Clarity for lake researchers' water quality questions

"Scientists engaged in a study of long-term water quality trends in Midwestern lakes found some good news: little change in water clarity in more than 3,000 lakes.

Look deeper, and the research becomes something more: a chronicle of a new source of data for scientists, data from residents of towns and villages surrounding the lakes..."

Lakes

EPA Releases First-Ever Baseline Study of U.S. Lakes
" The U.S. Environmental Protection Agency today released its most comprehensive study of the nation’s lakes to date. The draft study, which rated the condition of 56 percent of the lakes in the United States as good and the remainder as fair or poor, marked the first time EPA and its partners used a nationally consistent approach to survey the ecological and water quality of lakes. A total of 1,028 lakes were randomly sampled during 2007 by states, tribes and EPA.

“This survey serves as a first step in evaluating the success of efforts to protect, preserve, and restore the quality of our nation’s lakes,” said Peter Silva, assistant administrator for EPA’s Office of Water. “Future surveys will be able to track changes in lake water quality over time and advance our understanding of important regional and national patterns in lake water quality.”

The National Lakes Assessment reveals that the remaining lakes are in fair or poor condition. Degraded lakeshore habitat, rated “poor” in 36 percent of lakes, was the most significant of the problems assessed. Removal of trees and shrubs and construction of docks, marinas, homes and other structures along shorelines all contribute to degraded lakeshore habitat.

Nitrogen and phosphorous are found at high levels in 20 percent of lakes. Excess levels of these nutrients contribute to algae blooms, weed growth, reduced water clarity, and other lake problems. EPA is very concerned about the adverse impacts of nutrients on aquatic life, drinking water and recreation. The agency will continue to work with states to address water quality issues through effective nutrient management...

National Lake Fish Tissue Study
"Environmental monitoring provides crucial data for describing the condition of the environment and for assessing the effectiveness of pollution control activities. In the 1990s, EPA identified a lack of information necessary to accurately characterize the condition of the Nation’s surface waters and responded by designing a series of statistically-based surveys to produce information on the condition of lakes, streams, rivers, and coastal waters in the United States. The National Study of Chemical Residues in Lake Fish Tissue (or National Lake Fish Tissue Study) is one of the statistically-based surveys conducted by EPA since the late 1990s.

This study is a national screening-level survey of chemical residues in fish tissue from lakes and reservoirs in the conterminous United States (lower 48 states), excluding the Laurentian Great Lakes and Great Salt Lake. It is unique among national assessments of fish contamination in lakes because the sampling sites were selected according to a statistical (random) design..."