<?xml version='1.0' encoding='utf-8'?>
<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>Bjorn Thrandur Bjornsson</dc:contributor>
  <dc:contributor>Stephen D. McCormick</dc:contributor>
  <dc:creator>K. Nieves-Puigdoller</dc:creator>
  <dc:date>2007</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;Exposure to&amp;nbsp;hexazinone&amp;nbsp;(HEX) and&amp;nbsp;atrazine&amp;nbsp;(ATZ), highly mobile and widely used herbicides along rivers in the United States, is potentially harmful to Atlantic salmon, which have been listed as an&amp;nbsp;endangered species. To determine the effects of these contaminants on&amp;nbsp;smolt&amp;nbsp;development, juvenile Atlantic salmon were exposed under flow-through conditions to 100&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;μg&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;l&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;HEX, 10 and 100&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;μg&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;l&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;ATZ in fresh water (FW) for 21 days at 10&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;°C beginning in mid-April. Twelve fish per treatment were sampled in FW, following a 24&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;h&amp;nbsp;seawater&amp;nbsp;(SW) challenge and after growth for 3 months in SW. Exposure to 100&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;μg&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;l&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;HEX or 10&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;μg&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;l&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;ATZ caused no mortalities of smolts in FW or after SW challenge, while 9% of the fish exposed to 100&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;μg&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;l&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;ATZ died during exposure. Fish exposed to 100&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;μg&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;l&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;ATZ reduced feeding after 10 days of exposure and had an impaired growth rate in FW and during the first month in SW; compensatory growth occurred in the second and third month in SW. HEX and ATZ at 10&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;μg&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;l&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;exposure had no effect on plasma levels of&amp;nbsp;cortisol, growth hormone (GH), insulin growth factor I (IGF-I),&amp;nbsp;thyroxine&amp;nbsp;(T&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;) and plasma 3,5,3′-triiodo-&lt;/span&gt;&lt;span class="small-caps"&gt;l&lt;/span&gt;&lt;span&gt;-thyronine (T&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;), Cl&lt;/span&gt;&lt;sup&gt;−&lt;/sup&gt;&lt;span&gt;, Mg&lt;/span&gt;&lt;sup&gt;2+&lt;/sup&gt;&lt;span&gt;, Na&lt;/span&gt;&lt;sup&gt;+&lt;/sup&gt;&lt;span&gt;, Ca&lt;/span&gt;&lt;sup&gt;2+&lt;/sup&gt;&lt;span&gt;&amp;nbsp;in FW or after SW challenge. FW smolts exposed to 100&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;μg&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;l&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;ATZ had decreased plasma Cl&lt;/span&gt;&lt;sup&gt;−&lt;/sup&gt;&lt;span&gt;, Mg&lt;/span&gt;&lt;sup&gt;2+&lt;/sup&gt;&lt;span&gt;, Na&lt;/span&gt;&lt;sup&gt;+&lt;/sup&gt;&lt;span&gt;&amp;nbsp;and Ca&lt;/span&gt;&lt;sup&gt;2+&lt;/sup&gt;&lt;span&gt;&amp;nbsp;ions and increased cortisol. No effect on plasma levels of GH, IGF-I, T&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;or T&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;was found in FW smolts exposed to 100&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;μg&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;l&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;ATZ. Following SW challenge, fish previously exposed to 100&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;μg&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;l&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;ATZ had significant increases in&amp;nbsp;hematocrit, plasma cortisol, Cl&lt;/span&gt;&lt;sup&gt;−&lt;/sup&gt;&lt;span&gt;, Mg&lt;/span&gt;&lt;sup&gt;2+&lt;/sup&gt;&lt;span&gt;, Na&lt;/span&gt;&lt;sup&gt;+&lt;/sup&gt;&lt;span&gt;, Ca&lt;/span&gt;&lt;sup&gt;2+&lt;/sup&gt;&lt;span&gt;&amp;nbsp;and a decrease in T&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;and T&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;. It is concluded that under the conditions imposed in this study, HEX does not affect salinity tolerance of Atlantic salmon smolts, while ATZ causes ionoregulatory, growth and endocrine disturbance.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1016/j.aquatox.2007.05.011</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Elsevier</dc:publisher>
  <dc:title>Effects of hexazinone and atrazine on the physiology and endocrinology of smolt development in Atlantic salmon</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>