Draft California 2024 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 2 - San Francisco Bay Region

Water Body Name: Artesian Slough (Santa Clara County)
Water Body ID: CAR2053008020110912154710
Water Body Type: River & Stream
 
DECISION ID
152858
Region 2     
Artesian Slough (Santa Clara County)
 
Pollutant: Mercury
Final Listing Decision: List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Sources: A Source Unknown
TMDL Name: San Francisco Bay Mercury
TMDL Project Code: 6
Date TMDL Approved by USEPA: 02/12/2008
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.11 of the Listing Policy. Under section 3.11 when all other listing factors do not result in the listing of a water segment but information indicates non-attainment of standards, a water segment shall be evaluated to determine whether the weight of evidence demonstrates that water quality standard is not attained. If the weight of evidence indicates non-attainment, the water segment shall be placed on the CWA section 303(d) List. Two lines of evidence are available in the administrative record to assess the pollutant.

WILD beneficial use:
Fish used in the WILD assessment are limited to lengths that are within Calif. Dept. of Fish and Wildlife legal size limits applicable to this waterbody.
LOE 269217: 1 of 1 sample exceed the mercury objective and consist of 15 trophic level 4 fish.

COMM beneficial use:
Fish used in the COMM assessment are limited to lengths that are within Calif. Dept. of Fish and Wildlife legal size limits applicable to this waterbody.
LOE 269133: 1 of 1 sample exceed the mercury objective and consist of 17 trophic level 4 fish.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List as being addressed by an EPA-approved TMDL.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Tissue samples were compared with the sport fish objective and 1 of 1 sample exceed for the COMM beneficial use. The samples consist of trophic level 4 fish that are annual averages and are aggregated from at least eight fish and this meets the one exceeding sample of eight or more fish needed to determine non-attainment of the mercury objective following weight of evidence in Listing Policy section 3.11.
4. Artesian Slough is an integral part of San Francisco Bay which is impaired by mercury. The San Francisco Bay mercury TMDL was approved by US EPA on 2/12/2008. The TMDL applies to the lower portion of the watersheds draining to the Bay from tidal influence to open Bay water, including sloughs and former salt ponds.
5. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
 
 
Line of Evidence (LOE) for Decision ID 152858, Mercury
Region 2     
Artesian Slough (Santa Clara County)
 
LOE ID: 269133
 
Pollutant: Mercury
LOE Subgroup: Pollutant-Tissue
Matrix: Tissue
Fraction: Fish fillet
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Regional Monitoring Program - FISH data for Artesian Slough (Santa Clara County) to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the water quality threshold for Mercury. This LOE contains data only for trophic level 4 fish. The concentration of Mercury in fish collected within the same calendar year, for the same trophic level were averaged into a single sample for comparison with the objective. A total of 15 fish were aggregated into 1 annual averages, which consisted of 2 fish species (12 composite(s) of Largemouth Bass each composed of 1 fish per composite, 3 composite(s) of Striped Bass each composed of 1 fish per composite). Of these annual averages, 1 average(s), (Year(s): 2015) exceeded the objective.This LOE does not contain data from fish who's average length was outside of the legal size limits as described by the California Department of Fish and Wildlife Fishing Regulations.
Data Reference: Tissue data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the San Francisco Bay Basin: Controllable water quality factors shall not cause a detrimental increase in concentrations of toxic substances found in bottom sediments or aquatic life. Effects on aquatic organisms, wildlife, and human health will be considered.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)
 
Evaluation Guideline: The Statewide Sport Fish Water Quality Objective for the protection of the Commercial and Sport Fishing beneficial comes from the Statewide Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California, and is 0.2 mg/Kg wet weight skinless fillet samples of trophic level 3, or trophic level 4 fish (whichever is highest in the water body) over a one year averaging period. Trophic levels of applicable fish are defined in, but not limited to those in Attachment C of the Final Regulatory Language document (Appendix A) of State Water Resources Control Board Resolution No. 2017-0027.
Guideline Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Spatial Representation: Data were collected from 1 station(s). Station Code(s): ARTSLGH (Artesian Slough).
Temporal Representation: Data for this line of evidence were collected between 2015-06-13 and 2015-08-03. When composited fish were collected over multiple days, the first day of fish collection was used as the sample date in the LOE, both for LOE writing, and for averaging period purposes.
Environmental Conditions:
QAPP Information: SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..
QAPP Information Reference(s): This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.
 
Line of Evidence (LOE) for Decision ID 152858, Mercury
Region 2     
Artesian Slough (Santa Clara County)
 
LOE ID: 269217
 
Pollutant: Mercury
LOE Subgroup: Pollutant-Tissue
Matrix: Tissue
Fraction: Fish fillet
 
Beneficial Use: Wildlife Habitat
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Regional Monitoring Program - FISH data for Artesian Slough (Santa Clara County) to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the water quality threshold for Mercury. This LOE contains data only for trophic level 4 fish. The concentration of Mercury in fish collected within the same calendar year, for the same trophic level were averaged into a single sample for comparison with the objective. A total of 15 fish were aggregated into 1 annual averages, which consisted of 2 fish species (12 composite(s) of Largemouth Bass each composed of 1 fish per composite, 3 composite(s) of Striped Bass each composed of 1 fish per composite). Of these annual averages, 1 average(s), (Year(s): 2015) exceeded the objective.This LOE does not contain data from fish who's average length was outside of the legal size limits as described by the California Department of Fish and Wildlife Fishing Regulations.
Data Reference: Tissue data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the San Francisco Bay Basin: Controllable water quality factors shall not cause a detrimental increase in concentrations of toxic substances found in bottom sediments or aquatic life. Effects on aquatic organisms, wildlife, and human health will be considered.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)
 
Evaluation Guideline: The Statewide Sport Fish Water Quality Objective for the protection of Wildlife Habitat comes from the Statewide Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California, and is 0.2 mg/Kg wet weight skinless fillet samples of trophic level 3, or trophic level 4 fish (whichever is highest in the water body) over a one year averaging period. If trophic level 3 fish are used in the assessment then the Prey Fish Water Quality Objective must also be used to determine that the Sport Fish Objective is being met. Trophic levels of applicable fish are defined in, but not limited to those in Attachment C of the Final Regulatory Language document (Appendix A) of State Water Resources Control Board Resolution No. 2017-0027.
Guideline Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Spatial Representation: Data were collected from 1 station(s). Station Code(s): ARTSLGH (Artesian Slough).
Temporal Representation: Data for this line of evidence were collected between 2015-06-13 and 2015-08-03. When composited fish were collected over multiple days, the first day of fish collection was used as the sample date in the LOE, both for LOE writing, and for averaging period purposes.
Environmental Conditions:
QAPP Information: SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..
QAPP Information Reference(s): This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.
 
 
DECISION ID
143180
Region 2     
Artesian Slough (Santa Clara County)
 
Pollutant: PCBs (Polychlorinated biphenyls)
Final Listing Decision: List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Sources: Other Urban Runoff
TMDL Name: San Francisco Bay PCBs
TMDL Project Code: 7
Date TMDL Approved by USEPA: 03/29/2010
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. Four of the four samples exceed the 2.6 ppb OEHHA fish tissue evaluation guideline.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This listing is being addressed through the PCBs TMDL for San Francisco Bay approved by USEPA in 2010.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Four of the four samples exceed the 2.6 ppb OEHHA fish tissue evaluation guideline and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
5. This listing is being addressed through the PCBs TMDL for San Francisco Bay approved by USEPA in 2010.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation:
 
 
Line of Evidence (LOE) for Decision ID 143180, PCBs (Polychlorinated biphenyls)
Region 2     
Artesian Slough (Santa Clara County)
 
LOE ID: 269352
 
Pollutant: PCBs (Polychlorinated biphenyls)
LOE Subgroup: Pollutant-Tissue
Matrix: Tissue
Fraction: Fish fillet
 
Beneficial Use: Estuarine Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Regional Monitoring Program - FISH data for Artesian Slough (Santa Clara County) to determine beneficial use support and the results are as follows 0 of the 4 samples exceeded the water quality threshold for PCBs (Polychlorinated biphenyls). Data were collected for 4 fish species (1 composite(s) of Common Carp each composed of 1 fish per composite, 1 composite(s) of Largemouth Bass each composed of 5 fish per composite, 1 composite(s) of Striped Bass each composed of 2 fish per composite, 2 composite(s) of Striped Bass each composed of 3 fish per composite).
Data Reference: Tissue data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the San Francisco Bay Basin: Controllable water quality factors shall not cause a detrimental increase in concentrations of toxic substances found in bottom sediments or aquatic life. Effects on aquatic organisms, wildlife, and human health will be considered.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)
 
Evaluation Guideline: National Academy of Science guidelines (NAS 1972) establish a maximum total PCB Arochlor concentration of 500 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference: National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
 
Spatial Representation: Data were collected from 1 station(s). Station Code(s): ARTSLGH (Artesian Slough).
Temporal Representation: Data for this line of evidence were collected between 2015-06-13 and 2015-08-02. When composited fish were collected over multiple days, the first day of fish collection was used as the sample date in the LOE, both for LOE writing, and for averaging period purposes.
Environmental Conditions:
QAPP Information: SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..
QAPP Information Reference(s): This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.
 
Line of Evidence (LOE) for Decision ID 143180, PCBs (Polychlorinated biphenyls)
Region 2     
Artesian Slough (Santa Clara County)
 
LOE ID: 269320
 
Pollutant: PCBs (Polychlorinated biphenyls)
LOE Subgroup: Pollutant-Tissue
Matrix: Tissue
Fraction: Fish fillet
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 4
Number of Exceedances: 4
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Regional Monitoring Program - FISH data for Artesian Slough (Santa Clara County) to determine beneficial use support and the results are as follows 4 of the 4 samples exceeded the water quality threshold for PCBs (Polychlorinated biphenyls). Data were collected for 4 fish species (1 composite(s) of Common Carp each composed of 1 fish per composite, 1 composite(s) of Largemouth Bass each composed of 5 fish per composite, 2 composite(s) of Striped Bass each composed of 3 fish per composite, 1 composite(s) of Striped Bass each composed of 2 fish per composite). Of these, 3 species (Common Carp, Largemouth Bass, Striped Bass) exceeded the water quality threshold.
Data Reference: Tissue data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the San Francisco Bay Basin: Controllable water quality factors shall not cause a detrimental increase in concentrations of toxic substances found in bottom sediments or aquatic life. Effects on aquatic organisms, wildlife, and human health will be considered.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)
 
Evaluation Guideline: The modified OEHHA Fish Contaminant Goal for polychlorinated biphenyls in fish tissue is 2.6 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets. (Klasing, S., and R. Brodberg, 2008)
Guideline Reference: Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
 
Spatial Representation: Data were collected from 1 station(s). Station Code(s): ARTSLGH (Artesian Slough).
Temporal Representation: Data for this line of evidence were collected between 2015-06-13 and 2015-08-02. When composited fish were collected over multiple days, the first day of fish collection was used as the sample date in the LOE, both for LOE writing, and for averaging period purposes.
Environmental Conditions:
QAPP Information: SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..
QAPP Information Reference(s): This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.