Temporal Assessment of Chemistry, Toxicity and Benthic Communities in Sediments at the Mouths of Chollas Creek and Paleta Creek, San Diego Bay Jeffrey Brown Steven Bay Technical Report 668 - November 2011 Temporal Assessment of Chemistry, Toxicity and Benthic Communities in Sediments at the Mouths of Chollas Creek and Paleta Creek, San Diego Bay Jeffrey Brown and Steven Bay Southern California Coastal Water Research Project 3535 Harbor Blvd., Suite 110 Costa Mesa, CA 92626 Review Draft January 2005 Final Report November 2011 Technical Report 668 ABSTRACT This report describes the temporal variability of sediment conditions near the mouths of Chollas and Paleta Creeks, where they enter San Diego Bay, and also at reference stations. This investigation is an extension of the spatially-intensive study that was conducted at these sites in July and August 2001. Sediment samples were collected from two reference stations (CP2243 and CP2433), two Chollas Creek stations (C10 and C14), and two Paleta Creek stations (P11 and P17) over four additional sampling events between November 2001 and October 2002. The samples were analyzed for sediment chemistry (metals, PAHs, PCBs, DDTs, chlordanes), benthic community parameters (e.g., abundance, taxa, diversity, embayment Benthic Response Index) and toxicity measurements (amphipod survival test with whole sediments, sea urchin embryo development test with sediment-water interface, and sea urchin fertilization test with pore water). A 95% prediction limit based on a pool of stations representing ambient conditions in San Diego Bay (Baseline pool) was used to help evaluate impact. The prediction limit for metals data was based on a regression with sediment grain size (% fines). This study found that most sediment parameters were consistent over the five sampling periods at most stations. Much of the high variability that was observed was associated with 4,4’-DDT and chlordane measurements. There were a few instances where concentrations of As, Cd, Hg, Pb, PAHs, and PCBs had high variability. The variability was not consistently associated with any particular station or sampling event. The differences also did not appear to be related to season or rainfall. Some indicators were found to be consistently above or below the 95% prediction limit for all five sampling events. Total PCBs, PAHs and total chlordanes were consistently above the prediction limit at all Chollas and Paleta Creek stations, while Cu and Zn were consistently above or below the prediction limit on a station-by-station basis. The fact that most metals were not consistently above or below the prediction limit appears to be more a result of where the prediction limit was in relation to the range of measured values, rather than the amount of variability in the measurements. A weight of evidence approach was used to classify the potential for impairment at the stations. Consistent classifications over the time period were found at both reference sites and the two stations closest to the creek inlets (C14 and P17). Greater variability in the impairment classification was found at the other two stations; the classification for these stations varied from unlikely to likely impaired over time as a result of variations in the measures of biological impact (toxicity or benthic community composition). i TABLE OF CONTENTS page Abstract ................................................................................................................................ i List of Tables ..................................................................................................................... iii List of Figures .................................................................................................................... iv Introduction ......................................................................................................................... 1 Methods............................................................................................................................... 2 Study Design ................................................................................................................... 2 Field Methods ................................................................................................................. 2 Chemical Analysis .......................................................................................................... 4 Toxicity Testing .............................................................................................................. 6 Benthic Community Analysis ......................................................................................... 7 Data Analysis .................................................................................................................. 8 Results ............................................................................................................................... 11 Chemistry ...................................................................................................................... 11 Toxicity ......................................................................................................................... 17 Benthic Community Analysis ....................................................................................... 22 Lines of Evidence ......................................................................................................... 25 Weight of Evidence ...................................................................................................... 27 Discussion ......................................................................................................................... 29 Literature Cited ................................................................................................................. 32 Appendix A. Sampling location coordinates ................................................................. A-1 Appendix B Using Percent Fines to Determine Trace Metal Enrichment .................... B-1 Appendix C Ammonia influence in the sediment-water interface test .......................... C-1 Appendix D. Sediment fines and metal concentrations ................................................. D-1 Appendix E. Sediment organic contaminant concentrations .......................................... E-1 Appendix F. Amphipod survival in quarterly bulk sediment samples ............................ F-1 Appendix G. Sea urchin fertilization in pore water samples ......................................... G-1 Appendix H. Sea urchin development in sediment-water interface test ........................ H-1 Appendix I. Benthic species abundance .......................................................................... I-1 ii LIST OF TABLES page Table 1. ERM, PEL, and Consensus values used to evaluate sediments ......................... 34 Table 2. Data Quality Objectives and Criteria for metal analyses ................................... 35 Table 3. Data Quality Objectives and Criteria for organic constituents .......................... 36 Table 4. Summary of toxicity test data quality objectives ............................................... 37 Table 5. Average concentrations and variability of metals and % fines in sediments ..... 38 Table 6. Concentration of organic contaminants, and the SQGQ1 in sediments ............ 39 Table 7. 95% prediction limits from the Baseline Pool ................................................... 40 Table 8. Toxicity of whole sediment, sediment-water interface, and porewater ............. 41 Table 9. Concentrations of unionized ammonia (mg/L) in sediment samples ................ 43 Table 10. Benthic community measures and indicator species ....................................... 47 Table 11. Results of weight of evidence determination of aquatic life impairment ........ 49 Table 12. Key to determining site-specific impairment ................................................... 50 iii LIST OF FIGURES page Figure 1. Collection sites for the quarterly sampling events ........................................... 51 Figure 2. Rainfall amounts and seasonal totals during the quarterly sampling events .... 52 Figure 3. Concentrations of cadmium in quarterly sediment samples ............................. 53 Figure 4. Concentrations of chromium in the quarterly sediment samples ..................... 54 Figure 5. Concentrations of copper in the quarterly sediment samples ........................... 55 Figure 6. Concentrations of lead in the quarterly sediment samples ............................... 56 Figure 7. Concentrations of nickel in the quarterly sediment samples ............................ 57 Figure 8. Concentrations of zinc in the quarterly sediment samples ............................... 58 Figure 9. Concentrations of priority pollutant PAHs in the quarterly samples ............... 59 Figure 10. Concentrations of total PCBs in the quarterly sediment samples ................... 60 Figure 11. Concentrations of 4,4’-DDT and 4,4’-DDE in the quarterly samples ............ 61 Figure 12. Concentrations of total chlordanes in the quarterly sediment samples .......... 62 Figure 13. Sediment Quality Guideline Quotient (SQGQ1) in quarterly samples .......... 63 Figure 14. Amphipod survival in quarterly bulk sediment samples ................................ 64 Figure 15. Sea urchin development in quarterly sediment-water interface samples ....... 65 Figure 16. Sea urchin fertilization in quarterly pore water samples ...............................