Investigation of leaching of an antifouling agent from marine paint formulations using radiotracer technique

A radiotracer technique was used to investigate the leaching of an antifouling agent from different marine paint formulations with an objective to select the best paint formulation for bulk production. The antifouling agent (Diuron) itself was labeled with carbon-14 (half-life: 5,730?years, ??-energy: 156?keV) and used as a radiotracer. The different paint formulations added with radiolabeled Diuron were applied onto suitably selected substrates and measured for initial intensity of ??-radiation using a Geiger-Muller detector connected to a ratemeter. The painted substrates were subjected to shower tests for a pre-decided time and subsequently measured for ??-radiations. The comparison of intensity of ??-radiations in substrates prior and post shower tests provides information about leaching of antifouling agent Diuron from the paint formulation. The high leaching percentage of antifouling agent Diuron post shower tests indicates non-suitability of paint formulation for marine and civil structures. However, low leaching rate of Diuron will make a paint formulation more efficient and suitable. Based on the results of investigation, a paint formulation with minimum leaching rate was identified and selected for bulk production by a paint company.