Poisonous condensate?

nmacc

OK, not sure if this is a Gardening query at all, but here goes:

Got a call about 5 weeks ago from a friend who reported a sewage smell in the house. He opened up the woodwork under his stairs, revealing quite a substantial crawl space. I found a polyethylene mains water pipe that had been chewed by a rat & had been spraying the woodwork for a long time, resulting in damp & mould. I fixed the leak & we left the crawlspace exposed to dry.

It took about two weeks before I got back with a dehumidifier. It produced a LOT of condensate. They are keen gardeners, so rather than chuck the water down the drain, they used it on the flowers, plants & tomatoes.

It killed everything.

We can be sure that it was the condensate, because one of the jugs was thrown onto the lawn, where it killed a patch of grass. Someone walked through this patch and left a trail of footprint-shaped patches of death on the lawn.

I'm stumped. Any ideas anyone?

Stellaluna

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amandstu

Was the wood treated with damp or dry rot treatment? Does the actual dehumidifier use chemicals to do its job? Are your rats doing dope?

nmacc

No damp treatment that I'm aware of. It's not rat urine, noxious though their pee may well be.

The dehumidifier is a regular refrigeration-based condensing machine. The only odd thing is that it's producing a hell of a lot of condensate. I used the machine to dry out the very damp 1867 house in which I live, and it took about a day-&-a-half to fill the condensate jug. In this otherwise sound 1960s house they are getting a full jug every day & have been for the past three weeks.

I'll have to go back there & check to make sure there isn't another leak, but with that kind of dilution, it would have to be pure rat pee down there to kill off the greenery.

cheif kaiser

Could it have been caused by mould spores that the humidifier picked up ? Black mould which grows in damp dark places can be very dangerous to humans but not sure on it's effects on other plant life but I wouldn't imagine it would be very good for them!

nmacc

There was a trace of mould, but once again, with that kind of dilution it would have to be a version of the botanical equivalent of the Black Death!

My guess is that the that the wood is treated, the wood absorbed the water. When the area started to dry out, the water in the timber evaporated carrying with it some of the preservative, that then condensed in the humidifier.
Wood preservative can contain lots of chemicals, so I wouldn't eat any of the tomatoes that got watered.

Sulla Felix

Could it be the dehumidifier? If it's an old one, the solder etc might be breaking down and they just gave their lawn a nice case of heavy metal poisoning.

redser7

It's a puzzler alright. Very interesting. I imagine some testing of the condensate would show up something obvious. I wonder can lab tests be done? Is it affordable? Might be worth it if there s a danger? Maybe try the chemistry forum?

http://www.boards.ie/vbulletin/forumdisplay.php?f=391

nmacc

Oddly enough Redser, I originally began the post in Chemistry, then moved it here. I'll try moving it there.

I suggested to the friends that they should fill a bottle with the condensate and bring it to the council, asking for an analysis & claiming that it came from the taps to see what they find!

magicbastarder

the strange thing is that that water is essentially distilled water; if the preservative which may have been in the wood was not liquid, it should not be carried through to the distilled water.
might the cooling blades/fins on the dehumidifier be dirty?

nmacc

magicbastarder wrote: »

the strange thing is that that water is essentially distilled water; if the preservative which may have been in the wood was not liquid, it should not be carried through to the distilled water.
might the cooling blades/fins on the dehumidifier be dirty?

Indeed it is distilled water. It just seems to have the properties of distilled poitin.

The filters on the dehumidifier are clean, but of course the condenser could be dirty. However, if it's washed more than 20 litres of water over the fins, could there still be toxic dirt there?

amandstu

If there is an awful lot of water being sucked out by this dehumidifier perhaps there is a secondary leak you haven't found which contains something as well (rat poison? We have decades old saucers of rat pellets in our attic that are still intact : if they got wet and leaked maybe they could contaminate condensate) .

Did you smell the liquid ? No petrol smell? Anything else that could come out of a boiler for instance?

magicbastarder

might be worth doing a pH test on the water - i've seen soil pH tests for as little as a euro each, so it's a cheap and cheerful way to do an initial test on the water.

cheif kaiser

You could try emailing those brainy scientists at the Boanic Gardens, they may be able to help - http://www.botanicgardens.ie/herb/staff.htm