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Ground water radon concentrations were determined in three types of Middle Proterozoic rocks in the New Jersey Highlands. The rock types (hornblende granite, quartz-oligoclase gneiss, and pyroxene granite) were selected because of their suspected uranium contents (high, low, and low, respectively). It was hypothesized that high ground water radon concentrations might be associated with uranium-bearing rock units. Radon concentrations in 154 wells ranged from 36 pCi/L to 24,000 pci/L (picocuries per liter) with a geometric mean and a median of 1600 pci/L. Radon levels were greater than 300 pci/L (USEPA's proposed MCL for radon in drinking water) in 90% of the wells. None of the rock units studied had ground water radon levels consistently low enough to be regarded as a low priority for testing. Local mineralogy and structure were found to influence ground water radon concentrations. In highly deformed rock units, such as those in the New Jersey Highlands, there is considerable heterogeneity. Migmatites, alaskites and pegmatites which may not appear on a geologic quadrangle map due to their small size or because they are not exposed can affect radioactivity on a local scale.

Today's surface ocean is saturated with respect to calcium carbonate, but increasing atmospheric carbon dioxide concentrations are reducing ocean pH and carbonate ion concentrations, and thus the level of calcium carbonate saturation. Experimental evidence suggests that if these trends continue, key marine organisms—such as corals and some plankton—will have difficulty maintaining their external calcium carbonate skeletons. Here we use 13 models of the ocean–carbon cycle to assess calcium carbonate saturation under the IS92a ‘business-as-usual’ scenario for future emissions of anthropogenic carbon dioxide. In our projections, Southern Ocean surface waters will begin to become undersaturated with respect to aragonite, a metastable form of calcium carbonate, by the year 2050. By 2100, this undersaturation could extend throughout the entire Southern Ocean and into the subarctic Pacific Ocean. When live pteropods were exposed to our predicted level of undersaturation during a two-day shipboard experiment, their aragonite shells showed notable dissolution. Our findings indicate that conditions detrimental to high-latitude ecosystems could develop within decades, not centuries as suggested previously.