Hello again, Wladimir.  :)  

What exactly do you mean by "sensitivity"?  Are you trying to find out how toxic a chemical is to your species compared with other species? That is what I would understand by sensitivity. If that is what you want, then you need to do a literature search for toxicity data for your chemical on other species, and compare them with your own results. 

The US EPA Ecotox database has a huge collection of toxicity data:

https://cfpub.epa.gov/ecotox/

Once you have a good collection of data from a range of species, then you calculate a species sensitivity distribution for your chemical using software such as BurrliOz, which is free to download and use after you register with the CSIRO.

https://research.csiro.au/software/burrlioz/

You would then repeat this for each chemical you are interested in.  These curves will tell you how sensitive your species is to that chemical. compared with other species.

Concentration addition and independent action models have a completely different function: They are used to predict the effects of mixtures of chemicals on a species. This can be used in research, by measuring the effects of the chemicals individually and as mixtures, and comparing the experimental results with the predictions to determine which model gives the better fit. Or they can be used in risk assessments to try to predict environmental effects of mixtures of known concentrations when you have data for the toxicity of the individual components.

Does this answer your question?

Regards,

Anne

Dear Anne

Thank you for your response

Well, what I am trying to do is find out how toxic are different chemicals in one particular specie. Therefore I would like to know the any procedure for chemical toxicity distribution in order to reach that objective using toxicity models

Regards

Wlady

Ah. Have you actually done any experimental work yet, are you still planning experiments, or are you hoping to use results from the literature and do what might be called a "desktop study"?  My advice will be different depending on exactly what you are doing.

I don't know whether you want to describe your project on Researchgate, or whether you would prefer to email me, and explain what you are doing and what the overall objectives of your study are. You should be able to find my email on my university website.

Regards,

Anne

Comparing toxicity data among different studies with different water chemistry could be misleading especially for metals. So be careful if you have any metals in your analysis.   

Dear all, thank you for your kind responses.

Dear Anne, I will email you in order to explain my objectives of my study

Kind regards

Dear Wlady,

It will certainly help to have a clear idea of what you are trying to do.  :) 

In our previous discussion it seemed that I was making assumptions that turned out to be wrong, and that made things difficult. I'll wait for your email.

Regards,

Anne