Massachusetts Water Resources Authority MWRA’s Outfall Monitoring Overview 2015 Results October 12, 2016
MWRA Ambient Monitoring Moving discharge from Boston Harbor • ini2ally caused environmental concerns Comprehensive baseline monitoring • required by regulators (1992-2000) Ambient monitoring required by DITP • Permit (2000+) Major programma2c reviews in 2003 • and 2009-10 led to reduced Ambient Monitoring requirements Monitoring focuses on studies of • effluent, receiving water, sediment quality, and fish and shellfish 26
Outfall Monitoring Overview 2015 Highlights Effluent quality (Pla2num 9 award!) • Ousall Monitoring • – Water quality good year-round – Sediment animal communi2es were healthy – Tissue contaminants low Harbor/Bay icing, March 2015 27
2015 Was a Very Dry Year With Almost No Blending 60 500 Rainfall Average Primary-blended flows 450 Secondary flows 50 400 350 40 Rainfall (inches) Million gallons per day 300 30 250 200 20 150 100 10 50 0 0 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 Boston rainfall, 1990-2015 Average flow at DITP, 1999-2015 28
Total Solids Discharged (tons/day), 1990-2015 180 Sludge 160 Nut Island 140 Deer Island 120 Tons per day 100 80 60 40 20 0 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 29
Contaminants in DITP Effluent, 2015 250 Metals remained low in • 2015 Silver Chromium 200 Lead Organic contaminants Average pounds per day Nickel • Copper (not shown) are also 150 Zinc effec2vely removed by source control, secondary treatment 100 50 0 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 Metals in Effluent 30
Water Quality Monitoring 2015 Results • No evidence of adverse ousall impact • Dissolved oxygen in bokom waters stayed at healthy levels all year • No red 2de bloom in 2015 • Low abundances of a nuisance algae in May resulted in Con2ngency Plan threshold exceedance • Surface and bokom waters were colder than average in winter and early spring, which delayed plankton growth Collecting water samples in Massachusetts Bay 31
Boston Harbor Bacterial Water Quality Prior to Boston Harbor projects (1989-1991) Most Boston Harbor projects complete (post-2007) 32
Massachusetts Bay Bacterial Water Quality 33
Sediment Monitoring in Boston Harbor and Massachusetts Bay Collec2ng sediment profile images in Mass. Bay Collec2ng sediment samples off Deer Island 34
Sediments in Massachusetts Bay Remain Healthy 35
Harbor Sediment Communities Recover From Pollution Deer Island Flats Off Long Island 36
Fish and Shellfish Monitoring 37
Flounder Health in Boston Harbor • Diseased flounder were one cause of Boston Harbor being termed “Dir2est in the Na2on” • Liver tumors were last observed in 2004 • Prevalence of liver tumor precursors has decreased substan2ally in Boston Harbor • Tumor precursors are decreasing near ousall as well; 2015 levels were the lowest yet observed 38
Chlordane in Flounder Filet 39
Ambient Monitoring Confirms That Massachusetts Bay is Healthy 40
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