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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>Charles A. Cravotta III</dc:contributor>
  <dc:contributor>Paul E. Stackelberg</dc:contributor>
  <dc:contributor>Kenneth Belitz</dc:contributor>
  <dc:creator>Zoltan Szabo</dc:creator>
  <dc:date>2023</dc:date>
  <dc:description>&lt;div id="abstractBox" class="article_abstract-content hlFld-Abstract"&gt;&lt;p class="articleBody_abstractText"&gt;&lt;sup&gt;210&lt;/sup&gt;Po, which is of human-health concern based on lifetime ingestion cancer risk, is indirectly regulated in drinking water through the U.S. Environmental Protection Agency’s gross alpha-particle activity (GAPA) maximum contaminant level of 15 pCi/L (picocuries per liter). This regulation requires independent measurement of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;226&lt;/sup&gt;Ra for samples exceeding the GAPA screening level of 5 pCi/L. There is no such requirement for&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Po. Co-occurrence of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;226&lt;/sup&gt;Ra and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Po, alpha-emitting&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;238&lt;/sup&gt;U-decay-series progeny, might be helpful in locating high-&lt;sup&gt;210&lt;/sup&gt;Po waters but is unverified. Relations among&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Po,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;226&lt;/sup&gt;Ra, and GAPA evaluated for samples from 257 public-supply wells from Coastal Plain aquifers showed that concentrations of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;226&lt;/sup&gt;Ra correlated with GAPA but neither correlated with&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Po concentrations. The highest concentrations of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;226&lt;/sup&gt;Ra and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Po were found under differing geochemical conditions. The highest&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;226&lt;/sup&gt;Ra occurred in low-pH oxidizing waters and in neutral-pH reducing waters, where geochemical conditions render Fe–Mn-hydroxide sorbents inefficient.&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Po was highest (10.1 pCi/L) in reducing waters with high pH (&amp;gt;7.5, which results from progressive cation exchange), where&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;226&lt;/sup&gt;Ra was lowest─exchanged to clay minerals. Because&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;226&lt;/sup&gt;Ra and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Po did not co-occur, the GAPA screening might not be protective for&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Po. Independent&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;Po analysis is prudent, especially where groundwater is reducing with high pH and low&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;226&lt;/sup&gt;Ra concentrations.&lt;/p&gt;&lt;/div&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1021/acsestwater.2c00027</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>American Chemical Society</dc:publisher>
  <dc:title>Gross alpha-particle activity and high 226Ra concentrations do not correspond with high 210Po in the Atlantic and Gulf Coastal Plain aquifers of the United States</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>