Wang et al. (2025) develop a single-chamber microbial fuel cell (MFC) as a biosensor for the detection of hexavalent chromium (Cr(VI)) in wastewater. The MFC exploits the inhibitory effect of Cr(VI) on microbial electro-activity to generate a quantitative signal proportional to Cr(VI) concentration.
Key numbers
LOD: 0.0075 mg/L (7.5 µg/L, or 7.5 ppb) for Cr(VI) in wastewater. This is below typical Cr(VI) industrial discharge limits but above drinking water guidelines for total chromium (WHO: 50 µg/L total Cr) — the LOD is relevant for monitoring rather than compliance in this context.
Note: this sensor detects Cr(VI) specifically (hexavalent chromium), not total chromium. This is the correct speciation for Cr(VI) detection; total Cr must never be treated as Cr-VI. CC BY license.
Methods (brief)
MFC-based bioelectrochemical sensor. Cr(VI) inhibits microbial metabolism, reducing power output measurably. Environmental wastewater matrices. Not validated in food matrices. LOD 7.5 µg/L is reasonable for wastewater monitoring.
Implications
Testing: Cr(VI) is an HMT&C analyte (the program tracks Cr-VI, not total Cr). MFC-based sensors are an interesting emerging approach for environmental Cr(VI) screening, though ICP-MS with appropriate sample preparation remains the standard for food matrix Cr(VI) quantification.