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

# Supporting Information

## Regional Board 5 - Central Valley Region

Water Body Name: | Natoma, Lake
Water Body ID: | CAL5192100020020430135321
Water Body Type: | Lake & Reservoir

DECISION ID | 5056
Pollutant: | Mercury
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: | Resource Extraction
Expected TMDL Completion Date: | 2019
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under sections 3.4 and 3.5 of the Listing Policy. Under sections 3.5 a single line of evidence is necessary to assess listing status while under section 3.4, a minimum of two lines of evidence are needed to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. A health advisory against the consumption of edible resident organisms has been issued by OEHHA and water segment-specific data indicates the evaluation guideline for tissue has been exceeded. In addition many measurements of tissue mercury concentration exceed the available 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 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. A total of 11 fish species were collected. Exceedances of the CDFG criteria were recorded in 10 channel catfish (ranged from 1.1 to 1.9 mg/kg) and 14 largemouth bass (ranged from 0.27 to 0.86 mg/kg). These samples provide documentation in support of the fish consumption health advisory issued by OEHHA in September 2004 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: | 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 5056

LOE ID: | 728
Pollutant: | Mercury
LOE Subgroup: | Health Advisories
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | USGS and UCD collected a total of 11 fish species by electrofishing equipment or gill nets in August 2000, from September to October 2002, and in July 2003, at several sites in Lake Natoma, including the vicinity of Negro Bar and Mississippi Bar, the mouths of Willow Creek and Alder Creek, Natomas Slough, and near Nimbus Dam (Saiki et al., 2004; Alpers et al., 2004). Species collected included largemouth bass, smallmouth bass, spotted bass, channel catfish, white catfish, brown bullhead, black bullhead, redear sunfish, green sunfish, bluegill, and rainbow trout. Fish were measured and weighed; boneless and skinless individual fillets were submitted to University of California, Davis (the August 2000 and July 2003 samples) or the USGS Columbia Environmental Research Center (CERC) in Columbia, Missouri (the September to October 2002 samples) for total mercury analyses by atomic absorption spectrophotometry using either a Perkin Elmer Flow Injection Mercury System or a Milestone DMA-80 analyzer. Under TSMP, the California Department of Fish and Game (CDFG) collected largemouth bass (n= 15 in three composites), pike minnow (n= 16 in three composites), and sucker samples (n = 35 in nine composites) by electrofishing equipment or gill nets in 1979-1983, 1987, and 1990-1993 near the Highway 160 and Watt Avenue bridges on the lower American River. Fish were measured and weighed and made into composites using skin-off muscle fillet. Composite samples were homogenized at the CDFG Water Pollution Control Laboratory and analyzed for total mercury by cold vapor atomic absorption spectrophotometry (Rasmussen, 1995). For the Sacramento River Watershed Program, largemouth bass (n = 26 in seven composites), striped bass (n = 1), pike minnow (n = 25 in five composites), sucker (n = 35 in seven composites), white catfish (n = 9 in two composites), and redear sunfish (n = 10 in two composites) were collected by electroshock, nets, or hook and line from 1997 to 2002 at known fishing locations on the lower American River from Sunrise Avenue to Discovery Park. Fish were measured and weighed and made into composites using skin-off muscle fillet. Composite samples were homogenized at Moss Landing Marine Laboratory and analyzed for total mercury using a Perkin Elmer Flow Injection Mercury System (Saiki et al., 2004).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Fish consumption health advisory issued by OEHHA in September 2004.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: | OEHHA guidance tissue levels for methyl mercury (Klasing & Brodberg, 2004).
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Sample locations included Lake Natoma at Willow Creek, Mississippi Bar, Nimbus Dam, Alder Creek, Natomas Slough and Negro Bar.
Temporal Representation: | Collection dates for USGS and UCD sampling data from Lake Natoma ranged from Aug. 2000, Sept. and Oct. 2002, and July 2003.
Environmental Conditions: | Of the samples collected at Lake Natoma and the lower American River, largemouth bass (n = 64), bluegill (n = 78), pikeminnow (n = 41), sucker (n = 70), channel catfish (n =11), white catfish (n = 10) and redear sunfish (n = 20) had sufficient sample size (≥ 9 fish per species) of legal/edible size fish to be considered representative of mercury levels in those species, thereby allowing adequate estimation of the health risks associated with their consumption.
QAPP Information: | The health advisory was based on data from UC Davis monitoring programs and published U.S. Geological Survey (USGS) reports. The Policy considers documentation from these sources to be of adequate quality.
QAPP Information Reference(s):
LOE ID: | 727
Pollutant: | Mercury
LOE Subgroup: | Testimonial Evidence
Matrix: | -N/A
Fraction: | None
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | Supplemental information from a relational database and GIS for Hg. The present study was intended to assess the fishing intensity and mercury concentrations in fish tissue data that are currently available. This assessment will inform this goal of the CALFED Mercury Strategy as well as the goal of the Delta Tributaries Mercury Council to reduce the risk of mercury exposure of humans and wildlife. In order to serve these goals, critical information includes the relative distribution of fishing intensity and fish concentrations of mercury and knowledge of the communities from which anglers are originating. Fish tissue mercury concentrations >0.3 ppm have been measured in the Upper American River.
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):
LOE ID: | 729
Pollutant: | Mercury
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | Water, bed sediment, and biota in Lake Natoma and two tributaries in the lower American River watershed were sampled during 2002 and 2003, providing one of the first comprehensive assessments of mercury (Hg) and methyl mercury (MeHg) contamination and bioaccumulation associated with large-scale gold dredging in the Sierra Nevada. Larger fish from Lake Natoma had elevated Hg concentrations in axial muscle tissue (wet basis): 10 channel catfish (505 to 750 mm total length) ranged from 1.1 to 1.9 mg/kg; 14 largemouth bass (LMB) of legal catch size (340 to 490 mm) ranged from 0.27 to 0.86 mg/kg. Smaller fish (bluegill, redear sunfish, green sunfish, and LMB < 270 mm) generally had Hg < 0.30 mg/kg. At ten sites in Willow and Alder creeks, concentrations of MeHg in unfiltered water (0.05 to 0.76 ng/L) and filtered water (0.04 to 0.56 ng/L) correlated spatially with concentrations of MeHg in two taxa of invertebrates: Hydropsyche (caddisfly larvae, n=7) and Coenagrionidae (damselfly nymphs, n=6). In bed sediments (0-2 cm depth), potential rates of Hg methylation and demethylation correlated strongly with organic matter content, acid extractable Fe(II) concentration, and total reduced sulfur, but not with microbial sulfate reduction rates, indicating the possible role of iron-reducing bacteria in mercury methylation and demethylation (Saiki et al., 2004).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Central Valley RWQCB Basin Plan: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or produce detrimental physiological responses in human, plant, animal, or aquatic life.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: | USEPA criteria of 0.30 mg methyl mercury/kg wet weight as the fish tissue residue criterion that should not be exceeded (Klasing & Brodberg, 2004).
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | USGS and UCD collected a total of 11 fish species at several sites in Lake Natoma, including the vicinity of Negro Bar and Mississippi Bar, the mouths of Willow Creek and Alder Creek, Natomas Slough, and near Nimbus Dam.
Temporal Representation: | USGS and UCD collected a total of 11 fish species by electrofishing equipment or gill nets in August 2000, from September to October 2002, and in July 2003.
Environmental Conditions: | Documentation in support of fish consumption health advisory issued by OEHHA in September 2004. The specific objective was to determine if total mercury concentrations in skinless fillets of selected sport fish approach or exceed criteria for human health concerns.
QAPP Information: | QA Info Missing
QAPP Information Reference(s):