MWRAs Outfall Monitoring Overview 2015 Results October 12, 2016 - - PowerPoint PPT Presentation

Massachusetts Water Resources Authority

MWRA’s Outfall Monitoring Overview 2015 Results

October 12, 2016

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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

• Effluent quality (Pla2num 9 award!)
• Ousall Monitoring

– Water quality good year-round – Sediment animal communi2es

were healthy

– Tissue contaminants low

Outfall Monitoring Overview 2015 Highlights

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Harbor/Bay icing, March 2015

2015 Was a Very Dry Year With Almost No Blending

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Average flow at DITP, 1999-2015

10 20 30 40 50 60

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

Rainfall (inches)

Rainfall Average

50 100 150 200 250 300 350 400 450 500 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15

Million gallons per day

Primary-blended flows Secondary flows

Boston rainfall, 1990-2015

Total Solids Discharged (tons/day), 1990-2015

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20 40 60 80 100 120 140 160 180

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

Tons per day Sludge Nut Island Deer Island

• Metals remained low in

2015

• Organic contaminants

(not shown) are also effec2vely removed by source control, secondary treatment

Contaminants in DITP Effluent, 2015

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Metals in Effluent

50 100 150 200 250 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15

Average pounds per day

Silver Chromium Lead Nickel Copper Zinc

• 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

Water Quality Monitoring 2015 Results

31

Collecting water samples in Massachusetts Bay

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Boston Harbor Bacterial Water Quality

Prior to Boston Harbor projects (1989-1991) Most Boston Harbor projects complete (post-2007)

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Massachusetts Bay Bacterial Water Quality

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Sediment Monitoring in Boston Harbor and Massachusetts Bay

Collec2ng sediment profile images in Mass. Bay Collec2ng sediment samples off Deer Island

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Sediments in Massachusetts Bay Remain Healthy

Harbor Sediment Communities Recover From Pollution

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Deer Island Flats Off Long Island

Fish and Shellfish Monitoring

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Flounder Health in Boston Harbor

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• 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

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Chlordane in Flounder Filet

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Ambient Monitoring Confirms That Massachusetts Bay is Healthy