Detecting Micro Sized Particles In Water

<...distilled water, which is of known purity...>

Ahhh, um, er, no, it isn't, actually. Not without some numbers attached to it, anyway.

Personal experience of 1ppm of finely-divided ochre, which is opaque, in borehole water suggests that optical detection of anything at that level of suspension is very difficult. The levels of plastics indicated are lower than this by several orders of magnitude, and many transmit light readily.

Media filtration will take out most suspended solids. Then, what does one do with a couple of tons of finely-divided mixed plastic interspersed with dirt, bacteria and other "humungacite" (rhetorical question - NNTR)? Tipping it down the drain and thereby returning it to the environment via a watercourse, as happens when a conventional media filter back-washes, is clearly not an option!

That is why I specified "known purity" to allow for compensation for any contaminants in the water.

To dump the waste back into the source would be folly.

It should be buried in a landfill with a proper liner,but keeping in mind that nothing is 100% foolproof.

A single particle of smoke may be hard to detect,but in sufficient quantity it is easily detected.

The oil industry has no motive to detect finer particles,and no ROI,so of course they will say it is not possible.

It may be difficult,but not impossible.

Remember the tobacco companies?

Not personally.

IMHO:

Well,the tobacco company executives each testified to congress,under oath, that tobacco did not cause lung cancer.

In actuality,the companies hired a doctor to examine lung tissue of people that died from lung cancer in the 1950's.

He reported that within each and every tumor cell,there were traces of phosphorous.

Phosphorus in known to cause tumors.

Presumably,this was from the fertilizers used to grow tobacco.

The report was buried and never came to light until a few years ago.

The companies saw a lot of lawsuits ahead,so they did not want it known,"Just let the company last till I get my golden parachute,and let the next guy handle the problems." seemed to be the intent of the executives.

A corporation has no conscience,and the only motivation is profit and growth.

People are just warm bodies to the upper management,like the BP executive that just "wanted his life back" when he had to abandon his golf game and answer questions about the infamous well head blow out in the Gulf.(the Deepwater Horizon)

I imagine the 11 families wanted their loved one's lives back too.

Recycle it the old-fashioned way and burn it.

Some perspective:

Almost all bottled water contains microplastics, study shows

Plastic found in most bottled water, triggering World Health ...

" typically 10 plastic particles per litre of bottled water. Each particle is larger than the width of a human hair."

I saw no explanation of the source, but the distribution of plastic types seem to include most common thermoplastics.

I'm going to guess that eventually we'll be taught that ingested plastic is safe at X=ppm.

... speaking of distilled..

Can a larger sample of water be distilled until a drop is left (with plastic bits) for viewing on a slide?

It depends upon whether the heating surface temperature is below or above two other critical temperatures:

• The lowest melting temperature of any of the plastics in the mix, and
• The lowest auto-ignition temperature of any of the plastics in the mix.

If it is above then one gets "ground-in dirt and stains that ordinary powders leave behind".

Evaporation at partial vacuum with a low-grade heat source as the heating medium sounds as though it may work, perhaps.

Straight distillation would be loose a lot of compounds

...evaporation with a (clean ultrahydraphobic) funnel that makes up in extreme width for what it lacks in perceptible height?

The question being would all of those compounds absorb or reflect UV?

Regardless,that is the reason for zeroing the instrument with each reference sample,to negate any thing in the reference sample.

That's the root of the problem, would they or wouldn't they absorb or reflect UV. The debris probably does both to varying degree depending on the nature of the unknown debris. The dye identifies what debris is that type of plastic. That dyed debris is now easy to identify from the other debris because it not only absorbs UV light with some of the debris but it fluoresces a different wavelength of light than UV.

Oh! The question..

Count me out.

Very interesting method of analysis

I don't believe they tested for plastic in bottled water "in situ". Shining light through plastic and water to look for plastic should always detect plastic. Thus the larger than X concentrated filtrates must now separate plastic from other debris. This is the task of the material selective dye. Looking for anything captured by the filter will not identify what is plastic.

Common sense would dictate that the sample would not be contained in a plastic vessel,but made from another type of material,perhaps a quartz tube to prevent absorption by the sample container.

There are techniques in use already, with turbidity meters being among the equipment used. A turbidity meter will not differentiate between plastic and anything else, measuring merely the "cloudiness" of the water, for want of a better term. Turbidity is a reasonable measure of the level of suspended solids of all types.

Here's another study using micro Raman. Most of the particles in drinking water could be explained by the containers and caps themselves. Although they did find particles in glass bottles too.

https://www.ncbi.nlm.nih.gov/pubmed/29145085

I can't answer the original question, but it stands to reason, since plastic resistance to UV is highly variable, the absorption of UV also varies. Additives are used to extend the life of greenhouse films for example, and I would think there are as many variations on that as you can imagine.

I'm thinking that absorption is not the way to go. If you have very little plastic material, say, and it absorbs only 0.01% of the light, the intensity would be reduced from 100% to 99.99%, very difficult to detect.

If you shine a high power laser beam through the water, a reflection of 0.01% of the beam would be readily detectable in an off-beam direction.

I suspect that using the dye that binds to the plastic increases the sensitivity in that the fluorescence is a different color and can be viewed with an appropriate filter.

Some of my thoughts :

A. How much is a " large amount " ? If you ( the study ) were to quantify an amount, would you say it would be, 1 ounce per 100 gallons or 1 dram per 1000 gallons ?

B. A very expensive dye. Is the dye expensive because of the quantity sold : only available in a 1 gallon bottle, but how much of the dye is actually used for the test ? i.e 1 oz. or 3 drops ?

C. How was it determined which dye to use ? Was there a known type or quantity of plastic that would be in abundance over another lesser type ? Or does the test require different dyes to reveal all traces of plastic. What dye did they use ( chemical name ) ?

D. Contamination from the air : if a sample was drawn from a sealed container with a syringe and then transferred to another sealed container ( like is done with blood samples )

The back of my envelope suggests that, given particle size = (width of human hair * 1mm), with 10 particles/L, and given the sample is 1L in a cubic container, and given that all the samples are totally opaque, the light intensity transmitted through the container would be reduced by about 0.005% due to the presence of the particles.

Pretty tricky to detect, as Rixter said.

The number of particles could only be calculated if their sizes were known - which is not usually the case in such studies.

In the 80s and 90s, I was involved in the N Sea oil game, supplying seawater filters on well injection for secondary recovery. Typical requirement was 95% removal of particles > 5 μm, determined using a Coulter counter.

I used to have data on number of particles per ml of seawater, as function of diameter, but I can't find it, and nothing jumps out of the internet.

Don't know whether that adds anything to it!

One finds <...a large amount of very small...particles...> in milk.

Since the bulk of water handling and laboratory equipment these days is plastic, such a result is not surprising. Any wear product in the handling and processing is likely to be plastic, down to the process of screwing or snapping on the cap.

Even distilling won't necessarily remove the plastic because of the following mechanism. Boiling water involves bursting steam bubbles, which generate mist that potentially contains a particle. When the mist evaporates, it leaves a dry airborne particle that travels with steam to a condenser where it re-enters the distilled product. The filter beer by running it through diatomite (chalk). If it's good enough for beer, it's probably good enough for water.

If I were looking for plastic particles, I would use a ceramic filter with low micron or sub micron pore size, put the liquid through it and examine the filter surface for the plastic particles since the surface will have concentrated the plastic to detectable levels. Potentially the ceramic could be burned off for reuse.

The dye used for the evaluation is going to have some chemical activity to any surface it contacts, so there is a potential in any case for a false positive for dye attached to the test container surface or as carryover in the water itself.

One question I don't see yet is what type and size of plastic particles is actually of consequence to health of humans or to biota in the environment? Plastics are composed of organic molecules and are digestable by bacteria given enough time. Nylon was considered to be a "forever" material when first introduced, but certain bacteria learned to eat it within 30 years of it's introduction. One thing I learned in environmental science is that no scrap of energy is wasted. Something always learns to use that scrap of energy that is available and eventually that plastic is going to get converted to humic acid.

Ideonella sakaiensis, for one.

http://science.sciencemag.org/content/351/6278/1196

Others perhaps, as yet unidentified...

https://www.newscientist.com/article/2132650-newly-evolved-microbes-may-be-breaking-down-ocean-plastics/

I suppose we could also engineer a yeast that ferments plastic into good sippin' 'shine that we could also use as fuel or for more plastic precursor stock.

How 'bout a fungus that shapes plastic waste into Darwin Award trophies.

Then everyone could have a participation trophy, even the participatorially challenged ones.

I'll drink to that, but it'll be well water through copper pipes and out of a glass...

Perhaps flocculants would cause the particles to drop out,given sufficient time.

Look closely enough and one can find anything...

I would like to see the evidence that small amounts of plastic cause any harm to humans before agonizing over the corrective action needed...hopefully the counter measure might be as simple as drinking a beer every other day...

https://www.nationalgeographic.com/environment/2019/06/you-eat-thousands-of-bits-of-plastic-every-year/

OK. A brief Google search led me to this article. The primary effect this article found was if the particles were small enough an allergy immune system response occurs.

This might explain the rise in allergies. Since everybody's immune system is different, it will be hard to say who has been or might have allergies due to micro particles.

A lot of speculation, not conclusive that this is happening, only that under certain circumstances this might happen if indeed it is even possible...

From the second link...

" The knowledge on the adverse effects on human health due to the consumption of marine organisms containing microplastics is very limited, difficult to assess and still controversial. Thus, assessment of the risk posed to humans is challenging. Research is urgently needed, especially regarding the potential exposure and associated health risk to micro- and nano-sized plastics."

Translation = We still haven't found any harm to humans, and need more money to continue searching...So we've decided to try to scare you into funding our vacation work...

Speculation is not evidence...

Humans consume all manner of waste... bugs, dirt, dust, bacteria, viruses, plastic, poop, hair, skin cells, fungus, mold, mildew, every chemical there is, radioactive stuff, dander, every kind of mineral, microbes of every kind, and generally speaking we still live for 80+ years, so don't bother telling me what might be harmful because any and all of it might be harmful taken in excessive proportions....

Stop trying to spin the definition of evidence...

"the available body of facts or information indicating whether a belief or proposition is true or valid."

The only evidence you've shown is that there is no proof plastic is harmful to humans in the estimated consumed quantities...you've disproved your own case....

I'm not spinning anything. You are the one dismissing data that doesn't meet your preconceived notions.

To be accurate, nobody knows if micro-plastics are harmful to humans because they are already so ubiquitous. That doesn't mean they aren't harming us.

You could say the same thing about taco's....

No I cannot say the same thing. I did not provide any evidence about tacos. Do you need evidence about tacos now? Your clarity of thought is getting questionable.

The next point is find the source of the plastic particles and correct that.

which there are issues with defoliants using plastic particles within body wash that gets through sanitary and can eventually turn up in the water supply.