Interaction between three marine microalgae and two phthalate acid esters.

Area of Science:

• Environmental toxicology
• Marine biology
• Microalgal biotechnology

Background:

• Phthalates, including diethyl phthalate (DEP) and di-n-butyl phthalate (DBP), are common marine pollutants.
• Marine microalgae play crucial roles in aquatic ecosystems and can interact with environmental contaminants.

Purpose of the Study:

• To investigate the toxic effects and degradation capabilities of three marine microalgae species exposed to DEP and DBP.
• To understand the interactions between microalgae and phthalates, and the impact of pollutant mixtures.

Main Methods:

• Exposure of Chaetoceros muelleri, Cylindrotheca closterium, and Dunaliella salina to varying concentrations of DEP and DBP.
• Determination of 96-h 50% effect concentration (EC50) and no observed effect concentration (NOEC) based on cell density and chlorophyll a.
• Assessment of pollutant degradation rates and bioconcentration under single and mixed exposure conditions.

Main Results:

• Species sensitivity varied: DEP (Chaetoceros muelleri > Cylindrotheca closterium > Dunaliella salina) and DBP (C. closterium > C. muelleri > D. salina).
• Cylindrotheca closterium demonstrated significant adaptive ability and was the most effective species for degrading both DEP and DBP.
• Co-exposure to DEP and DBP inhibited degradation and increased bioconcentration, suggesting synergistic toxicity.

Conclusions:

• Marine microalgae exhibit differential responses to DEP and DBP exposure.
• Cylindrotheca closterium shows potential for bioremediation of phthalate pollution.
• Mixtures of DEP and DBP present a heightened risk to marine ecosystems due to inhibited degradation and increased accumulation.