Composting Pet Waste

Hi everybody. I'm fairly new to composting. We have a small worm-based composter.

What are the guidelines around composting things like your dog's poo? The cat's is a little more difficult to get at with all of the kitty litter, but the dog poo needs to go somewhere. 

What are the types of things I should be worried about? Parasites? What he eats?

I am not certain, but I think that there are some issues about pathogens in dog poop that can harm humans.

If you have a first rate compost system, you should be able to eliminate 98% of those problems, but ....  I think I would still have concerns.

An alternative approach would be to make a separate  compost pile (or pit) and figure that that compost (or pit) is for non edible composting.  So - suppose you had a spot for dog poop and you piled up the poop along with some sawdust ...  after a year or two, you could plant some sort of tree there. 

My parents have raised beagles in their back yard for years, and Mom puts the poop around the rosebushes and waters it into the soil.  They seem to like it (the roses, that is).

Robin 

laDiva2 wrote:
My parents have raised beagles in their back yard for years, and Mom puts the poop around the rosebushes and waters it into the soil.  They seem to like it (the roses, that is).

Robin 

That sounds pretty damn smart to me!

Alert! DON'T use dog or cat poo in the garden! they need to be composted into virtually nothing because of the different microbes in there. I've had this discussion with many different water quality/ salmon steward folks. There's even this fancy publications for big cities that equates the mountains of untreated dog poo in backyards to the pathogen load if half the human population of that city just pooed on their lawn.
Gross.

I want salmon to come back and that means clean waterways.

So, there's this bacteria thing excerpted from an email below. There's a big fancy 'container' that your supposed to buy for it. But I think this will work just as well : half buried plant pot + poo + bacteria = healthy decomposition.

The bummer I've heard from people who try it is that you have to add fresh poo every few days or the bacteria die off. Maybe there's something when you could just 'add a pinch' of bacteria whenever poo-pickup time actually happens.


http://www.doggiedooley.com/

But folks use humanure, wouldn't it be the same thing with dog poop?  If you composted it anyway.

I think there are ways to have clean rivers and dog poop.  I think there are also ways to have filthy rivers with no dog poop.  I think the thing to do is to find the path where folks can have dogs and we have clean rivers.

As for dog/cat poop in the garden,  I agree with kelda.  I wouldn't put it in my garden.

As for a bio product that decomposes poop - it already exists in all healthy soil.

humanure:  all successful uses I know of pretty much sterilize it first.

To Rachael's comment: I guess no it's a little different from humanure, just different bacteria and stuff, so I've heard (so it's very subjective of course). And humanure I tend to think of for perennials or forest only, not any smaller veggies....

I think this bacteria stuff that was recommended actually just breaks it down (with the aid of soil bacteria since it's in the ground), until there's not much of anything left anyway. So the question of what to do with it after is kind of unnecessary.

I think it's kind of like the 'green cone' concept. Green cone is usually for food scraps but the design (pretty similar to doggie dooley) keeps things breaking down so fast that it rarely fills up.

The bacteria in pet poop (any kind, really) is mostly a non-problem in a good compost pile.

BUT WAIT!

The real issue is the parasites, specifically roundworms.  I worked for a vet for 12 years and still don't really understand the complicated way these worms 'operate' in the animals.  But there's something about once the dog (esp) or cat has them, they kind of always have them to the extent they have eggs in their poop. 

An extremely high percentage (some sources say 'almost all') of puppies are born with worms. then they're wormed and people think the problem is solved.  But it's something like a Typhoid Mary problem: born with it or got it early, now shows no symptoms, but passes it on.

But then there are the eggs... they can live for many years in the soil, immune to extremes of heat or cold.

I try to do the best I can with my compost, turn it, moisten it, etc, but sometimes I still get weeds sprouting in my homemade potting mix, and that means not all the compost got high enough to kill off everything.

Don't do it!

Here's an article from Medscape Today:  http://www.medscape.com/viewarticle/573090

Sue

Unilateral edicts are always hard for me to read.  There will always be a dissenter (me, this time) who will say "I'd do that thing you say should never me done."

I'd do it.  But I wouldn't plan on using my compost on things I'm gonna eat. 

My compost pile is used to minimize my garbage stream, clean up the biodegradables (the quick ones anyway), and get a little somthing good out of the process.  I use my compost on trees, flowers, bad lawn areas, wherever I'd like to jumpstart some life.  I've used it to start veggie gardens too, but I guess I'm goofball that doesn't have that top of my list for using my compost.  I'm not an every year user for my veggies...they do fine without it.

Currently, I don't put my 3 dogs' poop in the compost pile, just for laziness' sake.  I have 3 acres, and I leave it where it lies and it goes away eventually.  However, if I happened to have the 1/4 acre my father has, I'd be cleaning up like crazy and I wouldn't have a problem using my compost pile to dispose of the poop.  Likely I'd avoid using it on my veggies, just for the mental ick factor of knowing that stuff's in there (I still have some poop issues to work through). 

And if I should ever decide to make veggie-used compost I'd either have a separate pile or stop putting poop in.  Would I worry about the worms I could have added to the area through years of composting poop?  Prolly not any more than I'd worry about what happened to that patch of earth where I happened to put my pile before I got there.  I guess I'm lazy minded too.

At any rate I wouldn't sweat the poop if you can say your pile isn't for edibles, and that makes it a bit less unilateral.

-Jeremy

Almost all of my compost is for veggies, which is why I wouldn't use it.  I don't have enough compost (no matter how much I make) to put under the ornamentals and trees.  If that's what you're doing, no problem.

But when most people ask about poop in compost, they're asking because of food contamination issues, and that's where the danger lies.

Sue

Okay, okay, I've had some rethinking of this issue.

Let's say a certain friend just buries humanure around their land, with no danger to the soil/water quality, and this gets me thinking about why it wouldn't be good (or not?) to bury dog/cat poo.

First, parasites aside. I don't know enough to hazard any guesses. So I'll just continue with my thought assuming that the dogs/cats do not have any wormies, etc.

A soils/industrial humanure friend has described to me the process of making poopies okay for the garden. Basically, solids are much easier to compost than liquids. So follow this train of thought.

No-no's with poop: Dog poo in lawns and sidewalks in an urban setting --> rain hits it -->gookie bad stuff gets into the runoff and eventually into the Sound. Also, human poo in poorly functioning septic systems --> rain leaches it down to streams --> streams are now high in nitrates, unpassable by fishies.
both of these are liquid problems

Okay with poop: Dog poo with that fancy 'bacteria' composter or even green cone --> it has chance to compost before being hit by rain--> nutrients go into the soil, okay. Humanure in outhouse or 55gallon drums--> mixed with carbon and starts composting before, you guessed it, rain hits it--> nutrients are available, bad stuff isn't, spread it under the fruit trees. These are both solids solutions.

So now, the question I ask myself is: what if you just bury the poo under the ground (whether human or animal), let's say a foot down. Is this a solid or a liquid? Will it have time to compost? Will any gookie stuff work its way into a body of water?

What do you think?

Buried poop is better than unburied poop.

But I would have lots of concerns about poop that is simply buried and nothing else is done with it.  Especially if it is raining that day and for the days to follow.

The concept of the dry outhouse is an attempt to have more poop composting and less leaching.  I think a combination of the dry outhouse and the willow trees would provide an even better solution.

Parasites are a real issue here, being some of them are transferable to humans.

It's not worth the risk in my mind to take the chance of getting worms myself over a bit of puppy poop. If it isn't composted completely and at a high enough temperature for one reason or another you have just created a breeding ground for those little critters and created an even worse scenario.

Composting it is fine, but I wouldn't be spreading it around, at all.

most internal parasites need a host to complete their life cycle. they wont' be just breeding and multiplying in your compost or dirt. pastures left fallow for a certain period of time are essentially deemed parasite free because without the lifecycle in almost constant continuem the parasites die off.

Leah, that is true for many parasites, but the Ascarid family is an exception.  They don't require an intermediate host, and they are very resistant to high and low temperature extremes, drying out, sunlight, and various chemicals.  And they can live in the soil for years.

They are fairly easily passed from pet poop to humans.  Young children who are constantly putting their hands and other items in their mouths are especially susceptible.

Their lifecycle is very complicated and I still don't understand it all, but if I understood my vet correctly, a very, very high percentage of puppies are born with them (almost all, he said), and even if they are properly wormed, they still never get rid of them completely, and I think they still are shedding eggs.

As the last poster indicated, it just isn't worth the risk.

Sue

I was unaware they could be infective for so long...

Once the eggs become infective, they can remain infective in the environment for years.4,10

http://www.cdc.gov/ncidod/dpd/parasites/ascaris/prevention.htm

geez. I'm probably loaded with parasites. I've always had dogs. no ill effects yet!

Wow, with such fear of these parasites the first quesitons would be:  Why have a dog?  Do you think the parasites are _only_ in the poop they leave outside?  Ever see a dog "drive" on your carpeting?  Lick their butts, then you?  I think you have more contact with your house than you do your composted area.  Sweating the parasites doesn't stop at the door.

I'm sorry if this reads inflammatory.  I don't mean to be.  But the simple answer as to what to do with the parasite-ridden, toxic, why-am-I-handling-this poop is to not have the creature that is producing it. 

The answer to the "what can I do with the poop from my biologically-accepted animal," then lots of answers have been put forth here. 

Maybe I'll die from these guys, maybe not.  I have 3 dogs.  I love them to death.  They love me.  I know I've gotten poo licks.  I know the parasitic risks and likelihoods (from my wife the vet, I've talked about some of the discussions from this board with her) and I'm willing to take the chances, and therefore keep the dogs, and their poop.

-Jeremy

Hi everyone, new here, yet it already feels like home. Thanks Paul for the heads up.

Just throwing in three and a half cents on this dog manure issue. We have just recently worked on a "pet policy" for a newly forming deep ecological community.   The parasite issues, the composition of the manure, etc were all valid issues. ie; are they eating organic food? If not what is in their food? Concerns were for our organic certification, as well as general health safety and the community values. 

END RESULT   First, if we have it, dog manure is organic matter and should be kept onsite.  No free ranging though, to control random dispersal.  All manure collected and composted seperatly in a dry location with the end results being added to the composted paper stream.  This mixture is then put into into the tree based hugelkulture. 

(Paper recycling is really just a different way to throw away garbage. Dont let your organic matter leave, COMPOST )

Secondly,  discussion about  pet compatibility with deep ecology tabled.
    Hopefully for awhile...ha.

ps. I have attached a produced document full of web research on dog manure and its ecological impacts.  The EPA identifies dog manure as a non-point source of pollution, so its definitly not benign.

Jeremy, one extreme tends to be just as bad as the other.

As long as you know the problem and are willing to expose yourself to them, fine.  You can grow your crops in straight, uncomposted dog and cat poop, it's up to you.  But I hope you have enough sense to limit such exposure for others.

Sue

i have heard of something called the pet poo converter, a worm compost bin. my solution was to mulch it, although it sucks when you get it on the wheels.

I think tomas has the best idea yet. I don't get too excited about the parasite thing. danger lurks everywhere. but it seems taking a little extra care is prudent. I bury dog poop in the yard. started doing that when I read somewhere that will keep them from digging in a certain spot. t

from what I read those little worms that can stay infective for so long can be picked up just through your barefeet.

"Humans can become infected with hookworms through ingestion of infective larvae or through direct penetration of the skin.7 When infective larvae penetrate the skin"

so if you got dogs don't go barefoot, or if there have ever been wild dogs in your area , or I guess if you live anywhere where something might have shit at some point......like anywhere.  really, we could get a little crazy with being scared of stuff.

Hookworms are estimated to infect 800 million people worldwide.

In children, hookworms can cause intellectual, cognitive and growth retardation, intrauterine growth retardation, prematurity, and low birth weight among newborns born to infected mothers.  It can also cause serious anemia.

If a person is too casual about hookworms in the south (usually where it doesn't freeze hard), women need to stay on top of their birth control methods.

Sue

well what about wild dog poop? coyote?

over the many years people have had dogs and didnt have to worry about dog poop..however..maybe there are modern pathogens that weren't around then, dont' know..but my guess is use common sense.

if you live in a small city yard..nope..get rid of it elsewhere..however..if you live on acerage like i do..i'm sure you could dig a pit where there is NO high water table..bury it..throw in a few leaves and other compost type materials..and some dirt..and plant a tree on top of it..

in the old days they always planted a tree whenever they moved their outhouses to a new hole..

Susan Monroe wrote:


If a person is too casual about hookworms in the south (usually where it doesn't freeze hard), women need to stay on top of their birth control methods.

Sue

that might be a bit extreme imo. those kinds of problems are usually only problems in situations where the immune system is already being severly challenged or malnutrition is playing a part. they don't cause those kinds of problems in relatively heatlhy individuals who have accesss to basic healthcare. hook worms are even implicated in being part of a symbiotic relationship of sorts. they appear to protect against immune system overdrive and might even be used to treat some health problems someday.

"Hookworms are a major cause of child and maternal morbidity in the tropical and subtropical regions of the developing world. They can cause intellectual, cognitive and growth retardation in vulnerable children, as well as intrauterine growth retardation, prematurity, and low birth weight."

this isn't something that is happening because somebody didn't clean up fido's poo in the back yard. it happens when people have unchecked parasite loads due to disease and malnutrition and generally poor hygiene. the kinds of places where they drink from the same river they and their animals bathe in.

http://www.medicalnewstoday.com/articles/82632.php

years ago when at the vet (a new one) I asked about checking for worms in the dogs. he did but they were all clean. I told him I was surprised and he said it is unusual to find an adult dog with any troublesome number of parasites in a fecal sample (not heartworms) because most develop a pretty good immunity to them after puppyhood. I can't help but think that we are only hurting ourselves by trying to be so ultra clean. it has long been known that kids who grow up in ultra clean enviroments suffer from more health problems (asthma and allergies)  than kids who grow up on farms and are exposed to a plethora of immune challenges. I also couldn't help but wonder how many vets rip off dog owners saying they need to be wormed when they don't.

Leah that is interesting, I have found worms however in our cats so we worm them on a fairly regular basis..of course, our cats basically hunt, as we need them to keep rodent populations down, so they may be getting them from the critters that they eat.

a really sick animal will deposit live worms. which is sure ugly..and likely not safe.

But I'm also in agreement with the fact that there is possibly a bit too much going on out there in the medical ..esp animal medical..society that is scarier than the worms themselves..like all the antibiotics and hormones in the food..etc..

sometimes you wonder what you can believe..but I'd say, if you think your animals might be infected, buy some wormer and use it accdg to directions..if not..don't..you can usually see some signs that they aren't doing normally..

we compost a lot of dog manure! mixed with wood chips and allowed to sit in a windrow for a year (cover in high rain fall areas and make sure any run off will be contained!) then mixed with wood ash and spread under fruit trees or used in flower beds. we have done this for 35 years, no detectable build up of any metals, just great fruit! before that we would pour it down ground hog holes!

swamp donk wrote:
! before that we would pour it down ground hog holes!

are you on to something there? did it work to deter ground hogs? I wonder if it would work to discourage gophers!!!

we had 70 acres that was loaded with hog holes leah! with our dogs we had lots to work with! liqufied it and poured it in the holes sealing them with the mound out side the hole, next day one hole would be open and the hog gone! not hurt but given an eviction notice!  only time i would not use this method is near a water source or high water table. see no reason it would not work on gophers! we needed them moved as a broken leg on a cow or horse is terminal!

You can take a fresh stool specimen in to your vet and have them do a fecal exam.  Some parasites are invisible to the naked eye.

I know people are getting tired of me saying this, but the dog roundworm has a complicated lifecycle.  Read this and see if you can see some problems:  http://www.marvistavet.com/html/body_roundworms_in_dogs___puppies.html

Leah, the ultra-clean, sanitize-the-whole-world thing certainly isn't doing us a lot of good when it comes to things like bacteria, but parasites are something else.  Sure, good nutrition can help the body resist problems, but where is the line between a good diet and a not-so-good diet?  Millions of people in the U.S. are nutritionally deprived due to a food supply that is severely lacking in minerals, not to mention the mania for junk food.  Fat people can be starved nutritionally almost as easily as a child in Ethiopia.

I was working for an insurance agency in town about ten years ago, and a crying woman kind of staggered in. We sat her down and gave her Kleenex and some water.  When she calmed down, she said she had just come from the eye doctor down the street.  Her 16-year-old daughter was now totally blind in one eye because of roundworms.

Here's the simplest explanation that I have found, it's from an online vet site if you want to read the whole thing http://www.dr-dan.com/roundwor.htm

"So what's the big deal with public health significance?
Here is where it gets a bit frightening! Roundworm larva have actually blinded young children and caused countless other problems.  The humans most affected are children from early neonatal age to four or five years of age, however any age can be affected. Why is this?  The secret lies in hand-to-mouth ingestion of roundworm eggs.  Lets say the cat uses the sandbox for a litter area.  Kids playing in the sand very easily can pick up eggs on their hands and where do their hands go?  Right in the mouth without being washed.

Once the embryonated roundworm egg reaches the intestine of the human it hatches and the larva penetrates the intestine wall.  From there it gains entry into the blood stream and may end up just about anywhere in the body including vital organs such as the eye, brain, liver, kidneys, heart wall, lungs, etc.  Since humans are an unnatural host for the roundworm larva, their body reacts and walls off the larva in little granuloma's (similar to what occurs in adult dogs and cats).  These granuloma's may cause sudden dysfunction of any of these organs resulting in illness.

The most often diagnosed illness is loss of sight in one eye. The roundworm larva is trapped in the optic disk behind the retina of the eye and a granuloma forms.  These granuloma's have been mistaken for retinoblastoma's (cancer of the retina) and the eye was mistakenly removed. I believe the reason the problem is so often diagnosed in the eye is because we know it is happening.  We experience loss of vision; the eye is removed and the larva is discovered.

Remember what I said above? When roundworm larva are encased in granuloma's they are impossible to kill with any anti-parasitic drugs and they are also impossible to detect.  How many cases of persons seizuring with no apparent cause could be related to roundworm larva?  It is impossible to know because the granuloma's are impossible to detect. We can't remove the brain and search for the larva microscopically.

I hope I didn't scare you by making you aware of this problem.  The problem is rare, but it "can" happen at any time.  This is an important reason for people to always wash their hands before eating or putting a finger in the mouth. Who knows, it could save your eye!"

Sue

I am interested in this because I have dogs and a young child. wiki says that infection rates in rural western areas are up to 37%! I have also read many pediatric pamphlets that say it is not unusual at all for kids to need to be treated for worms. I wouldn't let my daughter play in the backyard (with the dogs)when very young for this reason and that seems a reasonable precaution. also burying the dog poo seems reasonable and from what I have read is the best thing to do after simply throwing it away and that is what I do. but now...
I will be burying it in gopher holes

i was raised up along side of many, many dogs as was my father and my children. we showed and obedience trialed dogs as well as boarding dogs and came into constant contact with strange dogs with unknown worm infestations. we also raise sheep that suffer from worms from time to time,  even with that much contact we never once became infected with worms! may have just been luck or  we don't taste good! any country raised child should be tested periodically for parasites. composting with wood chips and treating with wood chips/lime does seem to kill off the worm eggs. gopher holing does make a sows ear into a silk purse!

I have sandy/loamy soil at my home & in my neighborhood. I have used cat poop & castor oil spray, trying to discourage the evil pocket gopher.

Our soil has superb drainage & the gophers dig thru it like crazy! They also dig deeper than in harder soils. Problem with these gophers is they are nomadic, & around here they can travel anywhere. Don't like what it's my yard? They'll just go next door for a while! Don't like the dog over here, well I'll go over there!

It is very hard to grow certain things here because of them. We planted a small blue spruce after Christmas one year. A couple months went by & the little tree didn't look right to me. It seemed like it was...leaning. So I touched the top of it and the whole tree moved, like a stick in a hole. Those dang gophers had eaten the whole root ball clean off the bottom of that tree. I effortlessly pulled the tree out of a hole in the ground, only to see it's sad little gnawed off stump. I went on a gopher war for a while. Just like I did when they ate $ 30.00 worth of tulip bulbs. But the gophers just come back...they always do. 

Parasite load under normal circumstances usually isn't an issue, but my concern comes from years of applying "composted" dung and it's possible effects.

Flinging a bit of fido's excrement here and there isn't something I would concern myself with, but as a practice and being done year over year creates a breeding ground for trouble in my opinion. Just my opinion mind you, and obviously others dis agree here....that's what makes America great.

Digging holes and burying it doesn't bother me much, but using it as topdress just goes against my better judgement.  Then there's that issue of what exactly is IN fidos food.......remember the recent recall of dog food due to it's contamination of melamine?

Yup, there are extremes on both sides of every issue, to each there own, but in the quest to be environmentally friendly, caution and long term thinking should also be a part of the equation.

Last year we had to get tetanus shots at the emergency room after handling a
horse that was diagnosed with it (our hands where in her mouth when checking her). Tetanus was an issue back in the day, and animals simply got burried. Well, once it is in the soil, it's not going away. Ever. The farm will have tetanus in the soil for posterity.

Is ethanol REALLY a green fuel? I don't believe it is due to the energy it takes to produce the stuff, but it has caught on, hasn't it?


Hope this helps...............LOL!

we have used composted dung for lawn, flower beds, vegies and fruit trees for many years! my grandfather started raising dogs in 1928 on a suburban lot (1/2 an acre) there was no sewer and no garbage pick up, what you produced stayed on your property! add to that the fact he raised pigeons and chickens. also, as the soil was very thin over a shale base they would haul in sand and clay when ever they could (granddad, my uncle and father) as well as shale chips from the basement and coal ash! one of my aunts became a public health nurse in the 60's and grew quite concerned about the toxicity of the brew in the backyard. there was no appreciable build of of any metals, no pathogens the soil, however was a bit on the acidic side so it was limed to correct PH. my grandfather passed away when he was 87 and my grandmother at 96, ate vegies out of the garden till the end. while there has been no manures incorporated since 1971 the garden still grows rank every year though no longer produces vegies (my aunt has a black thumb! in contrast too her mom who could grow any thing anywhere!) we have been on the farm here for close too 40 years (we produce a wheel barrow load a day) and have yet too see problems from using the dog waste under fruit trees. soil and tissue tests have been taken and no issues have shown up. we do have a mildly  alkaline soil however, 7.3 to 7.8 that may help kill patogens/parasites . using it on the garden however, no !! do have lots of sheep, chicken, cow and horse manures available!

Alkaline soil .....

I do seem to remember something about how e coli was not a beef issue until they were fed a nearly exclusive grain diet.  This made their poop more acidic and, therefore, more hospitable to e coli. 

Corroboration?

all animals from insects to humans poop its a natural process all is compostable, it becomes a problem when industry adds its pollution to it then pump it into rivers oceans ect especially heavy metals.
in the early days city's/towns were circled with Chinese market gardens that collected horse manure and human deposits from public houses all was composted then converted into fresh food for said town/city,

a scientist will always find for or against any issue depending on the results WANTED by the person/group suppling funding for those results, so i take little notice of what any scientist has to say. Plus the fact that chemical fertilizer company's don't want the general public to know that there are unlimited supplies of free fertilizers out there.

If you don't want dog poop in your compost fine, if you don't want human poop in your compost fine, but how are you going to dispose of this source of plant food in an environmentally friendly way.

You use cow, goat, sheep, rabbit manures ect for compost, do you think these animals are completely parasite free, personally i dont see any difference, shit is shit, in a well maintained compost system it should make no difference and should be safe, it's been done for eons.

It all boils down to the yuk factor, as children we are programed that playing with poo is dirty, its something every living type of animal does, but no one seems interested in an earth friendly way to dispose of it, until someone sees the $ that could be made.

 

I have blueberries not producing. I have dogs. I am moving the blueberies to a sunnier spot and plan to load up the planting holes with dog poo, since maybe the beads of fertilizer from the nursery wearing out are the problem. The poo will not touch the berries and noone outside my family will eat the berries this year- I promise that if I get a bumper crop I'll freeze them. However if I do I'll be tempted to continue using the dog poo as fertilizer!

I'm having a hard time understanding why it would be any safer to do anything other than compost pet waste - especially if you don't use it for food growing. 

Any other treatment seems to offer more or less the same risks.  Letting it lie where it falls seems to be the worst route to go as far as run off and surface exposure to feet, curious childrens' hands, and what not. 

I remember a barrel that served as the bagged up poop container for the dog park near my apartment in Philly....overflowing with months worth of baggies of poop....in a rainstorm....I thought of an idea for a compost system located in dog parks, but somebody else beat me to a marketable version of it.  (I'll go find that if there's interest)

But my dog is a secretive pooper!  He goes way out in the woods and we hardly ever see his poops.  He won't poop if you're in sight, much less on a leash...makes it interesting when we stay overnight in cities....I figure the forest gods will handle it.

Will someone please explain how a parasite/pathogen could get from the soil into a the fruit of a perennial (indirect contamination)?  I was once told that there's speculation even heavy metals can't cross the "stem barrior" of a fruit.  Is THAT true? 

I've also heard that cat feces can (very rarely) contain a seriously gnarly pathogen/parasite/something that can cause permanent brain damage for those who eat contaminated food.  But again, I want to know what the kind of contamination is.  If a cat poops under a tree (and buries it, like they tend to do) and I eat an apple from that tree later in the season, am I running the risk of ingesting brain eating pathogens from my cat?  I'm going to attempt to look this up.....

In my area, series of giant dams and erosion runnoff created by irresponsible logging are more responsible for the loss of the salmon, though I'm sure city runnoff in general doesn't help in the slightest. 

paul wheaton wrote:
Alkaline soil .....

I do seem to remember something about how e coli was not a beef issue until they were fed a nearly exclusive grain diet.  This made their poop more acidic and, therefore, more hospitable to e coli. 

Corroboration?

This is a different situation.

The number of e. coli is similar in either case, but stomach acid at normal human levels kills (or at least stunts the growth of) the varieties that thrive in healthy, grass-fed cattle. A diet of grain sets up conditions where bacteria can cross over. Also, when cattle switch diets, there's a good chance the new population of gut flora won't all be among the non-toxic varieties that have lived happily in mammal guts since the Jurassic: usually, some of them are of a more opportunistic, disease-causing strain, i.e. one that isn't adapted to live with mammals long-term at all.

I would guess parasitic worms would be adapted to survive best in soil that has been influenced by rotting dung: they probably find themselves in acidic soil more times than not, so a layer of alkaline soil might stop them from