My thoughts on nitrite.

[Randy Holmes-Farley]

IMO, nitrite is not something reefers need to be concerned with or measure.

Is it toxic at high levels (like 150 ppm)? Very likely yes. Published studies claim so, but I personally would not be sure that a study adding 150 ppm nitrite didn't accidentally have 0.5 ppm ammonia also present.

But is it ever toxic in a cycled reef aquarium? Highly unlikely, IMO, without dosing nitrite.

Is it ever toxic in any reef tank that can process ammonia? I cannot see how unless one set up a system to process a ton of ammonia fast before nitrite processing got ramped up.

 

[DrZoidburg]

I wish there were more studies on this. I tried finding various angel species, eels, all sorts of things with nothing turned up yet. I am familiar to how this mechanism works in salt water. However as I understand it at the same time chloride competition for active sites is occurring, nitrite is at a certain equilibrium with nitrous acid. More toward the nitrite balance. Nitrite possibly some nitrous acid does get in at a much slower rate because of this other than ingestion. Indicates that these are getting in if shown in blood plasma in some studies. (lower doses not extreme amounts) Nitrous acid being able to more easily get into gills. For people running certain calcium reactors, sulfur, bio pellets, some high C02 environments, or some dosing. I see occasionally having troubles with maintain ph. Even higher temperatures, or problems keeping it low. This would be instances where equilibrium could shift to more nitrous acid. Similar thing for ammonia/ammonium equilibriums ph dependent. That could be a huge factor. From what I gather chronic, acute, lethal, sublethal, lowest observed are all measures of toxicity. That would imply that there is toxicity. Why everyone says still its not toxic is beyond me at this point. I guess I'm beating a dead horse here. To many unknow variables. I hope to think anyone reading this be more careful in certain situations.

 

[DrZoidburg]

@Randy Holmes-Farley Mostly chronic exposure is what I'm hitting home at. Not exactly just lc50's. Too little studies, many variables, only few common kept species with documented effects in possible situations.

 

[DrZoidburg]

Oh I can add to that "unless one set up a system.." How about the thread I saw where the persons cat took a dump in their sump. That is definitely a situation lol. They were likely high in all numbers.

 

[Randy Holmes-Farley]

@Randy Holmes-Farley Mostly chronic exposure is what I'm hitting home at. Not exactly just lc50's. Too little studies, many variables, only few common kept species with documented effects in possible situations.

I'd certainly change my mind if a chronic study showed a problem at levels of nitrite that were typically present chronically.

 

[Randy Holmes-Farley]

I wish there were more studies on this. I tried finding various angel species, eels, all sorts of things with nothing turned up yet. I am familiar to how this mechanism works in salt water. However as I understand it at the same time chloride competition for active sites is occurring, nitrite is at a certain equilibrium with nitrous acid. More toward the nitrite balance. Nitrite possibly some nitrous acid does get in at a much slower rate because of this other than ingestion. Indicates that these are getting in if shown in blood plasma in some studies. (lower doses not extreme amounts) Nitrous acid being able to more easily get into gills. For people running certain calcium reactors, sulfur, bio pellets, some high C02 environments, or some dosing. I see occasionally having troubles with maintain ph. Even higher temperatures, or problems keeping it low. This would be instances where equilibrium could shift to more nitrous acid. Similar thing for ammonia/ammonium equilibriums ph dependent. That could be a huge factor. From what I gather chronic, acute, lethal, sublethal, lowest observed are all measures of toxicity. That would imply that there is toxicity. Why everyone says still its not toxic is beyond me at this point. I guess I'm beating a dead horse here. To many unknow variables. I hope to think anyone reading this be more careful in certain situations.

That might be a way to get more exposure, but the pka of nitrous acid in seawater is below 3, so the uncharged fraction of nitrite present at pH 8.2 is very small, unlike ammonia .

 

[DrZoidburg]

I'd certainly change my mind if a chronic study showed a problem at levels of nitrite that were typically present chronically.

I agree there is just not many of them. Not just in terms of 50+consecutive days or 4 weeks I do realize that is unrealistic. More like in paper above with clownfish or hypothetical situation above. Where x amount of day = x% vs time and concentration causing irreversible gill damage. Studies like that would say a lot. As well as species specific studies that people keep. Can you refer me to any that may exist?

 

[Wyvern]

I'll admit Im brand new to marine systems, only having several small freshwater aquariums, I have experienced sudden rises of Ammonia and Nitrite and seen how toxic they are in that environment, and while ammonia cycling my 109 Gallon bow (40 gal sump half full) I was reading conflicting aguments about waiting till Nitrites reach 0 Vs. A large WC and add a few fish.
During my cycle I dosed Ammonia for 2 weeks and then sit 2 weeks, Nitrites were off the chart still Nitrates past 80, so I drained 85 gallons- Nitrates still past 5/off the chart, Nitrates around 40 after a week and no changes to Nitrites I just decided to dump another 20 gallons, dose with Zyme 9 and add 2 clowns and a Midas blenny.

They were all happy, and I noticed Nitrites going down and within a week they were at 0.

I added a fairy wrasse and a small CUC and they are all peachy, still no Nitrites or ammonia and Nitrates below 20. Over a month since the first fish additions.

It would seem that in normal situations Nitrites are nothing more than an indication that bacteria is nitrifying, I feel Ammonia will kill fish well before it turns into Nitrites, and then turn into nitrates before adverse affects from that.

 

[Hans-Werner]

Sodium nitrite was and still is a common food additive and preservative. The nitrite ions from sodium nitrite are the same nitrite ions you find with a test kit.

Most are similar from 5 to upwards of 3000mg/L where 50% are dead in that time. That is marine fish. The safer ranges from less than .5mg/L to 15 mg/L for inverts and less than 5mg/L to 50mg/L fish in one article. Safer though still toxic.

Fish die from the conversion of hemoglobin to methemoglobin. What do you think is the toxic effect to invertebrates, that do not have hemoglobin for oxygen transportation. What causes the toxicity there?

It is also another unknown in common kept fish whether some fish take more nitrite via their stomach than through gills. Which would negate the effects chloride has on making nitrite absorption rates into body safer. Not to mention other variables or chemical reactions that increase toxicity as well as side effects caused even if they did not die.

The uptake through the intestine is finally similar to uptake by humans or swine, nevertheless toxicity of nitrite seems a bit species specific. Are there reasonable data for marine fish?

The application of potassium nitrite in agriculture inhibits nitrification. Also in saltwater aquaria the chloride seems to inhibit or slow down nitrification and also denitrification.

It seems a general biochemical problem that organisms or more specific their ion pumps cannot distinguish well between chloride ions and nitrite ions. Both ions show "competitive inhibition", means a large excess of one of both ions will inhibit the uptake of the other ones. This causes the buildup of nitrite during the nitrification and also during the denitrification process.

 

[Lasse]

I'd certainly change my mind if a chronic study showed a problem at levels of nitrite that were typically present chronically.

What you say about this ?

It is very high nitrite levels 25 and 50 mg/L NO2-N (82 resp 164 as NO2) but at least in one parametre they suppose that the lower was over the threshold level

This study show that there is a uptake route along the intestine

In this study of the green urchin - they found effect on gonad growth already at 1.6 mg/L NO2 (0,5 mg/L NO2-N)

This is about abalone and another sea urchin. Levels above 6,5 and 16.5 mg/L affect growth during a 2 weeks period

This is interesting too because it compare the sensitivity for nitrite in different salinities within the same species

During my cycle I dosed Ammonia for 2 weeks and then sit 2 weeks

How much ammonia did you totally dose ?

Sincerely Lasse

 

[DrZoidburg]

@Wyvern At what level when added fish? To my point though those are only noticeable results saying looks happy so its all good? Because a lot of documents I find lack information more geared to species or even species families we keep. How does one know damage permanent or not was made to them in that week it took to go down? Without proper reference to said species? That is why I am not convinced.

 

[DrZoidburg]

@Hans-Werner Its not just methemoglobinemia. As for the inverts I believe it may have something to do with the fact that some of them do not have normal blood. They have hemocyanin with copper center. Its a very different molecule than hemoglobin.

 

[Jeffcb]

IMO, nitrite is not something reefers need to be concerned with or measure.

Is it toxic at high levels (like 150 ppm)? Very likely yes. Published studies claim so, but I personally would not be sure that a study adding 150 ppm nitrite didn't accidentally have 0.5 ppm ammonia also present.

But is it ever toxic in a cycled reef aquarium? Highly unlikely, IMO, without dosing nitrite.

Is it ever toxic in any reef tank that can process ammonia? I cannot see how unless one set up a system to process a ton of ammonia fast before nitrite processing got ramped up.

Good. I will not worry about it.

 

[Randy Holmes-Farley]

What you say about this ?

Does not surprise me at all. Nor do I think reef tanks ever get to 25 ppm nitrite that was used.

Why pick on nitrite and not equally on nitrate that is more often attained at "toxic" levels in reef tanks than is nitrite:

Nitrate toxicity to aquatic animals: a review with new data for freshwater invertebrates - PubMed

Published data on nitrate (NO3-) toxicity to freshwater and marine animals are reviewed. New data on nitrate toxicity to the freshwater invertebrates Eulimnogammarus toletanus, Echinogammarus echinosetosus and Hydropsyche exocellata are also presented. The main toxic action of nitrate is due to...

pubmed.ncbi.nlm.nih.gov

". In the case of marine animals, a maximum level of 20 mg NO3-N/l may in general be acceptable. However, early developmental stages of some marine invertebrates, that are well adapted to low nitrate concentrations, may be so susceptible to nitrate as sensitive freshwater invertebrates."

 

[Hans-Werner]

Its not just methemoglobinemia. As for the inverts I believe it may have something to do with the fact that some of them do not have normal blood. They have hemocyanin with copper center. Its a very different molecule than hemoglobin.

Yes, I know, in crustaceans for example, while annelids like the polychaets again have hemoglobin. But causes nitrite also methemocyaninemia? And what is with the invertebrates without blood at all, like corals?

What do you think about my explanation of the nitrite buildup? Also @Lasse

 

[DrZoidburg]

I'm sorry hans I did not dig that deep into other inverts yet. Here is one study that mentions possible effects on hemocyannin https://pubmed.ncbi.nlm.nih.gov/31604159/

 

[DrZoidburg]

In the case of worms maybe that it is a lot more that absorbs through their skin. Faster absorption rates?

 

[Hans-Werner]

In the case of worms maybe that it is a lot more that absorbs through their skin. Faster absorption rates?

In my opinion rather unlikely. Like I mentioned, it is a matter of competition between chloride and nitrite. If an animal excretes chloride that diffundates through skin, gills etc., it will also excrete nitrite.

The problem in freshwater fish is the active uptake of chloride through the chloride cells in the gills. "By mistake" they also take up and enrich nitrite which causes the toxic concentration in the blood of freshwater fish.

 

[DrZoidburg]

There are circumstance where it possibly does go through skin and gills also. Mentioned above^ For "theory" on hemocyanin still thinking this over though. I had a thought maybe a chemical reaction with nitrite ruptured the cell in some way.

 

[Lasse]

Does not surprise me at all. Nor do I think reef tanks ever get to 25 ppm nitrite that was used.

The article take up sublethal effects and we do not know what happens in the long run with lower concentrations. It is not investigated enough And they did use 25 ppm Nitrite-N - corresponding to 82 ppm NO2. No I do not think you will have that in a reef tank

Why pick on nitrite and not equally on nitrate that is more often attained at "toxic" levels in reef tanks than is nitrite:

Because nitrite is a an intermediate compound caused by bad working nitrification. A bad working nitrification cycle can indicate other problems in the system - low oxygen saturation, to much dissolved organic carbon and so on. And we still not know of the sublethal effects. And people here recommend without hesitation other people to add fish in nitrite levels around 5 - 10 ppm. And that´s a level that easy can come up if you use the modern way of addition of ammoniumchlorid in order to start the aquarium

20 mg NO3-N

It is around 88 mg/L as NO3 - I use to recommend 2 to 5 mg/L NO3 and have never advocated for higher concentrations.

Sincerely Lasse