{"id":3947,"date":"2023-11-20T17:42:32","date_gmt":"2023-11-20T17:42:32","guid":{"rendered":"https:\/\/live-usc-dornsife.pantheonsite.io\/uscseagrant\/?page_id=3947"},"modified":"2024-04-18T16:14:11","modified_gmt":"2024-04-18T16:14:11","slug":"ddt-fingerprints","status":"publish","type":"page","link":"https:\/\/dornsife.usc.edu\/uscseagrant\/ddt-fingerprints\/","title":{"rendered":"DDT Fingerprints"},"content":{"rendered":"\n\n\n\n\n \n \n\n\n\n\n\n\n\n
\n\n \n
\n\n \n
\n\n \n

\n The production and mobility of DDT metabolites within sediments as controlled by the local diagenetic environment\n <\/h2>\n\n\n<\/div>\n \n \n
\n\n \n

Currently, there is no routine analytical method for sensitively measuring concentrations of most of the known DDT+ breakdown products and related byproducts. Berelson and partners will develop an identification and quantification method for at least 23 DDT+ compounds at very low concentrations at various ocean depths. Berelson will also investigate whether \u201cfingerprinting\u201d (\u2018isotomics\u2019) of DDT sources is possible\u2014in other words, this work will reveal if it will be feasible to trace DDT contamination from marine animals back to exact sources of DDT contamination on the seafloor. Berelson will weave the various threads of this project together into a model depicting DDT+ migration in deep water sediments. The produced model and novel analytical techniques will be critical for accurate and efficient future risk assessments for human and ecological health.<\/span><\/p>\n\n\n\n<\/div>\n \n \n <\/div>\n \n \n \n\n <\/div><\/div>\n\n\n\n\n \n \n\n\n\n\n\n\n\n

\n\n \n \n
\n\n \n

Detailed Research Objectives:<\/b><\/h3>\n
    \n
  1. Develop a sensitive and efficient ion-monitoring GC\/MS\/MS method to quantify DDT+ compounds in sediments and water at low (sub-ppb) concentrations.<\/span><\/li>\n
  2. Measure the vertical distribution of soluble DDT+ metabolites, particularly DDA, in sediment porewaters using gold-standard sampling methods. Samples will be collected via an <\/span>in-situ<\/span><\/i> pore water sampler coupled to a large multicorer device at three contrasting sites between Los Angeles Harbor and Dumpsite #2 (i.e., shelf near the Whites Point Outfall, slope, deep basin)\u00a0<\/span><\/li>\n
  3. Understand how the sedimentary diagenetic environment impacts the pathway and rate of DDT+ degradation. Using the analytical method established in objective 1, the spatial distribution of\u00a0 DDT+ compounds will be measured, along with a suite of other measurements to fully characterize the diagenetic environment (e.g., DIC, ammonium, nitrate, Fe, Mn and sulfide), in both sediments and porewaters from 3 distinct sites between LA Harbor and Dumpsite #2 (i.e., shelf near the Whites Point Outfall, slope, deep basin).<\/span><\/li>\n
  4. Assess whether DDT from the Palos Verdes shelf and deep-basin Dumpsite #2 have unique isotopic profiles in order to determine the viability of \u2018fingerprinting\u2019 DDT sources.<\/span><\/li>\n
  5. Develop a reaction-transport model of soluble DDA migration in deep water sediments to understand how much DDT metabolite could be escaping the sediment column and thus transported back into the water column.<\/span><\/span><\/li>\n<\/ol>\n

     <\/p>\n

    <\/h3>\n

    Key Results to Date:<\/b><\/h3>\n