Report Date: September 15, 2009 Technical Report #

Transcription

1 Bacterial Assessment: Arlington Manholes, Alewife Brook & Spy Pond March 25, 2009 Report Date: September 15, 2009 Technical Report # Summary: This report documents the results of a monitoring event that took place on March 25, Dry weather flows in seven stormwater manholes in the Town of Arlington were tested for fecal indicator bacteria (E. coli) to check for possible sewage contamination. Three manholes exhibited elevated bacteria concentrations, exceeding the Massachusetts Department of Environmental Protection (MassDEP) State Water Quality Standards for secondary contact / boating (1260 MPN/100 ml). Three stormwater outfall pipes to Alewife Brook and one to Spy Pond were also tested for bacteria. One Alewife Brook outfall and the Spy Pond outfall failed to meet water quality standards for primary contact / swimming. MyRWA recommends further IDDE investigations be undertaken to pinpoint the source of sewage contamination to the stormdrain system in Arlington. September 15, 2009 MYSTIC RIVER WATERSHED ASSOCIATION Technical Report #

2 2 CITATION This report was prepared by: Mystic River Watershed Association 20 Academy St. Suite 203 Arlington, MA Principal Investigators: Patrick Herron, Mary Beth Stevenson, Roger Frymire Water Quality Monitor: Roger Frymire Lab Analysts: EPA Region 1 Laboratory, Chelmsford MA This report describes hotspot monitoring data collected on a monthly basis by MyRWA under its MassDEP-approved Quality Assurance Project Plan with funding support from the Caswell Foundation, the United States Environmental Protection Agency, and the support of individual members and supporters. This report should be cited in the literature in the following manner: Bacterial Assessment: Arlington Manholes, Alewife Brook & Spy Pond, March 25, 2009 Technical Report Mystic River Watershed Association, Arlington, MA.

3 3 Table of Contents 1. Cover Sheet 2. Citation information 3. Table of Contents 4. Executive Summary a. Conclusions and Action Items 5. Base Report a. Introduction b. Methods c. Results 6. Quality Assurance, Quality Control, and Data Validation 7. Tables and Figures Results Maps Site Information

4 4 Executive Summary Bacterial Monitoring Results: March 25, 2009 MyRWA conducted a dry weather monitoring event in the Town of Arlington on March 25, The main goal of this monitoring event was to pinpoint the source of elevated bacteria concentrations that have been documented on multiple occasions at a major stormwater outfall (SPPRT2) that drains to Spy Pond (see maps on pp of this report). In addition, MyRWA collected samples from three stormwater outfall pipes that drain to Alewife Brook in order to monitor on-going problems with periodic bacterial contamination. The results of these monitoring efforts are described below, and a summary of the results can be found in Table 1. In cooperation with the Town of Arlington, MyRWA collected grab samples of dry weather flows from seven junction manholes located upstream of the Spy Pond stormwater outfall SPPRT2. Before and after collecting samples from the manholes, MyRWA tested water quality at the Spy Pond outfall to document water quality conditions. Both times, the outfall had bacteria levels that failed to meet MassDEP water quality standards for primary contact (SPPRT2, 737 MPN/100 ml at 6:53 am and 430 MPN/100 ml 9:35 am). Of the seven manholes that were sampled, three exhibited levels of E. coli bacteria that may have contributed to the contaminated flow observed at Spy Pond. The most extreme case of bacterial contamination was documented at manhole 67030, which is located at Arlmont Street west of Spring Street, about ½ mile upstream from the Spy Pond outfall. This manhole had dry weather flows coming in from the north and west. No bacterial contamination was documented in the west flow (67030W, nondetect for E. coli). The north flow had a bacteria concentration of 22,540 MPN/100 ml (67030N). This is a concerning level of contamination, and efforts should be taken to remove the source of bacteria to this manhole. Illicit discharge detection and elimination efforts (IDDE) such as dye testing or televised inspections should be undertaken in this drainage. The other two manholes to exceed the water quality standard for secondary contact were and Manhole is located at Hillsdale Road near Pleasant View Road (about ¼ mile upstream from the Spy Pond outfall) and had a bacterial concentration of 2,908 MPN/100 ml. Manhole , which had a bacteria concentration of 1,462, is located at Venner Road, and is only about 0.14 mile from the Spy Pond outfall. However, the sample collected from the Venner Road manhole was taken from a pool of water that appeared to have possibly been stagnant. In general, stagnant water conditions can be favorable to bacterial reproduction and may not be evidence of upstream sewage contamination. Additional bacterial testing in areas tributary to these two manholes, with the addition of ammonia and surfactants analyses, would provide further information about the source of bacteria. One of the three stormwater outfall pipes draining to Alewife Brook that MyRWA tested had moderately elevated bacteria levels (ARL026, 305 MPN/100 ml). A monitoring event in cooperation with the Town of Arlington to monitor bacterial levels at manholes upstream of ARL026 may help to pinpoint the source of bacteria at this outfall pipe. Conclusions & Action Items: 1. Manholes in the Spy Pond drainage: MyRWA recommends that further IDDE projects, such as dye testing or televised inspections, be undertaken in the drainages upstream from manholes 67030N, , and Alewife Brook outfall pipes: Further testing for sewage contamination in the drainage upstream from ARL026 to pinpoint the source of bacterial contamination is recommended.

5 5 Introduction Background. The Mystic Monitoring Network (MMN) was created in 2000 by the Mystic River Watershed Association (MyRWA) to collect valuable water quality data along the Mystic River and its tributaries. The MMN is a volunteer-based project that is made up of trained citizen volunteers, student interns, and scientific advisors throughout the region. The goals of the MMN are to establish a high quality baseline of data for the Mystic River Watershed, identify and address water pollution problems, raise public, municipal and state agency awareness of water quality in the Mystic, and create a network of informed and active citizen advocates. MMN s Hot Spot monitoring program at MyRWA allows the organization to test water quality in locations not regularly sampled in our baseline program or that are suspected of having problems with bacteria loading. Methods Water quality samples are always collected by trained MyRWA staff and volunteers following the protocol written in MyRWA s Quality Assurance Project Plan (QAPP). For centerline locations, bacteria samples are collected directly from the river and for end-of-pipe samples, water is collected directly from the outfall. In fresh water, samples are analyzed for the bacteria E. coli and in saltwater, samples are analyzed for the presence of Enterococcus. The bacteria samples are collected in sterile containers containing a sodium thiosulfate tablet and kept on ice until delivery to either the EPA lab in Chelmsford, or MyRWA s lab at Tufts University. Samples are analyzed using the Colilert method for enumerating colony forming units (cfu) of bacteria. Physical habitat parameters are measured according to the QAPP. A YSI meter is used to collect measurements for water temperature, dissolved oxygen, specific conductivity, and salinity. The coordinates of each sample location are recorded with a Garmin 76Cx GPS unit. Air temperature is recorded with an alcohol thermometer at the beginning and end of the sampling period. Data on precipitation during the past 48 hours are obtained from the USGS website (real-time data for stream gage located at Muddy River in Brookline: Results Below, tables and graphs summarize the results of bacteria sampling in each community. ND = bacteria not detected in sample. Each water body we tested is a Class B water body, and any bacteria level above 235 cfu/100 ml E. coli or 61 cfu/100 ml Enterococcus is a violation of the state water quality standard for bacteria. For reference purposes, we also compare our results to the bacteria water quality standard for boating established for a Class C water body (1260 cfu/100 ml E. coli or 350 cfu/100 ml Enterococcus).

6 6 Quality Assurance Quality control procedures have been documented for each parameter tested by MyRWA, and can be reviewed in Table B5-1 of the QAPP (approved December 2006). Quality control of data is ensured in several ways. YSI meters are subjected to pre- and post-calibration for each sampling event. Thermometers are calibrated on an annual basis. GIS coordinates are marked at an accuracy of 20. As discussed in the QAPP, field duplicates are not collected due to the heterogeneous nature of bacteria in an aquatic medium. EPA Region 1 Laboratory has submitted a copy of their quality assurance plan and standard operating procedures. They do not submit results of their quality control measures, such as relative percent difference, but QC protocol are followed according to their standard operating procedures (available on request). During this sample event, no violations of QC occurred. All samples were delivered to the EPA lab within the designated holding time, and the EPA lab did not report any violations of their standards. Data received from the EPA lab and collected from the field were entered into MyRWA s Excel database by the Project Manager and were checked for error by another staff person. No changes to the data entry were made. Following the QAPP, these data, as reported here, are sent to the Department of Public Works and the Board of Health of the relevant municipalities. After 30 days, the data will be sent to MassDEP, the EPA, conservation commissions of the relevant communities, and any other stakeholders that have expressed interest in receiving water quality data from MyRWA. A full list of these recipients is available upon request.

7 7 Table 1. Results of MMN bacteria sampling on 3/25/2009. Please refer to the maps and Appendix B for precise locations of sample sites. E. coli mpn/100 ml H2O Temp. C Sp. Cond. μs/cm Sample # Site ID DO mg/l Salinity Time (AM) Type Comments 1740 SPPRT :53 outfall :20 manhole large pool, possibly stagnant :30 manhole :06 manhole :16 manhole N :32 manhole W ND 8:38 manhole W ND 8:43 manhole 1748 SPPRT :35 outfall 1749 ARL :53 outfall 1750 ARL :00 outfall 1751 ARL :17 outfall

8 8 Maps In the maps below, blue labels indicate satisfactory water quality; yellow labels indicate failure of primary contact / swimming standards for a Class B water body (235 cfu / 100 ml); red labels indicate failure of secondary contact / boating standards for a Class C water body (1260 cfu / 100 ml). Map 1. Overview of sites sampled along in the Town of Arlington. 22,540 MPN E. coli / 100 ml 2908 MPN E. coli / 100 ml 1462 MPN E. coli / 100 ml

9 9 Maps 2-4. Manholes tested in Arlington. Hillsdale Road Arlmont Street

10 10 Maps 5-6. Outfall pipes tested at Alewife Brook.

11 Table 2. Site Information for samples collected on March 25, Sample Site Town Water Body Latitude Longitude Directions 1740 SPPRT2 Arlington Spy Pond Large stormwater outfall at southeast corner of Spy Pond Arlington manhole Venner Road manhole Arlington manhole Manhole on Hillsdale Road near Pleasant View Road Arlington manhole Manhole on Spring Street east of Morton Road Arlington manhole Manhole at north end of Morton Road N Arlington manhole Manhole on Arlmont Street west of Spring Street (north outflow) W Arlington manhole Manhole on Arlmont Street west of Spring Street (west outflow) W Arlington manhole Manhole on Spring Stree east of High Haith Road 1748 SPPRT2 Arlington Spy Pond Large stormwater outfall at southeast corner of Spy Pond 1749 ARL014 Arlington Alewife Brook First Arlington stormwater outfall upstream of Henderson St. bridge 1750 ARL013 Arlington Alewife Brook Second Arlington stormwater outfall upstream of Henderson St. bridge 1751 ARL026 Arlington Alewife Brook Arlington stormwater outfall at end of alley at Sunnyside Ave and Michael St. September 15, 2009 MYSTIC RIVER WATERSHED ASSOCIATION Technical Report #