Hello, everybody! In your opinion, in an environmental risk assessment, if exists, which is the most critical criterion: bioaccumulation potential, acute aquatic toxicity, or biodegradation? For example: which compound offers more risk to the environment and why?:
Compound 1: very high acute toxicity, low bioaccumulation, high biodegradability;
Compound 2: very high bioaccumulation, low acute toxicity; high biodegradability;
Compound 3: very low biodegradability; low acute toxicity; low bioaccumulation.
Thank you in advance!
1 and 3. The most 3.
Maybe I'm wrong, but biodegradability could be the determing factor. Bioaccumulation could be, but not as much. Toxicity is only relevant to the compound and not generally.biodegradability is how much it stays in the environment. Bioacumulation is a factor on concentration.
2 is the lowest.
Hi.
I think compound 2 with the very high bioaccumulation and low toxicity because I guess the organisme in this case is already toxicated even at low toxicity concentration, the time could play its role in this case.
Regards
Younes Boundir Mª Angeles Zorrilla Lopez-Perea thanks for answering. I think all the criteria are critical. High acute toxicity indicates that even in short term this compound can be very hazardous to organisms, however, it may depend on the environmental concentration. High bioaccumulation potential, can pass through the food chain, and cause adverse effects on organisms or not. Low biodegradability indicates that the compound can be persistent and cause chronic effects, however, even a rapidly biodegradable compound can be persistent depending on if it is frequently released in the environment. So that's why for me it's so difficult to determine the most critical criteria. Do you have any idea based on these points I gave.
1. In my opinion, the most critical is acute toxicity, because toxicity can be used as a direct environmental damage parameter.
2. The most dangerous is compound 1, because of its high acute toxicity.
Hello Irisdoris Rodrigues Souza
Very correct, then in opinion all 3 compounds are true in a way or another, the compound 1 with high toxicity still the most critical.
Regards
It is a very open ended question. There is no single answer to the toxicity potential question along these compounds of choice. All three factors are important for toxicity potential but there are other factors equally important, like exposure period, media: water or sediment, wind or mixing effect, type of chemical, dissolved organic carbon, particle concentration, size and shape of particles.
- Me too, I would vote for Compound 1. as the most hazardous. It could be an organic solvent, for for instance. Even if the effect does not last long, it may be devastating.
- Compound 3. is a good candidate, too: it could be microplastics, for instance. Although not toxic, they may prove alarmingly dangerous in the future. They do not bioaccumulate at this size, but with time they fracture to nanoplastics that, in contrast, bioaccumulate. Even if chemically neutral, nanoplastics are able to cross the cell membranes and cause physical damage within the living cell.
- Compound 2. seems to me contradictory. Bioaccumulation and biodegradation are somwhat opposing effects: if something can be easily consumed, it will not accumulate. It would help if you gave a concrete example.
Thank you very much for all the answers! I think all the answers give important contributions and are worth thinking about for a more in-deep discussion.
Dear Mrs Souza
I do not completely agree with the above. Acute water toxicity is important, but very toxic compounds get easily recognised and ev. banned. If they are not bioaccumulative or persistent, their impact will be minimal. For Bioaccumulating substances, the degree of chronic toxicity is more important. In my opinion, for the environment, biodegradation is key. Forever substances, like PFAS, are not so toxic neither bioaccumulative, but they do not degrade, and poses the ultimate threat. It was described as a bath tub without stopper, and with no possibility to empty whatsoever. How high do you allow the water to rise, knowing that if the bath tub is full, all is dead.
In my honest opinion, though No 1 is critical, the biggest headache will always come from No 2. Managing the pathways long-term becomes all the more so difficult. Even if there is high biodegradability, the scare of biomagnification is often ignored and comes back to haunt us. A toxic chemical upon degradation not always degrade to produce non-toxic compounds. No 1 would come in next. I am not really concerned of 3 with priority, as, if they are identified, considering the low biodegradability, ways may be devised to screen out for anthropogenic uses.
It all depends on the particular chemical since the rates are so different from one compound to another as the unit processes. The study goal will determine which combination of processes to focus.
hi
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Hmm, I'm not in agreement with considering chemicals benign if they do not bioaccumulate and aren't persistent. Atrazine is just one example of such a menacing chemical.
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