Toxicity, Biodegradation, and Metabolic Fate of Organophosphorus Pesticide Trichlorfon on the Freshwater Algae <i>Chlamydomonas reinhardtii</i>

Abstract

This study investigated the toxicity of trichlorfon (TCF) to the freshwater algae <i>Chlamydomonas reinhardtii</i>, as well as its biodegradation and metabolic fate. The growth of <i>C. reinhardtii</i> decreased with increasing TCF concentration, and the maximum inhibition ratio was 51.3% at 200 mg L^-1 TCF compared to the control. Analyses of pigment content, chlorophyll fluorescence, and antioxidant enzymes indicated that <i>C. reinhardtii</i> can produce resistance and acclimatize to the presence of TCF. The variations in pH during cultivation suggested that photosynthetic microalgae have innate advantages over bacteria and fungi in remediating TCF. A 100% biodegradation rate was achieved at a maximum concentration of 100 mg L^-1 TCF. Ten metabolites were identified by GC-MS, and the degradation pathways of TCF by the algae were proposed. This research demonstrated that <i>C. reinhardtii</i> is highly tolerant to and can efficiently degrade TCF. Thus, <i>C. reinhardtii</i> can be used to remove traces of TCF from natural water environments and to treat TCF-contaminated wastewater.