Environmental Impact of Irgarol 1051, a Biocide, on Marine Microalgae Metabolism: A Case Study of Chlorella salina and Dunaliella bardawil

Preventing fouling is crucial for maintaining ship performance, as it reduces speed, increases fuel consumption, raises greenhouse gas emissions, and spreads invasive species. Irgarol 1051, an antifouling agent (2, methythiol-4, tert-butylamino, 6-cyclopropylamino, s-triazine), is a toxic compound that impacts various marine species. It inhibits algal growth and disrupts key metabolites, posing a threat to the marine ecosystem. This study aimed to assess the toxic effects of Irgarol 1051 on Chlorella salina and Dunaliella bardawil, two nutrient-rich marine algae commonly used in fish feed. In addition, the suitability of the Mediterranean Sea coast for algal proliferation was assessed using geospatial techniques. The data were statistically examined using a two-way ANOVA test. Lethal and sublethal effects of Irgarol 1051 were measured in the laboratory to identify the consequences of this biocide on certain metabolite compositions. EC50 for C. salina and D. bardawil was estimated to be 0.50 µg·L−1 and 0.025 µg·L−1 respectively. IR spectroscopy of total cell constituents, protein profile, and the damaging effects of antioxidants have been evaluated for the two algal species. The findings of this study revealed that Irgarol 1051 negatively affected all the examined metabolites in both algal species, with more pronounced impacts on the wall-less alga Dunaliella bardawil compared to the walled alga Chlorella salina. A notable increase in total antioxidants was observed in both algae as the Irgarol concentration increased. The study reveals high algal growth areas near the Nile Delta along the Egyptian coast, potentially vulnerable to the effects of Irgarol 1051 due to nutrient runoff and eutrophication. The spatial analyses showed that the growth of C. saline and D. bardawil in Egyptian seawater is high in front of the Nile delta governorates: Port Said, Damietta, and Dakhalia shores reporting 6, 4.5, and 4 mg·m−3, respectively. The level of mass chlorophyll “a” in front of the Egyptian northern governorates can be ordered as follows: Port Said > Damietta > Dakahlia > North Sinia > Kafr El-Sheikh > Alexandria > Matrouh. This study highlights the use of spatial analyses to assess algal distribution, pollution impact, and ecosystem vulnerability along the Egyptian Mediterranean coast for effective environmental management.