This Alberta Environment and Parks (AEP) lotic quality control report investigates the bias and variability of data generated from the Long Term River Network (LTRN) and Tributary Monitoring Network (TMN) programs. In total, 323 field blank samples and 318 duplicate samples were taken from nearly 100 stations across the province of Alberta. Data analyses relate these QC samples to 4,482 provincial LTRN and TMN environmental samples taken between January 2016 and December 2019. There was a wide range of potential contamination (i.e. bias) and variability evident in the parameters monitored in the TMN and LTRN programs. Data end-users should be cognizant of this potential bias and variability in data generated by the LTRN and TMN programs. Parameters with low environmental concentrations, elevated potential for extraneous contamination and/or high variability should be interpreted with caution.