<?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>J. Bruce Moring</dc:contributor>
  <dc:contributor>Peter C. Van Metre</dc:contributor>
  <dc:contributor>David C. Reutter</dc:contributor>
  <dc:contributor>Barbara Mahler</dc:contributor>
  <dc:contributor>Allison A. Shipp</dc:contributor>
  <dc:contributor>Randy L. Ulery</dc:contributor>
  <dc:creator>Larry F. Land</dc:creator>
  <dc:date>1999</dc:date>
  <dc:description>&lt;p&gt;Water quality in the Trinity River basin was studied during 1992-95 as part of the USGS National Water-Quality Assessment (NAWQA) Program. Studies included chemical sampling of streams, streambed sediments, biota, and ground water; measuring distributions of biological communities in streams; and measuring physical characteristics of streams that affect biological habitat. The sampling design, in general, relates water-quality conditions to causative human and natural environmental factors. The occurrence of pesticides, for example, is related to land use. Trends are mixed, with a substantial improvement in the diversity of fish species downstream from Dallas and large decreases in regulated contaminants such as DDT; but increases in unregulated contaminants such as polychlorinated biphenyls.&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.3133/cir1171</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>U.S. Geological Survey</dc:publisher>
  <dc:title>Water quality in the Trinity River basin, Texas, 1992-95</dc:title>
  <dc:type>reports</dc:type>
</oai_dc:dc>