{"id":55,"date":"2022-12-12T05:35:50","date_gmt":"2022-12-12T05:35:50","guid":{"rendered":"https:\/\/books.gw-project.org\/dissolved-organic-carbon-in-groundwater-systems\/chapter\/humic-and-fulvic-acids\/"},"modified":"2022-12-13T01:26:58","modified_gmt":"2022-12-13T01:26:58","slug":"humic-and-fulvic-acids","status":"publish","type":"chapter","link":"https:\/\/books.gw-project.org\/dissolved-organic-carbon-in-groundwater-systems\/chapter\/humic-and-fulvic-acids\/","title":{"raw":"4.1 Humic and Fulvic Acids","rendered":"4.1 Humic and Fulvic Acids"},"content":{"raw":"<div class=\"humic-and-fulvic-acids\"><p class=\"import-Normal\">The first such indirect method for characterizing DOC was based on its humic and fulvic acid composition as has been discussed previously. Artinger and others (2000) provided an example of how quantifying humic and fulvic acids can be used to characterize groundwater DOC. This study collected 35 different samples of groundwater from four different aquifer systems in Germany. Because of the low DOC concentrations encountered, it was necessary to concentrate the DOC by adsorption onto XAD-8 resins as described by Thurman (1985). In samples exhibiting the low DOC typically observed in groundwater (0.1 to 2\u00a0mg\/L; ~8.3 to ~170 <em>\u00b5<\/em>mol\/L), humic acids comprised a relatively low percentage of the total DOC (&lt;\u00a010 percent). Fulvic acids, on the other hand, comprised up to 80 percent of total DOC in the low-DOC groundwaters. That is consistent with the greater solubility of fulvic acids. In contrast, in groundwater containing higher concentrations of DOC (10 to 100\u00a0mg\/L; ~830 to ~8,300 <em>\u00b5<\/em>mol\/L), humic acids comprised a much larger percentage of the total DOC (&gt;\u00a050 percent). Similar results have been found in other groundwater systems. In general, higher amounts of humic acids are associated with higher overall DOC concentrations.<\/p><\/div>","rendered":"<div class=\"humic-and-fulvic-acids\">\n<p class=\"import-Normal\">The first such indirect method for characterizing DOC was based on its humic and fulvic acid composition as has been discussed previously. Artinger and others (2000) provided an example of how quantifying humic and fulvic acids can be used to characterize groundwater DOC. This study collected 35 different samples of groundwater from four different aquifer systems in Germany. Because of the low DOC concentrations encountered, it was necessary to concentrate the DOC by adsorption onto XAD-8 resins as described by Thurman (1985). In samples exhibiting the low DOC typically observed in groundwater (0.1 to 2\u00a0mg\/L; ~8.3 to ~170 <em>\u00b5<\/em>mol\/L), humic acids comprised a relatively low percentage of the total DOC (&lt;\u00a010 percent). Fulvic acids, on the other hand, comprised up to 80 percent of total DOC in the low-DOC groundwaters. That is consistent with the greater solubility of fulvic acids. In contrast, in groundwater containing higher concentrations of DOC (10 to 100\u00a0mg\/L; ~830 to ~8,300 <em>\u00b5<\/em>mol\/L), humic acids comprised a much larger percentage of the total DOC (&gt;\u00a050 percent). Similar results have been found in other groundwater systems. In general, higher amounts of humic acids are associated with higher overall DOC concentrations.<\/p>\n<\/div>\n","protected":false},"author":1,"menu_order":6,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-55","chapter","type-chapter","status-publish","hentry"],"part":120,"_links":{"self":[{"href":"https:\/\/books.gw-project.org\/dissolved-organic-carbon-in-groundwater-systems\/wp-json\/pressbooks\/v2\/chapters\/55","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/books.gw-project.org\/dissolved-organic-carbon-in-groundwater-systems\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/books.gw-project.org\/dissolved-organic-carbon-in-groundwater-systems\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/books.gw-project.org\/dissolved-organic-carbon-in-groundwater-systems\/wp-json\/wp\/v2\/users\/1"}],"version-history":[{"count":1,"href":"https:\/\/books.gw-project.org\/dissolved-organic-carbon-in-groundwater-systems\/wp-json\/pressbooks\/v2\/chapters\/55\/revisions"}],"predecessor-version":[{"id":179,"href":"https:\/\/books.gw-project.org\/dissolved-organic-carbon-in-groundwater-systems\/wp-json\/pressbooks\/v2\/chapters\/55\/revisions\/179"}],"part":[{"href":"https:\/\/books.gw-project.org\/dissolved-organic-carbon-in-groundwater-systems\/wp-json\/pressbooks\/v2\/parts\/120"}],"metadata":[{"href":"https:\/\/books.gw-project.org\/dissolved-organic-carbon-in-groundwater-systems\/wp-json\/pressbooks\/v2\/chapters\/55\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/books.gw-project.org\/dissolved-organic-carbon-in-groundwater-systems\/wp-json\/wp\/v2\/media?parent=55"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/books.gw-project.org\/dissolved-organic-carbon-in-groundwater-systems\/wp-json\/pressbooks\/v2\/chapter-type?post=55"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/books.gw-project.org\/dissolved-organic-carbon-in-groundwater-systems\/wp-json\/wp\/v2\/contributor?post=55"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/books.gw-project.org\/dissolved-organic-carbon-in-groundwater-systems\/wp-json\/wp\/v2\/license?post=55"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}