Dear Duried Alwazeer thank you for asking this very interesting technical question. Lead compounds (under normal conditions mostly divalent lead) are either insoluble (PbS, Pb3O4) or soluble in water (PbCl2, lead(II) acetate etc.). Thus to the best of my knowledge they show no tendency to migrate from the aqueous phase into the organic / fat phase. However, the situation is completely different when you have organic lead(IV) compounds such as the famous tetraethyl lead, Pb(C2H5)4. Such compounds are only soluble in organic solvents but insoluble in water. For some basic information please have a look e.g. at the following link:

Lead in the Environment, and Health

http://www.agius.com/hew/resource/lead.htm

Good luck with your work and please stay safe and healthy! With best wishes, Frank Edelmann

Dear @Frank Edelmsnn, thank you very much for your helpful answer.

I would like to ask you about a phenomenon that we have envisaged during one of our assays. When we have prepared butter from acid cream (pH 4.5), we noted a high accumulation of lead in butter (mostly fatty phase) compared with buttermilk (aqueous phase). Can we explain this phenomenon by the solubility/migration of lead in/to fat? or by the aggregation of lead with organic matters such as proteins and fats found in butter? Or maybe by another Mechanism?

Have you an explanation for these results?

Best regards

Duried

Dear Duried Alwazeer many thanks for your kind response and new questions. Unfortunately I'm not a specialist in this field enough to provide you with a good explanation. We work in the field of organometallic chemistry, which is a discipline quite far away from your area of research. However, I just came across the following potentially useful article which might perhaps give you some idea:

Heavy metals and trace elements levels in milk and milk products

Article Heavy metals and trace elements levels in milk and milk products

The paper is freely accessible as public full ext on RG.

With best wishes, Frank Edelmann

Dear Frank T. Edelmann , many thanks for your kind response.

Dear Dr Duried Alwazeer,

I invite you to read these article:

https://pubmed.ncbi.nlm.nih.gov/29188328/

https://www.si.edu/MCI/downloads/articles/Tusoma_paper.pdf

Best regards,

Pr Hambaba

Dear Dr Duried Alwazeer . Organic forms of lead are fat soluble, and therefore have a particular tendency to distribute into (and harm) the brain. See the link: http://www.agius.com/hew/resource/lead.htm

Kindly see also the following link: https://www.ncbi.nlm.nih.gov/books/NBK158769/table/T15/

Also check please the following very good RG link: Article Lead Solubility and Mineral Structures of Co-Precipitated Le...

Dear readers of this interesting thread,

please allow me a friendly personal remark: When giving answers to a technical question like this one it is advisable to read previous answers in order to avoid duplications. In this case I just noted that the recently cited link Lead in the Environment, and Health

http://www.agius.com/hew/resource/lead.htm

has already been suggested on December 30th. In this context it is interesting to note that organic (organometallic) lead compounds can occur in the environment not only as a consequence of their anthropogenic uses, but also naturally as a result of bio-methylation processes. For more information about this, please see the following very interesting review article:

Concerning Organometallic Compounds in Environment: Occurrence, Fate, and Impact

Chapter Concerning Organometallic Compounds in Environment: Occurren...

This review is freely accessible as public full text on RG.

Please also have a look at the following discussion:

Honestly, what if all the respectable RG researchers gave "multiple answers" ?

https://www.researchgate.net/post/Honestly_what_if_all_the_respectable_RG_researchers_gave_multiple_answers

Please stay safe and healthy!