| Water Body Name: | Kent Lake (Marin County) |
| Water Body ID: | CAL2011302020210901030456 |
| Water Body Type: | Lake & Reservoir |
DECISION ID |
152835 |
Region 2 |
Kent Lake (Marin County) |
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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: | This pollutant is being considered for placement on the section 303(d) list under section 3.5 of the Listing Policy. Under section 3.5 a single line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess the pollutant. WILD beneficial use (prey fish objective): LOE 269146: 1 of 1 samples exceed the mercury objective and consist of 25 trophic level 3 and 4 fish. WILD beneficial use (sport fish objective): LOE 269191: 1 of 1 samples exceed the mercury objective and consist of 7 trophic level 4 fish (CDFW legal size). COMM beneficial use (sport fish objective): 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 269222: 1 of 1 samples exceed the mercury objective and consist of 7 trophic level 4 fish (CDFW legal size). 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 CWA 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. Tissue samples were compared with the prey fish objective and 1 of 1 samples exceed WILD beneficial. The annual average sample consists of 25 individual fish. Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. However, the fact that the sample is composed of 25 fish that independently accumulated enough mercury such that the average of all these fish exceeds the mercury objective indicates beneficial uses may be potentially threatened. 4. Tissue samples were compared with the sport fish objective and 1 of 1 samples exceed for WILD beneficial use and 1 of 1 samples exceed for the COMM beneficial use. Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. 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: | Decision written by SWRCB staff. |
| 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 not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded. |
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| LOE ID: | 269146 | ||||
| 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 SWAMP Sportfish Contamination in Lakes and Resrv data for Kent Lake (Marin County) to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the water quality threshold for Mercury. All fish collected between February and July of the same calendar year with a reported length of 50-150 mm were averaged into a single sample, independent of species of trophic level, for comparison with the objective. This LOE consists of a total of 25 fish, which were aggregated into 1 annual averages, consisting of 3 fish species (1 composite(s) of Green Sunfish each composed of 5 fish per composite, 2 composite(s) of Bluegill each composed of 5 fish per composite, 1 composite(s) of Bluegill each composed of 10 fish per composite). Of these annual averages, 1 average(s), (Year(s): 2016) exceeded the objective. | ||||
| Data Reference: | Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2. | ||||
| SWAMP Data: | 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 Prey 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 0.05 mg/Kg wet weight whole fish samples of any fish species between 50 to 150 mm in total length collected between February 1 and July 31. (SWRCB 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): 201KENTLK (Kent Lake). | ||||
| Temporal Representation: | Data for this line of evidence were collected between 2016-07-12 and 2016-07-12. 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. | ||||
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| LOE ID: | 269222 | ||||
| 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 SWAMP Sportfish Contamination in Lakes and Resrv data for Kent Lake (Marin 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 7 fish were aggregated into 1 annual averages, which consisted of 1 fish species (7 composite(s) of Largemouth Bass each composed of 1 fish per composite). Of these annual averages, 1 average(s), (Year(s): 2016) 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: | Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2. | ||||
| SWAMP Data: | 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): 201KENTLK (Kent Lake). | ||||
| Temporal Representation: | Data for this line of evidence were collected between 2016-07-12 and 2016-07-12. 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. | ||||
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| LOE ID: | 269191 | ||||
| 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 SWAMP Sportfish Contamination in Lakes and Resrv data for Kent Lake (Marin 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 7 fish were aggregated into 1 annual averages, which consisted of 1 fish species (7 composite(s) of Largemouth Bass each composed of 1 fish per composite). Of these annual averages, 1 average(s), (Year(s): 2016) 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: | Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2. | ||||
| SWAMP Data: | 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): 201KENTLK (Kent Lake). | ||||
| Temporal Representation: | Data for this line of evidence were collected between 2016-07-12 and 2016-07-12. 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 |
144850 |
Region 2 |
Kent Lake (Marin County) |
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| Pollutant: | Selenium |
| 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: | Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available. |
| Regional Board Decision Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. |
| State Board Review of Regional Board Conclusion and Recommendation: | |
| State Board Decision Recommendation: | |
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| LOE ID: | 269476 | ||||
| Pollutant: | Selenium | ||||
| LOE Subgroup: | Pollutant-Tissue | ||||
| Matrix: | Tissue | ||||
| Fraction: | Fish fillet | ||||
| Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms | ||||
| Number of Samples: | 5 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed SWAMP Sportfish Contamination in Lakes and Resrv data for Kent Lake (Marin County) to determine beneficial use support and the results are as follows 0 of the 5 samples exceeded the water quality threshold for Selenium. Data were collected for 5 fish species (1 composite(s) of Green Sunfish each composed of 5 fish per composite, 2 composite(s) of Bluegill each composed of 5 fish per composite, 1 composite(s) of Bluegill each composed of 10 fish per composite, 1 composite(s) of Largemouth Bass each composed of 10 fish per composite, 1 composite(s) of Largemouth Bass each composed of 5 fish per composite). | ||||
| Data Reference: | Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2. | ||||
| SWAMP Data: | 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 OEHHA Fish Contaminant Goal for selenium in fish tissue is 7.4 ppm. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day. A background dietary consumption rate of 0.114 mg/day is applied for this micronutrient. (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): 201KENTLK (Kent Lake). | ||||
| Temporal Representation: | Data for this line of evidence were collected between 2016-07-12 and 2016-07-12. 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. | ||||