Retrieve NTN data for all sites
Weekly Sample Data
Annual Averages, Calendar Year
Annual Averages, Water Year
Data users please note: Br data was removed on 10/15/2019
Notice regarding pH data analyzed from June 1, 2018 through February 4, 2020. This includes NTN sample IDs TT0001SW-TV1558SW and AIRMoN samples AE001L-AE0769L. This pH data set may have a slight bias due to the use of an incorrect pH meter calibration curve. All quality control samples associated with pH analysis during this timeframe met criteria (unless qualified otherwise) and thus the sample data are considered valid. However, a small pH bias of +/- 0.2 S.U. was detected when comparing samples analyzed with the corrected calibration to the original calibration. Low bias was observed for samples with pH < 5.6 and a high bias for samples with pH > 5.6.
In no case was the measured difference greater than 0.2 pH units. Please contact the CAL QA Manager Camille Danielson if you need additional information about this issue.