Science and Mathematics Education Commons^™

A Comparison Of Drinking Water Contamination In Buried Slab Wells, Other Large-Diameter Wells, And Drilled Wells, Rita M. Gergely

Journal of the Iowa Academy of Science: JIAS

This study presents the results of a statewide water well survey conducted by the Iowa Department of Public Health from 1993 to 1995 to determine whether there were statistically significant differences between well water contamination in buried slab wells, other large-diameter wells, and drilled wells. Wells were sampled for total coliform bacteria, fecal coliform bacteria, nitrate, and atrazine. Staff collected water samples and completed a site survey at each well, which included an interview with the occupant or owner and actual observations of the wellhead and surrounding area.

The study included 293 buried slab wells, 287 other large-diameter wells, and …

Interactive Effects Of Anthropogenic, Environmental, And Biotic Stressors On Multiple Endpoints In Hyla Chrysoscelis, Carol A. Britson, Stephen T. Threlkeld

Journal of the Iowa Academy of Science: JIAS

Multiple stressors have been proposed as causative agents for declining populations and increased incidence of malformations in amphibians although few studies have examined possible interactions among these stressors. We measured interactive effects of UV radiation, three chemicals, and interspecific competition (with Rana 1phenocephala) on multiple endpoints in Hyla chrysoscelis using a center point- and chemical-free control-enhanced 2⁴ factorial design. UV radiation was transmitted or filtered using OP-4 or OP-3 acrylite filters installed above 72, 500-liter mesocosms on 16 May 1997. Methyl mercury, chlorpyrifos, and atrazine were applied at levels of 0, 10, 50, and 100 % of 400 ppb, …

Mutant Weeds Of Iowa: V. S-Triazine Resistant Setaria Faberi Herrm, R. Thornhill, J. Dekker

Journal of the Iowa Academy of Science: JIAS

S-triazine resistance in giant foxtail (Setaria faberi Herrm.) has been reported previously, but not in the midwestern U.S. corn belt or Iowa. A study was conducted using a chlorophyll fluorescence assay to confirm the presence of resistance in one S. faberi population in Iowa. Variable chlorophyll fluorescence assays confirmed that a population of this species with this type of resistance exists in Iowa. This is the first report of s-triazine resistance in S. faberi, and the fourth species with this type of herbicide resistance, found in an Iowa agroecosystem.

Mutant Weeds Of Iowa: S-Triazine-Resistant Plastids Chenopodium Album L., Jack Dekker, Ronald Burmester

Journal of the Iowa Academy of Science: JIAS

S-triazine resistance in common lambsquarters (Chenopodium album L.) has been reported previously but not in Iowa. A study was conducted using a chlorophyll a fluorescence assay to confirm the presence of resistance in C. album populations in Iowa. Variable chlorophyll a fluorescence assays confirmed that mutations conferring resistance exist in five (5) geographically separated populations of C. album in Iowa: relatively greater fluorescence yields were measured in untreated resistant tissue compared with untreated susceptible plants, relatively greater fluorescence yield in treated compared with untreated susceptible leaf disks; and similar fluorescence yields of treated and untreated resistant tissue. This is the …