2004 outfall benthic monitoring report Massachusetts Water Resources Authority Environmental Quality Department Report ENQUAD 2005-15 Citation: Maciolek, NJ, RJ Diaz, DT Dahlen, B Hecker, IP Williams, and C Hunt. 2005. 2004 Outfall Benthic Monitoring Report. Boston: Massachusetts Water Resources Authority. Report ENQUAD 2005-15. 134 pages plus appendices. 2004 Outfall Benthic Monitoring Report Submitted to Massachusetts Water Resources Authority Environmental Quality Department 100 First Avenue Charleston Navy Yard Boston, MA 02129 (617) 242-6000 prepared by Nancy J. Maciolek1 Robert J. Diaz2 Deirdre Dahlen3 Barbara Hecker4 Isabelle P. Williams1 Carlton Hunt3 1ENSR Marine & Coastal Center 89 Water Street Woods Hole, MA 02543 2Diaz and Daughters 6198 Driftwood Lane Ware Neck, VA 23178 3Battelle 397 Washington Street Duxbury, MA 02332 4Hecker Environmental 26 Mullen Way Falmouth, MA 02540 September 30, 2005 Report No. 2005-15 2004 Outfall Benthic Monitoring Report September 2005 TABLE OF CONTENTS EXECUTIVE SUMMARY ...................................................................................................................................... VI 1. INTRODUCTION .......................................................................................................................................... 1-1 1.1 Background.............................................................................................................................................. 1-1 1.2 Design of the Benthic Monitoring Program............................................................................................. 1-3 1.3 Revision of the Benthic Monitoring Program .......................................................................................... 1-4 2. FIELD OPERATIONS................................................................................................................................... 2-1 2.1 Sampling Design...................................................................................................................................... 2-1 2.1.1 Soft Bottom.......................................................................................................................................... 2-1 2.1.2 Hard Bottom........................................................................................................................................ 2-1 2.2 Field Program Results.............................................................................................................................. 2-7 2.2.1 Vessel and Navigation......................................................................................................................... 2-7 2.2.2 Grab Sampling .................................................................................................................................... 2-7 2.2.3 Sediment Profile Imagery (SPI) ......................................................................................................... 2-8 2.2.4 Hard-Bottom Sampling....................................................................................................................... 2-9 3. 2004 CHEMISTRY......................................................................................................................................... 3-1 3.1 Status of the Bay ...................................................................................................................................... 3-1 3.2 Methods.................................................................................................................................................... 3-2 3.2.1 Grain Size, Total Organic Carbon, and Clostridium perfringens..................................................... 3-2 3.2.2 Organic Contaminants and Metals .................................................................................................... 3-2 3.2.3 Data Terms and Analyses ................................................................................................................... 3-3 3.3 Results and Discussion............................................................................................................................. 3-4 3.3.1 Sediment Properties 1992–2004 ......................................................................................................... 3-4 3.3.2 Organic Contaminants and Metals 1992–2004 ................................................................................. 3-7 3.3.3 Sewage Tracer Clostridium perfringens 1992–2004........................................................................ 3-10 3.3.4 Chemistry Interrelationships............................................................................................................ 3-16 3.4 Monitoring Questions and Conclusions ................................................................................................. 3-18 3.4.1 Monitoring Questions ....................................................................................................................... 3-18 3.4.2 Conclusions....................................................................................................................................... 3-19 4. 2004 SEDIMENT PROFILE IMAGING...................................................................................................... 4-1 4.1 Status of the Bay ...................................................................................................................................... 4-1 4.2 Methods.................................................................................................................................................... 4-4 4.2.1 Quick-Look Analysis........................................................................................................................... 4-4 4.2.2 Image Analysis.................................................................................................................................... 4-4 4.3 Results and Discussion............................................................................................................................. 4-4 4.3.1 Quick-Look versus Detailed Analysis................................................................................................. 4-4 4.3.2 Physical Processes and Sediments ..................................................................................................... 4-6 4.3.3 Apparent Color RPD Depth................................................................................................................ 4-6 4.3.4 Biogenic Activity ............................................................................................................................... 4-11 4.3.5 Successional Stage and Organism Sediment Index......................................................................... 4-11 4.3.6 Summary of 2004 SPI Data.............................................................................................................. 4-12 4.4 Conclusions............................................................................................................................................ 4-13 5. 2004 SOFT-BOTTOM BENTHIC INFAUNAL COMMUNITIES............................................................ 5-1 5.1 Status of the Bay ...................................................................................................................................... 5-1 5.1.1 Monitoring Program........................................................................................................................... 5-1 5.1.2 Benthic Communities ......................................................................................................................... 5-1 5.2 Methods.................................................................................................................................................... 5-2 5.2.1 Laboratory Analyses ........................................................................................................................... 5-2 5.2.2 Data Analyses...................................................................................................................................... 5-2 5.3 Results and Discussion............................................................................................................................. 5-4 i 2004 Outfall Benthic Monitoring Report September 2005 5.3.1 Species Composition of 2004 Samples ............................................................................................... 5-4 5.3.2 Benthic Community Analysis for 2004: Nearfield............................................................................. 5-4 5.3.3 Benthic Community Analysis for 2004: Farfield............................................................................. 5-12 5.3.4 Multivariate Analysis of 2004 Samples ............................................................................................ 5-18 5.3.5 Multivariate Analysis of 1994–2004 Nearfield Samples.................................................................. 5-26 5.3.6 Threshold Assessment....................................................................................................................... 5-33 5.4 Monitoring Questions ............................................................................................................................ 5-34 6. 2004 HARD-BOTTOM BENTHIC HABITATS AND FAUNA ................................................................. 6-1 6.1 Status of the Bay .....................................................................................................................................