Polybrominated diphenyl ethers (PBDEs) are organobromine compounds that are used as flame retardants in a wide variety of products, including building materials, electronics, furnishings, motor vehicles, airplanes, plastics, polyurethane foams, and textiles. Although PBDEs are not acutely toxic, they can bioaccumulate in higher trophic level organisms. Because of environmental and human health concerns, a number of PBDE formulations have been banned or voluntarily phased out (Sutton et al. 2015). PBDEs tend to occur in mixtures, but PBDE 209 is the dominant congener in sediments because it is the primary component of the commercial mixture DecaBDE. For the purposes of this program, PBDEs were summed based on 13 congeners that were analyzed during most years (Appendix 2), but PBDE 209 was not measured until 2011, and was not measured in 2017 due to a change in analytical laboratory. 

Trends were calculated for the Sum of PBDEs from 2010 to 2022 because there are significantly lower sample sizes for 2008 and 2009 for current urban sites.  Trends were calculated at both the statewide scale and at individual sites. The sum calculation was constituted of the following congeners: 17, 28, 47, 66, 85, 99, 100, 138, 153, 154, 183, 190 and 209.

There was no significant statewide trend for Sum PBDEs, but a number of individual sites showed significant increasing and decreasing trends. Significant increasing and decreasing trends were identified at twelve and four individual sites, respectively.
 
Reference

• Sutton R, Sedlak MD, Yee D, Davis JA, Crane D, Grace R, Arsem N. 2015. Declines in Polybrominated Diphenyl Ether Contamination of San Francisco Bay following Production Phase-Outs and Bans. Environmental Science & Technology 49(2):777-784.