Article Abstract:
The distribution of acetochlor in the hydrologic system after its first season of extensive use in the midwestern US is determined from 42 rain, 104 stream and 38 groundwater samples. Analysis of the water samples collected by the US Geological Survey during 1994 showed that acetochlor was present in 29% of rain samples from four sites in Iowa, 17% of the stream samples from 51 sites across nine states. It was not detected in groundwater samples from 38 wells across eight states. Following its application to corn in the Midwest, acetochlor showed higher concentrations in rains and streams. It was detected in 75% of the rainwater and 35% of the stream samples.
User Contributions:
Comment about this article or add new information about this topic:
Article Abstract:
The aquaeous behavior of atrazine which is being used extensively as corn herbicide in Iowa is studied. Groundwater samples are taken from an 11.2 kilometer section of Roberts Creek. These samples are then analyzed by means of gas chromatography and mass spectometry. Results indicate that instream degradation process reduces the concentration of atrazine of the water as it passes through section of the creek being used in the study.
User Contributions:
Comment about this article or add new information about this topic:
Article Abstract:
A new model selection procedure, called forward censored regression, proves useful in gathering environmental data with censored observation. Censored data, especially in most environmental data analyses, have values that are reported above some predetermined value. The method was able to estimate the significant factors affecting the total concentration of several contaminants from censored data.
User Contributions:
Comment about this article or add new information about this topic: