Bacteria Source Identification in Sediments: Mystic River, North Coastal, and Neponset River

1. MDEP–MDEM Program Review 2nd Quarter FY03 • Bacteria source identification • Mystic River sediments • North coastal sediments • Neponset River sediments, with PCB source identification

2. Quantifying Human Versus non-Human Sources of Bacteria • OBJECTIVES • Quantify bacterial sources • Assess bacteria timing • Demonstrate the feasibility of using rep-PCR • PROGRESS • Challenge samples • Source-typing results for seven dry-weather samples • PROGRESS Next Quarter • Laboratory and data analysis

3. Mystic River Sediment Study • OBJECTIVES • Map water depths and sediment thickness • Measure sediment quality • PROGRESS • Bathymetry and sediment thickness maps • Tufts contract • PROGRESS Next Quarter • Collect sediment cores • Laboratory and chemical analysis

4. North Coastal Sediment • OBJECTIVES • Sediment quality in Salem Sound and Saugus River • PROGRESS Next Quarter • Write the QAPP • Collect about 20 sediment-grab samples • Chemical analysis • elements (XRAL) • organics (ELISA) • Write draft report

5. Sediment Quality and Quantity in the lower Neponset River • PROGRESS THIS QUARTER

6. Cooperators • Massachusetts Executive Office of Environmental Affairs • U.S. Environmental Protection Agency • U.S. Geological Survey

7. Objectives • Measure water depths and sediment thickness • Assess sediment quality in the Neponset River • Determine specific sources of polychlorinated biphenyls

9. Bathymetry • Water depth data were collected using an echo sounder and sub-meter accurate GPS (over 5,000 soundings) • Walter Baker Impoundment about 3.1 MG • T&H Impoundment about 10.2 MG

10. Walter Baker Impoundment Bathymetry

11. Sediment Volume • Sediment thickness data were collected using a sub-bottom profiler and manual probing with a steel rod • Walter Baker Impoundmentabout 210,000 ft3 • T&H Impoundmentabout 790,000 ft3 • Braided Channel about 620,000 ft3 • NOTE: about 6,000 10 yrd. dump truck loads

12. Braided Channel Sediment Thickness

13. Sediment Sampling Design • Twenty surfical sediment samples were collected randomly throughout the Neponset River • Thirty-one sediment cores were collected in three areas of the river • These samples were analyzed for inorganic elements, organiccompounds and grain-size distribution

15. Core Processing • Cores were photographed and logged prior to homogenization • Cores were composited in Teflon bags. Each bag was rinsed with methanol, 5-percent nitric acid, and DIW, in that order

17. Sediment Chemistry • Sediment-grab and sediment cores are enriched with inorganic elements compared tobackground concentrations ofinorganic elements measured in sediment samples collected from parts of New England, as part of the National Uranium Resource Evaluation (NURE) program, specifically the Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program

22. Other Urban Rivers • Concentrations of elements and organic compounds measured in sediment-grab samples collected from the Neponset River were compared to concentrations of these constituents measured in surficial sediment collected from other urban rivers. • Generally, contaminant concentrations are equal to or less than those measured in other urban rivers, with a few exceptions.

25. Sediment Toxicity The potential toxicity of sediment-grab samples (based on measured concentrations of inorganic elements and organic compounds) was estimated by means of consensus bases sediment toxicity guidelines MPP = [(SMi /n) + SPCB/pec + SPAH/pec]/3 Where: Mi is the concentraiton of metal I, n is the number of metals tested, and pec is the probable effect concentrations

27. Sediment Disposal • Sediment-core chemistry data was compared with contaminant levels for soil reuse at landfills • Of the constituents tested, only PCBs exceeded reuse levels • Reactive sulfide data were all less than detection • Waiting on TCLP data

29. Data Representativeness • Data representativeness was tested by the following equation • Ni = (tc’ x Sx,I /y x Xi)2 + 1 • Where;Ni is the number of data (or samples) for property or constituent i; • tc is the value of student’s t for desired 2-sided confidence interval c with n-1 degrees of freedom where n is the number of‘ samples; • sx, i is the measured variance for property or constituent i; • xi is the average concentration measured of property or constituent i; and • y is the acceptable error, in percentage of the mean

31. PISCES Diffusion Samplers • PISCES samplers were deployed and retrieved two weeks later at strategic points along the Neponset River. • Hexane was decanted and sent to AXYS analytical for congener analysis.

33. PCB Fingerprinting • RMSD was determined as the square root of the sum of squared differences between normalized congener concentrations in the two samples divided by the number of congener pairs compared. • RMDS = [S (A-B)2/ n]0.5 • Where: • A, B are normalized congener concentrations, in nanograms per sample • n is the number of congener pairs

37. Toxic Equivalency Factors • PCB concentrations in the water was calculated from PISCES data by the formulaCw = Ms/(St)Where Cw is the concentration of the chemical in water, Ms is the mass of the chemical, t is the exposure time, and S is the sampling rate • Total toxic equivalency was calculated by the formula • TEQ = SCn * TEF • Where Cn is the concentration of the individual congener and TEF is the toxic equivalency factor

39. What’s Next? • Need to collect one more sediment-grab sample downstream of the Walter Baker Dam • Waiting on grain-size data for the sediment cores • Waiting on PCB congener data for selected sediment-grab and cores (10) • Waiting on TCLP results

40. Summary of Data Collected • Bathymetry of the Walter Baker and T&H impoundments • Estimates of sediment volume within the Walter Baker and T&H impoundments and the Braided Channel area • 20 sediment-grabs analyzed for elements, PCBs, pesticides, and grain-size distribution –5 of these samples were analyzed for PAHs

41. Summary of Data Collected • 34 sediment cores analyzed for elements, PCBs, pesticides, EPH, and grain-size distribution –5 of these samples were analyzed for TCLP and reactive sulfides • PCB congener data at 12 locations • PCB congener data on 10 sediment samples • Whew!