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The Amazing Science of Water Quality Analysis: How Indicator Bacteria Reveal the True Condition of Water?
Water quality safety is an indispensable part of modern life, especially as global water resources become increasingly stressed. Water quality analysis, especially bacteriological analysis, has become an important tool to ensure the safety of drinking water and waters. This article will uncover the science behind water quality analysis and explore how indicator bacteria can help us understand the true condition of our water.
Indicator bacteria refer to those bacteria commonly found in the intestinal tract of humans or animals, and their presence can often indicate potential contamination of sewage.
Purpose of water quality analysis
Bacteriological water quality analysis aims to estimate the number and types of bacteria present in the water. This detection method is not only related to the quality of the water, but also directly affects people's health. Generally, these analyzes focus on indicator bacteria rather than pathogens that pose a health threat. This means that by detecting the number of indicator bacteria, the potential presence of pathogens in the water can be inferred.
Importance of indicator bacteria
In water quality testing, non-specific E. coli, Escherichia coli (E. coli), and Pseudomonas aeruginosa are common indicator bacteria. Detection of these bacteria can help us infer whether sewage is present in the water. Especially for E. coli, the number is usually directly related to the degree of water pollution:
When indicator bacteria levels are low, it is reasonable to assume that pathogen levels will be even lower or not present at all.
Methods of microbiological analysis
There are various methods of water quality analysis, the most common ones are the following.
Direct plate counting method
This method counts the number of bacteria in the water by growing them to visible colonies. This requires diluting the original sample to ensure that 30 to 300 colonies are obtained for statistically significant results. Typically, this method is used to evaluate the effectiveness of water treatment, specifically the removal of microbial contaminants such as E. coli.
Membrane filtration method
This is a modified method commonly used in modern laboratories, which uses a special membrane filter to filter water samples and then culture them on culture media. This method can quickly and accurately count the number of bacterial colonies, and with the advancement of technology, the number of colonies can now be automatically counted through a microscope.
ATP test method
ATP test is a quick way to measure active microorganisms in water. It directly reflects the concentration and health of organisms by detecting the content of adenosine triphosphate (ATP). This method is very effective for rapid detection of contaminants, especially in water and industrial applications.
Analysis of pathogens
When the level of indicator bacteria in the water sample exceeds the standard, further special analysis of pathogens will be conducted. These pathogens may include salmonella, etc., depending on the source of contamination and the environment. In tropical areas, detection of Vibrio cholerae is also common.
Diversity of media
A wide variety of media are used in water quality analysis. For example, MacConkey agar is a medium specifically designed for the growth of Gram-negative bacteria, while mEndo agar is designed for the isolation of Salmonella. The development of these media provides important support for water quality monitoring.
MacConkey agar can clearly show the growth of lactose fermenting bacteria, further helping us identify contamination problems in water.
Future Outlook
With the advancement of science and technology, the accuracy and efficiency of water quality analysis are constantly improving. In the future, not only will these methods be further improved, but innovative water quality testing technologies will continue to emerge. Therefore, we must also remain vigilant in terms of environmental protection and public health, and review the safety of our water resources at any time.
Faced with the ever-changing environmental and water resources challenges, how should we further promote research and practice on water quality safety?
