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The MWRA outfall monitoring program. What we measure and what we have observed so far.

The MWRA outfall monitoring program. What we measure and what we have observed so far. Part 1. What we are monitoring. Objectives:. test for compliance with the Permit test for exceedance of contingency plan thresholds test whether environmental changes are greater than expected. Effluent.

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The MWRA outfall monitoring program. What we measure and what we have observed so far.

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  1. The MWRA outfall monitoring program.What we measure and what we have observed so far.

  2. Part 1. What we are monitoring.Objectives: • test for compliance with the Permit • test for exceedance of contingency plan thresholds • test whether environmental changes are greater than expected

  3. Effluent • pathogen indicators • residual chlorine • total suspended solids • biochemical oxygen demand • toxicity testing • PCBs • flow • pH • nitrogen loading • numerous organic and inorganic contaminants

  4. Water column • nutrients • chlorophyll • dissolved oxygen • temperature, salinity • light, water clarity • solids • phytoplankton • nuisance and noxious algae • zooplankton • photosynthesis, respiration • remote sensing, moored instruments • marine mammal observations • bacterial indicators, viruses • diffuser mixing

  5. 21 nearfield sites (in a grid near outfall site) 28 farfield sites (distant from the outfall site) 17 nearfield, 6 farfield surveys each year

  6. 1998 Whale sightings during MWRA surveys

  7. 1999

  8. 2000

  9. Sediments • soft bottom community structure • rock cobble communities • sediment oxygen • toxic metal and organic chemicals • sediment bulk characteristics • chemistry, tracers • nutrient and oxygen flux

  10. Sample locations for soft-bottom communities

  11. Fish and Shellfish • metals and organic chemicals, including pesticides and PCBs in flounder and lobster • bioaccumulation of toxic chemicals in transplanted mussels • liver disease in flounder

  12. Mussels: collection and deployment locations

  13. Part 2. What we have seen since the outfall was relocated.MWRA response to exceedances.

  14. In summer, the effluent discharged at the Massachusetts Bay outfall is trapped beneath the thermocline

  15. Ammonium concentration (NH4+ uM) Boston nearfield Cape Ann October 1999 October 2000

  16. Ongoing Monitoring Data reported to MWRA Notify: DITP Regulatory agencies OMSAP Public (web and libraries) < 90 days Annual Monitoring Report Nov 15 Threshold Exceeded? 5 days YES NO • Adjust operations if needed • Review supporting data • Collect additional data if needed • Evaluate MWRA • contribution w OMSAP and • regulators • Plan/schedule to address • MWRA impacts • Report every 30 days • to regulators, public on • evaluations, action and • follow-up Adverse impact? Threshold Level YES Warning NO Caution Quarterly Wastewater Performance Reports Evaluations, actions and follow-up

  17. Contingency Plan threshold exceedances for 2000 • Chlorine too high in treatment plant on 12/15/00. • Control equipment installed. • pH too low in treatment plant on 12/7/00. • Artifact of sampling procedure. • High chlorophyll in autumn 2000. • A regional event. • Low DO saturation in bottom waters in October 2000. • Recognition of natural phenomena in revising the threshold.

  18. Chlorophyll threshold exceedance autumn 2000

  19. Areal Chlorophyll (mg per square meter) September 6 2000

  20. Satellite images of chlorophyll, averaged by month October September 1997 1998 1999 2000 2001 J. Yoder1, J.O’Reilly2, S.Schollaert1, T. Ducas2 1URI,GSO,2NOAA, NMFS

  21. Harmful algal blooms in Massachusetts Bay • Paralytic Shellfish Poisoning (PSP) Alexandrium • Noxious blooms (aesthetics) Phaeocystis • Amnesic Shellfish Poisoning (ASP) Pseudo-nitzschia

  22. Alexandrium (cells/L) Phaeocystis (million cells/L) Pseudo-nitzschia (million cells/L) 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001

  23. Dissolved oxygen in bottom waters of the nearfield DO concentration (mg/L) DO saturation (percent)

  24. 90-second animation of the rocky-bottom video surveyin July 2001 in the nearfield

  25. The region surrounding the Massachusetts Bay Outfall site consists of a series of ridges and valleys.

  26. Vertical Exaggeration 12X

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