Deuterium labelled nonylphenols in an in-vitro model of percutaneous absorption of environmental xenoestrogens

A technical mixture of isomeric nonylphenols NP is formed as rather persist ent degradation product of nonionic surfactants and has become widespread i n the environment, e.g., in surface waters. Information about possible path ways for incorporation is needed for risk assessments, as NP has estrogenic properties. NP uptake after skin contact was determined using isolated and perfused bovine udders as models for human skin. NP-d(2) labelled in the p ositions ortho to the OH-group was prepared by an exchange procedure which did not measureably change the relative amount of isomers. Samples of udder perfusate, milk equivalent produced during the experiments and skin tissue were taken immediately before administration of 500 mg or 50 mg NP-d(2) on an udder skin area of 200 cm(2) and then for 5 h. They were analyzed by GC -MS for NP and NP-d(2) after cleanup by steam distillation and final extrac tion with SPME fibres, The results are an unambiguous proof of the penetrat ion of NP into the capillary system of living mammals after skin contact.