<descriptor thcode="2"><thesaurus thcode="2" name="USGS Thesaurus" scope="Topics and methods of scientific study carried out by USGS, with product types, scientific disciplines, geologic time, and types of institutional structure and activities.  Broad and shallow, used to help people find scientific information." creator="U.S. Geological Survey" rights="Public domain" edition="2.0" date="2020-01-09" codetype="number" prefix="topic" uri="https://www2.usgs.gov/science/USGSThesaurus" tblname="term" nonpref="nonpref" relterm="relterm" root_code="1" contact="pschweitzer"><category><term thcode="25" code="29" name="distinct labels" parent="26" scope="Preferred labels (descriptor texts) are distinct within the thesaurus. A concept can be specified either by its unique identifier (code) or by the text of its descriptor."/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="13" name="transitive" parent="12" scope="Narrower terms have an &quot;is a&quot; relationship with their broader terms, and generally can be described as part-of, type-of, or instance-of the broader term."/><term thcode="25" code="21" name="disciplines" parent="2" scope="Broad categories of human inquiry or activity, such as scientific disciplines."/><term thcode="25" code="20" name="methods" parent="2" scope="Actions taken to obtain or analyze information"/><term thcode="25" code="19" name="organizational functions" parent="2" scope="Things that organizations do, typically including various types of programs, projects, and services."/><term thcode="25" code="7" name="temporal" parent="2" scope="Terms indicate periods of time, such as chronostratigraphic units, named historical periods or intervals surrounding known historical events, or seasons."/><term thcode="25" code="5" name="theme" parent="2" scope="Terms indicate domains of human concern, such as scientific discipline, societal problems, or characteristics of earth, space, oceans, and living things."/><term thcode="25" code="29" name="distinct labels" parent="26" scope="Preferred labels (descriptor texts) are distinct within the thesaurus. A concept can be specified either by its unique identifier (code) or by the text of its descriptor."/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="13" name="transitive" parent="12" scope="Narrower terms have an &quot;is a&quot; relationship with their broader terms, and generally can be described as part-of, type-of, or instance-of the broader term."/><term thcode="25" code="21" name="disciplines" parent="2" scope="Broad categories of human inquiry or activity, such as scientific disciplines."/><term thcode="25" code="20" name="methods" parent="2" scope="Actions taken to obtain or analyze information"/><term thcode="25" code="19" name="organizational functions" parent="2" scope="Things that organizations do, typically including various types of programs, projects, and services."/><term thcode="25" code="7" name="temporal" parent="2" scope="Terms indicate periods of time, such as chronostratigraphic units, named historical periods or intervals surrounding known historical events, or seasons."/><term thcode="25" code="5" name="theme" parent="2" scope="Terms indicate domains of human concern, such as scientific discipline, societal problems, or characteristics of earth, space, oceans, and living things."/></category><altlabel><altlabel>USGSThesaurus</altlabel><altlabel>USGSThesaurus</altlabel></altlabel></thesaurus><term thcode="2" code="1293" name="waste treatment and disposal" parent="548" scope="The chemical and physical methods to recycle or dispose of materials which, without treatment, are deemed to have no further value or are too contaminated to be used."/><uf><usefor name="nuclear waste repositories"/><usefor name="radioactive waste repositories"/><usefor name="sewage disposal"/><usefor name="waste repositories"/><usefor name="waste treatment"/><usefor name="wastewater treatment"/></uf><bt><term thcode="2" code="548" name="human impacts" parent="1174" scope="The effects, intentional or unintentional, beneficial or harmful, direct or indirect, which human activities have upon the environment and living things."/><term thcode="2" code="1174" name="topics" parent="1" scope="Themes, subjects, and concerns for which USGS information resources are relevant."/><term thcode="2" code="1" name="Categories" scope="Thematic terms for categorizing information resources.  This thesaurus is intended to support finding and understanding scientific information."/></bt><rt><term thcode="2" code="2273" name="coal ash" parent="2271" scope="Solid waste material remaining from the burning of coal."/><term thcode="2" code="769" name="contamination and pollution" parent="1174" scope="Introduction of harmful substances into the environment by human action or natural processes."/><term thcode="2" code="311" name="ecology" parent="650" scope="Study of the relations between living plants and animals and their environment."/><term thcode="2" code="1998" name="mine waste" parent="1199" scope="Earth materials removed during mining and concentrated in piles or beds, typically near the site of extraction.  Tailings are mine waste that has been processed to remove valuable components; unprocessed mine waste includes overburden removed to reach commodity materials such as ore or coal."/><term thcode="2" code="750" name="mining hazards" parent="548" scope="Dangerous conditions which result from the extraction of naturally occurring mineral deposits.  Includes tunnel collapses, fires, and explosions."/><term thcode="2" code="2272" name="slag" parent="2271" scope="Solid waste material produced by the industrial processing of ore materials."/><term thcode="2" code="1075" name="social sciences" parent="1019" scope="Sciences concerned with the structure and interrelationships of human societies, human institutions and organizations, and human culture over time."/><term thcode="2" code="2271" name="solid industrial waste material" parent="1199" scope="Waste solid materials produced by industrial processing of earth materials, not simply material extracted in the search for ores."/><term thcode="2" code="1295" name="wastewater discharge" parent="1311" scope="Water that is returned or reused after release from a wastewater treatment plant."/></rt></descriptor>