San Francisco Bay Regional Water Quality Control Board September 2013

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San Francisco Bay PCBs TMDL – Implementation at Cleanup Sites

PCB TOTAL MAXIMUM DAILY LOAD (TMDL)

Basin Plan section 7.2.3, San Francisco Bay Polychlorinated Biphenyls TMDL, should be 

considered during site investigations and cleanups throughout the Region, particularly but not 

exclusively at sites located on the Bay margin. Of particular concern, and often overlooked, is 

the fact that PCBs in surface soil can be mobilized by stormwater runoff and flow to the Bay. 

Fish tissue PCB concentrations are the direct cause of impairment to the Bay, and therefore the 

numeric target of the TMDL is a fish tissue PCB concentration protective of human health. The 

TMDL’s fish tissue screening level of 10 ng/g represents a ten-fold reduction in fish tissue PCB 

concentration. To achieve this, surface sediment PCB concentrations in San Francisco Bay 

must be reduced to an average of 1 ug/kg. The TMDL’s wasteload allocations were developed 

with the goal of achieving a ten-fold decrease in PCB sources to the Bay.

Of the sources to the Bay, stormwater runoff contributes the greatest mass of PCBs. The PCB

TMDL establishes a wasteload allocation for stormwater of 2 kg/yr total PCBs, which represents 

a ten-fold decrease over the current estimated load. In an effort to achieve this reduction, Bay 

Area municipalities are pilot-testing remedial actions in areas where street sediments contain 

PCBs in the 1 mg/kg range before any remedial action is taken. Municipalities will spend 

millions of dollars to achieve the ten-fold reduction in PCBs required by the TMDL.

ACHIEVING THE PCB ALLOCATION AT CLEANUP SITES

Stormwater runoff from sites containing residual PCBs in soils after state- and federal-ordered 

cleanup contributes to sediment concentrations in the Bay, and such contributions must be 

essentially eliminated in order to achieve the TMDL target. For cleanup sites, the TMDL calls for 

implementing “on-land source control measures, to ensure that on-land sources of PCBs do not 

further contaminate in-Bay sediments.”

PCBs cleanups that occur in urban areas often have a cleanup goal based on protection of

human health, and this can allow residual PCB concentrations close to or exceeding 1 mg/kg to 

remain in surface soils. Regardless of the cleanup goal, it is important that cleanup sites 

do not contribute any PCBs to surface water runoff. Remedial actions should be 

conducted so as to eliminate all means of conveyance of PCBs from cleanup sites, 

including sediment runoff, vehicular drag out, and airborne dust. Achieving this may 

require a durable cover of soil, hardscape, or structures to prevent surface exposure of PCBs. 

The goal is to have zero discharge of residual PCBs at cleanup sites. 

PCBs in aquatic environments require cleanup to ecological risk-based concentrations that are 

generally much lower than the one mg/kg human health level. For example, a San Francisco 

Bay tidal marsh PCB cleanup concentration was established at 90 ug/kg PCBs to protect 

clapper rails.
San Francisco Bay Regional Water Quality Control Board September 2013

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RECOMMENDED PCB ANALYTICAL METHODS

Sampling and analyses are needed to confirm that PCB levels are low enough to achieve the 

TMDL targets. For cleanup sites in the San Francisco Bay area, the analytical method for PCBs 

in soils should be capable of detecting total PCBs well below 1 mg/kg dry weight and 

approaching 25 ug/kg dry weight for soil, with a high likelihood that all PCBs present in the 

sample are detected. The Water Board’s own Surface Water Ambient Monitoring Program uses 

a Reporting Level of 0.2 μg/kg for most PCB congeners in sediment.

Analytical methods that we know will attain this data quality objective, and that we recommend 

using at all cleanup sites, include the following:

• EPA Method 8270D (semivolatiles in soils/waste) modified by EPA Method 1625. Method 

1625 is the application of isotope dilution/recovery correction to GC/MS methodology. Total 

PCBs are determined by summing the individual congener results. Results can be reported 

as either, or both, congeners or aroclors. Ball-park cost for this analysis is $375/sample.1

• EPA Method 1668A or 1668C, which combine high-resolution GC with high-resolution mass 

spectrometry (HRGC/HRMS). Results are reported for all 209 congeners in μg/kg dry 

weight. Ball-park cost for this analysis is $800-900/sample.

1 An alternative is to use the 

same method, but report results for the 40 PCB congeners monitored by the SF Bay 

Regional Monitoring Program: PCBs 8, 18, 28, 31, 33, 44, 49, 52, 56, 60, 66, 70, 74, 87, 95, 

97, 99, 101, l05, 110, 118, 128, 132, 138, 141, 149, l51, 153, 156, 158, 170, 174, 177, 180, 

183, 187, 194, 195, 201, and 203. Cost for this alternative may be about 15% less than the

full congener analysis.1

• Note that cleanups conducted under the authority of the Toxic Substances Control Act 

(TSCA) have their own PCB analysis requirements. Contact the U.S. Environmental 

Protection Agency, Region 9, TSCA staff or see http://www.epa.gov/Region9/pcbs/ for 

further information. 

Other analytical methods (such as 8082) generally do not identify and quantify all the PCB 

congeners that may be present at a cleanup site, which can result in inadequate cleanups. 

Municipalities are finding PCBs in roads and gutters that may be traced back to “closed” 

cleanup sites that did not use reasonably rigorous analytical methods and/or cleanup standards. 

Methods such as 8082 identify and quantify aroclors by gas chromatography (GC) with an 

electron capture detector (ECD). Each aroclor consists of a number of PCB congeners. The 

aroclor is identified by the retention times of the highest peaks in the chromatogram, and is 

quantified by comparing the height or area of those peaks to those of a pure aroclor standard. 

Between 5-8 aroclors are typically reported in an 8082 method, depending on the lab method 

used. Some high production aroclor mixtures, such as 1270 (almost 100% congener 209), are 

rarely included in the method. In addition, PCBs in the environment undergo volatilization, 

partitioning, chemical transformation, photo-degradation, and biodegradation over time. These 

changes confound the matching of an environmental sample to an aroclor pattern. As a result, 

other analytical methods often do not measure the total PCBs present in an 

environmental sample, and we do not recommend relying on such methods at this time.

 1 Axys Analytical, personal conversation. May 1, 2012.
San Francisco Bay Regional Water Quality Control Board September 2013

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CAULK SAMPLING & ANALYSIS2 

Structures, especially non-residential buildings, constructed or renovated between 1950 and 

1980 may have PCBs in caulking and other building materials. A local study found that PCBs 

are prevalent in the caulk in Bay Area buildings constructed during that timeframe. PCBs were 

detected in 88% of the caulk samples tested; 40% of the samples contained > 50 ppm PCBs 

and 20% contained > 10,000 ppm PCBs. Please refer to the study’s project page for more 

information about PCBs in caulks and sealants.

The following methods are recommended for sampling and analyzing caulk and sealants 

suspected of containing PCBs: Remove a one inch strip (or ~10 g) of the sealant sample from 

the structure using a utility knife with a solvent-rinsed, stainless-steel blade. Collect one sealant 

sample per sealant type on each structure to fully characterize the PCB content in the 

structure’s sealants.

PCBs can be present in the percentage range in caulk, so a high resolution method is not 

necessary. EPA Method 8270 (semi-volatile organic compounds by gas chromatography-mass 

spectrometry) is appropriate. Report analytical results as the total of 209 PCB congeners, or the

shorter list of 40 congeners above may be used.

BMPs for Controlling PCBs 

Best management practices (BMPs) for controlling PCBs during removal from structures can be 

found at http://www.epa.gov/epawaste/hazard/tsd/pcbs/pubs/caulk/caulkcontractors.htm.

BMPs for controlling sediment during site grading and other construction activities are available 

at http://cfpub.epa.gov/npdes/stormwater/swppp.cfm.

 2 Further information on PCB-containing caulks and sealants can be found at 

http://www.sfestuary.org/projects/detail.php?projectID=29 and http://www.epa.gov/pcbsincaulk/.