Our March 25 meeting will be at 12 pm US Eastern time. Zoom link here and full information below. Our speaker will be Dr. Raees Ahmad, who will give a talk entitled: “Effect-directed Analysis of Hazardous Organic Chemicals Released from Ship Hull Hydroblasting Effluents and Their Emission to Marine Environments”.
Raees Ahmad is currently a Postdoctoral Research Scientist at The Connecticut Agricultural Experiment Station (CAES) in New Haven, Connecticut, USA. He holds undergraduate and master’s degree in Analytical Chemistry from the University of Malakand, Pakistan, where he focused on the photodegradation of dyes using molecularly imprinted polymers. He earned his Ph.D. in Analytical Chemistry from Kyungpook National University in Daegu, South Korea, where he developed an advanced effect-directed analysis (EDA) technique that integrates offline/online two-dimensional liquid chromatography–Mass Spectrometry with in-silico QSAR tools to identify both targeted and non-targeted contaminants in environmental matrices. At CAES, his research focuses on the suspect and non-targeted analysis of contaminants of emerging concern (CECs) and their transformation products in wastewater influent and effluent from treatment plants, as well as studying their accumulation and effects in plants.
Abstract: Hydroblasting operation on ship hulls is one of the major sources of chemical discharge into marine ecosystems, releasing biocides, binders, pigments, and additives. These activities contribute an estimated 6% to 17% of the daily biocide input from antifouling paint residues. However, most studies to date have focused primarily on target biocides, leaving other toxic chemical classes inadequately explored. This study applied effect-directed analysis to assess hydroblasting effluents using ultra-performance liquid chromatography coupled with high-resolution mass spectrometry. Toxicity screenings of both unfractionated and fractionated effluent samples revealed significant toxic effects on zebrafish embryos. Non-target analysis identified 68 compounds in the positive electrospray ionization mode and 25 compounds in the negative mode. Among these, specific toxic compounds responsible for the observed effects were identified within the fractions, with seven toxicants confirmed at Level 1 identification using reference standards. Quantitative analysis estimated the release of these toxicants to range from 0.16 to 121.83 g for the studied ship. When extrapolated to global hydroblasting operations, annual emissions of these toxic chemicals were estimated to be over 16 tons. These findings underscore the substantial environmental risks associated with hydroblasting effluents and emphasize the need for targeted mitigation strategies to reduce their ecological impact on marine ecosystems.