Ecologists have long been sounding the alarm that the reserves of absolutely pure water on the planet are rapidly declining: traces of toxins and heavy metals are found in many natural reservoirs around the planet. Some of these hazardous substances also enter drinking water. And in many cases, a person does not even realize that his drink contains heavy metals.
The main paradox is that even if the water in the initial section of the water supply is actually clean, this does not guarantee that it will remain the same after passing through the pipes. For example, American experts analyzed the water in the Flint (Michigan) water supply. It turned out that there is no lead in the liquid coming out of the city’s sewage treatment facilities, but this dangerous substance is already present in the tap water in the housing of the townspeople.
That is why scientists are increasingly talking about the need to test drinking water for the presence of heavy metals, such as lead or cadmium, by taking samples directly from taps. This is exactly what a group of scientists from the University of California (San Diego) and researchers from Quantitative BioSciences are doing.
According to the researchers, it is possible to draw objective conclusions about the state of drinking water only under the condition of constant monitoring, and not sporadic analyzes. And for this it is important to develop a testing system that can be installed directly on the taps, the water from which people use for drinking. To this end, a team of scientists used a completely new approach: to monitor drinking water for the presence of heavy metals in it, in which the researchers used bacteria as sensors.
E. coli as a sensor of drinking water pollution
The bacterium E. coli, also known as E. coli, is known to many as the causative agent of many dangerous intestinal diseases. But California scientists used a harmless strain of bacteria for their research. Bioengineers and biologists have discovered that the genes of bacteria react to a polluted environment in a special way.
Combining knowledge from different industries, including bioengineering, synthetic biology, microfluidics, mathematics and other sciences, scientists have created a unique system that monitors water quality for 2 weeks and signals when pollutants enter it.
The system developed by scientists consists of 2000 different strains of bacteria embedded in a special chip made of durable translucent material. This plate is divided into tiny chambers, each containing a single strain of bacteria. Tiny channels lead to the chambers, through which the studied water moves.
In each of these 2000 strains, scientists have introduced genetic material that allows the bacteria to emit fluorescent signals at certain times. In a specific case: if a pollutant is in the water and it comes into contact with the built-in gene, the bacterium begins to glow.
The processor registers and analyzes the bacteria’s light signals, so scientists can determine when the bacteria are in contact with the pollutant. This particular study used heavy metals as an indicator, but in the same way, artificial intelligence and the system itself can be programmed to detect other pollutants. Therefore, it can be assumed that this discovery will provide new opportunities not only for researchers, but also for users in the future.
- Sources of
- University of California. – Scientists design way to use harmless bacteria to detect heavy metals in drinking water.
- PNAS. – Genome-scale transcriptional dynamics and environmental biosensing.