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DECISION ID |
9912 |
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| Pollutant: |
Sediment Toxicity |
| 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 |
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| Weight of Evidence: |
This pollutant is being considered for listing under section 3.6 of the Listing Policy. Under section 3.6 a single line of evidence is necessary to assess listing status.
One line of evidence is available in the administrative record to assess toxicity in Lobos Creek. Based on the readily available data for this water body, the weight of evidence indicates that there is sufficient justification available against 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 concerning current conditions and supporting the listing decision satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. Sediment toxicity was detected in only one sample and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. In addition, the sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. |
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| RWQCB Board Decision / Staff Recommendation: |
After review of the available data and information, Water Board staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there is insufficient number of exceedances to confirm toxicity and to determine that the standards are not met. |
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| SWRCB Board Decision / Staff Recommendation: |
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| USEPA Decision: |
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| LOE ID: |
21284 |
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| Pollutant: |
Sediment Toxicity |
| LOE Subgroup: |
Pollutant-Sediment |
| Matrix: |
Sediment |
| Fraction: |
None |
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| Beneficial Use: |
Warm Freshwater Habitat |
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| Number of Samples: |
1 |
| Number of Exceedances: |
1 |
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| Data and Information Type: |
TOXICITY TESTING |
| Data Used to Assess Water Quality: |
Data used to evaluate sediment toxicity comprise one sediment sample collected by the SWAMP in spring 2005. This sample displayed statistically significant toxicity during the Hyalella azteca test. Hyalella azteca growth was only 76% of the control. |
| Data Reference: |
Data collected by the Surface Water Ambient Monitoring Program, San Francisco Bay Regional Water Quality Control Board. Years 4 and 5 Assessment |
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| Water Quality Objective/Criterion: |
All waters shall be maintained free of toxic substances that are lethal to or that produce other detrimental responses in aquatic organisms.
There shall be no chronic toxicity in ambient waters. Chronic toxicity is a detrimental biological effect on growth rate, reproduction, fertilization success, larval development, population abundance, community composition, or any other relevant measure of the health of an organism, population, or community. |
| Objective/Criterion Reference: |
San Francisco Bay Basin (Region 2) Water Quality Control Plan (Basin Plan) |
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| Evaluation Guideline: |
Sediment toxicity was evaluated according to the SWAMP methodology. Sample toxicity was determined by comparing mean organism response in samples and in negative controls. Statistical evaluation (alpha = 0.05) and a default threshold of 80% of the control value were used to establish whether the sediment exhibited significant toxicity adversely impacting aquatic organisms. |
| Guideline Reference: |
Revised approach to toxicity test acceptability criteria using a statistical performance assessment. Environmental Toxicology and Chemistry, vol. 16, No. 6, pp 13221329 |
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| Spatial Representation: |
Data were collected at one sampling location at the lower part of Lobos Creek. |
| Temporal Representation: |
A sample was collected in spring season (April 2005). |
| Environmental Conditions: |
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| QAPP Information: |
All samples were collected and analyzed using procedures comparable with the SWAMP Quality Assurance Management Plan (SWRCB, 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)
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DECISION ID |
9911 |
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| Pollutant: |
Toxicity |
| 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 |
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| Weight of Evidence: |
This pollutant is being considered for listing under section 3.6 of the Listing Policy. Under section 3.6 a single line of evidence is necessary to assess listing status.
One line of evidence is available in the administrative record to assess toxicity in Lobos Creek. One of three water samples exhibited limited toxicity.
Based on the readily available data for this water body, the weight of evidence indicates that there is sufficient justification available against 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 concerning current conditions and supporting the listing decision satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. Water toxicity was observed in one of three samples and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy or demonstrate with confidence that standards are not met.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. |
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| RWQCB Board Decision / Staff Recommendation: |
After review of the available data and information, Water Board staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there is insufficient number of exceedances to confirm toxicity and to determine that the standards are not met. |
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| SWRCB Board Decision / Staff Recommendation: |
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| USEPA Decision: |
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Lines of Evidence (LOEs) for Decision ID 9911 |
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| LOE ID: |
21282 |
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| Pollutant: |
Toxicity |
| LOE Subgroup: |
Pollutant-Water |
| Matrix: |
Water |
| Fraction: |
None |
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| Beneficial Use: |
Warm Freshwater Habitat |
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| Number of Samples: |
3 |
| Number of Exceedances: |
1 |
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| Data and Information Type: |
TOXICITY TESTING |
| Data Used to Assess Water Quality: |
Three samples were collected to evaluate water toxicity. Selenastrum growth was significantly lower (64.8%) than the control in one sample collected during winter wet season in February 2006. This sample displayed statistically significant water column toxicity. |
| Data Reference: |
Data collected by the Surface Water Ambient Monitoring Program, San Francisco Bay Regional Water Quality Control Board. Years 4 and 5 Assessment |
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| Water Quality Objective/Criterion: |
All waters shall be maintained free of toxic substances that are lethal to or that produce other detrimental responses in aquatic organisms.
There shall be no chronic toxicity in ambient waters. Chronic toxicity is a detrimental biological effect on growth rate, reproduction, fertilization success, larval development, population abundance, community composition, or any other relevant measure of the health of an organism, population, or community. |
| Objective/Criterion Reference: |
San Francisco Bay Basin (Region 2) Water Quality Control Plan (Basin Plan) |
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| Evaluation Guideline: |
Water toxicity was evaluated according to the SWAMP methodology. The U.S.EPA whole effluent toxicity protocol (U.S.EPA 1994) was used to test the effect of water samples on three freshwater test organisms. Statistical evaluation (alpha = 0.05) and a default threshold of 80% of the control value were used to establish whether water exhibited significant toxicity adversely impacting aquatic organisms. |
| Guideline Reference: |
Revised approach to toxicity test acceptability criteria using a statistical performance assessment. Environmental Toxicology and Chemistry, vol. 16, No. 6, pp 13221329 |
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Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms. EPA/600/4-91/002. Third Edition. July 1994 |
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| Spatial Representation: |
Data were collected at one sampling location at the lower part of Lobos Creek. |
| Temporal Representation: |
Samples were collected in spring season (April 2005), dry season (June 2005) and winter wet season (February 2006). |
| Environmental Conditions: |
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| QAPP Information: |
All samples were collected and analyzed using procedures comparable with the SWAMP Quality Assurance Management Plan (SWRCB, 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)
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