| Water Body Name: | Ruth Lake |
| Water Body ID: | CAL1094003020020720144550 |
| Water Body Type: | Lake & Reservoir |
DECISION ID |
9589 |
Region 1 |
Ruth Lake |
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| Pollutant: | Mercury |
| Final Listing Decision: | Do Not List on 303(d) list (TMDL required list) |
| Last Listing Cycle's Final Listing Decision: | New Decision |
| Revision Status | Revised |
| Impairment from Pollutant or Pollution: | Pollutant |
| Regional Board Conclusion: | Mercury in Ruth Lake is being considered for placement on the Section 303(d) List under Section 3.5 of the Listing Policy. One line of evidence is available in the administrative record to assess this pollutant. None of the 2 composite total mercury samples exceed the evaluation guideline used to interpret the toxicity water quality objective. The evaluation guideline is the tissue residue criterion of 0.3 mg/kg from the "Water Quality Criterion for the Protection of Human Health: Mathylmercury" (USEPA 2001). Total mercury is usually analyzed for most fish studies and assumed to be 100% methylmercury for the purposes of risk assessment (Klasing & Brodberg 2008).
Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the Section 303(d) list in the Water Quality Limited Segments category (i.e., sufficient justification to not list). 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) None of the 2 composite samples exceed the evaluation guideline, and this does not exceed 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. |
| Regional Board Decision Recommendation: | After review of the available data and information, North Coast Regional Water Board staff concludes that the water body-pollutant combination should not be placed on the Section 303(d) List because applicable water quality standards are being attained. |
| State Board Review of Regional Board Conclusion and Recommendation: | |
| State Board Decision Recommendation: | After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board. |
| USEPA Action (if applicable): | |
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| LOE ID: | 21171 | ||||
| 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: | 2 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | Fish tissue analysis | ||||
| Data Used to Assess Water Quality: | None of the 2 total mercury composite samples of fish from Ruth Lake exceed the evaluation guideline. Sample composite concentrations range from 0.20 mg/kg to 0.24 mg/kg. Sample composites were made from fish of each species of approximately the same size. For Trinity Lake, 2 sample composites were made as follows: 6 bluegill that range in fork length size from 201 mm to 218 mm, and 2 rainbow trout from 408 mm to 435 mm. Sample composites were analyzed for total mercury with the assumption that 100% of the total mercury value represents the methylmercury content of tissue. Data is summarized by the California Department of Water Resources (DWR 2001; DWR 2007). | ||||
| Data Reference: | Mercury Contamination in Fish from Northern California Lakes and Reservoirs. State of California. The Resources Agency. Department of Water Resources. Northern District. July 2007 | ||||
| Data for Mercury Tissue in Northern California Lakes, 2000-2001 | |||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | Per the Basin Plan (NCRWQCB 2007): All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, bioassays of appropriate duration, or other appropriate methods as specified by the Regional Water Board. | ||||
| Objective/Criterion Reference: | Water Quality Control Plan (Basin Plan) - North Coast Region (Region 1) | ||||
| Evaluation Guideline: | Per the Water Quality Criterion for the Protection of Human Health: Methylmercury (USEPA 2001): the Ambient Water Quality Criterion for methylmercury is the tissue residue criterion of 0.3 mg methylmercury per kg of fish (0.3 mg/kg). This is the concentration in fish tissue that should not be exceeded to protect human health based on a total fish and shellfish consumption-weighted rate of 0.0175 kg fish/day. Total mercury is usually analyzed for most fish studies and assumed to be 100% methylmercury for the purposes of risk assessment (Klasing & 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 | ||||
| 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 in Ruth Lake. | ||||
| Temporal Representation: | Samples were collected on September 27 and October 4, 2001. | ||||
| Environmental Conditions: | There are no known environmental conditions (e.g., seasonality, land use practices, fire events, storms, etc.) that are related to these data. | ||||
| QAPP Information: | Samples were collected, processed, and analyzed in accordance with the methods described in "Mercury Contamination in fish from Northern California Lakes and Reservoirs" (DWR 2007), which closely follows the Quality Assurance Management Plan for the State of Californias Surface Water Ambient Monitoring Program (Puckett 2002). | ||||
| QAPP Information Reference(s): | Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version) | ||||
| Mercury Contamination in Fish from Northern California Lakes and Reservoirs. State of California. The Resources Agency. Department of Water Resources. Northern District. July 2007 | |||||