Fate of organophosphate flame retardants and its biotransformation products in aquatic environment

Abstract

Nowadays, tens of thousands of artificially-synthesized chemicals surround us. As the industry develops, the chemicals used in manufacturing are exponentially increasing. Flame retardants are chemicals added to control the combustion of products such as electronics, clothing, and furniture. Hundreds of flame retardants are consumed worldwide by millions of tons per year within the manufacturing industry. Flame retardants contained in such a large amount as various products are substances that can affect human health and the environment. Brominated flame retardants used in the past have been restricted from the industry not only because of the toxicity in the parent compound itself but also its transformation products. Accordingly, the use of alternative organophosphate flame retardants (OPFRs) has been gradually growing since the 2000s. Nevertheless, research on OPFRs is still insufficient. Although studies on the toxic effects of OPFRs on humans are ongoing, there is less research on the effects in the aquatic environment. In the case of aquatic species, the study on the aquatic ecosystem fate of OPFRs is essential. Because biotransformation products in species may affect the upper trophic levels or the human body ultimately. In addition, the existing brominated flame retardants had a strict regulation due to the toxicity of biotransformation products as well as the parent compound. Biotransformation products in OPFRs are expected to be similar to existing flame retardants, but no confident studies have been done. In this study, biotransformation of OPFRs was identified according to species of the aquatic food chain. This aim is to identify the fate of biotransformation in species and to predict their impact on the aquatic environment. The first strategy is to investigate OPFRs in aqueous environments. Comparisons of OPFRs’ characteristics, years, and regions are based on the chemicals and accumulation of OPFRs detected in freshwater fish in the lakes. A second research direction is to select a representative OPFR and predict the biotransformation mechanisms through exposure to aquatic species. Existing brominated flame retardants were regulated due to the toxicity of transformation products. So, the study of biotransformation of new substances is essential. The third study strategy is to compare the biotransformation products of OPFR through a representative species in aqueous trophic levels and suggest the effects of OPFRs on the aqueous environment. Appropriate extraction processes to species and analytical methods were applied according to the research direction. This study identified the aquatic fate of OPFRs and biotransformation. Research into ecosystem impacts is indispensable for new alternative substances to be used. Therefore, this study predicted the effect of OPFRs on the aquatic environment as an alternative flame retardant. These results are expected to provide useful indicators to consider environmental impacts when OPFRs are produced in the industry.