INORGANIC BORON HEALTH-EFFECTS IN HUMANS - AN AID TO RISK ASSESSMENT AND CLINICAL JUDGMENT

This is a review of human response to elevated levels of boron contain ing compounds with emphasis on studies containing sufficient detail fo r evaluation of dose-response relationships. Qualitative information i s also included where it will assist assessment of risk or contribute to clinical judgment. Skin absorption and dermatitis is also reviewed. Quantitative data are sparse, especially for infants and children. Fo r acute oral doses in children, there are only two data points where d ose and temporal relationships have been estimated with some care and where recovery was uneventful; these come from a single paper. Doses w ere 94.7 mg B/kg in a 24-day infant and 30.4 mg B/kg in a 14-month inf ant. Effects were irritability, mild diarrhea with vomiting, marked er ythema in the diaper area at 94.7 mg, and sparse, mildly erythematous macular rashes on the face and neck at 30.4 mg. Adults given intraveno us doses averaging 25 mg B-10/kg (range 19-46 mg B-10/kg) over a 75-se cond period responded within 2 minutes with nausea followed by vomitin g, excitation, and subsequent mild depression. No-effect levels for hu mans can be established at about 1 g of boric acid per day (2.5 mg B/k g/day). The chronic adverse effect level is 5.0 mg B/kg/day. Infant re sponse al high levels is similar enough to adult responses that it is reasonable to assume that the infant is not more sensitive than the hu man adult. Non-systemic effects of boron are minor. Respiratory exposu re in industry has not caused chronic pulmonary effects. Skin exposure does not cause dermatitis. (C) 1997 Wiley-Liss, Inc.