As part of a case-control study conducted to test the association between indoor air radon levels and lung and other cancers, 539 air and 547 water radon samples were measured from homes with drilled wells throughout Maine. The factors tested for an association with air radon levels were season, house construction, draftiness of house, heating source, basement construction, radon levels in the water supply, and the type of overburden and bedrock underlying the house. Logistic regression was used to determine which variables were significantly associated with indoor air radon levels of 4 pCi/L or above and to assess their relative importance. House construction, water radon levels, and overburden permeability showed the strongest association with air radon levels. Woodframe homes were 10 times more likely than mobile homes to have an air radon level of 4 pCi/L or more (95 percent confidence interval [CI] = 1.1 to 103), and brick or stone houses were 108 times more likely to have high air radon levels (CI = 6.7 to 1,760). Homes with water radon between 10,001 and 100,000 pCi/L were 6 times more likely to have high air radon (CI = 1.6 to 22.7), and homes with water radon levels above 100,000 pCi/L were 54 times more likely to have air levels of 4 pCi/L or above than were homes with water radon at or below 1,000 pCi/L (CI = 1.9 to 1,529). Homes built over sand and gravel were 12 times more likely to have high air radon than homes built over clay (CI = 4.1 to 37.1), and homes built over two-mica granite were 4 times more likely to have high air radon than homes built over low-grade metamorphic rock (CI = 1.4 to 11.5). In addition, high air radon levels were more likely in the winter than in the summer (odds ratio [OR] = 2.9, CI = 1.3 to 6.2) and in homes heated with electricity than with other sources of heat (OR = 3.5, CI = 1.4 to 8.8).

Globally, peraluminous two-mica granites have produced significant amounts of Sn, W, U, F, Th, Be, Ta, Nb, Mo, and Li, but peraluminous granitoids in southern Arizona are known to contain significant concentrations of only W and Be. Major, minor, trace, and rare earth element data from peraluminous granitoids and pegmatites in Arizona are compared with their geochemical counterparts in western and eastern Europe, the New England states, and the Maritime Provinces of Canada. Each Arizona sample has the petrographic characteristics of a two-mica granite with varying proportions of biotite, muscovite, magnetite, garnet, apatite, fluorite, ilmenite, topaz, and zircon. Geochemical and statistical analysis of a large data base of new analyses reveals distinct geochemical differences between peraluminous two-mica granitoids in southern Arizona and their locally productive counterparts elsewhere. All of the samples exhibit similar concentrations of the major oxides SiO 2 , Al 2 O 3 , and TiO 2 , but they differ markedly in K 2 O, CaO, P 2 O 5 , and Fe 2 O 3 /FeO*. Distinct groups of strictly defined I- and S-type granites cannot be distinguished either within or between the Arizona outcrop areas studied; there are, however, clear separations into ilmenite and magnetite series granitoids. Comparatively, the Arizona granitoids have lower K 2 O/Rb, Rb/Sr, and P 2 O 5 values, and smaller concentrations of the lithophile elements Be, Cs, Li, Rb, Sn, U, and W relative to their European counterparts. Correspondence analysis, a type of principal components analysis, is used to discern the statistical variations and groupings of the data and to reinforce the geochemical concepts derived from scattergram chemical plots. Six factors describe 93 percent of the data. The first three factors account for 84.2 percent of the data variation and define major-element variation, lithophile-element enrichment or depletion, and the presence or absence of P 2 O 5 . The results of this study suggest that Sn, W, and U enrichment in peraluminous granites is largely governed by the lithophile-element concentrations of the source rocks. In addition, magmatic differentiation indices, the presence of higher levels of P 2 O 5 , and the oxidation state of the intrusion vary with the final concentration levels of lithophile elements in a granitoid. Hydrothermal redistribution appears minimal in the fresh material studied. Low contents of lithophile elements in the crustal source of peraluminous granitoids in southern Arizona appear to account for the paucity of associated economic lithophile element mineralization.