Blue-green Algae Bloom Update
The blue-green algae bloom in the Charles River has now subsided.
Blue-green algae, or cyanobacteria, are aquatic bacteria that can produce toxins which are harmful to humans, dogs and other mammals. If you see water that looks bright green or contains bright green strands avoid contact with the water as much as possible and wash contacted areas after exposure. Common reactions to the toxins include rashes, eye irritation, and possible gastrointestinal distress.
Blue-green Algae News
Blue-green algae in the Charles River watershed
(also known as cyanobacteria) has been present in Eastern Massachusetts and the Charles River
for years, but the issue has recently become a
concern due to the type and quantity of blue-green algae that is present.
CRWA is part of a collaborative effort working to develop a protocol for
monitoring blue-green algae levels in the river during the summer months,
and notifying the public of potential risks from the toxins blue-green
algae can produce in the water. We are committed to providing the public
with information on blue-green algae conditions through our daily water
quality flagging program.
One of the common blue-green algae found in the Charles
River is Microcystis,
which grows naturally in calm, warm, shallow water that is rich in
nutrients (nitrogen and phosphorous). Microcystis
secretes a toxin when it dies, and accumulations of this toxin can pose a
health risk to humans and animals. Unfortunately, there is not a direct
correlation between visible algae in the water and toxin levels, so it can
be difficult to determine when the water is safe. We are testing for both
blue-green algae cell counts and toxin levels on a regular basis, and
advise river users to use caution if blue-green algae is visible,
particularly in large quantities. Click here for a simple field guide to
help identify blue-green algae.
The Massachusetts Department of Public Health defines a bloom as the presence of any of the following:
cyanobaceria concentrations >70,000 cells/ml of water
cyanotoxin levels >14 parts per billion (ppb)
presence of a visible cyanobacteria scum or mat
A sample warning sign posted by MA Department of Conservation and Recreation an dMA Department of Public Health during severe blue-green algae blooms
combination of factors, such as excess nutrients, warm temperatures, and
sunlight, encourage blue-green algae growth. The presence of
nutrients, such as phosphorus, is mainly due to runoff from large impervious surfaces in urban areas
(streets, parking lots, lawns) and from direct discharges such as
wastewater treatment facilities. Click here to learn more about the impact of phosphorus in the Charles.
Blue-green algae becomes a serious problem when it grows
in abundance, preventing light and oxygen from getting into the water. In the Charles, severe
algae blooms are usually caused by heavy rainstorms that bring an enormous
influx of nutrients to the river, followed by hot weather that leads to
warm water temperatures, creating perfect conditions for algae growth. Direct discharges of heated
water likely contribute to blue-green algae growth as well.
CRWA Works to Prevent Blue-green Algae Blooms
CRWA projects help prevent blue-green algae blooms by addressing the key contributors:
- high nutrient levels
- warm water temperatures
- low streamflow.
works on several fronts to monitor and address blue-green algae
growth in the Charles River. While there are currently no recognized methods to eliminate the
cyanobacteria from the water, blooms can be prevented by reducing the
river’s nutrient levels and water temperature.
Quality Monitoring - CRWA has taken a lead role in monitoring the
water quality of the river. Once a month, more than 60 volunteers gather
at 35 sites along the river to collect water samples, measure depth and
temperature, and record river conditions. The data collected is used to
identify problems in the river and trends in water quality, and to track
the progress of efforts to clean up the Charles. CRWA staff also collect water quality data from potential pollution
“hot spots” and from tributaries to the river in an effort to track
down possible sources of pollution.
Program - Our daily water quality flagging program presents the
daily flag colors of the river's health, which signify whether or not the
river is safe for boating at nine boating locations from Watertown to Boston. Flag colors are based on bacteria levels, blue-green
algae counts, and rainfall-based prediction models. A blue flag
indicates suitable boating conditions; a red flag indicates potential
Reduction - CRWA has spearheaded a project to quantify the
nutrient levels that negatively impact the Charles River and to identify the sources of these nutrients. Working with the
Massachusetts Department of Environmental Protection and the U.S.
Environmental Protection Agency, CRWA has spent five years collecting
streamflow and water quality data to create a Total Maximum Daily Load (TMDL)
for the Charles River. The TMDL report analyzes the pollution contributions from different
sources and establishes the amount of pollutant the river can sustain and
still meet water quality standards. Sources of excess nutrients, such as
phosphorous, include stormwater runoff from urban areas (streets, parking
lots, lawns), direct discharges to the river, such as from wastewater
treatment facilities, and releases from the sediments accumulated at the
bottom of the river. The information from the report is used to identify
areas of the river where nutrient levels are high and establish priorities
for remediation. The most promising approach to restoring the river’s
nutrient balance appears to be cleaning up polluted stormwater runoff,
most of which reaches the Charles with little or no treatment at all.
Advocacy - In addition to using scientific research to protect the Charles River
and its watershed, CRWA works to reform state water law, policy and
practice to preserve aquatic habitat and maintain streamflows. Among its
current legal initiatives, CRWA is working to protect aquifers and
maintain summer flow levels, which will reduce temperatures and improve
water quality, and to prevent excessive discharges of hot water into the
river. Higher water temperatures are known to exacerbate toxic algal
blooms, harm fish populations and decrease water clarity.
Thanks to determined advocacy by Conservation Law Foundation and CRWA, the Gen On Energy, LLC cogeneration plant in Cambridge is switching to a closed-loop system. The plant will capture most of the heat generated by the plant and distribute it as steam through a new pipeline to be built across the Craigie Dam. The modifications will enable the company to drastically reduce the amount of water it withdraws from the Charles River, removes heat from the plant, and double the amount of steam it can sell to heat buildings in Boston.
Blue-green Algae in the
CRWA's algae sampling for 2008 has been conducted with support from REI.