{"id":3945,"date":"2023-11-20T17:42:19","date_gmt":"2023-11-20T17:42:19","guid":{"rendered":"https:\/\/live-usc-dornsife.pantheonsite.io\/uscseagrant\/?page_id=3945"},"modified":"2024-04-18T16:10:46","modified_gmt":"2024-04-18T16:10:46","slug":"a-baseline-for-ddt-contamination","status":"publish","type":"page","link":"https:\/\/dornsife.usc.edu\/uscseagrant\/a-baseline-for-ddt-contamination\/","title":{"rendered":"A Baseline for DDT Contamination"},"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 Foundational Research for deep ocean dumping of DDT+ waste to discover how much is out there, where it is, and what it is doing today\n <\/h2>\n\n\n<\/div>\n \n \n
\n\n \n

Recent analysis has confirmed that DDT+ bulk waste was not contained in barrels, and that some was likely \u201cshort dumped\u201d between the California mainland and designated legal dumpsites in the San Pedro and Santa Monica Basins. Through field, laboratory, and analytical efforts, Valentine and collaborators will determine the quantity and spatial extent of this pollution, and the potential for degradation, movement, or interaction with living organisms. The research team will quantify the diversity of DDT+ products within sediment core samples and model timescales of DDT+ degradation, as well as mechanisms of transport from sediments. <\/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. Quantify the inventory of all known 45 DDT+ compounds and other relevant contaminants (i.e., PCBs, heavy metals, petroleum wastes) in the sediments of the deep San Pedro Basin, focused on the major short-dumping areas between Dumpsite 2 and the California mainland. A depth integrated sampling method will sample the sediment (surface to depth of 12-24 cm) across 40 stations that are presumed to capture variability and gradients of DDT+, based on observed patterns of DDX in recently collected sediment cores.<\/span><\/li>\n
  2. Determine the current spatial extent and emplacement of short-dumped DDT+ wastes. A nested quantitative sediment analysis plan will be driven by the findings and concurrently collected cores from objective 1. Analyzing the vertical depth resolution of DDX (4,4- and 2,4- DDT, DDE and DDD) across 40 stations @ 15 depths per station will inform additional analyses for other analytes including DDX+ (TCPM, TCPMOH, 2,4- and 4,4- DDMu), other non-target analytes, heavy metals, microbial population and sediment properties (e.g., grain size and CHN).<\/span><\/li>\n
  3. Determine the mobility, degradation and exposure potential of these DDT+ wastes. Geochemical and modeling analysis based on DDT+ concentration distributions and observed molecular fractionation patterns will provide useful constraints on aqueous transport flux from sediment to water column. The extent to which biodegradation has affected the DDT+ inventory of the San Pedro Basin, and the microbial mechanisms by which this occurs, will be assessed using both chemical distributions of DDX, DDX+ and non-targeted analyses as well as a comparative analysis of microbial community composition and targeted metagenomic sequencing.<\/span><\/li>\n<\/ol>\n

     <\/p>\n

    <\/h3>\n

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