Massachusetts 2012 Beachwater Quality Summary
Reported Sources of Beachwater Contamination
(number of closing/advisory days)
- 863 (100%) unknown contamination sources
Massachusetts has more than 500 public and semipublic marine beaches along 204 miles of sandy shore that line Atlantic waters. The monitoring program is a collaborative effort between local boards of health and the Massachusetts Department of Public Health (MDPH) and is administered by MDPH.
What Are the Water Quality Challenges and Improvements in Massachusetts?
No-discharge zones, designated by the U.S. EPA, prohibit boats from discharging both treated and untreated sewage, which can contaminate beachwater. Within no-discharge zone boundaries, boat operators are required to retain their sewage onboard for disposal at sea (beyond 3 miles from shore) or onshore at a pump-out facility.
In June 2012, the coastal waters of Mount Hope Bay (near the communities of Dighton, Berkley, Freetown, Somerset, Swansea, and Fall River) were designated a no-discharge zone, along with the state waters south of Cape Cod and surrounding Nantucket and Martha’s Vineyard (off the coast of Chilmark, West Tisbury, Tisbury, Oak Bluffs, Edgartown, Gosnold, Falmouth, Mashpee, Barnstable, Yarmouth, Dennis, Harwich, Chatham, and Nantucket). With the addition of these waters, more than 95% of Massachusetts’s coastal waters are now no-discharge zones.
Reducing Combined Sewer Overflows
Many urban areas along the coast of Massachusetts are served by combined sewer systems that treat both stormwater runoff and sewage before discharging it to surface waters. These systems can be overwhelmed by the volume of stormwater and sewage they receive during heavy storms, resulting in discharges of raw or partially treated sewage. The Massachusetts Water Resources Authority North Dorchester Bay CSO Storage Tunnel, a 17-foot-diameter combined-sewer overflow tunnel in South Boston, began operating on June 1, 2011. In addition to holding combined sewer overflows for later treatment, this tunnel stores stormwater flows during all but the largest rainstorms and pumps both stormwater and combined sewer overflow for treatment as capacity allows, thus preventing a large source of bacteria from reaching the beaches of South Boston.
What Does Beachwater Monitoring Show?
In 2012, Massachusetts reported 644 coastal beaches, of which 18 (3%) were assigned a monitoring frequency of daily, 470 (73%) once a week, 21 (3%) every other week, 91 (14%) once a month, and 1 (<1%) less than once a month; 43 (7%) were not assigned a monitoring frequency. In 2012, 4% of all reported beach monitoring samples exceeded the state’s daily maximum bacterial standard of 104 colonies/100 ml. The beaches with the highest percent exceedance rates of the daily maximum standard in 2012 were Cockle Cove Creek–Parking Lot (69%) and Cockle Cove Creek–Ridgevale (54%) in Barnstable County, Pierce in Bristol County (42%), Donovan’s in Suffolk County (36%); Pond at Lucy Vincent Beach in Dukes County (33%), and Smith Beach in Norfolk County (31%). Nantucket County had the highest exceedance rate of the daily maximum standard in 2012 (10%), followed by Norfolk (9%), Essex (6%), Suffolk (5%), Dukes (4%), Bristol (4%), Plymouth (3%), and Barnstable (3%). NRDC considers all reported samples individually (without averaging) when calculating the percent exceedance rates in this analysis. This includes duplicate samples and samples taken outside the official beach season, if any.
Note that some beaches have a sampling variance. Under Massachusetts regulations, a variance allows for less-frequent sampling at beaches that have no potential sources of contamination and that have gone two years without an exceedance. The exceedance rate may be higher in counties with beaches under a variance, in part because the cleanest beaches in the county are not sampled as frequently as other beaches.
Massachusetts Percent of Samples Exceeding the State's Daily Maximum Bacterial Standard for 546 Beaches Reported 2008-2012*
* Please note that only samples from a common set of beaches monitored each year from 2008-2012 are included in the bar chart.
What Are Massachusetts's Sampling Practices?
The monitoring season starts as early as Memorial Day at some beaches and lasts through Labor Day for most.
The MDPH coordinates the efforts of a range of collaborators including local boards of health, the Barnstable County Department of Health and the Environment, and the Massachusetts Department of Conservation and Recreation. The MDPH determines sampling practices, locations, standards, and notification protocols and practices throughout the state. Samples are collected in 3 feet of water, 1 foot below the surface. State water quality regulations require that all public and semipublic freshwater and marine bathing beaches in Massachusetts be monitored during the bathing season for bacterial contamination. (Semipublic beaches are not open to the general public, but more than a single owner is allowed use.) The sampling frequency for Massachusetts’s beaches is based on use and the potential for pollution problems. As noted above, if a beach has been monitored weekly for the two most recent consecutive years and no exceedance of standards has been found, and if a sanitary survey conducted by a registered sanitarian reveals no potential sources of pollution at that beach, the beach managing entity may be allowed to sample less frequently.
Beachwater quality samples must be taken in the areas where there are the most swimmers. However, beach operators are encouraged also to sample where outfalls and other sources of contamination are present. When an exceedance is found, sampling is generally conducted every day until the standards are met, after which the beach is reopened. Also, beaches that issue preemptive rainfall advisories generally sample on the day of rainfall or the day after. States that monitor more frequently after an exceedance is found or after rainfall will tend to have higher percent exceedance rates and lower total closing/advisory days than they would if their sampling frequency did not increase after an exceedance or a rain event.
How Many Beach Closings and Advisories Were Issued in 2012?
Total closing/advisory days for 323 events lasting six consecutive weeks or less decreased 32% to 863 days in 2012 from 1,273 days in 2011. For prior years, there were 1,256 days in 2010, 1,478 days in 2009, and 1,102 days in 2008. In addition, there were 2 extended events (156 days total) and no permanent events in 2012. Extended events are those in effect more than six weeks but not more than 13 consecutive weeks; permanent events are in effect for more than 13 consecutive weeks. For the 323 events lasting six consecutive weeks or less, 80% (690) of closing/advisory days were due to monitoring that revealed elevated bacteria levels, 16% (139) were preemptive due to heavy rainfall, and 4% (34) were preemptive due to other reasons.
How Does Massachusetts Determine When to Warn Visitors About Swimming?
Beaches are closed to swimming when the single-sample maximum or the geometric mean standard is exceeded. Whether beach action days are reported to the EPA as closings or advisories, restrictions and notifications are the same. For marine beaches, the standard is a single-sample enterococcus maximum of 104 cfu/100 ml, or the geometric mean of the five most recent samples within the current bathing season of 35 cfu/100 ml. There is no requirement that the geometric mean be calculated on the basis of samples taken over a 30-day period.
In addition to fecal indicator bacteria monitoring, beaches must be tested for oil, hazardous materials, and heavy metals if there is information indicating possible contamination.
Preemptive rainfall standards are in use at several beaches on Boston Harbor, and preemptive rainfall closings are issued after any significant rainstorm at a bathing beach with a history of violations of water quality standards. In addition to preemptive rainfall closings and closings due to bacterial exceedances, the local board of health and/or MDPH can close a beach for any other reason if they believe there is a threat to human health, such as an oil spill. Beaches also can be closed if there is a red tide (a bloom of the harmful algal bacterium Alexandrium) that decreases visibility in the water to such an extent that the beach operator considers it a rescue safety hazard. Local boards of health can also preemptively close beaches that have consistently elevated bacterial indicator levels.
Massachusetts 2012 Monitoring Results and Closing/Advisory Days