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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Paul E. Stackelberg</dc:contributor>
  <dc:contributor>Charles A. Cravotta III</dc:contributor>
  <dc:creator>Zoltan Szabo</dc:creator>
  <dc:date>2020</dc:date>
  <dc:description>&lt;div class="article_abstract"&gt;&lt;div class="container container_scaled-down"&gt;&lt;div class="row"&gt;&lt;div class="col-xs-12"&gt;&lt;div id="abstractBox" class="article_abstract-content hlFld-Abstract"&gt;&lt;p class="articleBody_abstractText"&gt;On the basis of lifetime cancer risks, lead-210 (&lt;sup&gt;210&lt;/sup&gt;Pb) and polonium-210 (&lt;sup&gt;210&lt;/sup&gt;Po) ≥ 1.0 and 0.7 pCi/L (picocuries per liter), respectively, in drinking-water supplies may pose human-health concerns.&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Pb and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Po were detected at concentrations greater than these thresholds at 3.7 and 1.5%, respectively, of filtered untreated groundwater samples from 1263 public-supply wells in 19 principal aquifers across the United States. Nationally, 72% of samples with radon-222 (&lt;sup&gt;222&lt;/sup&gt;Rn) concentrations &amp;gt; 4000 pCi/L had&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Pb ≥ 1.0 pCi/L.&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Pb is mobilized by alpha recoil associated with the decay of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;222&lt;/sup&gt;Rn and short-lived progeny.&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Pb concentrations ≥ 1.0 pCi/L occurred most frequently where acidic groundwaters inhibited&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Pb readsorption (felsic-crystalline rocks) and where reducing alkaline conditions favored dissolution of iron–manganese- (Fe–Mn-) oxyhydroxides (which adsorb&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Pb) and formation of lead–carbonate complexes (enhancing lead (Pb) mobility).&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Po concentrations ≥ 0.7 pCi/L occurred almost exclusively in confined Coastal Plain aquifers where old (low percent-modern carbon-14) groundwaters were reducing, with high pH (&amp;gt;7.5) and high sodium/chloride (Na/Cl) ratios resulting from cation exchange. In high-pH environments, aqueous polonium (Po) is poorly sorbed, occurring as dihydrogen polonate (H&lt;sub&gt;2&lt;/sub&gt;PoO&lt;sub&gt;3&lt;/sub&gt;(aq)) or, under strongly reducing conditions, as a hydrogen-polonide anion (HPo&lt;sup&gt;–&lt;/sup&gt;). Fe–Mn- and sulfate-reduction and cation-exchange processes may mobilize polonium from mineral surfaces. Po&lt;sup&gt;2+&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;occurrence in low-to-neutral-pH waters is attenuated by adsorption.&lt;/p&gt;&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1021/acs.est.0c00192</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>American Chemical Society</dc:publisher>
  <dc:title>Occurrence and geochemistry of lead-210 and polonium-210 radionuclides in public-drinking-water supplies from principal aquifers of the United States</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>