4) is also higher than liquid test kits show for that water in PO4 equivalent. So I think that the tests show only soluble components while ICP-MS shows pure elemental compound. I'm not sure what methods are used in water companies, and I'm not sure I have good quality last mile pipes either...


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## Vsevolod Stakhov (27 Feb 2021)

jaypeecee said:


> "The cost of each analysis...", is that the cost of each water parameter?


No, that's the cost of one sample analysis with 59 (well, 56 currently) parameters. That's why I have considered it as a good option comparing to liquid test kits...


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## dw1305 (27 Feb 2021)

Hi all, 


Vsevolod Stakhov said:


> mass-spectography analysis of the Cambridge city tap water


Very useful. 


AverageWhiteBloke said:


> has a map in here showing the geology in the UK.


As the other have said we aren't likely to have much magnesium (Mg) in our tap water <"for geological reasons">. Some of the confusion has arisen because in the USA many of their limestones have <"undergone dolomitization">. The "dolomitization" link has the relevant maps.

The same geological reasons also applies to potassium (K), although you are more likely to get measurable levels in surface water from agricultural usage.


Vsevolod Stakhov said:


> For now, I mix APFUK (0.05) with Chempack Iron (2% Fe, 3% Mn, 6% Mg)


That was going to be my suggestion as a <"manganese (Mn) source">.

cheers Darrel


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## jaypeecee (27 Feb 2021)

Hi @Vsevolod Stakhov 

I'm even more excited now! I'll be back on here a bit later.

JPC


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## Vsevolod Stakhov (27 Feb 2021)

dw1305 said:


> That was going to be my suggestion as a <"manganese (Mn) source">.


I can definitely see the positive effect from this fertiliser as I've been using it for some months (not daily though since so far). I have linked it to Fe chelates stability but it seems that it could be related to Mn in fact. However, I'm quite concerned about unchelated Mn: it is toxic and not very stable even in 6-7 PH range. Whilst it should be stable in the original sollution due to SO4 anions providing very low PH it might not be very stable in the fish tank.
Another thing that is a bit confusing is that I have bought another similar garden ferilizer today (the same 2% Fe on EDDHA/DTPA and 6% of Mg) but the amount of Manganese is 10 times lower comparing to Chempack according to the label:




Probably, I should also send my hand-made micro to ICP-MS as well


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## dw1305 (27 Feb 2021)

Hi all,


Vsevolod Stakhov said:


> Another thing that is a bit confusing is that I have bought another similar garden ferilizer today (the same 2% Fe on EDDHA/DTPA and 6% of Mg) but the amount of Manganese is 10 times lower comparing to Chempack according to the label:


My guess is that they are actually the same mix, and one of the labels has <"got lost in the powers of ten">. I don't have any reference, but I'd guess it is the "3.0%" that is wrong and it is actually 0.3% Mn.


Vsevolod Stakhov said:


> However, I'm quite concerned about unchelated Mn:


You get a reasonable amount in some hard water, to the extent that they remove it from some tap water. I don't think that is because of toxicity issues, but because it makes the water taste bitter. 

cheers Darrel


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## X3NiTH (27 Feb 2021)

0.05mg/L of Mn in drinking water makes it taste foul to humans, it’s a good job plants don’t have taste buds (at least not like ours)! I target that value every micro dose 4x a week, unchelated, if there’s any chelation with Mn it’s with either Gluconate, Ascorbic, Humic or Fulvic acid in the tank when it’s dosed, maybe some unbound FeDTPA if it can, all of them advantageous and fully plant digestable. Acids in the micro Humates in the macro!


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## Vsevolod Stakhov (27 Feb 2021)

dw1305 said:


> You get a reasonable amount in some hard water, to the extent that they remove it from some tap water.


Not in our tap water definitely. 0.04ppb (not ppm) is almost zero and Mn is depleted even quicker in fish tanks (especially in more alkaline one), while other traces, such as Zn or B have tendency to accumulate. So I clearly see that Mn and (at lower degree) Cu elements are disappearing in fish tanks even when using daily EI dosing (something like 0.022ppm = 22ppb of Mn on EDTA from APFUK). But Mn in EI tap water tank is <0.0125ppb, that looks like zero to me. Even 0.13ppb (0.00013ppm) in the second aquarium is not very adequate amount. Is it possible that some aquatic plants are acting like super concentrators of this element?


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## X3NiTH (28 Feb 2021)

Vsevolod Stakhov said:


> Is it possible that some aquatic plants are acting like super concentrators of this element?



Very possibly, looking at the most basic of photosynthetic organisms Cyanobacteria who have a great affinity for Fe can’t prevent themselves uptaking Mn and will scavenge whatever is available, when it’s present at levels of 10ppm+ it can’t moderate it anymore and it becomes toxic internally to it resulting in cell disruption (this effect was seen with marine Cyano). The only way to be sure is to perform an experiment to test for loss in the water column via uptake by Fire Assay on the test plant and then measure its elemental content to measure differences.


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## X3NiTH (28 Feb 2021)

I’m wondering if the Mn level should be read as mg/L instead of ug/L, the Tap water has probably had some form of flocculation performed on it to remove metals such as Iron and Mn specifically because they both make it taste bad (and stain laundry), 0.04 would bring it just under the taste threshold if it was mg/L, it’s almost non existent measured in ug/L. How does the analysis compare to an official water provider report for Mn content, if it’s not stated in the report is there mention of flocculation moderation performed on the water before its piped to the tap.


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## Vsevolod Stakhov (28 Feb 2021)

X3NiTH said:


> How does the analysis compare to an official water provider report for Mn content, if it’s not stated in the report is there mention of flocculation moderation performed on the water before its piped to the tap.


Here it is: Manganese ug/l: <0.9 <0.9 <0.9 (with 50ug/l as limit). Taken from https://www.cambridge-water.co.uk/media/2399/z2-cambridge-city-south-2019.pdf
I'd say that the report is quite close to what ICP-MS has found with the exception of Iron, but Iron difference might be related to the different measurement methods.


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## dw1305 (28 Feb 2021)

Hi all, 


Vsevolod Stakhov said:


> Not in our tap water definitely.


It is <"back to the chalk">. It is very nearly pure CaCO3, you can tell this by the colour, if it had anything else in it the <"white cliffs of Dover"> would be a lot less white. 

The Chalk was laid down, over a long time period, <"in a deep oceanic basin"> and hasn't really been altered since. 

cheers Darrel


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## Vsevolod Stakhov (28 Feb 2021)

dw1305 said:


> It is <"back to the chalk">. It is very nearly pure CaCO3, you can tell this by the colour, if it had anything else in it the <"white cliffs of Dover"> would be a lot less white.


TBH, I am just not sure about one thing: how comes that the tap water has a lot of NO3 (30ppm) and has almost no K. I know that agriculture does not usually use KNO3 preferring urea or NH4NO3 as nitrogen source (that is all nitrified towards soluble nitrates apparently). However, K is also used in all fertilizing techniques and all K salts are very soluable. Finally it turns out that the tap water has very few K comparing to NO3, which is good to know as is, so I'm mostly curious here.


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## dw1305 (1 Mar 2021)

Hi all,


Vsevolod Stakhov said:


> how comes that the tap water has a lot of NO3 (30ppm) and has almost no K.





Vsevolod Stakhov said:


> However, K is also used in all fertilizing techniques and all K salts are very soluble.


The simple answer is I don't know and I would have expected that there should be appreciable levels of potassium (K) for that reason. A little bit of digging may have found the answer.

The <"Soil Minerals and Plant Nutrition: The Nature Education Knowledge Project"> (which looks a very useful resource) suggests that the differences are mainly to do with differences in cation and anion exchange capacity. For nitrogen (N) it says:


> _..... In soils, N applied through fertilizers and mineralized N from organic matter mostly ends up in the NO3- form. Due to the limited anion exchange capacity of most soils, leaching of applied N in the form of NO3- ions is a common water quality problem, particularly in agricultural regions. It also represents an important economic inefficiency, because producers apply excessive amounts of fertilizer to compensate for the leaching......._


and for potassium (K):


> _...........Phyllosilicates retain and release K for plants from non-exchangeable or fixed (i.e., exchanged very slowly and only when the K concentration in soil water drops below a threshold value) and exchangeable forms. Potassium ions present on the exchange sites are adsorbed by outer-sphere complexation and are readily available for plant uptake....... On the other hand, illite, vermiculite, and interstratified 2:1 clay minerals release fixed or non-exchangeable K from interlayer sites through cation exchange and diffusion processes at slower rates than the exchangeable K........_


<"Zörb C, Senbayram M, Peiter E. Potassium in agriculture--status and perspectives. _J Plant Physiol._ *171(9)* pp 656-69"> suggests that the plant roots play an important part in potassium acquisition.


> ...... Average soil reserves of K are generally large, but most of it is not plant-available. Therefore, crops need to be supplied with soluble K fertilizers) ......... Recent investigations have shown that organic exudates of some bacteria and plant roots play a key role in releasing otherwise unavailable K from K-bearing minerals.


I know <"that similar processes"> makes iron (Fe) plant available.

cheers Darrel


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## X3NiTH (1 Mar 2021)

I did some digging also yesterday and as Darrel mentions CEC, yes it’s the action of Illite clays in the overlying landscape around Cambridgeshire and in soil that retain the K leaving an average of 2-3ppm K in surface waters, the number can go up to about 20ppm if there is heavy rainfall. It’s actually surprising how much K and other major Ions like Mg can be bound up and retained in soil and clays. Tangentially to the conversation Clay can uptake maximally saturated solutions of Magnesium Sulphate to form a silky gel like compound, this is how you make the glue for pottery called ‘Slip’.


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## X3NiTH (1 Mar 2021)

This was an interesting brief pdf that I saved on the subject of Heavy Soils -



			https://www.nutrientmanagement.org/potash-for-heavy-soils/
		


Also this Geochemical Atlas is quite interesting for comparative analysis -



			http://nora.nerc.ac.uk/id/eprint/18016/1/Advanced_Soil_Geochemical_Atlas_of_England_and_Wales.pdf


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