After cross-referencing the locations of the pivots with their groundwater concentrations, they found that none of the 76 wells feeding into the full-rust pivots contained nitrate above the 10 mg/L threshold established by EPA with the average nitrate concentration being 2.4 mg/L. Most, but not all, of the groundwater supplying the part-rust pivots also sat below the threshold with an average of 4.5 mg/L. The pivots classified as no-rust had a wider range of classifications averaging 7.8 mg/L and reaching levels as high as 44 mg/L. Statistical analysis confirmed a clear difference; however, it was noted that larger sample sizes could further support the team’s conclusion. The team also observed that the rusty pivots occurred in patches. Although the researchers are not sure of what is responsible for the nitrate-rust link, they do have a hypothesis. This hypothesis involves the microorganisms, especially the bacteria, living in soil and groundwater. This information can potentially be used to help screen for areas for the potential absence of nitrate and, in an ideal world, could indicate areas at higher- or lower-risk for nitrate contamination before it becomes a problem. However, the proposed screening method is only applicable in areas that feature a fair amount of iron, typically areas adjacent to streams or rivers.