{"id":638,"date":"2019-11-26T20:12:04","date_gmt":"2019-11-27T04:12:04","guid":{"rendered":"https:\/\/sites.sandiego.edu\/sdpollutiontrackers\/?p=638"},"modified":"2019-11-26T20:12:04","modified_gmt":"2019-11-27T04:12:04","slug":"saltons-sea-sediment-whats-in-it","status":"publish","type":"post","link":"https:\/\/sites.sandiego.edu\/sdpollutiontrackers\/2019\/11\/26\/saltons-sea-sediment-whats-in-it\/","title":{"rendered":"Salton’s Sea Sediment… What’s In It?!"},"content":{"rendered":"

If you are a California native, you would have heard of The Salton Sea<\/em><\/span>. The Sea is actually a lake located in the Imperial and Coachella Valleys that was accidentally made (Fig. 1). A massive flood from the Colorado River broke through a canal nearby and the water from the Colorado River flowed for 18 months into a once dry, desert basin. Today, the only bodies of water that feeds the Sea are from the rivers nearby and agricultural runoff and sewage systems from the nearby community. The Rivers (New River and Alamo River) themselves are impacted by wastes from urban and agriculture land use. Since the last decade, risks of contaminants in the water and sediment of Salton Sea has been of concern. From previous studies, volatile (and semi volatile) compounds and metals have been examined and found in the Sea. In our lab’s study, we set out to analyze Salton Sea’s sediment.<\/p>\n

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Figure 1<\/strong>. Map of the Salton Sea.<\/p>\n

The Chemical Analysis of Sediments<\/em> lab’s purpose was to learn how to analyze the sediment sample, chemically and physically, in order to find the organic contents within it. There were a few parts to this lab:<\/p>\n

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  1. Gas Chromatography-Mass Spectrometry\n
      \n
    1. Untargeted<\/li>\n
    2. Targeted<\/li>\n<\/ol>\n<\/li>\n
    3. Laser Particle Scattering Spectrometry<\/li>\n
    4. Measuring carbonate and organic content<\/li>\n<\/ol>\n
      \n

      Preparing the Sediment<\/em><\/span><\/p>\n

      The sediment from the Sea was dried for a few days and using the QuEChERS method (an extraction method) pesticides that were in the sediment were extracted. This liquid extract was used for the GC-MS runs. For the particle analysis via light scattering, 2 grams of sediment and 2 mL of water was made in a tube and this was the sample to be analyzed.<\/p>\n

      GC-MS<\/strong><\/span><\/p>\n

      Splitless, untargeted run of the sediment extract was done in SCAN mode and it looked for things that were within the 45 – 475 m\/z range. The mass spec data was analyzed and the peaks were assigned to different compounds that were matched from the GC-MS library. After this was done, another GC-MS run was done but this time using the SIM SCAN method which looks for specific target compounds. Whatever pesticide we were looking for, the mass ranges (at least 3) for that specific pesticide was looked for. The following pesticides have been identified in the Sea’s sediment:<\/p>\n