Framework for human health risk assessment of non-cancer effects resulting from short-duration and intermittent exposures to chemicals.

Durations of exposure to chemicals, whether for single, repeated or intermittent periods, may vary from those upon which most guidance values are normally based. Because it is presently not feasible to conduct toxicity studies or develop toxicity reference values (TRVs) specific to each scenario of interest, methods are needed to address these various durations, drawing as much as possible on existing TRVs. A working framework was developed to address the potential for non-cancer effects resulting from continuous short-duration and intermittent exposures to chemicals.

Methylmercury blood guidance values for Canada.

Exposure to methylmercury (MeHg) from fish and marine mammal consumption continues to present a public health concern. To date, developmental neurotoxicity is the most sensitive health outcome, forming the basis for health-risk assessments and the derivation of biomonitoring guidance values. This article summarizes existing Health Canada MeHg blood guidance values for general population and expands them to include a harmonized provisional interim blood guidance value of 8 microg/L based on the existing provisional Tolerable Daily Intake for children, pregnant women and women of childbearing age.

Penetration of chloroform, trichloroethylene, and tetrachloroethylene through human skin.

In vitro dermal absorption was measured for three volatile organic compounds in dilute aqueous solution through freshly prepared and previously frozen human skin. The permeability coefficients at 26 degrees C for chloroform (0.14 cm/h) and trichloroethylene (0.

Effect of environmental conditions on the penetration of benzene through human skin.

The in vitro penetration of [14C]benzene through freshly prepared human skin was examined under a variety of skin conditions associated with swimming and bathing. The experimental system utilized a recirculating donor solution and a flow-through receiver solution, and was modified to accommodate the analysis of volatiles. The permeability coefficient of 0.