1. SPECIATION AND BIOAVAILABILITY OF COPPER IN SAN DIEGO BAY. Free Copper Ion Concentration as Main Vector to Study the Effect of Copper Leaching from Antifouling Paints Ignacio Rivera-Duarte 1, Gunther Rosen 1, D. Bart Chadwick 1, Lora Kear-Padilla 2, Alberto Zirino 3 1 SPAWAR Systems Center, San Diego, California, U.S.A. 2 Computer Science Corporation, San Diego, California, U.S.A. 3 Scripps Institution of Oceanography, La Jolla, California, U.S.A. Presented at: International Symposium on Prevention of Pollution from Ships and Shipyards, New Orleans LA November 5-7, 2003

2. BACKGROUND San Diego Bay, California  Copper is an ubiquitous contaminant in harbors.  Sources include:  antifouling paints,  industrial processes,  stormwater.  Point source discharges were terminated in San Diego Bay since 1964. Marinas Non-point Sources Shipyards Navy Bases Urban Streams Power Plants

3. TOTAL COPPER LOADING FOR SAN DIEGO BAY  Primary Sources:  antifouling coatings,  hull cleaning,  cooling water,  NPDES discharges,  non-point source runoff.  Antifouling paints are main steady source (67%).  Total loading:  dry season ~17800 kg y -1,  wet season 18900 kg y -1.  Source data:  Johnson et al., 1998.  PRC, 1997.  SCCWRP.  Navy.  RWQCB. Storm water 7 % Navy Hull Clean 2 % Civil Hull Leach 38 % Civil Hull Clean 14 % Other Vessel Leach 2 % Navy Other 16 % Point Source (NPDES) 9 % Direct Rainfall 0.1 % Navy Hull Leach 11 % Atmospheric Loading 0.2 % Base Flow 0.7 %

4. COPPER TOXICITY COMPLIANCE  Water Quality Criteria (WQC) are based on toxicity thresholds for either total or dissolved metal concentration in laboratory water.  WQC does not take into consideration the varying ability of natural waters to complex and detoxify metals. Polychaete worm Florida pompano Commonrangia Mummichog Green crab Copepod Sheep head Spot Top smelt Copepod Polychaete worm Mysid Polychaete worm Tidewatersilverside Copepod Mysid Atlanticsilverside Inlandsilverside Winter flounder Red abalone American lobster Copepod Black abalone Dungeness crab Soft-shell clam Copepod Eastern oyster Sea urchin Pacific oyster Coot clam Summer flounder Blue mussel 0 10 20 30 40 50 60 70 80 90 100 1101001,00010,000 Dissolved copper concentration (µg L -1 ) Cumulative probability (%) Acute toxicity data Cumulative probability fit Lower 95% confidence limit Upper 95% confidence limit 3.14.8 Proposed EPA dissolved copper acute WQC Proposed EPA dissolved copper chronic WQC

5. FREE ION ACTIVITY MODEL  The “free ion” model (Buffle et al., 1990) is a framework for evaluating toxicity based on chemical speciation.  Free ion activity is regulated by the total metal concentration and the system buffering capacity (complexation capacity or L).  The system buffering capacity may vary significantly either or both spatially or temporally. TOTAL COPPER CONCENTRATION AVAILABLE ( COMPLEXATION CAPACITY or L ) NOT AVAILABLE DISSOLVED COPPER Cu

6.  Full range of spatial and temporal conditions.  Configured with 25 cells along axis of bay ~ 1 km scale.  Two year assessment with six sampling events.  Integrate toxicological, physical, chemical and biological sampling efforts. SAMPLING STRATEGY Shelter Island Commercial Basin MOUTH HEAD 117.25 117.2 117.15 117.1 32.75 32.7 32.65 32.6

7. 32.7 32.72 32.74 SD26, August 2000, Salinity SALINITY DISTRIBUTIONS  Distributions of hydrographic parameters indicated two distinct regimes:  North Bay: mixing with ocean.  South Bay: evaporation. 32 32.5 33 33.5 34 34.5 35 35.5

8. COPPER DISTRIBUTIONS  Conservative annual concentration distributions.  Total and dissolved copper are at steady-state, indicating that sources are remaining constant.  Increases from mouth to head of the bay.  Distributions are controlled by mixing and show a strong correlation with residence time. 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 123456789101112131415161718192021222324252627 Box (station) number Dissolved Cu (µg L ) 0 5 10 15 20 25 30 35 40 45 50 55 Dissolved Cu (nM) August 30, 2000 January 30, 2001 May 11, 2001 September 19, 2001 February 27, 2002 May 14, 2002 EPA chronic WQC 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 123456789101112131415161718192021222324252627 Total Cu (µg L ) 0 5 10 15 20 25 30 35 40 45 50 55 60 65 Total Cu (nM) August 30, 2000 January 30, 2001 May 11, 2001 September 19, 2001 February 27, 2002 May 14, 2002

9. HEALTHY & UNHEALTHY COPPER CONDITIONS  Healthy steady-state hypersaline conditions from summer to fall.  Exceeds chronic WQC (3.1 µg L -1 ) in winter, associated with rainfall events.  Transition conditions in spring.

10. COPPER TOXICITY AND COMPLEXATION  Integrated temporal distributions, average ± standard deviation at each station.  Mytilus galloprovinciallis (mussel) is more sensitive to copper effects than Strongylocentrotus purpuratus (purple sea urchin) or Dendraster excentricus (sand dollar).  Decrease in sensitivity to copper to the head of the Bay.  Similar results for CuCC measured by CuISE and DPASV.  CuISE indicate an increase in CuCC to the head of the bay. 0 5 10 15 20 123456789101112131415161718192021222324252627 Box (station) number CuCC ([Cu] µg L -1 ) 0 50 100 150 200 250 300 350 CuCC ([Cu] nM) CuISE DPASV 0 5 10 15 20 25 30 35 40 EC 50 ([Cu] µg L -1 ) 0 100 200 300 400 500 600 EC 50 ([Cu] nM) D. excentricus M. galloprovincialis S. purpuratus

11. REGULATION OF COPPER TOXICITY  Copper bioavailability / toxicity is regulated by complexation capacity.  Bioavailability / toxicity is species dependent.  Mussel and CuISE have similar response.  Regulation is done by keeping free copper ion below a toxic threshold level. 0 5 10 15 20 25 30 35 05101520 CuCC ([Cu] µg L -1 ) EC 50 ([Cu] µg L -1 ) 0 100 200 300 400 500 0100200300 Cu-CC ([Cu] nM) EC 50 ([Cu] nM) M. galloprovincialis D. excentricus S. purpuratus One to one ratio

12. COPPER TOXICITY TO LARVAE

13. COPPER TITRATION AND Cu-ISE

14. COPPER TOXICITY AND pCu Tox Chemical method Biological method pCu Tox

15. TOXIC TRESHOLD OF FREE COPPER ION  Difference in sensitivity among species: mussel > urchin = sand dollar.  Toxic threshold concentration of free copper ion relatively constant spatially and temporally.  Mussel larvae EC 50 threshold response at pCu Tox  11. 8.5 9.0 9.5 10.0 10.5 11.0 11.5 12.0 123456789101112131415161718192021222324252627 Box (station) number pCu Tox 8.5 9.0 9.5 10.0 10.5 11.0 11.5 12.0 [Cu(II) aq ] (M) (10 -y ) D. excentricus M. galloprovincialis S. purpuratus NON-TOXIC TOXIC

16. FREE COPPER ION DISTRIBUTIONS  Seasonal variation, with highest concentrations observed during winter (January 2001).  Associated to seasonal changes in availability of binding materials (ligands, suspended sediments).  Toxic conditions to Mytilus larvae (pCu  11) only occurred during January 2001.  Mean concentration for all of other the surveys was 12.8 ± 0.26 pCu. 0 10 20 30 40 50 60 70 80 11.011.211.411.611.812.012.212.412.612.813.013.213.413.613.814.0 Free Copper Ion (pCu) % Occurrence 30-Aug-00 30-Jan-01 11-May-01 19-Sep-01 27-Feb-02 14-May-02 3456789101112131415161718192021222324252627 Box (station) number Cu(II) aq (pM) 30-Aug-00 30-Jan-01 11-May-01 19-Sep-01 27-Feb-02 14-May-02

17. CONCLUSIONS  Copper bioavailability / toxicity in San Diego bay follows free ion activity model.  Toxic effects (EC 50 ) for mussel larval development observed at  10 -11 M (  pCu 11) free copper ion.  Toxic threshold concentration of free copper ion is independent of spatial and temporal effects.  Free copper ion concentration is the main factor to study the toxic effects of copper in the bay. Including copper leached from antifouling paints.  Need to study chemical speciation of copper released from antifouling paints in order to determine its environmental effects.

18. ACKNOWLEDGEMENTS  Office of Naval Research 6.2 program.  Strategic Environmental Research and Development Program (SERDP).