Issues of the Environment: Toxic Algae In Toledo's Water Supply
Last week, stores in Washtenaw County sold out of bottled water due to an influx of residents from the Toledo, Ohio area where local tap water was declared unfit to consume after toxic algae blooms infected Lake Erie.
Washtenaw County residents get their water from surface and groundwater sources, not from the Great Lakes (accept perhaps in Ypsilanti and the surrounding townships which receive water from mixed sources via the Detroit Water and Sewer Department (DWSD), and at this time harmful blue-green algae is not impacting our water.The guest is Gary Fahnenstiel. He is a research Scientist at the U of M's Graham Sustainability Institute. Our discussion centers around the toxic algae in Toledo's water supply, how such events occur and under what climatic conditions, and how this type of event would impact the water supply in our local Washtenaw County region.
Water Sources in Washtenaw County
The primary use of groundwater in Washtenaw County is to supply drinking water. Well water is the only water source available to County residents that do not fall into a community water system. With the exception of the service are of Ann Arbor, which draws approximately 15% of its water from the ground and the portions of the County served by the City of Detroit Water and Sewer Department, all of Washtenaw County’s community water systems are sourced by groundwater.
Ann Arbor and surrounding townships - The City of Ann Arbor’s tap water is sourced from the Huron River’s Barton Pond.
Ypsilanti and nearby townships - In the late 1960s, Wayne County officials proposed a concept for regional wastewater treatment for the Huron River watershed called "SuperSewer," which would include western Wayne County, eastern Washtenaw County, and southern Oakland County. In 1972, officials in Washtenaw County feared a project to stop the pollution of the Huron River would never be built so they proposed building a new Ypsilanti regional wastewater treatment plant (WWTP) in order to receive 75% federal funding. The result of these factors was the formation of the Ypsilanti Community Utilities Authority in 1974. In 1972, the Township of Ypsilanti contracted with the Detroit Water and Sewer Department (DWSD) to provide water to the Township, [and more recently Superior Twp draws its water from a connection to Ypsilanti’s supply. Augusta, York, Pittsfield, and Ypsilanti Twps also are contracted to receive water from DWSD. ]
Drinking water for the City of Ypsilanti was originally obtained from deep wells and the Huron River. The water was processed and distributed by the Catherine Street Water Treatment Plant (WTP). Due to the economics of maintaining the Catherine Street WTP and the contamination of the City's well field, YCUA constructed a water main that provides water purchased from DWSD to the City of Ypsilanti in 1995 and the Catherine Street WTP was closed in 1996. The meter vault that measures the volume of water flowing into the City of Ypsilanti is located on Tyler Road. Today, YCUA provides drinking water to approximately 110,000 people and wastewater services to approximately 250,000 people and the average daily flow of wastewater to the YCUA WWTP is approximately 22.3 MGD. (Source: www.ycua.org/history.htm)
According to a water supply map supplied by DWSD, the water used by Washtenaw County residents comes from the “Northeast”, not Lake Huron which does supply much of Wayne County. (Source: www.dwsd.org/images_n/map_water_supply.gif)
According to the United States Geological Survey, “As the Nation's concerns over water resources and the environment increase, the importance of considering groundwater and surface water as a single resource has become increasingly evident. Issues related to water supply, water quality, and degradation of aquatic environments are reported on frequently. The interaction of groundwater and surface water has been shown to be a significant concern in many of these issues. For example, contaminated aquifers that discharge to streams can result in long-term contamination of surface water; conversely, streams can be a major source of contamination to aquifers. Surface water commonly is hydraulically connected to ground water, but the interactions are difficult to observe and measure and commonly have been ignored in water-management considerations and policies.” (Source: pubs.usgs.gov/circ/circ1139/)
Blue-green algae (cyanobacteria) are any of a number of species of microscopic bacteria that are photosynthetic. They may exist as single cells or groups of cells. They occur naturally in surface waters.
When conditions are optimal, including light and temperature, levels of nutrients (i.e., phosphorous and nitrogen, and the ratio of the two), and lack of water turbulence, blue-green algae can quickly multiply into a bloom. [In areas infested with Zebra Mussels the decreased turbidity of the water and the phosphorous/nitrogen ratio may be disturbed may lead to an increase in blue-green algae.]
Blue-green algae blooms are likely to occur more often in warmer months.
Zebra Mussel Connection
Zebra mussels, once just a Great Lakes problem, are taking over the nation's inland lakes - an invasion MSU scientists think is rocking the ecosystem. Once a lake is infested with zebra mussels, an unusual bloom of blue-green algae scum called microcystis often follows. Zebra mussels invade lakes most used by people, and microcystis can produce toxins potentially harmful to wildlife and people. The mussels eat virtually everything they can filter - except for microcystis, which they spit out. The theory is that the mussels help foster a blue-green algae bloom by reducing competing algae. (Source: www.sciencedaily.com/releases/1998/…0919115852.htm)
What is a Blue-green Harmful Algal Bloom?
Blue-green algae HABs in freshwater lakes and ponds, occur when specific types of photosynthetic bacteria (cyanobacteria aka blue-green algae) form blooms (visible, dense build-ups). Under certain conditions, these may produce harmful toxins.
Not all blooms produce toxins
It is not easy to tell if a bloom will produce toxins harmful to human health or animals. Large populations of blue-green algae may be required to produce toxins at a high enough level to affect those using the water for drinking or recreational use. Laboratory analysis of a water sample is needed to confirm the presence of toxins.
Environmental conditions that may trigger a bloom
Blooms may be triggered by a combination of water and environmental conditions, including:
- excess nutrients (phosphorus and nitrogen)
- low-water or low-flow conditions
- calm water
- warmer temperatures
Are some lakes more likely to have a blue-green algae HAB?
Some waterbodies appear to be more likely than others to have frequent blooms. Studies conducted in New York State and elsewhere continue to look at the specific triggers for each lake exhibiting blue-green HABs.
How long does a bloom last?
Blue-green algae HABs may be short-lived, appearing and disappearing in hours, or long-lived, persisting for several weeks, depending on the weather and the characteristics of the lake.
What time of year do blue-green algae HABs occur?
Blue-green harmful algal blooms are most likely to occur between July and October, but have been reported in NYS as early as March and as late as November.
How are lakes affected by blue-green algae?
Blue-green algae blooms can alter lake ecosystems by:
- reducing oxygen levels
- preventing the growth of beneficial algae
- producing toxins that are directly harmful to fish and other organisms
Reduce oxygen levels
As the bloom dies and decomposes, the amount of oxygen in the water decreases and can threaten fish and other aquatic life.
Prevent beneficial algal growth
The large thick bloom mats can block sunlight needed for other beneficial algae to grow and reduce the quality and amount of food resources available to the food web.
Toxic to fish and other organisms
Blue-green algae cells may produce toxins, however the toxins are not always produced and what controls toxin production is poorly understood.
The toxins are released when the cells break open; this can happen naturally during die off, when algaecides are applied, or in the stomach when ingested by people or animals. The toxins may be harmful to fish and other organisms. These nerve, liver and skin toxins can also sicken people, pets or livestock if consumed or ingested in large quantities, and can cause rashes or other allergic reactions.