# Draft 2008 California 303(d)/305(b) Integrated Report

# Supporting Information

## Regional Board 5 - Central Valley Region

Water Body Name: | Curry Creek (Placer and Sutter Counties)
Water Body ID: | CAR5192200020070510155010
Water Body Type: | River & Stream

DECISION ID | 13108
Pollutant: | Pyrethroids
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Urban Runoff/Storm Sewers
Expected TMDL Completion Date: | 2021
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. Three 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 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. Three of 3 samples exceed the narrative toxicity objective and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. Sediment-bound pyrethroid pesticide concentrations were used to calculate toxic units (TUs) of multiple pyrethroid pesticides observed in sediments. Pyrethroid TU analyses correlated with distribution and magnitude of toxicity. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
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.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 13108

LOE ID: | 21928
Pollutant: | Pyrethroids
LOE Subgroup: | Pollutant-Sediment
Matrix: | Sediment
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 3
Number of Exceedances: | 3
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Asses Water Quality: | Three of three sediment toxicity testing samples violated the narrative toxicity objective. The three toxic (Mean mortality + standard deviation) sediment samples were collected from:Curry Creek at Fiddyment Road10/15/04: 100+010/24/04: 100+03/10/05: 98+7.1The toxicity observations were associated with pyrethroid pesticides. LC50s for sediment-bound pyrethroids were used in this study as toxicity threshold benchmarks in a Toxic Unit (TU) analysis normalized to organic carbon content. The TU analysis of Curry Creek sediment samples demonstrated that the three toxic samples had pyrethroid pesticide concentrations that would be expected to be acutely toxic. The three toxic samples had an average of 11.5 ¿ 27.03 TUs of pyrethroid pesticides. Bifenthrin appears to play a dominant role in the toxicity observations, but was not the only pyrethroid found in toxic sediment samples. Other pyrethroids observed in the toxic samples from Curry Creek included cyfluthrin, cypermethrin, deltamethrin, esfenvalerate, lambda-cyhalothrin, and permethrin. LC50 concentrations for a 10-day exposure of Hyalella azteca to pyrethroid contaminated sediments were determined by Amweg et al., 2005. (Amweg, E.L., D.P. Weston, and N.M Ureda. 2005. Use and toxicity of pyrethroid pesticides in the Central Valley, California, U.S.A. Environ. Toxicol. Chem. 24:966-972 (with correction in Environ. Toxicol. Chem. 24:1300-1301)).
Data Reference: | Pyrethroid insecticides and sediment toxicity in urban creeks from California and Tennessee. Environmental Science and Technology, 40(5): 1700-1706
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. (CVRWQCB, 2007)All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life. (CVRWQCB, 2007)
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | Statistically significant difference from control sediment using Dunnett's test in 10-day Hyalella azteca sediment toxicity tests. Arcsin squareroot transformation was used when necessary to meet the assumptions of normality and homogeneity of variance. Steel¿s test was used for comparison to control if these assumptions were not met after transformation.
Guideline Reference:
Spatial Representation: | Three samples were collected from one location on different occasions (October 15, 2004; October 24, 2004; and March 10, 2005) from Curry Creek at Fiddyment Road in the City of Roseville. Sediment toxicity was observed from all three samples. Sample location:Curry Creek at Fiddyment Road
Temporal Representation: | Samples were collected August 2004 - August 2005.The creek is formed from runoff from a subdivision and emerges from an underground pipe at the sampling location. Curry Creek upstream of the sample location consists predominately residential land use.
Environmental Conditions: |
QAPP Information: | Monitoring was conducted in accordance with the Quality Assurance Project Plan for Monitoring prepared for the Sacramento River Watershed Program (SRWP 1999a, 1999b, 2000b, 2001b, 2002b, 2003b, 2006).
QAPP Information Reference(s):