Status and Trends: LISS Environmental Indicators

What are beach closure days?

Beach closure days are the number of days beaches are closed in a year.  Beaches are closed to protect swimmers from potential harm or illness caused by pathogens or other contamination. Health departments sample coastal bathing waters to determine whether the water exceeds an acceptable level of 104 CFU (Colony Forming Units)/100mL  for the indicator bacteria, Enterococcus. This bacteria may indicate the presence of pathogens that can lead to gastrointestinal illnesses (GI) among swimmers. Pathogens are disease-causing organisms, including bacteria and viruses. More often, beach managers in Connecticut and New York close beaches preemptively when high rainfall generates stormwater runoff that may contain animal waste, untreated sewage discharge or other contaminants. As of 2010, there were 137 monitored beaches along Long Island Sound’s shoreline in New York and as of 2011, there were 73 monitored beaches in Connecticut. Yearly variations in closures are a product of rainfall patterns and incidents such as sewer-line ruptures.

what does this indicate?

Elevated concentrations of this indicator may reflect ongoing problems with pathogen contamination in Long Island Sound and may lead to closed beaches. Closed beaches can have an economic impact because they prevent people from being able to fully enjoy the Long Island Sound shoreline.

status

High incidents of closures in Connecticut in 2010 and 2011 were attributed to heavy rainfall and the impact of Tropical Storm Irene (in 2011).  Those years also were  exceptionally high years when one or more sampling stations at a beach reported a single sample Enterococcus result >104 CFU/100mL and at the same time the beach was not under a closure or advisory (source: Connecticut’s 2011 Annual Report for the US EPA Beach Grant) .The high incidents of closures in New York in 2009 were attributed to heavy rainfall. Some health departments also indicate that beach closures have increased since the mid-2000s adoption of a new test for bacterial pathogens for marine waters (the Enterococcus standard). New York City beaches were added to this indicator in 2006.

Data Notes

New York data (NY)  includes Long Island Sound beaches in Nassau, Suffolk, and Westchester. New York City (NYC) beaches in Long Island Sound were added to this indicator in 2006. NY data is not yet available for 2011.

Regarding the EPA approved marine recreational water quality indicator bacteria Enterococcus, it is important to note that this indicator was shown by EPA through epidemiological study to often associate in a predictable way with swimmer illness most likely caused by pathogens in human fecal contamination. Enterococcus is not considered by EPA to be a pathogen that causes swimmer illness, but may be present when illnesses occur. An indicator bacteria was chosen because directly assaying the concentration(s) of pathogens that may cause swimmer illness has been shown to be very difficult in a timely way. As it is, the analytic methods used to assay the concentration of Enterococcus in marine recreational water require a minimum 24 hours for culturing the bacteria. A water sample collected today will have analytic results reported on the following day (source: e-mail communication with Jon Dinneen, Connecticut Department of Public Health).