Foam in Streams in Dublin Mountains looks dodgy. What is it ?

BeerSteakBirds

I have attached a photo taken of a section of stream in the Dublin Mountains recently.

Can anyone shed light upon what this foam is ? Is it from Acid rain or chemicals ? Is it harmful ? it doesnt look natural but someone tried to assure me it was ...

ytpe2r5bxkn0c1

You see that foaming where a rush of water gets stalled by an obstacle. No unusual.

St. Leibowitz

Foam in turbulent water is caused by a surficant trapping air. Detergent is probably the surficant most common to us, and we see its effects when washing the dishes.

However, there are many natural surficants. Some of these are released by algae and plants during decomposition, and also when living, and is known as DOC (dissolved organic carbon) once it enters a water stream. In rivers and streams, DOC can be created by water plants, but often gets washed in from the surrounding land. After very high rainfall, the DOC content in watercourses would be very high due to the flushing of surrounding land, and therefore the foaming at turbulent spots particularly active. Lakes and streams with brown water indicate high DOC, and are particulaly prone to foaming.

So given the location (which appears to be away from industry), the recent heavy rain, and the high flowrate, it looks like your example is natural. The recent Tolka example happened during a dry spell, and downstream from industry, and so was immediately of a suspicious nature.

BeerSteakBirds

Thanks . It just looks so unnatural to me for some reason. Is it poisonous or is the water in such a location less safe to drink ?

ytpe2r5bxkn0c1

I wouldn't recommend drinking river water in any area with farming activity locally.

Zoo4m8

If it bothers you don't drink it..but it's never done me any harm and will still drink from a stream on occasion..

gozunda

It's a fairly natural phenomenon - this from a poem written by William Allingham. (1824–1889)


UP the airy mountain,
Down the rushy glen,
We daren't go a-hunting
For fear of little men;
Wee folk, good folk,
Trooping all together;
Green jacket, red cap,
And white owl's feather!

Down along the rocky shore
Some make their home,
They live on crispy pancakes
Of yellow tide-foam;

Some in the reeds
Of the black mountain lake,
With frogs for their watch-dogs,
All night awake.

High on the hill-top
The old King sits;
He is now so old and gray
He 's nigh lost his wits.
With a bridge of white mist
Columbkill he crosses,
On his stately journeys
From Slieveleague to Rosses;

Or going up with music
On cold starry nights
To sup with the Queen
Of the gay Northern Lights.

They stole little Bridget
For seven years long;
When she came down again
Her friends were all gone.
They took her lightly back,
Between the night and morrow,

They thought that she was fast asleep,
But she was dead with sorrow.
They have kept her ever since
Deep within the lake,
On a bed of flag-leaves,
Watching till she wake.

By the craggy hill-side,
Through the mosses bare,
They have planted thorn-trees
For pleasure here and there.
If any man so daring
As dig them up in spite,
He shall find their sharpest thorns
In his bed at night.

Up the airy mountain,
Down the rushy glen,
We daren't go a-hunting
For fear of little men;
Wee folk, good folk,
Trooping all together;
Green jacket, red cap,
And white owl's feather!

SpaceTime

Most likely natural if you're up the mountains however, surfactants from septic tanks and treatments facilities get into rivers.

This is why I make sure I use biodegradable detergents.

ecover dishwasher tablets work just fine for example. You don't really need most of the chemicals that are being marketed at you.