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Whatever is toxic to fish would be toxic to humans too, right? And Q. about plants

  1. Sep 7, 2009 #1
    I'm making a small-scale aquaponics system at home (except I'm not eating the fish). There might be some random chemicals that will probably leech into the water from the materials I used (plumbing parts degrading/oxidizing, etc.), or had directly added (I used household ammonia to begin the nitrogen cycle; I'm still waiting for the manufacturer to e-mail me back the MSDS for their product, or at least tell me straight up whether it is just pure ammonia diluted in water)

    The questions:

    1. If the fish die from poisoning from unknown chemicals, and I have been eating from the plants being grown from the system, would the build-up in my body be negligible?

    2. Would the plants' roots even transport the harmful chemicals present in the water into their leaves?

    I'm only particularly worried about the possible additives in the household ammonia. Although the label said it contained no phosphates and no fragrances. Apparently, if it contained surfactants, the container would fizz up if shaked. There was a tiny wee-bit of fizz that formed, but so miniscule compared to shaking other ammonia containing products which contained other additives. It might have just been air bubbles.
     
  2. jcsd
  3. Sep 10, 2009 #2
    Re: Whatever is toxic to fish would be toxic to humans too, right? And Q. about plant

    If there are chemicals leeching into the system, then there is a possibility of a human building up sufficent quantities of the chemicals after eating anything from the system to also be toxic. This would mostly be heavy metals since very small quantites of organics would be metabolized by the higher organism. Acute posioning is a possibility but less likely than chronic ingestion of heavy metals or long-life chemicals. Plants will also absorb chemicals/heavy metals but should be okay to eat in moderation.

    As for the ammonia, most likely there are not major toxic chemicals in what you are using. A small ammont of frothing would be expected in a concentrated solution. Even if there are surfactants in the ammonia, you shouldn't need to continually add ammonia once you have established a viable ecosystem. BTW, ammonia is very toxic to fish, so be careful of adding to much to you aquasphere if there are fish inhabiting your system.
     
  4. Sep 12, 2009 #3
    Re: Whatever is toxic to fish would be toxic to humans too, right? And Q. about plant

    Toxicity is tricky because it is relative to the organism. Classic case is Hydrogen Dioxide poisoning. Too much Hydrogen Dioxide and it will kill humans but humans need just the right amount. Fish would die without it though.

    Speaking from my own fish experiments, some species are incredibly difficult to kill... gold fish for example. They are very tolerant of less than ideal environments.

    Back to your aquaponic set up. How are you going to measure its effectiveness and efficiencies? Fish weight? Amount of food and energy inputs? Plant growth? Do you have a constant?
     
  5. Sep 19, 2009 #4
    Re: Whatever is toxic to fish would be toxic to humans too, right? And Q. about plant

    I've no clue, I'm just a hobbyist and not a scientist. I can only do the most basic observations...
     
  6. Sep 19, 2009 #5
    Re: Whatever is toxic to fish would be toxic to humans too, right? And Q. about plant

    ammonia is toxic to fish, but not so much to plants. when the bacteria convert ammonia to nitrite, that is even more toxic to fish. by the time another bacterial strain converts the nitrite to nitrate, most species of fish will not be affected by it.

    your best bet for seeding a tank is to use a fish like a molly that is tolerant to both ammonia/nitrite and fresh/saltwater.

    there's no telling what's in your ammonia bottle. quite a bit of household ammonia is the sudsy type, and maybe even the non-sudsy type is bottled on the same equipment.
     
  7. Sep 19, 2009 #6

    Borek

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    Staff: Mentor

    Re: Whatever is toxic to fish would be toxic to humans too, right? And Q. about plant

    You got it reversed.
     
  8. Sep 21, 2009 #7

    alxm

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    Science Advisor

    Re: Whatever is toxic to fish would be toxic to humans too, right? And Q. about plant

    Most things that are toxic to fish are toxic to humans. But not everything. Not everything that's toxic to dogs is toxic to humans. (e.g. chocolate)

    Whether it builds up in your body or not depends entirely on the toxin. Some bioaccumulate, others don't. It's the former we're trying to get rid of. (heavy metals, DDT)

    Household ammonia is usually.. just ammonia. Which isn't much of a cause for concern if it goes down the drain. It's not toxic in small amounts, it's also already in sewage anyway (from urine for instance), and water-treatment plants take care of it. It's no biggie.

    (BTW: It's 'leach', not 'leech'. A leech is an animal. Common mistake.)
     
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