| Water Body Name: | Coyote Hills Slough (Alameda County) |
| Water Body ID: | CAR2041000020210623030219 |
| Water Body Type: | River & Stream |
DECISION ID |
145431 |
Region 2 |
Coyote Hills Slough (Alameda 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 |
| TMDL Name: | San Francisco Bay Mercury |
| TMDL Project Code: | 6 |
| 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. One line of evidence is available in the administrative record to assess the pollutant. WILD beneficial use: Tissue - LOE 269104: 1 of 1 samples exceed the mercury objective and consist of 15 trophic level 3 and 4 fish. 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 15 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 15 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. Coyote Hills 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: | 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: | 269104 | ||||
| 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 - EEPS data for Coyote Hills Slough (Alameda 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 within the same calendar year with a reported length of 50-150 mm were averaged into a single sample, independent of species or trophic level, for comparison with the objective. This LOE consists of a total of 15 fish, which were aggregated into 1 annual averages, consisting of 1 fish species (3 composite(s) of Mississippi silverside each composed of 5 fish per composite). Of these annual averages, 1 average(s), (Year(s): 2010) exceeded the objective. | ||||
| 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 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): COHIL (Coyote Hills Slough, deep in-COHIL). | ||||
| Temporal Representation: | Data for this line of evidence were collected between 2010-10-05 and 2010-10-05. 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. | ||||