A sensitive, wide-ranging comprehensive toxicity indicator based on microbial fuel cell.

Area of Science:

• Environmental Science
• Analytical Chemistry
• Microbiology

Background:

• Petrochemical wastewater contains toxic pollutants requiring effective detection methods.
• Conventional toxicity indicators often lack sensitivity and have limited detection ranges.
• Microbial fuel cells (MFCs) show potential for environmental monitoring applications.

Purpose of the Study:

• To introduce and validate a new toxicity detection indicator, the average current inhibition rate (ACIR), for MFCs.
• To evaluate the toxicity of copper(II), 2,4-dichlorophenol (2,4-DCP), and pyridine in petrochemical wastewater using ACIR.
• To compare the performance of ACIR with conventional indicators like voltage inhibition rate.

Main Methods:

• Application of MFCs for toxicity assessment.
• Calculation of the average current inhibition rate (ACIR) considering the entire toxic effect process.
• Analysis of microbial community shifts in the anode chamber using principal component analysis (PCA).

Main Results:

• ACIR demonstrated higher sensitivity and wider linear detection ranges for copper(II) (0.3-100 mg/L), 2,4-DCP (0.4-1000 mg/L), and pyridine (0.1-1000 mg/L).
• Median effective concentrations were determined as 34.32 mg/L for copper(II), 36.18 mg/L for 2,4-DCP, and >1000 mg/L for pyridine.
• ACIR correlated with a reduction in electrogenic bacteria (e.g., Geobacter, Arcobacter) and microbial community shifts observed via PCA.

Conclusions:

• The average current inhibition rate (ACIR) is a superior indicator for toxicity detection in MFCs compared to conventional methods.
• ACIR provides a more comprehensive and sensitive evaluation of toxic effects from petrochemical pollutants in wastewater.
• Changes in electrogenic bacterial populations are linked to pollutant toxicity and can be monitored using ACIR.