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16 STATE OF THE ESTUARY AQUATIC LIFE CONTEXT Pollutants in water and INDICATOR The “safe for aquatic life” water quality indicator measures mercury concentrations in the food web, the toxicity of Estuary waters in laboratory tests, and concentrations of chemical pollutants in water. Bench- marks for these measures have been established by the San Francisco Bay and Central Valley Regional Water Quality Control Boards. BAY DELTA 0.00 STATUS & TRENDS 0.07 0.17 a hundred pollutants are Over PA RT S P E R B I L L I O N I N S M A L L F I S H DELTA 180 25 0.57 2012 2011 2010 2009 2008 2009 2006 2003 2000 1997 1994 0 2012 2011 2011 2009 2010 2006 2009 2003 2008 2000 2007 240 50 2009 2011 2006 2007 2003 2002 2000 1997 1994 2012 2011 2010 2009 2008 2012 2011 2010 2009 2008 60 75 Poor 50 100% Fair Fair- Poor 40 60 DELTA DELTA Fair- Poor Poor no data PPB 30 BAY Good 20 BAY PPB 120 Good 10 0 21 Good Good Fair BAY P E R C E N T O F S A M P L E S T H AT W E R E N O N -T OX I C T O I N V E R T E B R AT E S 2013 2012 2011 2010 2009 WAT E R T OX I C I T Y MERCURY centrations in Estuary water are sometimes high enough to affect the development and survival of aquatic invertebrates. Mercury con- centrations in the Estuary food web have not changed perceptibly over the past 40 years, and are expected to decline very slowly in the next 30 years. Important improvements in Estuary water quality have occurred in the last four years. A major success story for the Bay continued to unfold, as declining trends in polybrominated diphenyl ethers (PBDEs) in wildlife BAY and sediment DELTA documented were 0.00 following an industry phase-out and 0.07 state ban. With increased attention 0.17 to impacts from invasives and trash, PPM 0.27 0.37 more rapid improvement can be 0.47 expected on this water quality front. D Poor Poor 2012 2011 2010 2009 2008 2009 2006 2003 2000 1997 1994 DETAILS GRADE C Fair Fair Fair- Poor 2012 2011 2010 2009 2008 2007 2011 2007 2002 quality goals, and are considered to pose very low risk to aquatic life in the Estuary. Overall, water quality is fair with regard to protection of aquatic life. Several pollutants are still prob- lems, however, including mercury, invasive species, pesticides, and trash. Pollutant con- 0.57 BAY Fish-eating birds like these terns are most at risk from mercu- ry in their food. B Photo: Verne Nelson routinely monitored and found at PPM 0.27 0.37 concentrations that meet water 0.47 A Good Good Good sediment pose a threat to the health and survival of species at all levels of the Estuary’s food web. In an effort to protect them, water quality laws and regulations require that the Estuary be clean enough to support abun- dant, diverse native communities of plants and animals. However, human activities contin- ue to add contaminants to the ecosystem via municipal and DELTA industrial discharges, agricul- BAY tural and urban runoff, and other pathways. 100% Species both at the bottom of the food chain, as 75 well as the fish and birds that eat them, can suffer from toxic or reproductive effects. 50 Birds that dive for fish, or forage in the mud 25 for food, face significant risks from mercury 0 exposure, for example. The region’s water quality monitoring programs perform diverse measurements to evaluate whether pollutants are causing adverse impacts on the health and survival of species that live in the Estuary. 2015