HSPiP ver.6 will have a equation to predict Bioconcentration Factor (BCF). Humans are producing so many chemicals that the oceans have become a soup of microplastics. From the plastics, plasticizers and other substances are concentrated in Daphnia magna, fish, and finally come back to humans.
Since BCF is the degree of accumulation in fat, I thought I might be able to sort it out using Hansen solubility parameters, but it doesn’t seem to be that easy.
I am collecting data, but it is very limited.
In the absence of BCF data, the octanol/water partition ratio, logKow, is often used instead, but this is obviously a mistake.
For example, we collected more than 300 compounds whose mutagenicity was known and whose BCF was known.
The horizontal axis is meaningless because it is the number of the compound, but the compounds with mutagenicity are placed after 250. The vertical axis is taken as logBCF.
If the logBCF is greater than 1, there is an 80% probability that the mutagenicity is positive.
However, if we set the vertical axis to logKow, we don’t know anything.
If we look at the old paper (1993), it is also stated that there is a correlation between logKow and logBCF when there is little data.
Pharmaceutical Society of Japan 1993, vol39, pp494
The limitations pointed out in the paper, such as the fact that the Mackay equation satisfying the linear relationship is only valid when the activity coefficients are equal, or that they deviate significantly for polyhalogenated compounds, have been forgotten for some time.
Therefore, the ability to estimate logBCF is important. Here is a list of compounds that are considered to be endocrine-disrupting chemicals. We used the Y-MB2021 to estimate logBCF, logKow, and logS for these structures.
The accuracy of the logBCF is not yet sufficient, as the values may vary from literature to literature. However, it is very valuable because it can be calculated from the structure alone.
There is a concern that these endocrine disruptors can feminize marine organisms. It is said that this is because these compounds are very similar to female hormones. Therefore, a variety of compounds are being regulated.
For example, bisphenol A has been identified as an active substance agonist that acts on estrogen receptor alpha (ESR1) to produce estrogen-like effects. Therefore, polycarbonate baby bottles are no longer used.
If I calculate the HSP of Bisphenol A and 17β-estradiol (female hormone), I can see that they are very similar. The overall feel of the molecule and the fact that it has hydroxyl groups on both ends are also very similar. We can also see that it acts on estrogen receptor alpha.
The esters of phthalic acid are also used as plasticizers for various polymers.
The dibutyl ester of phthalic acid has almost the same HSP as progesterone (pregnancy hormone).
The structure and HSP of oral contraceptives (pills) can also be summarized as follows.
The important point is that most oral contraceptives are artificial progestins.
These are not just “suspected endocrine disruptors,” but endocrine disruptors themselves. In other words, in environments where the use of the pill is commonplace, such as in Europe and the United States, excreted artificial progestogens are poured down rivers and into the ocean, leading to the feminization of marine life.
I plotted these progestogens and environmental hormones in Hansen space.
Drag Shift-Drag option-Drag, and click on the sphere that is displayed. The names will be displayed. The blue sphere shows the progestin and the red sphere shows the environmental hormone.
If the fish become female, the eggs will not hatch and the fish will not be able to eat them.
In order to prevent this from happening, we need an adsorbent that can adsorb compounds in this HSP range.
A material with a similar HSP and a large surface area is suitable.
That being said, I hope that more people will be willing to provide data so that the accuracy of the BCF estimation can be even higher.