A Mass Budget of Polybrominated Diphenyl Ethers in San Francisco Bay, CA John J. Oram, Lester J. McKee, Christine E. Werme, Mike S. Connor, and Daniel R. Oros

Introduction Flame retardants in plastics and textiles Ubiquitous environmental pollutants Only recently included in environmental assessments Appear to be exponentially increasing throughout the world Transport pathways not fully understood Thought to be similar to PCBS, OC Pesticides. Recent bans on Penta- and Octa- mixtures BDE 47 and 209 chosen for this paper due to overlap in SF Bay regional monitoring. This paper is first of its kind for PBDEs in urban rivers PBDE mass budget for urbanized estuary

SF Bay Area is Global Hot Spot PBDE-47 in Human Tissues 35 U.S. (San Francisco, adipose) 30 Sweden (adipose) Germany (whole blood) 25 Canada (milk) Finland (milk) 20 PBDE-47, ng/g lipids Japan (milk) 15 Sweden (milk) 10 5 1981 1983 1985 1987 1990 1992 1994 1996 1998 2000 Source: Kim Hooper et al. Cal EPA

Pieces of the Mass Budget Bay water and sediment Inventory Unfiltered water at Mallard Island, Coyote Creek, Guadalupe River, and Zone 4 Line A Tributary loads Effluent and sludge from 3 tertiary plants Wastewater loads

Bay Inventory

Guadalupe River WY 2005

Mallard Island BDE-47 (ng/L) SSC (mg/L)

Comparison of Tributaries (ng/L) BDE 047 : BDE 209 Guadalupe = 0.2 Coyote = 0.2 Mallard = 1.2

Why more BDE 047 @ Mallard? Two hypothesis are emerging: Atmospheric depostion to Central Valley (EXTERNAL) 47 more volatile than 209 = greater potential for long-range atmos transport & depostion Dissolved loads greater (INTERNAL) 47 more soluble than 209; Combined with long residence time of Delta (weeks to months) may make dissolved loads more important BDE 047 : BDE 209 Guadalupe = 0.2 Coyote = 0.2 Mallard = 1.2

* * * * Normalized to SSC

Summary of Loads (Kg)

Mass Budget Model Hindcast – Estimation/Verification of Loads

Mass Budget Model Forecast – Plausible Future Trajectories

Mass Budget Model Loss Pathways Under Zero Loads Scenario Outflow and Degradation Are Most Important Loss Pathways

Conclusions SF Bay is global hot spot Loads dominated by local tributaries (stormwater runoff) and wastewater Model provides useful framework for integrating / synthesizing information SF Bay at critical juncture in terms of recovery