Quantification of toxic effects of the organochlorine insecticide endosulfan on marine green algae, diatom and dinoflagellate

Abstract

Organ chlorine insecticide endosulfan (ES) is one of the persistent organic pollutants (POPs) and it may pose a serious threat to microalgae. Here, we evaluate the toxic effects of ES on three marine microalgae, <span style="mso-bidi-font-size:12.0pt" lang="EN-GB">including the diatom <i style="mso-bidi-font-style:normal">Ditylum brightwellii, </i>dinoflagellate<i style="mso-bidi-font-style:normal"> Prorocentrum minimum</i> and green algae <i style="mso-bidi-font-style:normal">Tetraselmis suecica</i>. <span style="mso-bidi-font-size:12.0pt" lang="EN-GB">The endpoints used for toxicity assessment were changes in cell counts and chlorophyll <i style="mso-bidi-font-style:normal">a</i> levels. Median effective concentration (EC₅₀) was calculated after 72 h-ES exposures and the values for <i style="mso-bidi-font-style:normal">D. brightwellii</i>, <i style="mso-bidi-font-style:normal">P. minimum,</i> and <i style="mso-bidi-font-style:normal">T. suecica </i>were determined to be 0.0013<span style="mso-bidi-font-size:12.0pt" lang="EN-GB">, 0.025<i style="mso-bidi-font-style:normal"><span style="mso-bidi-font-size:12.0pt" lang="EN-GB">, </span></i><span style="mso-bidi-font-size:12.0pt" lang="EN-GB">and 0.045 <span style="mso-bidi-font-size:12.0pt" lang="EN-GB">mg L^-1, respectively. These results indicate that our marine microalgae were very sensitive to the ES exposure even under environmentally realistic concentrations. Particularly, the diatom <i style="mso-bidi-font-style:normal">D. brightwellii</i> was most sensitive to ES, when compared to data available on freshwater microalgae.

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