|The critical adenosine triphosphate (ATP) concentration in treated ballast water|In: Marine Pollution Bulletin. Macmillan: London. ISSN 0025-326X; e-ISSN 1879-3363, meer
Adenosine triphosphate (ATP); Ballast water; Compliance; Model; IMO; Compliance monitoring devices (CMD); Phosphoric acid benzalkonium chloride (P-BAC)
Measuring Adenosine triphosphate (ATP) provides a proxy to check compliance with IMO's ballast water D-2 standard: <10 cells mL−1 in the 10–50 μm size class. Measured with standard boiling techniques the ATPconcentration in aquatic eukaryotic microorganisms is 0.6 mol m −3. Model calculations with 10–50 μm spherical organisms show their ATP content is 0.2 to 20 pg cell−1, in line with several cell lysis data. However, at 10 cells mL−1, these ATP contents lead to a maximum of only 2 to 200 pg ATP mL−1, at least 7.5× below a D-2 test kit 1500 pg ATP mL−1 upper limit. Differentcell shape and ATP extraction scenarios to reach 1500 pg ATP mL −1 are discussed but remain improbable. Because cell lysis data are inconclusive, and a novel phosphoric acid-benzalkonium chloride method indicates up to 3× higher ATP concentrations, an independent test kit validation and a comparison of all three techniques are recommended.