Arsenic concentrations at one background and one compliance monitoring well. Three years of observations for background well, two years of observations for compliance well, four samples per year for each well.
EPA.92c.arsenic3.dfA data frame with 20 observations on the following 3 variables.
Arsenica numeric vector of arsenic concentrations
Yeara factor indicating the year of collection
Well.typea factor indicating the well type (background vs. compliance)