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Old 09-01-2002, 01:06 PM
astro astro is offline
Join Date: Jul 1999
Location: Taint of creation
Posts: 33,150
Tomato plants grown on human waste water effluent OK to eat?

Because tomato seeds have a gelatinous coating they can survive a trip through the intestine and the sewer system and are often seen in the spray fields of waste water treatment facilities where the waste water sludge is treated and sprayed on fields as a nitrogen enhancer and more bio-friendly way of breaking down the waste.

Not that these would be the first tomatoes of choice, but if I were hungry and desperate to wat them could these tomatoes potentially carry any pathogens, heavy metals or other harmful substances to the person consuming it because of the medium on which they were grown?

At the treatment plant

While often undigested tomato plants and pumpkin vines sprout out of the sludge

What happens to tomato seed which you "eat" when they pass through your body?

- nothing, it passes through the human digestive tract intact and ends up ready to grow Example, when Gas Works Park was built, they were in the early years of starting to compost and use sewage sludge as an organic soil amendment. Many of the "mountains" there were filled and shaped with Seattle sewage sludge. The following year, the ground was covered with a terrific cover of tomato plants. We no longer encourage the use of sewage sludge for areas where you are going to be planting edible crops.
Old 09-01-2002, 03:06 PM
Tuckerfan Tuckerfan is offline
Join Date: Jan 2001
Location: Gallatin, TN
Posts: 21,676
I would think that it depends upon how well the waste water is treated beforehand. There's a city in California that uses basically a series of ponds, marshes and plants to purify its waste water to a high degree. (It's located in a popular park!) I would imagine that plants grown in some of the later parts of that kind of treatment system would be safe to eat.

Also, I doubt that if you were only going to eat one or two of the tomatoes from another site that didn't clean its waste as well,, you'd have anything to worry about.
***Don't ask me, I don't post here any more, and I'm probably not even reading this now.***
Old 09-01-2002, 03:33 PM
Hirsel Hirsel is offline
Join Date: Mar 2002
Location: Copenhagen
Posts: 17
Hey my girlfriend is just doing a project about this question.
This will be a report for the Danish government about, whether
it is save to use human waste as fertilizer. The most important
question is the question of human parasites, such as cryptosporidium.
If you eat your tomato then chances are that you infect yourself
with a human parasite, which gets passed on again and again.
The parasites will die if there was enough time between sowing
the tomato and bringing out the manure, but in the described
case this was not the case.
Old 09-01-2002, 07:18 PM
handy handy is offline
Join Date: Mar 1999
Location: Pacific Grove, Calif
Posts: 17,493
My neightbor in California used it in the 70's. He bought it at the store, its called MILORGANITE. Yes, they dry it & then you buy it in a bag. He had the best growing plants I ever saw & I ate a lot of them too.

As a matter of fact, this is well covered right here dude:


They are kind of gentle about what's in it & what it's made of:
"However, because Milorganite is a by-product of a wastewater treatment process, it must meet additional quality and safety standards not imposed on traditional fertilizers, and is further regulated by the U.S. Environmental Protection Agency and the Environmental regulatory agencies of individual states."

Yeah, believe it or not.
Old 09-02-2002, 03:21 AM
Ringo Ringo is offline
Charter Member
Join Date: Apr 1999
Location: Houston, TX, USA
Posts: 11,261
Correct me if I'm wrong astro, but I believe your question is not whether or not it is safe to use human waste as fertilizer (which the Japanese have done without problem for a long time), but rather whether tomato seeds that have passed through a human digestive system produce fruit that is safe from contamination.
Old 09-02-2002, 07:38 PM
AskNott AskNott is offline
Charter Member
Join Date: Mar 1999
Location: Anderson, IN,USA
Posts: 14,662
I'll reply on two tracks: First, effluent from your city's sewage plant probably should not be used for food fertilizer. The reason, changed in recent years, is that industrial waste contains metallic ingredients which can find their way into your tomato. The processing probably, probably kills bacteria before it can hurt you.

Second, human waste that hasn't been that thoroughly processed should not be used for growing food, ever. My older brother got hepatitis from eating the native food in S. Korea several years ago. The Koreans used human dung as fertilizer, directly. Folks would crap in the streets, and dung sellers would gather it to sell to farmers. Hepatitis survives digestion, and it finds its way into food plants. My brother spent months in the hospital.
"You know what they say about sleeping dogs; you can't trust 'em." --Oliver Faltz
Old 09-03-2002, 12:17 AM
Spiratu Spiratu is offline
Join Date: Jun 2001
Location: Central PA
Posts: 240
Sewage sludge used as fertilizer is called "biosolids." According to my introductory Soils textbook (Soil Science & Management, Plaster, 1997), the main risks are from heavy metals that accumulate in human waste, such as lead, arsenic, and cadmium. There is no recorded case, according to the book, of a disease outbreak from pathogens in biosolids. Supposedly, up to 80% of the sewage sludge applied to land is used in agriculture nowadays (the rest going to landfills, i suppose).
That said, however, my book also goes on to note that biosolids need to meet certain requirements before they can be used to grow plants for human consumption; that is, they have to be tested for heavy metals and pathogens before they can be applied. So, unless the sludge in question is already being used to grow some sort of crop, it's probably a pretty good idea to assume that it's not safe.


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