# Draft 2008 California 303(d)/305(b) Integrated Report

# Supporting Information

## Regional Board 5 - Central Valley Region

Water Body Name: | Mendota Pool
Water Body ID: | CAW5512000020021001113547
Water Body Type: | Wetland, Freshwater

DECISION ID | 12695
Pollutant: | Mercury
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Resource Extraction
Expected TMDL Completion Date: | 2021
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the 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. Three lines of evidence are available in the administrative record to assess this pollutant. Four of the samples exceed the water quality objective. 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 section 303(d) list in the Water Quality Limited Segments category. 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 43 samples exceed the USEPA fish tissue criterion for human health 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.
RWQCB Board Decision / Staff 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.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 12695

LOE ID: | 22625
Pollutant: | Mercury
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 5
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Five Largemouth Bass composite samples were collected for tissue analysis at one location from Mendota Pool. One of the 5 samples exceeded the USEPA fish tissue criterion for human health. The wet weight mercury concentrations of the 5 samples ranged from 0.15 ppm to 0.32 ppm, with an average of 0.23 ppm. All of the composite samples were collected from fish with average total lengths greater than 150 mm, which represent fish most commonly caught and consumed by sport fishers and their families.
Data Reference: | SWRCB-DWQ. 2002. Toxic Substances Monitoring Program: Freshwater Bioaccumulation Monitoring: TSM Program Data 1978-2000. State Water Resources Control Board, Division of Water Quality
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life. The objective applies regardless of whether the toxicity is caused by a single substance or the interactive effect of multiple substances.
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | The USEPA Fish Tissue Residue Criterion for methylmercury in fish is 0.3 mg/kg (0.3 ppm) for the protection of human health. This is the concentration in fish tissue that should not be exceeded based on a total fish and shellfish consumption-weighted rate of 0.0175 kg fish/day. (USEPA, 2001)
Guideline Reference: | Water Quality Criterion for the Protection of Human Health: Methylmercury. Final. United States Environmental Protection Agency Office of Science and Technology Office of Water. EPA-823-R-01-001. January 2001
Spatial Representation: | Samples were collected at one location near the middle of Mendota Pool.
Temporal Representation: | Fish samples were collected during five sampling events from 12/11/1986 to 5/27/2000.
Environmental Conditions: | Significant gold mining activity occurred during the Gold Rush era within the tributaries upstream of Mendota Pool (USGS, 2005).
QAPP Information: | Data quality: Good.. Quality Control for the fish sampling, tissue preparation, mercury analysis, and QA sample analysis portions of the 1986-1988 data was conducted as described in the Toxic Substance Monitoring Reports for 1986 and 1988-89 (Rasmussen, 1988; Rasmussen and Blethrow, 1991). Quality Control for the fish sampling, tissue preparation, mercury analysis, and QA sample analysis portions of the 1996-2000 data was conducted as described in the Environmental Chemistry Quality Assurance and Data Report for the Toxic Substances Monitoring Program, 1996-2000 (CDFG, 2001).
QAPP Information Reference(s):
LOE ID: | 22626
Pollutant: | Mercury
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 2
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Two Largemouth Bass composite samples were collected for tissue analysis at one location from Mendota Pool. One of the 2 samples exceeded the USEPA fish tissue criterion for human health. The wet weight mercury concentrations of the 2 samples were 0.25 ppm and 0.35 ppm. Both composite samples were collected from fish with average total lengths greater than 150 mm, which represent fish most commonly caught and consumed by sport fishers and their families.
Data Reference: | SWRCB. 2003. Toxic Substances Monitoring Program: Freshwater Bioaccumulation Monitoring Program 2001-2003. State Water Resources Control Board, Division of Water Quality. Unpublished Data.
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life. The objective applies regardless of whether the toxicity is caused by a single substance or the interactive effect of multiple substances.
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | The USEPA Fish Tissue Residue Criterion for methylmercury in fish is 0.3 mg/kg (0.3 ppm) for the protection of human health. This is the concentration in fish tissue that should not be exceeded based on a total fish and shellfish consumption-weighted rate of 0.0175 kg fish/day. (USEPA, 2001)
Guideline Reference: | Water Quality Criterion for the Protection of Human Health: Methylmercury. Final. United States Environmental Protection Agency Office of Science and Technology Office of Water. EPA-823-R-01-001. January 2001
Spatial Representation: | Samples were collected at one location near the middle of Mendota Pool.
Temporal Representation: | Fish samples were collected during two sampling events on 11/7/2001 and 6/19/2003.
Environmental Conditions: | Significant gold mining activity occurred during the Gold Rush era within the tributaries upstream of Mendota Pool (USGS, 2005).
QAPP Information: | Data quality: Good.. Quality Control for the fish sampling, tissue preparation, mercury analysis, and QA sample analysis portions of this study was conducted as described in the Environmental Chemistry Quality Assurance and Data Report for the Toxic Substances Monitoring Program, 2001-2002 (CDFG, 2003).
QAPP Information Reference(s):
LOE ID: | 22624
Pollutant: | Mercury
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 36
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Fish were sampled for tissue analysis at one location from Mendota Pool. A total of 2 out of 36 samples exceeded the USEPA fish tissue criterion for human health. The average wet weight mercury concentration in fish tissue was 0.12 ppm for all 36 samples collected. The number of fish collected per sample, the measured mercury concentrations in fish tissue, and the number of exceedances are, by species: Bluegill- 2 samples, 0.07 and 0.2 ppm, no exceedances; Brown Bullhead- 4 samples, 0.03-0.05 ppm (average 0.04 ppm), no exceedances; Carp- 7 samples, 0.02-0.22 ppm (average 0.1 ppm), no exceedances; Channel Catfish- 8 samples, 0.04-0.14 ppm (average 0.09 ppm), no exceedances; Largemouth Bass- 9 samples, 0.1-0.42 ppm (average 0.23 ppm), 2 exceedances; Redear Sunfish- 6 samples, 0.02-0.15 ppm (average 0.08 ppm), no exceedances. All 36 samples were collected from fish with total lengths greater than 150 mm, which represent fish most commonly caught and consumed by sport fishers and their families.
Data Reference: | Fish Mercury Project, Year 1 Annual Report, Sport Fish Sampling and Analysis. Collaborating parties: San Francisco Estuary Institute, California Department of Fish and Game, Moss Landing Marine Laboratories, California Office of Environmental Health Hazard Assessment. Final Technical Report. CBDA Project # ERP 02D-P6729. May 2007
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life. The objective applies regardless of whether the toxicity is caused by a single substance or the interactive effect of multiple substances.
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | The USEPA Fish Tissue Residue Criterion for methylmercury in fish is 0.3 mg/kg (0.3 ppm) for the protection of human health. This is the concentration in fish tissue that should not be exceeded based on a total fish and shellfish consumption-weighted rate of 0.0175 kg fish/day. (USEPA, 2001)
Guideline Reference: | Water Quality Criterion for the Protection of Human Health: Methylmercury. Final. United States Environmental Protection Agency Office of Science and Technology Office of Water. EPA-823-R-01-001. January 2001
Spatial Representation: | Samples were collected at one location from Mendota Pool near the Delta-Mendota Canal inflow canal.
Temporal Representation: | Fish samples were collected during two sampling events on 9/22/2005 and 10/25/2005.
Environmental Conditions: | Significant gold mining activity occurred during the Gold Rush era within the tributaries upstream of Mendota Pool (USGS, 2005).
QAPP Information: | Data quality: Excellent.. Quality Control for all of the elements described in section 6.1.4 of the Policy was conducted in accordance with the Laboratory QAPP developed by Moss Landing Marine Laboratories (MLML, 2005). This data was also collected and analyzed in accordance with the CALFED Mercury Project QAPP (Puckett and van Buuren, 2000).
QAPP Information Reference(s):

DECISION ID | 7199
Pollutant: | Selenium
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Sources: | Agricultural Return Flows | Agriculture | Groundwater Withdrawal | Other
Expected TMDL Completion Date: | 2019
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for listing under section 2.2 of the Listing Policy. Under this section of the Policy, a minimum of one line of evidence is needed to assess listing status. Based on the readily available information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination in the Water Quality Limited Segments Being Addressed portion of the section 303(d) list. USEPA in its final decision for the 2006 303(d) list, has determined that a TMDL has not been approved by USEPA for this pollutant water body combination. Therefore, this water body pollutant combination is being placed back on the 303(d) list (TMDL required list) pending completion and USEPA approval of a TMDL.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The Regional Board will update this decision when new data and information become available and are assessed.
SWRCB Board Decision / Staff Recommendation: | This is a decision made by the State Water Resources Control Board and approved by the USEPA in 2006 . No new data were assessed by the Regional Board for 2008. The decision has not changed.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 7199

LOE ID: | 3435
Pollutant: | Selenium
LOE Subgroup: | Pollutant-Water
Matrix: | Not Specified
Fraction: | None
Beneficial Use: | Wildlife Habitat
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | A TMDL and implementation plan has been approved for this water segment-pollutant combination. The San Joaquin River Watershed Selenium TMDL was approved by RWQCB in 1996.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: |
Temporal Representation: |
Environmental Conditions: |
QAPP Information: | QA Info Missing
QAPP Information Reference(s):