Chemical disposition of boron in animals and humans.

Elemental boron was isolated in 1808. It typically occurs in nature as borates hydrated with varying amounts of water. Important compounds are boric acid and borax.

Comparison of lead bioavailability in F344 rats fed lead acetate, lead oxide, lead sulfide, or lead ore concentrate from Skagway, Alaska.

An animal model using rats was developed to initiate investigations on the bioavailability of different sources of environmental lead. Lead must be absorbed and transported to target organs like brain, liver, kidney, and bone, before susceptible cells can be harmed. The bioavailability and therefore the toxicity of lead are dependent upon the route of exposure, dose, chemical structure, solubility, particle size, matrix incorporation, and other physiological and physicochemical factors.

Tissue disposition of boron in male Fischer rats.

Boric acid (H3BO3), an inorganic acid with widespread commercial use and consumer exposure, impairs fertility in male rodents at dose levels lower than those required to cause other adverse effects. Previous studies found a testicular lesion in adult Fischer rats fed 9000 ppm boric acid (1575 ppm boron) and slightly reduced basal serum testosterone levels. A CNS-mediated hormonal component to this lesion was suggested.

Long-term accumulation of hexachlorobenzene in adipose tissue of parent and filial rats.

The concentrations of hexachlorobenzene (HCB) in adipose tissue were similar for F0 and F1b generations in rats fed 20 ppm HCB until 45 weeks of age. Nulliparous females receiving treatment equivalent to the HCB-treated F0 generation rapidly accumulated HCB in their fat and, by 13 weeks of age, the residue values coalesced with values in 13-week-old F1a females which had received additional HCB via the placenta and milk. Between 13 and 30 weeks of age, steady-state storage was approached and no significant increase in HCB concentrations occurred through 65 weeks of age.

Method for the confirmation of chlorophenols in human urine by LC with an electrochemical detector.

A method is described for the confirmation of chlorophenols in human urine. A hydrolyzed urine sample is analyzed by both gas chromatography (GC), and liquid chromatography (LC) with electrochemical detection and the results compared. A discussion of these results, including factors affecting separation, detection, and confirmation of chlorophenols in human urine, is included.

Improved method for hexachlorobenzene and mirex determination with hexachlorobenzene confirmation in adipose tissue: collaborative study.

A previously published method for determination and confirmation of hexachlorobenzene (HCB) in adipose tissue was also applied to mirex residues. A modified procedure for both residues was collaboratively studied by 12 laboratoires. The procedure specifies direct application of an extracted or rendered fat sample to a Florisil cleanup column and one-fraction elution.

Organophosphorus pesticide poisonings in humans: determination of residues and metabolites in tissues and urine.

The analyses of four organophosphorus pesticide poisoning cases, three of which resulted in death, are reported. The case histories of the subjects, along with the analysis of tissues, urine, and blood for the levels of pesticides and metabolites are given. The pesticides involved include dicrotophos, chlorpyrifos, malathion, and parathion.

Simplified micro perchlorination method for polychlorinated biphenyls in biological samples.

Simplified methodology is presented for the micro determination of polychlorinated biphenyls (PCBs) in biological samples, by conversion to the decachlorobiphenyl (DCB) derivative. Beef adipose tissue and human milk extracts were fortified with PCB standards at 0.1--5.

Electron capture gas chromatographic determination of Kepone residues in environmental samples.

The pollution of the environment with Kepone (decachlorooctahydro-1,3,4-metheno-2H-cyclobuta[cd]pentalen-2-one) by an industrial manufacturer of the pesticide resulted in the contamination of several terrestrial media, including biological life, near the entry of the insecticide into the ecosystem. The substrata investigated and for which residue methodology was developed included river sediment, soil, water, shellfish, and finfish. Rigorous extraction techniques utilizing the Soxhlet apparatus and the Polytron tissue homogenizer were required for complete removal of Kepone from the samples.

Improved recovery of hexachlorobenzene in adipose tissue with a modified micro multiresidue procedure.

Using the described methodology the recovery of hexachlorobenzene from adipose tissue was significantly increased over that normally obtained with other multiresidue procedures. The recovery of other commonly encountered chlorinated hydrocarbon pesticides was not affected nor was the "background" from adipose tissue intolerable. Although extensive work has not been done, it is likely that improved recovery of hexachlorobenzene could be expected from other tissues.

PCB metabolism in rats following prolonged exposure to Aroclor 1242 and aroclor 1016.

Several mono- and dihydroxy metabolites of di-, tri, and tetrachlorobiphenyl have been identified in the urine of rats fed prolonged diets of Aroclor 1016 or Aroclor 1242. Combined gas chromatography-mass spectrometry was used for characterization of the metabolic products.

Rapid determination and confirmation of low levels of hexachlorobenzene in adipose tissues.

The described procedure can be utilized for rapid, simple quantitation and confirmation of hexachlorobenzene in fatty tissue at levels as low as 5 ppb without the use of sophisticated and expensive equipment. Interferences can be circumvented in many instances without additional separation by selection and preparation of the appropriate derivative.