Analysis of nitrate in near-surface aquifers in the midcontinental United States: An application of the inverse hyperbolic sine Tobit model
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Abstract
A nonnormal and heteroscedastic Tobit model is used to determine the primary factors that affect nitrate concentrations in near-surface aquifers, using data from the U.S. Geological Survey collected in 1991. Both normality and homoscedasticity of errors are rejected, justifying the use of a nonnormal and heteroscedastic model. The following factors are found to have significant impacts on nitrate concentrations in groundwater: well screen interval, depth to top of aquifers, percentages of urban residential, forest land, and pasture within 3.2 km, dissolved oxygen concentration level, and presence of a chemical facility and feedlot. The effects of explanatory variables on nitrate concentration are explored further by calculating elasticities. Dissolved oxygen concentration level has more notable effects on nitrate concentrations in groundwater than other variables.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Analysis of nitrate in near-surface aquifers in the midcontinental United States: An application of the inverse hyperbolic sine Tobit model |
| Series title | Water Resources Research |
| DOI | 10.1029/96WR02102 |
| Volume | 32 |
| Issue | 10 |
| Year Published | 1996 |
| Language | English |
| Publisher | American Geophysical Union |
| Contributing office(s) | Iowa Water Science Center, Toxic Substances Hydrology Program |
| Description | 9 p. |
| First page | 3003 |
| Last page | 3011 |
| Country | United States |
| Online Only (Y/N) | N |
| Additional Online Files (Y/N) | N |
| Google Analytic Metrics | Metrics page |