Hello,

I don't deal with fish, but perhaps either subchronic or subacute might apply.

Best Regards

Dear Mrs. Haighton,

thank you for the advices. I will use subchronic I guess.

Regards,

Giorgio

Dear Giorgio Sperandio,

I think that in this case there are subchronic  exposures.

In experiments in rodents have this chronic effects (considering the duration of their life, metabolic characteristics, etc).

Should take into account the nature of the studied parameters.

Dear Giorgio

Acute toxicity is always expressed by the dose or concentration in mg/kg, and chronic toxicity in mg/kg/day. Animals laboratory such as the rat refers to toxicity long-term when the duration of the test is greater than 1/10 of the life of the animal (usually 6 months, one or two years). Your trial seems to me more as a trial in the short term (lower than 1/10 of the life of animals, e.g, 14 days, 28 days and 90 days) and therefore it will be qualified as sub-chronic test

Dear Giorgio!

Dear Mehennaoui Smail,  

there are not rodents, it is  -   Perca fluviatilis.

It will be qualified as sub-chronic test. I agree. Sub-chronic test - chronic test?

All this is very conditional.

14 days - subacute effect.

28 days - sub-chronic test. 

But 90 days - chronic test.  Mice and rats live 2-2.5 years - 730-912 days.

1/10 of the life of the animal - 70-90 days.

You can refer to hundreds of articles on toxicology, which indicates the time of chronic exposure to xenobiotics in rodents.

The term sub-chronic intoxication is rarely used in toxicology.

And who is determined postulated found that chronic effects it is 1/10 of the life of the animal?

And why not 1/5 of the life of the animal or 1/20 - 1/30 of the life of the animal?

If a person consumes alcohol daily 1 year - this is a chronic alcoholic intoxication (~ 1/70-1/80 of the life).

Dear Zabdrobskii, dear Giogio

I agree with you. I understand that the tests performed by Girogio were not in rodents. I just gave classical information usually used in toxicology to differentiate acute, short-term toxicity and long-term toxicity. When it comes to assess the long term toxicity of a new therapeutic substance  for example, it should be taken into account the time of its use in the target species. Therefore why not six months or one year?

Best regards

Dear Mehennaoui Smail,

thank you very much  for a number of refinements,  I completely agree with you.

I also approved your previous opinion. I expressed my  view  in terms of experimental toxicology  (medicine).

Best regards.

Dear Dr. Zabrodskii and Dr. Smail,

many thanks for the replies and clarification. Following your advices I will use the term subchronic for this kind of time-span and model animal.

Best regards,

Giorgio Sperandio

Dear Giorgio Sperandio,

yes, it is quite appropriate definition.

Best regards.

Hello,

Chronic test  > 3 months (Low concentratios)

Acute test usually 96 hours (High concentrations). In bivalves you can do chronic test between  60 – 90 days, I was working with Anadara (A. similis and A. tuberculosa) at 60 days exposition, observing changes in gonads especially.

Best regards

Dear Monica Zambrano,

I agree with you. Shronic test between 60 - 90 days. I agree.

If the specified exposure time, in toxicology studies (rodents) xenobiotic exposure for 30 days can be called as a sub-chronic and chronic. In my opinion, it is not important if the specified exposure time. Shronic test between 60 - 90 days. I agree.

You write:

Chronic test> 3 months (Low concentratios)?  This is someone defined as a law?

Clearly, the low concentrations (doses). At higher concentrations (doses) animals will not live up to 1-3 months. Various xenobiotics have different coefficients of cumulation.

Chronic test  = 2 and > 2 months (Low concentratios, doses ). 

In experimental toxicology (medicine) models and methods may differ from those in Environmental Toxicology.

Dear Dr, Zabrodskii

I agree with you too. This certainly changes according to the species , compound and cencentración , my acute tests were always 96 hours for these bivalves, even less time for planktonic species. There are many variables that each researcher has to be adjusted according to what you will be studying .

I usually trabjo PAH and in the case of naphthalene , the acute toxicity is high, contrary to less soluble compounds and higher molecular weight . Certainly the characteristics of the compound and species are key to determining the test conditions

Best regards.

Mónica

Dear Mónica,

thank you very much. With interest I read your articles.

Best regards.

Pavel. 

Dear Colleagues: The first thing that comes to mind here when I read this is concentration. What were the levels of Cd exposure? If the levels of Cd were relatively high then it can mask the terminology of chronic  so concentration is important. On the other hand if they were low they could not be considered acute. But although we discuss terminologies and even define them the importannce of the study is the effects of the exposure if any.  The exposure is defined by how it was done so you can define it as subchronic or even acute as long as you state it up front and define it. So the importance is under these conditions what were the effects and the findings.

Hello,

Chronic heavy metal toxicity exposure is that when a biomodel is permanently placed into a polluted environment (which is temporary accomplished in your study), exposed to a fixed quantity of pollutant and/or you can design other ways of evaluating response changes by changing pollutant presence in a series of steps. It’s valuable for measuring time response at a certain dose and evidently you need a larger number of individuals because you probably need to sacrifice them for quantifying in each time interval selected and/or for each step or be sure that sample extraction without sacrificing individuals do not affect directly or imminently the response you are determining. Different pollutant quantities can be evaluated in replicas.

Acute heavy metal toxicity exposure implies a single elevate dose at expected acute toxicity / lethal effects. This dose may be selected by previous reports of toxicity or by testing for example higher concentrations than those found in the polluted area. In this case, it is useful for knowing limits for life maintenance and tolerance to change related to adaptation level.