Detection & Monitoring of HABs in Theory & Practice

Session: 37. - Harmful Algal Blooms (HABs) and their Toxicity: Remote Sensing and Modeling Approaches

Sheela Agrawal, Northeast Ohio Regional Sewer District, [email protected]
Judy Westrick, Wayne State University, [email protected]

Abstract

WRF Grant 4647 identified several limitations for existing ELISA and LC/MS/MS based methods used to detect and quantify microcystins (MC) in water. For ELISA, these included variable antibody cross-reactivity toward MC variants, measurement error associated with extrapolation beyond the EC₂₀- EC₈₀ range of the calibration curve, shifting calibration curves,   variability introduced by manual vs. automated ELISA implementation (e.g. analyst proficiency) and potential interference from MC degradation byproducts as identified using LC/MS/MS. For LC/MS/MS findings included a lack of MC certified standards, purity and dissolution issues with existing reference standards, the limited scope of the existing LC/MS/MS method, and minimal vetting of sample additives.

These limitations could impact analytical results and subsequent regulatory action. Using cross-reactivity as an example, it is possible to under/overestimate ELISA-determined total MC concentration. This is of concern when health advisories are set near the method reporting limit. Moreover, a confirmatory technology like LC/MS/MS may be unable to quantify a previous ELISA detection, due to the limited scope of existing methods; current methods can only quantify 6 of the 150+ known MC variants. More research is needed to address each method’s limitations to ensure that regulatory agencies and utilities engage in an appropriate microcystin public health response.

1. Keyword
Microcystis

2. Keyword
harmful algal blooms

3. Keyword
drinking water

4. Additional Keyword
Analytical detection methods