A comment about ammonia and cycling

[Lasse]

I'm skeptical of the generic claim that ammonium is completely not toxic

The idea that NH3 is the form to worry about is well founded, and I'm not suggesting otherwise.

The statements sometimes made by folks that NH4+ is "not toxic" is not established, IMO.

Assessment of ammonia toxicity in tests with the microalga, Nephroselmis pyriformis, Chlorophyta

Previous studies of an industrial effluent have indicated toxic effects by the ammonium/water system in tests with the unicellular green alga, Nephros…

www.sciencedirect.com

"Joint toxicity with additive effects of ammonia and ammonium ions was indicated, but the toxicity of ammonium ions was almost a factor 100 less (EC50, 24 h exposure, 224 μM or 3140 μg ammonium–nitrogen/L)."

Even if it is Swedish article you refer to - I do not understand their calculations of Contribution to toxicity in table 1 in the full text - here. The pH they work with is from 7.5 to 8.7 and their reported NH3 content (from 0.013 to 0.031 mg/L) is enough for affecting a NH3 sensitive algae without contributing from NH4 IMO

Sincerely Lasse

 

[Randy Holmes-Farley Verified Community Expert]

Even if it is Swedish article you refer to - I do not understand their calculations of Contribution to toxicity in table 1 in the full text - here. The pH they work with is from 7.5 to 8.7 and their reported NH3 content (from 0.013 to 0.031 mg/L) is enough for affecting a NH3 sensitive algae without contributing from NH4 IMO

Sincerely Lasse

I'm not suggesting it is a definitive paper. I'm just showing to to indicate that

1. It is difficult to distinguish the effects of NH4+ in the presence of NH3
2. It is not a settled issue to the science community

"Our data seemed to fit a joint toxicity model of contributions of ammonia and ammonium ions. Joint toxicity with these components have been observed with fish and crustacea but to our knowledge not previously in algae [17–19,6]."

 

[HuduVudu]

Do you mean when initially cycling?

Are you talking about a theoretical cycling using ammonium chloride?

I thought you guys were using it for coral growth.

Clearly I misunderstood what it was being used for. I apologize and will butt out of your post.

Sorry.

 

[GARRIGA]

salt water has about 19400 ppm Chloride. So - there is no real way that chloride will be affected dramatically. Second - as 'Total ammonia' is used (NH4+), by definition, free ammonia (NH3) will also decrease (its a mathematical equation). So - if the total ammonia is 0, the free ammonia will be 0. In a running (cycled tank) and NH4+ will be rapidly converted eventually to nitrite and nitrate - and if conditions are right to N2 gas.

Not sure you said anything different

 

[Lasse]

1. It is difficult to distinguish the effects of NH4+ in the presence of NH3

Yes it is - if the pH is to high.

The dependence of the NH3 / NH4 ratio on pH is well known and well documented in science literature. NH3 toxicity to various organisms is also well known. With a given total NH3 / NH4 it is easy to manipulate pH, hence the NH3 / NH4 ratio and concentration of NH3 will vary (and NH4 also of cause) With rise in NH3 (and decline in NH4) with increasing pH so is the toxicity of NH3 easy to show and determine. The same is if you lower the pH - but rise the total NH3/NH4 content - it is easy to calculate the free NH3 and as long as you are below the toxic level of NH3 - total mortality of NH4 can be determined.

In freshwater - where pH around 6.5 is common, I have never heard of a mortality even though total NH3 / NH4 has been well above 10 - 20 ppm. Before one really understood the relationship between pH, NH3, NH4 and nitrification - back in the 30 - 50: ties - water changes were a big no-no - it would be old and yellow water if the fish were to survive.

Sincerely Lasse

 

[Randy Holmes-Farley Verified Community Expert]

Yes it is - if the pH is to high.

The dependence of the NH3 / NH4 ratio on pH is well known and well documented in science literature. NH3 toxicity to various organisms is also well known. With a given total NH3 / NH4 it is easy to manipulate pH, hence the NH3 / NH4 ratio and concentration of NH3 will vary (and NH4 also of cause) With rise in NH3 (and decline in NH4) with increasing pH so is the toxicity of NH3 easy to show and determine. The same is if you lower the pH - but rise the total NH3/NH4 content - it is easy to calculate the free NH3 and as long as you are below the toxic level of NH3 - total mortality of NH4 can be determined.

In freshwater - where pH around 6.5 is common, I have never heard of a mortality even though total NH3 / NH4 has been well above 10 - 20 ppm. Before one really understood the relationship between pH, NH3, NH4 and nitrification - back in the 30 - 50: ties - water changes were a big no-no - it would be old and yellow water if the fish were to survive.

Sincerely Lasse

I agree that pH is a way to try to distinguish the effects, but I do not think it is perfect and hence my skepticism of the "no" toxicity of ammonium. If you change the pH you necessarily change other things like the nature of cell surface receptors. thus attributing tox changes to only the NH3/NH4+ ratio ignores other effects and makes interpretation difficult.

Copper, for example changes toxicity vs pH even when the copper form (speciation) may not change:

Ocean acidification increases copper toxicity differentially in two key marine invertebrates with distinct acid-base responses - Scientific Reports

Ocean acidification (OA) is expected to indirectly impact biota living in contaminated coastal environments by altering the bioavailability and potentially toxicity of many pH-sensitive metals. Here, we show that OA (pH 7.71; pCO2 1480 μatm) significantly increases the toxicity responses to a...

www.nature.com

"Thus, changes in metal toxicity under OA may not purely be driven by metal speciation in seawater and may be far more diverse than either single-stressor or single-species studies indicate. This has important implications for future environmental management strategies."

IMO, there's no a priori reason to assume ammonium is different.

 

[Randy Holmes-Farley Verified Community Expert]

In any case, I'm not trying to prove ammonium is toxic or not. I'm just skeptical, as are the researchers in the paper, that ammonium is "not" toxic at some level.

 

[MnFish1]

Not sure you said anything different

Point being - there is no toxicity or problem from Chloride due to ammonia production from bacteria or fish - which was what the poster was wondering about?

 

[MnFish1]

I thought you guys were using it for coral growth.

Clearly I misunderstood what it was being used for. I apologize and will butt out of your post.

Sorry.

Actually it was an interesting question. no reason to butt out.

 

[Lasse]

NH3 is a gas - NH4 is an ion. Gases can penetrate through cell membranes both out and in. Gases tends to reach equilibrium on both sides of cellmebranes

Ions need transport capabilities - active pumps or active channels - can be transported against concentrations. according to fish - the only transport mechanism according to ammonium I know about is a transport mechanism out from the fish through the gills. Some scientist says that it not even exist an active transport mechanism out from the fish. They say that all NH3/NH4 transport out and in goes through diffusion of NH3. For my part, I believe in active transport channels / pumps of ammonium out of the fish. The reason for this is that I in some tests in fish farms have seen a fast and steady rise of total ammonium directly after feeding the fish. But never the less - have never seen any proposal of the opposite - active NH4 transport into the fish. If that exist - we should not talk about non toxic effect at all with ammonium - in that case - it would be as toxic as NH3 because it should accumulate in the fish body.

I think that a statement I read here is interesting from our different point of view, My bold

NH3 is the most toxic form to aquatic life, but NH4 + is the most toxic form in the body

Sincerely Lasse

 

[SlugSnorter]

Ammonium is not a common English word.I think you're trying to say 'free ammonia' there should not be much in your tank.

no, I do not mean to say ammonia (NH3) I mean to say Ammonium (NH4+)

 

[Randy Holmes-Farley Verified Community Expert]

Ions need transport capabilities - active pumps or active channels - can be transported against concentrations. according to fish - the only transport mechanism according to ammonium I know about is a transport mechanism out from the fish through the gills.

No, they do not.

One other way is through tight junctions between cells in the gills and elsewhere. It is known that ammonium can get through marine fish gill tight junctions.

Ammonia Production, Excretion, Toxicity, and Defense in Fish: A Review - PMC

Many fishes are ammonotelic but some species can detoxify ammonia to glutamine or urea. Certain fish species can accumulate high levels of ammonia in the brain or defense against ammonia toxicity by enhancing the effectiveness of ammonia excretion ...

www.ncbi.nlm.nih.gov

"For marine fishes (Figure (Figure5),5), despite the presence of NHE, which facilitates Na+ absorption, little to no ammonia excretion occurs through Na+/ NH+4 exchange (Wilkie, 2002) because of the presence of favorable NH3 and NH+4 diffusion gradients. Unlike freshwater fishes, marine fishes have leaky tight junctions between mitochondrion-rich cells, which increase cation permeability for Na+ secretion. Therefore, a significant portion of ammonia can be excreted through NH+4 diffusion through the paracellular route in seawater fishes"

Since tight junction transport is purely driven by concentration gradients, if ammonia is higher outside than in, it can penetrate from the outside to the blood.

 

[Lasse]

No, they do not.

One other way is through tight junctions between cells in the gills and elsewhere. It is known that ammonium can get through marine fish gill tight junctions.

Ammonia Production, Excretion, Toxicity, and Defense in Fish: A Review - PMC

Many fishes are ammonotelic but some species can detoxify ammonia to glutamine or urea. Certain fish species can accumulate high levels of ammonia in the brain or defense against ammonia toxicity by enhancing the effectiveness of ammonia excretion ...

www.ncbi.nlm.nih.gov

"For marine fishes (Figure (Figure5),5), despite the presence of NHE, which facilitates Na+ absorption, little to no ammonia excretion occurs through Na+/ NH+4 exchange (Wilkie, 2002) because of the presence of favorable NH3 and NH+4 diffusion gradients. Unlike freshwater fishes, marine fishes have leaky tight junctions between mitochondrion-rich cells, which increase cation permeability for Na+ secretion. Therefore, a significant portion of ammonia can be excreted through NH+4 diffusion through the paracellular route in seawater fishes"

Since tight junction transport is purely driven by concentration gradients, if ammonia is higher outside than in, it can penetrate from the outside to the blood.

I have seen that - but IMO - it is not proven by my experiences. This means that ammonium (NH4) could (or should) be as toxic as NH3 for saltwater fish. If it is this way - with no or low active transport of ammonium through the gills - can you explain for me how we can transport salt water fish in small plastic bags for + 48 hours. After this long transport - water pH is around 6.5 and ammonium concentrations in the water can be between 1-2 ppm NH3. Inside the organism - it is ammonium that is toxic and therefore must be minimized.

Since tight junction transport is purely driven by concentration gradients, if ammonia is higher outside than in, it can penetrate from the outside to the blood.

Even so - the active transport capability must surpass any possible re-leakage of ammonium.many, many times because these high ammonium levels you can measure in the transport bags

I have very difficult to believe that you can reach an outside ammonium concentration of 2 ppm without an dominated active transport through the gills. An interesting thing with these plastic bags is also - a rise in the pH without exchanging most of the water (after a long transport in this bag) will kill the fish directly. This is the reason why you cant use the acclimation (drop or "cup" acclimation) with fishes transported more than 24 hours. You must either acclimate the fish with low pH saltwater (can be done with CO2) or just move the fish directly into a tank. If the transport have been very long - this tank needs to be lowered in pH too IME. NH3 (that will be formed from the dominated (nearly 100%) NH4 specie in pH 6,5) - can penetrate the gills back into the fish and transforming back to NH4 in the blood. And believe me - this happens very fast and there is no differences between salt and fresh water species.

Therefore, a significant portion of ammonia can be excreted through NH+4 diffusion through the paracellular route in seawater fishes"

I think that the critical worf here is "can" (my bold)

Unlike freshwater fishes, marine fishes have leaky tight junctions between mitochondrion-rich cells, which increase cation permeability for Na+ secretio

Another question - how is it with these salmon species that can live in both fresh and salt water. The rainbow trout as an example - it can live in both fresh and salt water and. If this is a physical thing - how does it looks like in these fishes (I have been with in many crazy ideas in my life - one example is a man that figure out that if you had the pH around 6.7 you could farm Rainbow trout in high ammonium concentrations - and indeed we have Rainbow trouts to survive in ammonium levels exceeded 50 ppm without problems - in freshwater but these rainbows was later transferred to pure saltwater without problems.

Sincerely Lasse

 

[Randy Holmes-Farley Verified Community Expert]

I have seen that - but IMO - it is not proven by my experiences. This means that ammonium (NH4) could (or should) be as toxic as NH3 for saltwater fish. If it is this way - with no or low active transport of ammonium through the gills - can you explain for me how we can transport salt water fish in small plastic bags for + 48 hours. After this long transport - water pH is around 6.5 and ammonium concentrations in the water can be between 1-2 ppm NH3. Inside the organism - it is ammonium that is toxic and therefore must be minimized.

No, it does not mean NH4+ must be equally toxic to NH3. Penetration of tight junctions is slow. Much slower than NH3 through the bilayer. Hence the suggestion that is is 100x less toxic.

While the ammonium through tight junctions may or may not be "proven", the penetration of charged molecules through junctions between epithelial cells is extremely well established. It is just slow. I use that mechanism in my job to deliver therapeutics.

 

[Lasse]

No, it does not mean NH4+ must be equally toxic to NH3. Penetration of tight junctions is slow. Much slower than NH3 through the bilayer. Hence the suggestion that is is 100x less toxic.

While the ammonium through tight junctions may or may not be "proven", the penetration of charged molecules through junctions between epithelial cells is extremely well established. It is just slow. I use that mechanism in my job to deliver therapeutics.

But in the bitter end - the example with transport in plastic bags shows that it must be a dominate active transport of NH4 from the organism into the water in both salt water and alkaline/high pH freshwater at least. In very soft, low pH water it can - in theory - the diffusion of NH3 be the major pathway - but the fact that most soft water species can survive, grow and spawn even in alkaline water indicate a possible active transport. You may be right about a slow diffusion of NH4 trough the mechanism you describe - but a diffusion take place in line with a concentration decline - the fact that we can detect many ppm NH4 in transport water (both in fresh and saltwater) more than indicate an active transport against a concentration.

Sincerely Lasse

 

[Randy Holmes-Farley Verified Community Expert]

But in the bitter end - the example with transport in plastic bags shows that it must be a dominate active transport of NH4 from the organism into the water in both salt water and alkaline/high pH freshwater at least. In very soft, low pH water it can - in theory - the diffusion of NH3 be the major pathway - but the fact that most soft water species can survive, grow and spawn even in alkaline water indicate a possible active transport. You may be right about a slow diffusion of NH4 trough the mechanism you describe - but a diffusion take place in line with a concentration decline - the fact that we can detect many ppm NH4 in transport water (both in fresh and saltwater) more than indicate an active transport against a concentration.

Sincerely Lasse

If NH4 is 100x or more less potent than NH3 in a marine fish, then it becomes very challenging to determine whether toxicity at, say 25 ppm NH4+ is from the small amount of NH3 present, or the large amount of NH4+ present, or both.

 

[Lasse]

This is dam easy to test

Look at this table - its done with this tool. Around 0.2 ppm NH3 in water is rather well documented to be near lethal for sensitive species. The table is valid for 35 psu and 25 degree Celsius And it shows (if 100 times lesser dangerous that you need around 20 ppm total NH3 + NH4 and pH around 7.5 before it can affect the toxicity from the NH3.

If we should test if 18 ppm total NH3 + NH4 is toxic by itself - we just add 18 ppm total NH3 + NH4 - lower the pH with carbon dioxide to 6.8 (it means 0.0537 in NH3 and its seen as safe). If the sensitive species still die - maybe I can buy the hypothesis. But till that day . I´m stick with the fact that it is the NH3 that is the reason for ammonia intoxication

Now I do not say that high ammonium levels (NH4) is good - there can be other negative aspects of high ammonium levels that is not acute toxic - I see this exactly the same as I see high nitrite levels in salt water - they are not acute toxic but can have other sublethal negative effects

Sincerely Lasse

 

[Randy Holmes-Farley Verified Community Expert]

This is dam easy to test

Look at this table - its done with this tool. Around 0.2 ppm NH3 in water is rather well documented to be near lethal for sensitive species. The table is valid for 35 psu and 25 degree Celsius And it shows (if 100 times lesser dangerous that you need around 20 ppm total NH3 + NH4 and pH around 7.5 before it can affect the toxicity from the NH3.

If we should test if 18 ppm total NH3 + NH4 is toxic by itself - we just add 18 ppm total NH3 + NH4 - lower the pH with carbon dioxide to 6.8 (it means 0.0537 in NH3 and its seen as safe). If the sensitive species still die - maybe I can buy the hypothesis. But till that day . I´m stick with the fact that it is the NH3 that is the reason for ammonia intoxication

Now I do not say that high ammonium levels (NH4) is good - there can be other negative aspects of high ammonium levels that is not acute toxic - I see this exactly the same as I see high nitrite levels in salt water - they are not acute toxic but can have other sublethal negative effects

Sincerely Lasse

That is exactly the sort of experiment the paper I posted did, showing growth in the presence of ammonia at two different pH values . However, to do such an experiment quantitatively over a small pH range requires very precise measurements of toxicity.

 

[Spare time]

This is fun lol

 

[MnFish1]

no, I do not mean to say ammonia (NH3) I mean to say Ammonium (NH4+)

I apologize - your reply to my post didn't make sense to me - so - I though that you perhaps mis-spoke. I said exactly what you did in the OP. If there is a x amount of NH4 - there will be a mathematically calculable amount of NH3 based on pH, etc.

My specific question (as others have been discussing) - is whether NH4 itself is toxic.