3 resultados para Cyanobacterial Toxins
em Iowa Publications Online (IPO) - State Library, State of Iowa (Iowa), United States
Resumo:
Lake Morris is the larger of two lakes which serve as the municipal water supply for the City of Chariton, Iowa. As a site for fishing and boating, it also serves as a significant recreational resource for area residents. Its ability to sustain these uses has been significantly impaired by long-term and ongoing accumulation of sediment and sediment-borne nutrients from both public and private land within the watershed. This accumulation has resulted in reduced water depth, reduced water-holding capacity, reduced quality of the fishery, increased water turbidity, increased growth of undesirable algae, and increased cost of treating the water for municipal uses. Water quality projects undertaken in the past, notably the Lucas Lakes Project of the 1990s, made important progress in reducing sedimentation from privately-owned land higher in the watershed, but paid little attention to land owned by the City of Chariton immediately surrounding the lakes. A recent reassessment of gully erosion within the watershed shows serious, ongoing erosion on that City-owned land. This project proposes a two-part approach to improving the water quality in Lake Morris. First, we propose that a complement of five SolarBee water circulation devices be installed in Lake Morris to provide near-term and continuing improvements in water quality, by inhibiting cyanobacterial growth and thereby removing the need for treatment of the lakes with copper sulfate. Second, we propose the installation of erosion-control structures on primarily City-owned land surrounding the lake, to provide a major reduction in ongoing sedimentation.
Resumo:
The Iowa Department of Public Health (IDPH), Division of Environmental Health, Health Assessment Program gives people information about harmful chemicals and organisms in their environment. Blue-green algae are microscopic organisms that are naturally present in lakes and streams. Some blue-green algae produce toxins that could pose a health risk to people and animals when they are exposed to them in large enough quantities. This fact sheet answers questions about blue-green algae.
Resumo:
The Railroad Avenue groundwater contamination site (the site) is in West Des Moines, Polk County, Iowa. Located on approximately 120 acres. The site comprises mixed residential, industrial and commercial properties. Underneath the site, chlorinated volatile organic compounds (VOCs) have contaminatcd the shallow (i.e., 30-50 feet deep) groundwater. These compounds have compromised several shallow wells within the West Des Moines water works system. A contamination source, however, has not yet been identified. In 1993, routine water analysis by the City of West Des Moines identified 1, 2 cis-dichlorocthylcne (1, 2 cis-DCE) at a concentration of 1.2 μg/L (micrograms) per liter of water) in the water supply. Subsequently. several shallow municipal wells were found to be contaminated by VOCs, including 1. 2 cis-DCE, trichloroethylene (TCE), tetrachloroethylene (PCE) and benzene. Five of these wells have been taken out of service. Because of the impact on the West Des Moines water supply, the U.S. Environmental Protection Agency (USEPA) has assigned the site to the National Priorities List. Surface water und sediment at the site have not been impacted by the VOCs. Testing for VOCs in surface soils has not revealed any significant VOC contamination. Subsurface soils -- generally 8 feet or greater in depth -- are contaminated with VOCs, but at levels which should not present a health hazard. The past, present, and future health hazard category chosen for this site is no apparent public health hazard. This category is used when exposure to toxins might be occurring or might have occurrcd in the past, but at levels below any known health hazard. Analysis of available environmental data has not revealed that residental or commercial water customers are or have been exposed to VOCs at concentrations that might cause any adverse health effects.