Risk assessment of herbicide mixtures in a large European lake

Lake Geneva is one of the largest European lakes with a surface area of 580 km2. Its catchment area covers 7400 km2, of which approximately 20% is arable land. Monitoring campaigns have been carried out in 2004 and 2005 to determine the contamination of the lake by pesticides. The results highlight the widespread presence of herbicides in water, the measured concentrations for most substances remaining constant in 2004 and 2005. However, for some individual herbicides the concentrations increased drastically (e.g., the herbicide foramsulfuron). We assessed the environmental risk of the herbicides detected in the lake using water quality criteria recently determined for the Swiss environmental protection agency. Furthermore, we assessed the risk of herbicide mixtures, grouped based upon their mode of action. Generally, the risk estimated for all single substances is low, except for some sulfonylurea compounds. For these substances, the measured concentrations are higher than the predicted no-effect concentration. Impact on the flora of the lake can therefore not be excluded. When mixtures of pesticides with similar mode of action are taken into account, the risk remains lower than the mixture water quality criteria for all groups, but can reach as high as one third of this quality criteria. A further step would therefore be to assess the risk of the total pesticide mixture, including similar and dissimilar modes of action

Optimizing a remotely sensed proxy for plankton biomass in Lake Kivu

Many regions of the world, including inland lakes, present with suboptimal conditions for the remotely sensed retrieval of optical signals, thus challenging the limits of available satellite data-processing tools, such as atmospheric correction models (ACM) and water constituent-retrieval (WCR) algorithms. Working in such regions, however, can improve our understanding of remote-sensing tools and their applicabil- ity in new contexts, in addition to potentially offering useful information about aquatic ecology. Here, we assess and compare 32 combinations of two ACMs, two WCRs, and three binary categories of data quality standards to optimize a remotely sensed proxy of plankton biomass in Lake Kivu. Each parameter set is compared against the available ground-truth match-ups using Spearman's right-tailed ρ. Focusing on the best sets from each ACM-WCR combination, their performances are discussed with regard to data distribution, sample size, spatial completeness, and seasonality. The results of this study may be of interest both for ecological studies on Lake Kivu and for epidemio- logical studies of disease, such as cholera, the dynamics of which has been associated with plankton biomass in other regions of the world.

Lake Darling: A Snapshot of Success, 2006

Before improvements were made, a number of factors were hurting the water quality in Lake Darling and driving people toward other lakes.

GIS Mapping: Creating Solutions for Rock Creek Lake, 2004

Rock Creek Lake is at risk. The centerpiece of Rock Creek State Park in Jasper County, Rock Creek Lake offers visitors a range of recreational opportunities, including the second busiest campground in Iowa and great fishing. However, many different factors are threatening the lake. Action is being taken to improve the lake for today’s visitors and to preserve the lake for future generations. GIS mapping is helping to make those improvements possible.

DNR Interactive Mapping: A tool for Iowa Agriculture, 2006

The planning tools you need to improve both your farming operation and Iowa’s streams and lakes are right at your fingertips. With DNR interactive mapping online, you can access a large amount of information for free and without special software.

Repairing the Impaired: Two Iowa Success Stories, 2005

More than 200 lakes, streams and rivers are on Iowa’s impaired waters list. Pollutants prevent these waters from supporting aquatic life, or from being used for drinking water or for full body recreational contact, like swimming. While improving Iowa’s water quality may seem a daunting task, two southern Iowa lakes show that it can be done.

Brushy Creek Lake: Improving Our Lake for the Future, 2006

While the quality of water in Brushy Creek Lake is currently adequate, a number of factors in the watershed (the surrounding area that drains into the lake) could put that water quality at risk. Sediment from the large watershed could fill in the lake and affect water clarity. Nutrients, like nitrogen and phosphorus, could cause algae blooms and other problems. Without preventative measures, potential manure and chemical spills could harm aquatic life in the lake. Using conservation farming practices and building structures like wetlands will work to maintain and even improve the lake’s water quality. Taking steps now to implement these critical practices will help prevent water quality problems, preserving water quality for future generations.

Restoring Our Pride in Badger Creek Lake, 2006

For years, Badger Creek Lake has been a source of pride for people living and farming nearby. Today, as the quality of water in the lake declines and new residents move to the area, the people of Badger Creek Lake need to maintain and renew that pride by improving their lake.

Cedar Lake Watershed Project, 2004

For years, Cedar Lake has been there for the Winterset community, providing drinking water, offering recreational opportunities, teaching students outdoors lessons and giving wildlife a home. With water quality a serious concern, it is now our turn to be there for the lake.

A Return to Clear Creek, 2006

At one time, Clear Creek lived up to its name. Originally set among the prairie and oak savannah of the Iowa River valley, legend has it that early settler and Johnson County sheriff Samuel Trowbridge gave the creek its name because of its pristine waters. However, the stream’s natural protections began to weaken as more settlers moved into Iowa. Over time, the prairie disappeared, livestock trampled streambanks, the creek was dredged and straightened, wetlands were drained and urban areas began to take their toll.

Project AWARE 2006 Iowa River, 2007

This monthly report from the Iowa Department of Transportation is about the water quality management of Iowa's rivers, streams and lakes.

Intensive Watershed Investigations at Iowa Beaches, 2005

This monthly report from the Iowa Department of Transportation is about the water quality management of Iowa's rivers, streams and lakes.

Year 5 Accomplishments, 2005

This monthly report from the Iowa Department of Transportation is about the water quality management of Iowa's rivers, streams and lakes.

Cyanobacteria in Iowa Waters, 2005

This monthly report from the Iowa Department of Transportation is about the water quality management of Iowa's rivers, streams and lakes.

Water Quality Summary, 2004

This monthly report from the Iowa Department of Transportation is about the water quality management of Iowa's rivers, streams and lakes.