Finding low cost, rapid tests to monitor microcystins in water is paramount to protect environmental and public health worldwide. Bioassays like Protein Phosphatase Inhibition Assay (PPIA) and Enzyme-linked Immunosorbent Assay (ELISA) have many advantages over liquid chromatography–tandem mass spectrometry (LC-MS/MS). Analytical cost per sample was found to be $136 by ELISA and $365 by LC-MS/MS. An agreement of 76% was found between ELISA and LC-MS/MS results from 2010 to 2012 (n=854) on the basis of Method Detection Limits (MDLs). Among samples with LC-MS/MS results >1.5μg/L, ELISA missed 3 samples in 2010, 1 in 2011 and none in 2012.
Correlation between PP2A and ELISA was strong (R2=0.8155, p=0.8054, n=27) in surface water samples but non-existent in drinking water (R2=0.0366, p=0.0665, n=38). PP2A was found useful for monitoring non-coloured surface water but not for drinking water. A 2-tier test system is proposed: tier-1 ELISA and tier-2 PP2A for surface water samples.