Name: How Much Bacteria Is In Your Drinking Water?
Uploaded: 2021-04-17T07:43:41.000Z
Duration: 4 min 9 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

That glass of water you're drinking probably contains 10 million bacteria.

Researchers at Lund University in Sweden revealed exactly how many bacteria is living in the

According to their paper in Applied Microbiology and Water Resources, our drinking water has

eighty thousand bacteria per MILLILITER, and a couple thousand more bacteria species in

Using flow cytometry, a laser-based system, scientists counted what was previously uncountable:

every tiny particle flowing through our water pipes.

Then using DNA sequencing, they uncovered a huge diversity of bacteria lurking behind

This is like turning on the lights in a dark room.

We knew stuff was going on around us, but didn't know exactly what was involved.

For example, in a 2013 issue of Water Science and Technology, researchers isolated four

types of microorganisms commonly found in drinking water: Sphingobium, Xenophilus, Methylobacterium,

These are mostly harmless genuses of bacteria found in soil, on leaves and in lakes.

How'd it get from the Yukon to your glass?

Drinking water is fed by snow and rain which streams down mountainsides to rivers where

it's pumped, diverted or dammed to provide a supply of drinking water.

Bacteria hitches a ride on that trip too, all the way to your parched throat and beyond.

The water is filtered between the lake and your home though.

Water treatment plants use increasingly finer meshes, sands, settling and aeration tanks

to filter out particles, and often add chlorine, or use ultraviolet light to kill any microorganisms.

The city of Hong Kong created a helpful graphic to show how they add Alum, Lime, Chlorine,

and polyelectrolytes, to clean and clarify their water before sending it on to their

They even add a bit of fluoride for dental hygiene.

Once out of the treatment plant though, the water is exposed to bacteria once again…

When left to it's own devices in an aqueous environment, bacteria will form what's called

Biofilms are like plaque on your teeth, or kombucha… only less… no, about equally

And our water systems are FILLED with them.

But again, don't freak out, think of these films of bacteria like our gut microbiota,

Researchers in the International Journal of Environmental Health said biofilms "represent

Though gross looking, they're generally not harmful; some are even healthful!

In nature, they provide self-cleaning potential for soils, sediments and water, but in our

pipes biofilms may be trapping dangerous pathogens before they get to you!

Government agencies at every level test municipal water supplies in order to keep citizens safe.

No doubt this is partly why the United Nations' Global Drinking Water Quality Index rates

the US as having some of the best water in the world.

But trying to make our systems 100-percent "clean" -- that is bacteria free -- might

According to Professor Catherine Biggs at the University of Sheffield, "The way we currently

maintain clean water supplies is a little like using antibiotics without knowing what

infection we're treating," it works, but just like in our gut, we might be harming the good

We don't want to kill ALL bacteria in our water, but as techniques improve, we can filter

out the bad bacteria, and leave the biofilms to help out.

We know you love watching online, but we're excited to announce DNews is now on Science

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Does the discovery of water bacteria put you off tap water?