Keitaro Nishiyama

Adsorption and elution of cadmium on hair.

Adsorption and elution of cadmium on human and mouse hair were studied by the use of radioactive isotope technique. Hair with Cd accumulated solely from the hair follicle was obtained from mice injected with cadmium 109. Cadmium adsorption on human hair, when brought into contact with a solution of cadmium chloride tagged with cadmium 109 occurred with an individual variation, ranging from 0 to 100% of Cd present in the solution. This variation seemed to have been the result of individual variation in hair acidity. A nearly complete removal of Cd from the hair could be obtained by using a sufficiently strong solution of an acid. However, the different treatments applied were not effective for separate analysis of exogenous and endogenous hair Cd.

Residual tetrachloroethylene in dry-cleaned clothes

A large amount of residual tetrachloroethylene (TCE), up to 13.6 mg/g, was found in dry-cleaned clothes. The amounts varied among dry-cleaning establishments as well as with the type of fiber. The causes of these variations are discussed. Air TCE concentrations in the closed environment of dry-cleaning outlets were elevated: the highest reading was 4.8 mg/m3. The expired air of outlet employees also showed an increased level of TCE (average, 36.9 micrograms/m3). Increased air contamination from TCE released from dry-cleaned clothes was also observed in the home of a consumer. To reduce environmental contamination from TCE released from any of these sources, the amount of residual TCE in dry-cleaned clothes should be minimized.

Adsorption and elution of metals on hair

The adsorption of zinc and lead on hair was dependent on the acidity of the hair and/or the medium in which the hair sample was immersed, suggesting that hair is an ion exchanger. The pKa was estimated to be between 4.5 and 5.0. The coexistence of mercuric ion or PCMB reduced zinc adsorption by only a few percent, whereas zinc inhibited mercuric ion adsorption to a greater extent. These facts suggest that the binding sites in hair for metals are located on functional groups like carboxyl groups rather than sulfhydryl groups.The removal and/or elution of metals from hair were observed for 18 elements by various washing procedures. By treating hair with a water solution of detergent, alkaline metals were eluted to a great extent, whereas alkaline earth metals were eluted to some extent. The other metals did not vary with any procedures tested.

Observations on the progress of chlordane contamination in humans by blood and sebum analysis

Chlordane residues were determined in human blood and sebum samples. The residue levels in both types of samples were remarkably increased in pest control operators and in the general population living in an area heavily contaminated with chlordane. The compound with the highest level among the residues in the blood of control subjects was oxychlordane followed bytrans- non- achlor andtrans- chlordane, while in the sebum, the highest levels found was that oftrans-chlordane followed bycis-chlordane andtrans-nonachlor. The sebum residue was similar to technical chlordane in its component pattern, but it largely originated from sources other than simple exogenous contamination. Thus, sebum might be a unique and available sample source for evaluating direct exposure to technical chlordane.A progressive state of contamination was observed in residents whose homes had been treated with chlordane.

Quantitation of chlordane residues in mothers' milk.

Chlordane residues were determined in human milk samples. Quantitative analysis was conducted for six residual compounds in the milk of 29 healthy Japanese donors who had experienced no occupational exposure to chlordane. All six compounds were detected in the milk from each donor. Geometric mean levels in whole milk (ng/ mL) and milk fat (ng/g), respectively, were:trans-nonachlor 0.55, 15.7; oxychlordane 0.39, 11.5;cis-nonachlor 0.14, 4.00;cis-chlordane 0.09, 3.08;trans-chlordane 0.04, 1.20; heptachlor epoxide 0.66, 20.0.In terms of the concentration (in both the whole milk and fat), a significant positive correlation was noted between any two compounds oftrans-nonachlor,cis-nonachlor, and oxychlordane. The residue level of each of these compounds had a significant positive correlation with the lipid content of the milk.The level of chlordane residues in human milk was not very high, but the data suggest widespread chlordane contamination among the general Japanese population.