{"id":140,"date":"2022-07-13T18:05:23","date_gmt":"2022-07-13T18:05:23","guid":{"rendered":"https:\/\/books.gw-project.org\/fluoride-in-groundwater\/?post_type=part&#038;p=140"},"modified":"2022-07-18T19:12:07","modified_gmt":"2022-07-18T19:12:07","slug":"natural-geochemical-processes-causing-high-fluoride-groundwater","status":"publish","type":"part","link":"https:\/\/books.gw-project.org\/fluoride-in-groundwater\/part\/natural-geochemical-processes-causing-high-fluoride-groundwater\/","title":{"raw":"9  Natural Geochemical Processes Causing High-Fluoride Groundwater","rendered":"9  Natural Geochemical Processes Causing High-Fluoride Groundwater"},"content":{"raw":"<div class=\"natural-geochemical-processes-causing-high-fluoride-groundwater\">\r\n<p class=\"import-Normal\">High-F groundwaters originate overwhelmingly from natural geogenic processes having specific physical and chemical conditions. Assuming an F-bearing mineral occurs in the aquifer, F concentrations may increase by:<\/p>\r\n\r\n<ul>\r\n \t<li class=\"import-Normal\">development of a Na-HCO<sub class=\"import-GWPsubscript\">3<\/sub> type groundwater;<\/li>\r\n \t<li class=\"import-Normal\">interaction with a F-rich aquifer such as felsic (silicic) and alkaline igneous rocks, or phosphoritic sediments;<\/li>\r\n \t<li class=\"import-Normal\">development of a saline type groundwater or low-Ca brine (ionic strength effect);<\/li>\r\n \t<li class=\"import-Normal\">calcite precipitation or precipitation of other relatively insoluble Ca minerals;<\/li>\r\n \t<li class=\"import-Normal\">dissolved inorganic carbon (DIC) increase and\/or P<sub>CO<sub>2<\/sub><\/sub> decrease;<\/li>\r\n \t<li class=\"import-Normal\">increasing temperature (associated with precipitation of a Ca-bearing mineral and DIC); and,<\/li>\r\n \t<li class=\"import-Normal\">extremes of pH (high or low).<\/li>\r\n<\/ul>\r\n<p class=\"import-Normal\">Many of these features are prevalent in arid and semi-arid environments, and high-F groundwater is commonly found in aquifers under such conditions. Other processes may well play a role, but the listed processes are likely the most important for aquifers not contaminated by industrial waste sources. As shown by the geochemical modeling examples, development of Na-HCO<sub class=\"import-GWPsubscript\">3<\/sub> type waters, calcite precipitation, and P<sub>CO<sub>2<\/sub><\/sub> are all interrelated. From the examples that follow, a pattern emerges that aquifers with elevated F are saturated to supersaturated with respect to calcite and fluorite.<\/p>\r\n\r\n<\/div>","rendered":"<div class=\"natural-geochemical-processes-causing-high-fluoride-groundwater\">\n<p class=\"import-Normal\">High-F groundwaters originate overwhelmingly from natural geogenic processes having specific physical and chemical conditions. Assuming an F-bearing mineral occurs in the aquifer, F concentrations may increase by:<\/p>\n<ul>\n<li class=\"import-Normal\">development of a Na-HCO<sub class=\"import-GWPsubscript\">3<\/sub> type groundwater;<\/li>\n<li class=\"import-Normal\">interaction with a F-rich aquifer such as felsic (silicic) and alkaline igneous rocks, or phosphoritic sediments;<\/li>\n<li class=\"import-Normal\">development of a saline type groundwater or low-Ca brine (ionic strength effect);<\/li>\n<li class=\"import-Normal\">calcite precipitation or precipitation of other relatively insoluble Ca minerals;<\/li>\n<li class=\"import-Normal\">dissolved inorganic carbon (DIC) increase and\/or P<sub>CO<sub>2<\/sub><\/sub> decrease;<\/li>\n<li class=\"import-Normal\">increasing temperature (associated with precipitation of a Ca-bearing mineral and DIC); and,<\/li>\n<li class=\"import-Normal\">extremes of pH (high or low).<\/li>\n<\/ul>\n<p class=\"import-Normal\">Many of these features are prevalent in arid and semi-arid environments, and high-F groundwater is commonly found in aquifers under such conditions. Other processes may well play a role, but the listed processes are likely the most important for aquifers not contaminated by industrial waste sources. As shown by the geochemical modeling examples, development of Na-HCO<sub class=\"import-GWPsubscript\">3<\/sub> type waters, calcite precipitation, and P<sub>CO<sub>2<\/sub><\/sub> are all interrelated. From the examples that follow, a pattern emerges that aquifers with elevated F are saturated to supersaturated with respect to calcite and fluorite.<\/p>\n<\/div>\n","protected":false},"parent":0,"menu_order":9,"template":"","meta":{"pb_part_invisible":false,"pb_part_invisible_string":""},"contributor":[],"license":[],"class_list":["post-140","part","type-part","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/books.gw-project.org\/fluoride-in-groundwater\/wp-json\/pressbooks\/v2\/parts\/140","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/books.gw-project.org\/fluoride-in-groundwater\/wp-json\/pressbooks\/v2\/parts"}],"about":[{"href":"https:\/\/books.gw-project.org\/fluoride-in-groundwater\/wp-json\/wp\/v2\/types\/part"}],"version-history":[{"count":6,"href":"https:\/\/books.gw-project.org\/fluoride-in-groundwater\/wp-json\/pressbooks\/v2\/parts\/140\/revisions"}],"predecessor-version":[{"id":359,"href":"https:\/\/books.gw-project.org\/fluoride-in-groundwater\/wp-json\/pressbooks\/v2\/parts\/140\/revisions\/359"}],"wp:attachment":[{"href":"https:\/\/books.gw-project.org\/fluoride-in-groundwater\/wp-json\/wp\/v2\/media?parent=140"}],"wp:term":[{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/books.gw-project.org\/fluoride-in-groundwater\/wp-json\/wp\/v2\/contributor?post=140"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/books.gw-project.org\/fluoride-in-groundwater\/wp-json\/wp\/v2\/license?post=140"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}