Bioavailability of Metals in the Indoor Environment

Personal care products that are potential indoor sources of elements include home remedies, underarm antiperspirants, and cosmetics. Zinc oxide and titanium oxide are used in many commercial sunscreen products, and zinc oxide (as calamine) has long been recognized for its healing properties (Lansdovm and Taylor 1997). Aerosolized aluminum chlorohydrate, a common antiper-spirant formulation, is one of many potential indoor sources of Al (Fishbein, 1991). Sainio etal., 2000) determined Ni, Pb, Co, As, and Cr concentrations in commercial eyeshadows, and found that 75% of the colors contained more than 5 pg g of at least one of the elements. Lead-containing remedies and cosmetics used by some Middle Eastern and Asian communities are listed by ATSDR (2000). Two Mexican folk remedies which contain Pb are azarcon and greta, which are used to treat empacho, which is a colic-like illness (ATSDR, 2000). 

There are many data gaps and areas of controversy associated with quantifying expo- 

One of the major factors influencing biological availability and toxic action of particle-bound metal compounds is their solubility under the pH and ionic strength conditions of human body fluids. Mullins and Norman (1994) measured metals in windblown dust from mine wastes as a function of particle size, which determines where in the respiratory tract the particle-bound metals will eventually settle, and as a function of solubility in different body fluids. They found that compounds of Cd and Mn in the 10-pm fraction were highly soluble in simulated stomach fluid (40 to 91%) and simulated lung fluid (27 to 100%). Compounds of As were fairly soluble in stomach fluid (17 to 37%) but not in lung fluid (0.1 to 

while solubilities of Pb compounds varied widely amongst waste sites (from 0.3 to 25% in lung fluid and from 4 to 36% in stomach fluid). 

A few studies have explored the potential of the toy safety test for screening household dust samples in areas where elevated metal levels are suspected, such as inner urban settings and mining towns. Duggan and Williams (1977) used the standard 0.07 M HCl extraction protocol to determine available Pb in street dust compared to total Pb extracted with aqua regia (HCl/HNOj). Later, Harrison (1979) applied the same approach for the determination of Pb, Cr, Co, Cu, Cd, Ni, and Zn in household and exterior urban dusts. Both studies yielded 

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