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DECISION ID |
16475 |
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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 placement on the section 303(d) list 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 this pollutant. One of the samples exceed the water quality objective.
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.
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. One of two samples exceeded the exhibited significant acute and chronic toxicity to Ceriodaphnia dubia 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. |
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| RWQCB Board Decision / Staff 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 because applicable water quality standards are not being exceeded. |
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| SWRCB Board Decision / Staff Recommendation: |
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| USEPA Decision: |
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| LOE ID: |
28254 |
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| Pollutant: |
Toxicity |
| LOE Subgroup: |
Toxicity |
| Matrix: |
Water |
| Fraction: |
None |
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| Beneficial Use: |
Warm Freshwater Habitat |
| Aquatic Life Use: |
Wildlife Habitat |
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| Number of Samples: |
2 |
| Number of Exceedances: |
1 |
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| Data and Information Type: |
TOXICITY TESTING |
| Data Used to Assess Water Quality: |
One out of two samples exhibited significant acute and chronic toxicity to Ceriodaphnia dubia. Water quality samples were taken and tested for toxicity to Pimephales promelas and Ceriodaphnia dubia in compliance with the Surface Water Ambient Monitoring Program's monitoring and testing parameters. |
| Data Reference: |
Surface Water Ambient Monitoring Program data for all watersheds in the Los Angeles Region 2001-2005. |
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| Water Quality Objective/Criterion: |
The Basin Plan states at there shall be no acute or chronic toxicity in ambient waters outside mixing zones. |
| Objective/Criterion Reference: |
Water Quality Control Plan Los Angeles Region R4 Basin Plan |
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Basin Plan Amendments to the Water Quality Control Plan Los Angeles Region R4 Basin Plan as of 02/02/2009 |
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| Evaluation Guideline: |
Toxicity was defined as a statistically significant effect in the sample exposure compared to the control using EPA recommended hypothesis testing (parametric Dunnett's Test or non-parametric Fisher's Exact Test). |
| Guideline Reference: |
Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fourth Edition |
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| Spatial Representation: |
Water toxicity monitoring was conducted in Tujunga Wash at station 412LARBLL (Lat: 34.1872, Long: -118.4978). |
| Temporal Representation: |
A grab sample was taken on 06/20/05 and 07/11/05. |
| Environmental Conditions: |
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| QAPP Information: |
Data was collected in compliance with the sampling and monitoring procedures detailed in the Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. |
| 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 |
16412 |
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| Pollutant: |
Indicator Bacteria |
| Final Listing Decision: |
List on 303(d) list (TMDL required list) |
| Last Listing Cycle's Final Listing Decision: |
New Decision |
| Revision Status |
Revised |
| Sources: |
Source Unknown |
| Expected TMDL Completion Date: |
2021 |
| Impairment from Pollutant or Pollution: |
Pollutant |
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| Weight of Evidence: |
This pollutant is being considered for placement on the section 303(d) list under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status.
One line of evidence is available in the administrative record to assess this pollutant.
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. Six of six samples exceed the Basin Plan Water Quality Objective for indicator bacteria in REC-1 waters and this exceeds the allowable frequency listed in Table 3.2 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 met. |
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| RWQCB Board Decision / Staff Recommendation: |
After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem. |
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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 16412 |