Assessment of Metals Toxicity Using a Nitrifying Bacteria Bioassay Kit Based on Oxygen Consumption

Area of Science:

• Environmental Science
• Analytical Chemistry
• Microbiology

Background:

• Rising levels of emerging contaminants in water necessitate advanced water quality evaluation methods.
• Traditional bioassays present ethical concerns, complexity, high costs, and only provide endpoint measurements.
• Nitrifying bacteria bioassays show high sensitivity to toxic substances, aiding in water pollution identification.

Purpose of the Study:

• To introduce a novel nitrifying bacteria bioassay kit for detecting heavy metal contaminants in water.
• To develop an expedited method for analyzing oxygen consumption for sensitive data generation.
• To provide a precise, economical, and effective alternative to existing water quality monitoring techniques.

Main Methods:

• Development of a novel nitrifying bacteria bioassay kit.
• Optimization of assay conditions, determining ideal ammonia (NH4+-N) concentration (100 mg/L) and acclimated culture volume (1 mL).
• Determination of EC50 values for various toxic metals using the bioassay and metagenomics analysis to identify key bacterial species.

Main Results:

• The bioassay successfully detected a range of toxic metals, with determined EC50 values including chromium (0.51 mg/L), silver (2.90 mg/L), copper (2.90 mg/L), nickel (3.60 mg/L), arsenic (4.10 mg/L), cadmium (5.56 mg/L), mercury (8.06 mg/L), and lead (19.3 mg/L).
• Key nitrifying species identified include Nitrosomonas spp., Nitrobacter spp., and Nitrospira spp.
• The optimized bioassay demonstrated simplicity, reliability, and suitability for field screening and real-time monitoring.

Conclusions:

• The novel nitrifying bacteria bioassay kit is a precise, economical, and effective tool for heavy metal detection in water.
• This method offers a significant improvement over traditional, complex, and ethically concerning water quality testing approaches.
• The bioassay enhances the effectiveness of water quality monitoring programs through its ease of use and reliability.