Publications

Regional ground-water flow at the Fort Leonard Wood Military Reservation (FLWMR) generally is east and west away from a regional ground-water divide towards the Big Piney River and Roubidoux Creek. Ground-water flow in the northern FLWMR is strongly affected by solution-enlarged fractures and bedding planes in the Roubidoux Formation and Gasconade Dolomite. Several large springs located...

The Iowa River alluvial aquifer in Iowa County, Iowa (fig. 1), underlies an area of intensive agricultural activity where pesticides and nitrogen-based fertilizers are extensively used. The effects of changing land use on shallow ground-water quality in part of the Iowa River alluvial aquifer are currently being investigated as part of the U.S. Geological Survey (USGS) National Water...

Herbicide compounds were prevalent in ground water across Iowa, being detected in 70% of the 106 municipal wells sampled during the summer of 1995. Herbicide degradation products were three of the four most frequently detected compounds for this study. The degradation product alachlor ethanesulfonic acid was the most frequently detected compound (65.1%), followed by atrazine (40.6%), and...

Certain events provide a unique opportunity to test the monitoring capability of AVHBR imagery. On 26 August 1992, Hurricane Andrew passed through Louisiana, impacting a large area of forested wetlands. One response to the widespread defoliation resulting from the hurricane impact was an abnormal bloom of new leaves and new growth in the underlying vegetation between September and...

The hypothesis that migratory birds accumulate persistent organochlorine pesticides (POPs) during the winter in Latin America has been prevalent for many years, particularly since 1,1,1-trichloro-2,2–bis(p-chlorophenyl)ethane (DDT) was banned in the United States in 1972. It has been suggested that peregrine falcons (Falco peregrinus), black-crowned night herons (Nycticorax nycticorax)...

Seasonal ichthyoplankton surveys were made in the lower Laguna Madre, Texas, to compare the relative utilization of various nursery habitats (shoal grass, Halodule wrightii; manatee grass, Syringodium filiforme; and unvegetated sand bottom) for both estuarine and offshore-spawned larvae. The species composition and abundance of fish larvae were determined for each habitat type at six...

Concentrations of metals in sediment interstitial water (pore water) and those extractable from sediment with weak acids can provide important information about the bioavailability and toxicological effects of such contaminants. The highly variable nature of metal concentrations in these matrices requires instrumentation with the detection limit capability of graphite furnace atomic...

Mesocosms have been primarily used as research tools for the evaluation of the fate and effects of xenobiotic chemicals at the population, community, and ecosystem levels of biological organization. This paper provides suggestions for future applications of mesocosm research. Attention should be given to the configuration of mesocosm parameters to explicitly study regional questions of...

The potential threats to humans and to terrestrial and aquatic ecosystems from environmental contamination could depend on the sum of the concentrations of different chemicals. However, direct summation of environmental data is not generally feasible because it is common for some chemical concentrations to be recorded as being below the analytical reporting limit. This creates special...

Eight whole sediment samples from Antarctica (four from Winter Quarters Bay and four from McMurdo Sound) were toxicologically and chemically evaluated. Also, the influence of ultraviolet radiation on the toxicity and bioavailability of contaminants associated with the sediment samples was assessed. The evaluations were accomplished by use of a 10-day whole sediment test with Leptocheirus

Communities of submerged aquatic vegetation (SAY) are important components of many freshwater, brackish, and marine aquatic ecosystems. They prevent erosion by baffling the impacts of waves, especially from storms. These aquatic plant communities remove nutrients and other pollutants from river and runoff inputs to coastal areas, preventing their entry into surrounding waters. They...

The Iowa Department of Natural Resources. Geological Survey Bureau: the University of Iowa Hygienic Laboratory; and the U.S. Geological Survey (USGS) have been working together to address this question. As part of the Iowa Ground-Water Monitoring Program (IGWM). water samples have been collected from selected Iowa municipal wells since 1982. An examination of this data identified two...