Beryllium dating method
In its review of beryllium, ATSDR (2002) reported that surveys have detected beryllium in less than 10% of samples of U. surface water and springs, but detection limits are not reported in the review. air have typically been less than the detection limit of 0.03 ng/m (ATSDR 2002).
The low water concentrations probably reflect beryllium’s typically entering water as beryllium oxide, which slowly hydrolyzes to the insoluble compound beryllium hydroxide (EPA 1998b). Natural sources of airborne beryllium are windblown dust and volcanic particles, estimated to contribute 5 and 0.2 metric tons per year, respectively, to the atmosphere (Table 2-1).
Insoluble particles deposited in the upper respiratory tract and tracheobronchial tree are cleared by mucociliary transport; those deposited in the pulmonary regions are cleared by a number of mechanisms and pathways, primarily via alveolar macrophages.
The clearance of insoluble compounds from the lung was generally shown to be biphasic, with clearance half-times of days (via mucus transport and alveolar macrophages) to years (by dissolution and other translocation mechanisms) (Schlesinger 1995; NCRP 1997).
Exposures that lead to the principal end points of concern in connection with beryllium now—cancer and chronic beryllium disease (CBD)—are likely to have distinct physiochemical and dose-response characteristics.
The following specific questions were formulated to guide the literature review: We first describe beryllium sources and uses and then briefly review beryllium toxicokinetics.
Substantial fractions of inhaled beryllium doses are removed by mucociliary clearance and enter the gastrointestinal tract.
It has many unique chemical properties, being less dense than aluminum and stronger than steel (EPA 1998b).
Because of its small atomic size, its most stable compounds are formed with small anions, such as fluoride and oxide.
The toxicokinetic profile of beryllium compounds varies with solubility; more soluble forms undergo greater systemic absorption, distribution, and urinary elimination.
EPA (1998b) did not identify any human studies of the deposition or absorption of inhaled beryllium but provides a review of the available animal studies.
In 1991, world beryllium production was estimated at 3,600 metric tons (Rossman et al. Releases of beryllium are exceptionally high in Ohio because the sole U. producer and processor of beryllium (Brush Wellman) is located there.