The shallow, poorly-confined, sand and gravel aquifer underlying the lower
Malheur River basin is contaminated by nitrate and metabolites of the herbicide
dimethyl tetrachloroterephthalate (DCPA), first detected in 1983 and 1985,
respectively. The aquifer supplies water for the Ontario municipal water system,
domestic and industrial uses, and irrigation. In response...
Land application of industrial wastewater with high levels of nitrogen requires
adequate management practices to prevent groundwater pollution by nitrates. In this study
a predictive computerized model was developed for nitrate leachate concentrations
resulting from land application of wastewater onto crop systems including poplars. The
study included a literature review,...
This study investigated the use of radon-222 as an in situ partitioning tracer for quantifying nonaqueous phase liquid (NAPL) saturations in the subsurface. Laboratory physical aquifer models (PAMs), field experiments, and numerical simulations were used to investigate radon partitioning in static (no-flow) experiments and in single-well, 'push-pull' tests conducted in...
Grass seed production in Oregon's Willamette Valley traditionally relied on open field burning for straw residue disposal and nutrient recycling. Changes in residue management from open field burning to methods that remove straw coincided with rapidly declining K soil test values. A survey of grass seed fields showed that many...
Three studies were conducted related to the measurement and impact of
stream sediment fecal coliform (FC) bacteria on stream water quality. In part one
an enumeration technique for sediment FC was defined and statistically
characterized. This characterization necessitated the development of a sample
splitting mechanism, which was found to split...
Low concentrations of dissolved copper have been shown to adversely
affect the olfactory system of endangered salmonids, impairing their ability to avoid predators and likely increasing predation. It is believed that only the free ionic (Cu2+ free) and weakly complexed forms are bioavailable to organisms; these forms typically account for...