How to poison a river

I realise that this is a really weird question to be asking, I'm probably going to be put on some sort of goverment list, but it's not as malicious as it sounds.

I'm writing a short story for my creative writing degree about a small fishing village, and I want one of the characters to poison the river to kill the fish. I've been doing a bit of research but it's kind of a hard question to google. "How would I poison a river?"

So I figured that the escapist is as smart a bunch commenters as any other forum, so I'd ask if any of you guys could shed some light. I don't even know if it's possible.

It would be a fairly small river, not too near the river mouth and salmon would be the fish being poisoned. As simple a delivery method as possible, It's got to be feasible. It's probably do-able with several tonnes of sulphuric acid, but I don't know anyone with access to that.

Thanks for the help :)


You could introduce an invasive, brutal, non-native species like the Asian Carp, Piranha or Snakehead (yeah, I loves me some River Monsters). That would take too long though. There's also Phiesteria, aka "The Cell From Hell" which will not only kill fish but also have adverse effects on people. Then there's Vibrio Vulnificus, which is just plain nasty for humans but I'm not certain that it will affect fish. Finally, you could follow real life and dump a ton of nitrogen-rich fertilizer into the water, causing algal blooms, creating oxygen-depleted dead zones, causing most of the fish to suffocate.

Not in real life, of course.

I suppose you could also just make up a plant similar to the ones used in real life to tip arrows with poison. Your character could collect large amounts of it and start feeding it slowly into the river somehow.

If you google water purification tablets it should give you examples on why they would be necessary when out in the wild. You could work from there.

If you want the fish to die, raise the water temperature somehow. That'll kill them just as easily. Something upriver has to be able to heat the water a few degrees, but it could work. Small earthquake ruptures a sulphur gas pocket? That could work, too.

Fish toxins sound interesting.

I suppose if you want to go apocalyptical you could have Karenia brevis blooming in the river. They are phototrophic single-cellular organisms responsible for the "red tide", which regularly kills lots of wildlife by deoxygenizing the water and also producing potent neurotoxin.
And it effectively turns the water into blood, which makes for nice dramatic effects.

Mercury can kill of aquatic life really quick. Dump one or two oildrums with that stuff in a small creek/river and you should start seeing unhappy fish fairly fast.

As simple a delivery method as possible, It's got to be feasible. It's probably do-able with several tonnes of sulphuric acid, but I don't know anyone with access to that.

'Simple' and 'feasible' are relative. Poisoning a river is not an easy thing to do. It basically depends on how much money the character has, and how good they are at lying.

Also, consider that it might not matter. If poisoning the river is a plot device rather than the plot (ex. if the poisoning is just one small element in a larger story vs. the entire story being an investigation of who is poisoning the river and how), it's probably best just to have the character dump a few barrels of unknown chemicals (that burn exposed skin and eyes) into the river and call it a day. You don't want to go too deep on something that has no real importance in a short story, otherwise the story ceases to be short.

That's done, now for the fun.
1- Mercury is a good bet; it's very hard for individuals to get, but at industrial levels it comes out to about one US dollar an ounce. If the character has a few thousand dollars and the ability to fake credentials/ bribe governmental regulators, it's probably the most simple to just buy a barrel or two and dump it into the river. It's straightforward, easy for the reader, and gets poisoning the river out of the way so the plot can continue.

2- As AWAR points out, fish toxins (natural agents derived from plants) can work, although I don't know how easy they would be to get. For instance, one plant described on AWAR's list can deal with a 100sqft pond with only 0.5 kg of the mixture. If you want something a little exotic or out of the ordinary, this could work (you can hand-wave how they got the plants with brief mentions of black markets and the internet).

3- Cyanide fishing is a possibility. I don't know how much is needed, but the chemical is fairly widely produced for industrial reasons, and getting a few drums to throw in the water shouldn't be hard.

4- Zap the fishies. This one might be the most feasible, actually; the character gets a few portable generators, weaves some nets out of copper wire, and spends a couple of nights electrocuting everything in the river. It's not foolproof, but it works and has a certain 'Occam's Razor' ring to it. Dynamite fishing also works for the less patient, although that stretches the limits of 'poisoning'.


Do you want the poisoning to be accidental or deliberate and malicious because that would change how you did it.

The accidental, just introduce a new element to the ecosystem, be it a new predator or a competitor for food, or a virus.

As for deliberate, the easiest way would be dumping chemicals, or introducing a new kind of virus.


Reply to Thread

This thread is locked