Contaminant Data Display and Download (CD3) is a web-based visualization tool for accessing water quality data for the San Francisco Bay-Delta region, including the Bay Regional Monitoring Program’s long-term dataset. The tool has been redesigned to leverage other interactive mapping efforts and offers impressive new functionality, including enhanced spatial querying and dynamic statistical summaries and charts. All public data uploaded to SFEI-ASC's Regional Data Center, including data beyond the San Francisco Bay-Delta, are available through this tool.


1. What data are available?

Data from different programs are available through CD3. Click here for more detailed information on the datasets. Consult the Metadata page for information on the fields included in the data download.

2. Are data comparable to CEDEN?

Yes, all data are stored in SFEI’s Regional Data Center database and follow the California Environmental Data Exchange Network’s (CEDEN) data standards and business rules. CEDEN's controlled vocabulary lists or codes are located here.

3. How often are data updated?

Data displayed in CD3 are updated on a weekly basis.

4. Who should I contact if I have questions, find any errors, or would like to upload new data?

SFEI’s Data Services Team at can answer any questions, address errors, or help you with uploading new data to SFEI’s Regional Data Center database and to CEDEN.

5. Are results expressed in wet weight or dry weight?

The Units field indicates if a result is expressed in wet weight (ww) or dry weight (dw).

6. How can I get a copy of a program or project’s Quality Assurance Plan (QAPP)?

Contact SFEI’s Data Services Team at Please note that not all data providers send SFEI a copy of their QAPP.

7. What are the data handling rules for the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP)?

The results provided by CD3 may differ slightly from those previously reported in RMP annual reports, since results are updated as needed to address data errors and meet standardization requirements of the state. Measurements vary by year and test material, but typically include a suite of contaminants (metals and organics) and ancillary data. Missing data are either not available (e.g., parameters were not measured in every year), or the data are being reanalyzed and will be made available at a later date.

Missing data and changes in target RMP parameters are listed in the RMP Annual Monitoring Results reports.

SSC/TSS: Beginning in 2002, the water quality measurement total suspended solids (TSS) was replaced by the parameter suspended sediment concentration (SSC).

Grain Size: In 2008-2012, grain size was analyzed using an optical laser method (reporting % volume) for sand and finer fractions (<2mm). For samples with granule+pebble fractions (measured as % dw), results were scaled to total 100% assuming equal density.

In 2008-2012, grain sizes reported by the optical method may show variable agreement with sieving methods for sand particles due to their relative transparency and smaller subsamples analyzed.

Organic Sums: Organic group sums, for example "Sum of PCBs (SFEI)", are calculated by SFEI based on the target analytes for an analyte group; the exact number and the group constituents may vary over the years.

Metal Data: All metals from 1993 to 2008 are reported as near totals. Beginning in 2009, water and tissue trace metals (Ag, Al, Cd, Cu, Fe, Pb, Mn, Ni, and Zn) are reported as total concentrations. Chemical analyses of sediment samples is generally performed on the <2mm fraction.

MDLs: While every effort is made to obtain the method detection limit (MDL) value from the labs, if none is available, other detection limits may be provided (e.g., instrument detection limit, sample detection limit, reporting limit). However, all detection/reporting limits are stored in the MDL field. Although some MDL values may appear truncated in the cross-tabulated output (e.g., 0.00), full results are provided in the flat file Excel worksheet.

Tissue Reference Sites: Two reference station codes (T-0 and T-1) are included in the tissue results for some years. T-0 indicates that the reference bivalve was analyzed before being deployed. T-1 indicates that the reference bivalve was analyzed after being deployed.

RMP Sampling Strategy: From 1993-2001 RMP sampling sites for water, sediment and bivalve tissue were at fixed locations throughout the Estuary. Starting in 2002 the RMP changed to a random sampling design for both water and sediment. The bivalve sampling sites remain at fixed locations. All sites, whether random or fixed, are associated with an Estuary region.

PCB Sums: Beginning in 2009, the following three PCB Sums are reported:

  • Sum of 40 PCBs - This sum is calculated using the standard 40 PCBs and is reported for all years when available.
  • Sum of 208 PCBs - This sum provides an index of the PCBs present in Aroclor mixtures. The one PCB excluded is PCB 11, which is abundant in some matrices but is derived from pigments (e.g., Hu and Hornbuckle. 2009. Inadvertent Polychlorinated Biphenyls in Commercial Paint Pigments. Environmental Science & Technology, 44 (8), p.2822-2827, Apr 2010) and not Aroclors. PCB 11 does not have dioxin-like potency and has different sources than Aroclors.
  • Sum of 209 PCBs - This sum is provided solely for comparison to other studies that use this statistic. SFEI does not recommend using this sum for comparison to any Aroclor-based thresholds (the TMDL target, OEHHA thresholds, etc.) - the Sum of 208 PCBs is better for that purpose.

Co-eluting PCB and PBDE congeners: During the analytical process, some PCB and PBDE congeners (co-eluting PCBs and PBDEs) cannot be distinguished as separate congeners and thus are quantified as a complex of one or more congeners. When a reportable congener is co-eluting with another congener, we flag this result according to the following rules:

  • If a reportable congener co-elutes with another reportable congener, then the dominant congener (established from the literature) contains a qualifier "DO" and the quantitative result. For example, PCB 056 often co-elutes with PCB 060, and PBDE 008 often co-elutes with PBDE 011. The dominant congeners, PCB 060 and PBDE 008, will have "DO" in the qualifier field and the concentration measured in the result field. PCB 056 and PBDE 011, the non-dominant congeners, will have "DO060" and “DO008” in the qualifier field referring the user to look for the quantitative result in congener PCB 060 and PBDE 008, respectively. The qualifier alerts the user that the result is a mixture of more than 1 congener, and identifying the dominant congener that makes up the highest percent of the mixture.
  • If a reportable congener co-elutes with a non-reportable congener, then the reportable congener has the qualifier "DO" and the quantitative result.

8. How can I view surface model maps?

Surface model maps, similar to the ones included in the Status and Trends section of The Pulse of the Bay reports, can only be generated for RMP sediment and water chemistry data that can be displayed as quartiles. There are two types of surface model maps available in CD3: Surface Model and RMP Pulse Style Surface Model. The RMP Pulse Style maps (1) exclude wet year data for sediment, (2) exclude pre-2002 historical station data, and (3) include only data from the following bay segments: Suisun Bay, San Pablo Bay, Central Bay, South Bay, and Lower South Bay. Individual RMP Pulse Style Surface Models may differ from those depicted in The Pulse of the Bay due to variation in data processing methods.

9. What are HUCs?

A Hydrologic Unit Code (HUC) identifies a watershed within a hierarchical system dividing drainage basins into progressively smaller nested geographic areas. The size of the hydrologic unit decreases as the level of HUC subdivision increases: a HUC8 unit consists of one or more HUC10 units, each of which consists of one or more HUC12 units. In CD3, users can filter results spatially by HUC8, HUC10, and HUC12 boundaries. Visit the USGS website for more information.

10. Why can't my data be displayed as quartiles on the map?

In order for data to be displayed as quartiles, the results must be divided into 4 numeric groupings. In cases where quartiles are not displayed, either there is not a sufficient number of results or range among the values for the selected analyte/unit combination to evaluate as quartiles.

11. How should I cite San Francisco Bay RMP data?

Regional Monitoring Program (RMP) for Water Quality in San Francisco Bay (

12. What is the difference between Conventional analytes displayed under the test material of Basic Water Quality versus Water Chemistry?

Basic Water Quality measurements are taken in the field. Water Chemistry results have been analyzed in a laboratory according to specific analytical methods.

13. What is the difference between the different data download tools?

The Download Mapped Data tool allows you to download the data you have mapped, which is one analyte for a test material. The Direct Download Tool allows you to download data for a project with the options to select all project data, one analyte group and sub-group, or one or more analytes. Both downloads are saved to your computer.