Urinary levels, tissue concentrations and lung inflammation after nose-only exposure to three different chemical...

This study aimed to determine the toxicity and toxicokinetic of three Be chemical species A total of 120 mice (four groups of 30) were nose-only exposed. The first group was used as a control while the three others were exposed to 250 microg m(-3) of fine particles of three different Be species (Be metal, Be-F; Be oxide, BeO-F; Be aluminium, BeAl-F). Exposure lasted over three consecutive weeks, five days per week and 6 h per day. Blood and several tissues were collected one week after exposure. Urines were collected before the beginning of exposure, at the end of every week of exposure and one week after exposure. Results showed that urine concentrations were different from one Be species to another and that excretion continued after the end of exposure. Except for BeO-F, where Be urine concentrations were stable during the three weeks of exposure, concentrations of Be-F and BeAl-F reached a peak after the first week. According to particle size, BeO-F obtained the highest theoretical pulmonary deposition rate, which partially led to the highest Be lung concentration. This group also presented the lowest urine concentration but that did not lead to more severe lung inflammation. Moreover, even if BeAl-F obtained the lowest percentage theoretical pulmonary deposition, it showed the highest Be urinary concentration, the lowest Be lung concentration and the lowest lung toxicity. In this specific case, a high Be concentration in urine did not reflect a high exposure or a severe toxic effect.