Chemical hazard of robotic hull in-water cleaning discharge on coastal embryonic fish

Abstract

Introduction The biological settlement of marine organisms on vessels is a major problem for global shipping, causing various problems to vessels or marine structures. Antifouling paints have been applied to the surface of vessels and marine structures to prevent biofouling. All hull cleaning processes, including dry-dock and in-water cleaning, can release chemical contaminants into the marine environment, where they are known as "hotspots" of contamination in marine environment. However, many countries have not yet established effective evaluation methods for waste mixture disposal or management guidelines for area cleaning. We investigated the developmental toxicity of embryonic flounder, an organism sensitive to chemical contamination, to clarify the potential toxic effects of remotely operated vehicles (ROV).

Results and Discussion The composition of metal was dominated by Iron, Zinc and Copper. In the organic biocide composition, CuPT and ZnPT was the most abundant biocide in ROV A and ROV B cleaning wastewater. The wastewater from two in-water robot cleaning wastewater produced a largely overlapping suite of developmental malformations including pericardial edema, spinal curvature, and tail fin defects. In analyses of differential gene expression profiles using high-throughput RNA sequencing, genes associated with muscle development were commonly altered significantly. Gene enrichment analysis of embryos with ROVs exposure Embryos exposed to ROV B wastewater exhibited cell signaling and transport, whereas embryos exposed to A wastewater exhibited nervous system development and cell development. We analyzed the gene regulatory network for genes associated with significant GO terms in ROVs and identified key genes in each pathway. In the ROV A wastewater exposed embryos gene regulatory network. Our results can help to provide comprehend the effects of hull cleaning wastewater contamination on non-target coastal organisms.