Arsenic levels

ReefTankHunter · 12/04/2018, 03:25 PM

Was wanting to know if 0.044 ppm of Arsenic level was dangerously high.
I'm running GFO, And also changed salt brand as well.
Any recommendations

Jonesrd1 · 12/04/2018, 04:40 PM

Quote:

Originally Posted by ReefTankHunter

Was wanting to know if 0.044 ppm of Arsenic level was dangerously high.
I'm running GFO, And also changed salt brand as well.
Any recommendations

How was your Arsenic level determined, ICP or test kit? If by test kit what is your phosphate level? Ron

ReefTankHunter · 12/04/2018, 07:05 PM

ICP, test for arsenic, and po4 is .01.
But have plenty of HA.

Jonesrd1 · 12/04/2018, 10:49 PM

Sorry to hear that you have the HA. I asked about ICP because if you were using the colorimetric method for arsenic/arsenate, phosphate gives you a false positive. Personally I would not worry too much about 44 ppb of arsenic but I would try to eliminate the source if possible. The average clean seawater concentration is 1.7 ppb. Ron

ReefTankHunter · 12/05/2018, 06:30 AM

Thanks Ron.

Chitownpw · 02/17/2019, 03:35 PM

Quote:

Originally Posted by Jonesrd1

Sorry to hear that you have the HA. I asked about ICP because if you were using the colorimetric method for arsenic/arsenate, phosphate gives you a false positive. Personally I would not worry too much about 44 ppb of arsenic but I would try to eliminate the source if possible. The average clean seawater concentration is 1.7 ppb. Ron

A recent ICP test showed .035 ppm arsenic for my tank, and I had 0.04 ppm phosphorus. This wasn't triton but was some place in Colorado (Coral Vue) with which i'm not to impressed / pleased. I used triton about a year earlier and no arsenic showed. So false positive are not uncommon?

What are other sources for arsenic in the tank - magnesium supplements?

bertoni · 02/17/2019, 04:15 PM

False values seem fairly common with such testing. The trace elements are hard to test accurately at a price point we can afford as hobbyists. I wouldn't worry very much about the arsenic reading. I might check my RO/DI setup to make sure it was functioning properly. Arsenic can show up in some water supply systems.

Most supplements could end up with a bit of arsenic in them, but I can't think of one that is more likely to cause a problem. A problem batch could show up in most products, but I hope that's unlikely.

Jonesrd1 · 02/17/2019, 04:31 PM

Quote:

Originally Posted by Chitownpw

A recent ICP test showed .035 ppm arsenic for my tank, and I had 0.04 ppm phosphorus. This wasn't triton but was some place in Colorado (Coral Vue) with which i'm not to impressed / pleased. I used triton about a year earlier and no arsenic showed. So false positive are not uncommon?

What are other sources for arsenic in the tank - magnesium supplements?

Arsenic is notoriously hard to measure in seawater so I don’t want to criticize any lab’s method determination limit. Unfortunately unless you are measuring specifically for arsenic and take a number of sample prep steps the PQL for arsenic is ~0.05 ppm in my experience. Therefore, any concentration below this indicates only at most a positive for the presence of arsenic not a believable concentration. So I would take your .035 with a grain of salt. Trace elements, kalk and magnesium sulfate would be my top three guesses after the salt mix. Sorry I can’t be more help. Without running everything specifically for low level arsenic you could never be sure. If you are having a specific problem I doubt it is arsenic. If you are having no problems don’t worry about arsenic at all. Ron

Chitownpw · 02/17/2019, 05:59 PM

I am actually going to run some samples through a local university to see if there is any real concern.

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bertoni · 02/17/2019, 08:41 PM

A local college might be able to do the tests properly. I don't know much about what's involved, so I can't add anything useful.

Chitownpw · 02/18/2019, 05:48 PM

Quote:

Originally Posted by bertoni

A local college might be able to do the tests properly. I don't know much about what's involved, so I can't add anything useful.

If you are in the Chicago area, Loyal has an environmental science department that runs ICP tests (with acid reduction) at various price points depending on the scope of what want tested. There is a website.

Jonesrd1 · 02/18/2019, 08:54 PM

Quote:

Originally Posted by Chitownpw

If you are in the Chicago area, Loyal has an environmental science department that runs ICP tests (with acid reduction) at various price points depending on the scope of what want tested. There is a website.

It will be interesting to see their results for seawater. Also I am sure you know ICP is a sample introduction method, not a type of analysis/detection. OES, MS, AAS, AES.... would be some of the analytical/detection methods that determine what elements and MDL/PQLs apply. Hope this helps you to determine what you need.

Chitownpw · 02/21/2019, 08:17 AM

Quote:

Originally Posted by Jonesrd1

It will be interesting to see their results for seawater. Also I am sure you know ICP is a sample introduction method, not a type of analysis/detection. OES, MS, AAS, AES.... would be some of the analytical/detection methods that determine what elements and MDL/PQLs apply. Hope this helps you to determine what you need.

They use MS with acid digestion.

Chitownpw · 03/04/2019, 06:27 PM

Quote:

Originally Posted by Chitownpw

They use MS with acid digestion.

I got my ICP test results back. I did 4 tests from the following sources: kitchen sink, top-off (RO/DI) water, reef tank and reef tank with added mag supplement. [it was only around $100 for the 4 tests, not bad]

I read that mag supplements can be a source of arsenic. I use Fritz supplement which is a newer player in the market but a company that LFS switched to and recommends. Given this, I took one of the samples (each sample was about 10 oz) from my reef tank and added about 3 ml of Fritz's mag supp).

Results of interest -

RO/DI Sample - less than .002 mg/l of As
Reef Tank - .066 mg/l of As
Reef Tank w/Mag Supp - .075 mg/l of As

I'm not saying this conclusively shows that the supplement is the source of the arsenic but...

bertoni · 03/04/2019, 11:11 PM

The other possibility is the salt mix.

Chitownpw · 03/05/2019, 02:20 PM

Quote:

Originally Posted by bertoni

The other possibility is the salt mix.

Which is also Fritz Pro - however, just to reiterate, the sample with the added magnesium supplement had higher levels of arsenic.

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bertoni · 03/05/2019, 04:07 PM

Yes, but those numbers are quite close in terms of expected accuracy, in my opinion.

Chitownpw · 03/05/2019, 04:12 PM

Quote:

Originally Posted by bertoni

Yes, but those numbers are quite close in terms of expected accuracy, in my opinion.

They were effectively the same sample but one just had additional magnesium supplement. The other thing that was surprising was that the copper reading was higher with the sample that included the supplement. I plan on switching salts and will run an ICP test for each of the salt mixes using fresh RO/DI for each mix. Maybe that will also narrow things.

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12/04/2018, 03:25 PM	#1
ReefTankHunter Registered Member Join Date: Jan 2011 Location: Greenville SC Posts: 392	Arsenic levels Was wanting to know if 0.044 ppm of Arsenic level was dangerously high. I'm running GFO, And also changed salt brand as well. Any recommendations Last edited by ReefTankHunter; 12/04/2018 at 03:55 PM.

12/04/2018, 10:49 PM	#4
Jonesrd1 Registered Member Join Date: Mar 2015 Location: Oregon Posts: 81	Sorry to hear that you have the HA. I asked about ICP because if you were using the colorimetric method for arsenic/arsenate, phosphate gives you a false positive. Personally I would not worry too much about 44 ppb of arsenic but I would try to eliminate the source if possible. The average clean seawater concentration is 1.7 ppb. Ron __________________ Ron Jones Current Tank Info: 55g mixed reef Last edited by Jonesrd1; 12/04/2018 at 11:07 PM. Reason: Forgetfulness

02/17/2019, 04:15 PM	#7
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	False values seem fairly common with such testing. The trace elements are hard to test accurately at a price point we can afford as hobbyists. I wouldn't worry very much about the arsenic reading. I might check my RO/DI setup to make sure it was functioning properly. Arsenic can show up in some water supply systems. Most supplements could end up with a bit of arsenic in them, but I can't think of one that is more likely to cause a problem. A problem batch could show up in most products, but I hope that's unlikely. __________________ Jonathan Bertoni

02/17/2019, 08:41 PM	#10
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	A local college might be able to do the tests properly. I don't know much about what's involved, so I can't add anything useful. __________________ Jonathan Bertoni

03/04/2019, 11:11 PM	#15
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	The other possibility is the salt mix. __________________ Jonathan Bertoni

12/04/2018, 07:05 PM	#3
ReefTankHunter Registered Member Join Date: Jan 2011 Location: Greenville SC Posts: 392	ICP, test for arsenic, and po4 is .01. But have plenty of HA.

12/05/2018, 06:30 AM	#5
ReefTankHunter Registered Member Join Date: Jan 2011 Location: Greenville SC Posts: 392	Thanks Ron.

02/17/2019, 05:59 PM	#9
Chitownpw Registered Member Join Date: Oct 2013 Location: Chicago Posts: 218	I am actually going to run some samples through a local university to see if there is any real concern. Sent from my iPhone using Tapatalk

03/05/2019, 04:07 PM	#17
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	Yes, but those numbers are quite close in terms of expected accuracy, in my opinion. __________________ Jonathan Bertoni