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Puget Sound

Sediment Sampling Data

Sediment Sampling Maps

    Glossary of Definitions in Pop-up Windows on Maps

    • Station ID: A unique code name for the location where the sample was taken.
    • TEQ 1/2 DL: This is a number that summarizes the dioxin/furan and PCB data that takes into account that some types of these compounds were not detected.
    • Depth: The depth at which the sediment sample was taken
    • Location: The lat/long coordinate for the sample point
    • TOC: Total Organic Carbon- The amount of organic material (versus mineral) within that sediment sample.
    • Total Fines: The total silt and clay fraction (less than 230 microns in size) ¬†within that sediment sample.
    • DL: Detection Limit. This indicates the compound was analyzed for but not detected.
    • J: Indicates an estimated value. Used when the instrument reading indicates the presence of an analyte and the result is less than the project's required reporting level but greater than zero.

Dioxin Survey Map

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In the summer of 2008, the US EPA's ocean monitoring vessel, the BOLD, sampled sediments in the Puget Sound. Due to point source pollution outfalls and legacy manufacturing sites, there are toxic sediment hot-spots in certain areas in the Sound. The goal of this 2008 survey, however, was to establish a sediment quality baseline for the Puget Sound that was focused on non-hot spot areas. This was the most extensive survey involving analysis of high-profile bioaccumulative contaminants such as dioxins/furans and PCBs ever conducted in Puget Sound. Sediment samples were collected and analyzed at 70 locations throughout the Sound. The results of this survey found that sediment contamination in non hot-spot areas in Puget Sound is quite low.

There are three maps that show the findings from this survey- the first map above shows dioxin levels, the second shows PCB congener levels, and third map shows detected concentrations of pesticides, semi-volatile organic compounds, and metals. Click each point on the maps to learn about the finding associated with that sample point. To view full detail regarding that sample point, click on the "View Details" link associated with each point.

The samples were analyzed for concentrations of dioxin/furan and polychlorinated biphenyl (PCB) congeners, as well as the standard list of contaminants of concern which includes semi-volatiles, polycyclic aromatic hydrocarbons, Aroclor PCBs, pesticides and trace metals, and sediment conventionals (total organic carbon, grain size distribution, and percent solids).

Different dioxin compounds have different toxicities and dioxins are most often found in mixtures rather than as single compounds in the environment. The most toxic types of dioxin are 2,3,7,8-TCDD and 1,2,3,7,8-Pentachlorodibenzodioxin. A method has been established for comparing the toxicity of different types of dioxins and PCBs to the toxicity of the most toxic dioxins and adding together the toxicity of mixtures of dioxins/PCBs. This method is called the "Toxicity Equivalence" or TEQ.

This data visualization tool, Socrata, not only allows you to view the data associated with the sediment sample points taken from EPA's survey vessel, the BOLD, but allows you to customize the views of the data in spreadsheet form for a variety of purposes. The datasets are available here for your use. The following links may provide helpful information and, with the exception of the US EPA, are located outside the EPA.gov domain.

PCB Congeners Map

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Pesticides, Semi Volatile Organic Compounds, and Metals Map

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