Potential for reducing indoor styrene exposure from copied paper through use of low-emitting toners.

Tests were conducted using 53-L dynamic chambers to determine airborne styrene emission rates over time from freshly copied paper. Copies were produced on a single photocopier using two toners manufactured for this copier but having different styrene contents. The resulting emission models were used to predict whether indoor styrene concentrations resulting from copied paper in a typical office might be significantly reduced by use of a low-emitting toner for a given copier. The styrene emissions were best represented by either a 3rd-order decay model or by a power law model having an exponent between 0.3 and 0.5 (R2 = 0.94-0.99). The two toners resulted in copied paper having significantly different styrene emissions (p < 0.01), with unit mass emissions over 1000 hr being nine times greater with the higher-emitting toner. But copied paper is predicted to produce peak indoor styrene concentrations in a typical office no more than 1% of the World Health Organization health-based guideline. Thus, for the toners considered here, indoor styrene exposures from copied paper appear to be too limited to provide incentive for switching to the lower-emitting toner. The ability to generalize these conclusions is limited by the fact that only one copier and two toners could be tested.

Variations in the emissions of volatile organic compounds from the toner for a specific photocopier.

A laboratory thermal desorption apparatus was used to measure emissions from a number of nominally identical photocopier toners--manufactured to meet the specifications of one specific model copier--when these toners were heated to fuser temperature (180-200 degrees C). The objective was to assess how potential volatile organic compound (VOC) emissions from the toner for a given copier can vary, depending upon the production run and the supplier. Tests were performed on a series of toner (and associated raw polymer feedstock) samples obtained directly from a toner manufacturer, representing two production runs using a nonvented extrusion process, and on toner cartridges purchased from two local retailers, representing three different production lots (histories unknown). The results showed that the retailer toners consistently had up to 350% higher emissions of some major compounds (expressed as microgram of compound emitted/g of toner), and up to 100% lower emissions of others, relative to the manufacturer toners (p < or = 0.01). The manufacturer toners from one production run had emissions of certain compounds, and of total VOCs, that were modestly higher (13-18%) than those from the other run (p < or = 0.01). The emission differences between the retailer and manufacturer toners are probably due to differences in the manufacturing processes and/or feedstocks used to produce the toners from these different sources.

Cost Analysis of Activated Carbon Versus Photocatalytic Oxidation for Removing Organic Compounds from Indoor Air.

A cost comparison has been conducted of 1 m3/sec indoor air cleaners using granular activated carbon (GAC) versus photocatalytic oxidation (PCO) for treating a steady-state inlet volatile organic compound (VOC) concentration of 0.27 mg/m3. The commercial GAC unit was costed assuming that the inlet VOCs had a reasonable carbon sorption affinity, representative of compounds having four or more atoms (exclusive of hydrogen). A representative model PCO unit for indoor air application was designed and costed, using VOC oxidation rate data reported in the literature for the low inlet concentration assumed here, and using a typical illumination intensity. The analysis shows that, for the assumptions used here, the PCO unit would have an installed cost more than 10 times greater, and an annual cost almost seven times greater, than the GAC unit. It also suggests that PCO costs cannot likely be reduced by a factor greater than 2-4, solely by improvements in the PCO system configuration and reductions in unit component costs. Rather, an improved catalyst having a higher quantum efficiency would be needed, increasing reaction rates and reducing illumination requirements relative to the catalysts reported in the literature. GAC costs would increase significantly if the VOCs to be removed were lighter and more poorly sorbed than assumed in this analysis.

Sex difference in daily water consumption of rats: effect of housing and hormones.

Females rats consume more water than males per day when consumption is indexed to body weight. We examined the developmental expression of this sex difference as well as the organizational and activational influences of testosterone (T). The amount of water consumed from weaning to adulthood exhibited a linear decrease with age in both sexes. The development of a sex difference in water consumption was evident immediately after weaning in singly housed animals, but did not emerge until about Day 42-45 in group-housed animals, when females began to consume greater amounts of water than males. Castration at weaning had minimal effects on the sex difference. Treating dams with testosterone propionate (TP; 0.3 mg/kg; E15-E20) resulted in a significant increase in adult water consumption in offspring of both sexes, but the sex difference remained. Overall, these data indicate that gonadal steroids are not the primary organizational influence on this sex difference. The greater water consumption in females is consistent with other studies demonstrating sex differences in plasma vasopressin levels, as well as differences in vasopressin sensitivity.

Sexual fantasies, gender, and molestation history.

A total of 314 university students (107 males and 207 females) completed a questionnaire examining reports of childhood sexual abuse history and extent and type of adult sexual fantasies. Multivariate main effects of gender and abuse history were found, as well as a multivariate interaction between these variables. Males had more fantasies of forcing someone to have intercourse with them, participating in an orgy, and having sex with a stranger. Subjects with histories of sexual abuse had more sexual fantasies than their nonabused peers in four of five categories. Finally, sexually abused women reported more fantasies of being sexually forced than did women without sexual abuse histories or men regardless of molestation history. In several instances, fantasies correlated with especially early and extended abuse.

Interaction of naltrexone with postnatal administration of testosterone and estrogen on neurobehavioral sexual differentiation in rats.

The present study examined whether some effects of gonadal sex hormones on neurobehavioral sexual differentiation might be mediated by endogenous opioids. Male and female pups were administered sesame oil, testosterone propionate (TP; 25 micrograms) or estradiol benzoate (EB; 10 micrograms) on postnatal Days 2 and 3. Half of each group was also administered naltrexone (N; 50 micrograms) twice daily on these two days. Females were studied for effects of the treatments on puberty. Males and females were studied in adulthood for open field behavior, daily water intake, and saccharin consumption and preference for 0.125, 0.25, and 0.50% saccharin solutions. TP treatment significantly delayed the date of vaginal opening, whereas EB treatment significantly accelerated the date. N treatment potentiated this effect of TP, but had no effect in EB treated females, nor did it influence the anovulatory sterility produced by both hormone treatments. N treatment alone had no effect on puberty in females or open field behavior of either sex. The drug produced an overall increase in female saccharin consumption and preference, but no effect was observed in males on these measures. Both TP and EB treatment produced marked increases in daily water consumption in females, an effect which was significantly attenuated by N treatment. Effects of both hormones on saccharin consumption were sex dependent and partially antagonized by N treatment. Finally, we observed a sex difference in daily water intake wherein females were found to consume approximately 20% more water on a body weight basis in a 24-hr period than males. Postnatal TP and EB treatment increased adult daily water consumption in females above the level of controls. This increase was partially antagonized by N. Treatment with N alone had no effect on female water consumption, but produced a small decrease in male consumption. Overall, these results provide preliminary evidence that some organizational effects of TP and EB on nonreproductive sex differences may be mediated by endogenous opioids.