| Abstract
| - This study assesses the role of the blue-green algal species present in the soil in the dissipation ofendosulfan and its metabolites in the soil environment. Two Anabaena species, Anabaena sp. PCC7120 and Anabaena flos-aquae, were used in this study. Anabaena sp. PCC 7120 produced threeprincipal biotransformation compounds, chiefly endosulfan diol (endodiol), and minor amounts ofendosulfan hydroxyether and endosulfan lactone. Trace amounts of endosulfan sulfate were detected.In comparison, the biotransformation of endosulfan by Anabaena flos-aquae yielded mainly endodiolwith minor amounts of endosulfan sulfate. An unknown compound was produced up to 70% fromendosulfan spiked in the medium inoculated by A. flos-aquae after 8 days of incubation. Therefore,the endosulfan fate was dependent on the species. Within 1 day of incubation, two Anabaena speciesproduced low amounts of β-endosulfan after application of α-endosulfan. These results suggest thepresence of isomerase in the Anabaena species. Further studies using a fermentor to control themedium pH at 7.2 to minimize chemical hydrolysis of endosulfan revealed a major production ofendodiol with minor amounts of endosulfan sulfate and the unknown compound. These results showedthat the production of the unknown compound might be dependent on the alkaline pH in the mediumand that the production of endodiol by A. flos-aquae might be biologically controlled. This study showedthat two algal species could contribute in the detoxification pathways of endosulfan in the soilenvironment. Keywords: Endosulfan; endosulfan diol; endosulfan sulfate; Anabaena flos-aquae; Anabaena sp. PCC7120; fermentor
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