Cyanobacteria are photosynthesizing bacteria that may produce cyanotoxins that can cause illness to exposed human and animal populations. A bloom is a visually identified concentration of cyanobacteria that discolors the water. Cyanobacterial cells may be found at the water surface, at a defined depth, or present throughout the water column.
In Summer 2017, DWGWPD collaborated again with the Vermont Department of Health (VDH), to offer at no cost cyanotoxin analysis of raw and finished water at the VDH laboratory for the 22 Lake Champlain-sourced water systems for 12 weeks (July through September).
Disinfection byproducts (DBPs) can form when naturally occurring organic carbon reacts with chemical disinfectants such as chlorine. These disinfectants are used to protect public health by controlling microorganisms but high DBPs can have health effects. This is particularly a concern with surface water sources where organic carbon can be high and water systems are required to disinfect. In Vermont, DBPs are often highest in summer or fall when organic carbon and temperature are highest.
Sampling for DBPs
All public water systems must perform water quality monitoring to demonstrate that the water provided to customers is safe to drink. The kinds of samples that are required, the number of samples that are required, and the frequency of collection are based on the water system type, population, treatment, and water quality history. Water quality monitoring requirements for TNC water systems can be divided into two general categories: source permitting water quality monitoring and routine water quality monitoring.
The Revised Total Coliform Rule (RTCR) is effective April 1, 2016 and utilizes regular bacteria (coliform) monitoring as an indicator for system integrity, to signal possible fecal contamination, and the presence of waterborne pathogens. The RTCR applies to every public drinking water system in Vermont. This new rule is an update to the 1989 Total Coliform Rule and provides some key changes.
Cyanobacteria Importance to Drinking Water Facilities
The Division provides real-time, up-to-date monitoring schedules on its website, available through the MONITORING SCHEDULES tool.