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Q: safety limts for endosulfan (a pesticide) residues in soil ( Answered 5 out of 5 stars,   2 Comments )
Subject: safety limts for endosulfan (a pesticide) residues in soil
Category: Health
Asked by: dixiejack-ga
List Price: $200.00
Posted: 23 May 2006 06:36 PDT
Expires: 22 Jun 2006 06:36 PDT
Question ID: 731641
i had some soil samples tested for a piece of land i am buying.  the
testing company "only tests", they do not have the safety limits for
what they find. so, i have no idea if this is really bad, or so-so, or
absolutly nothing to worry about.  it is agricultural land, but i will
be building a house and living there(maybe). I have grandchildren
visiting occasionally, a dog and two horses & cats.the test sample
came back with 2199 parts per million of endosulfan II, and 8900 parts
per million of endosulfan sulfate.  please help me make a decision, as
soon as possible.your credentials are important also.i have researched
this until my brain is exploding, but i cannot find anything about
soil contamination.
Subject: Re: safety limts for endosulfan (a pesticide) residues in soil
Answered By: pafalafa-ga on 23 May 2006 16:31 PDT
Rated:5 out of 5 stars

Thank you for bringing your question to Google Answers.

For your information, I am a biologist with 20+ years of experience in
environmental affairs.

The levels of endosulfan and endosulfan sulfate (a breakdown product
of the pesticide) are extraordinarily high.  So high, in fact, as to
be hard to accept at face value.

For starters, though, do not return to the property.  If the levels
truly are as reported, then this is a highly contaminated site.

Your question stated that the levels found were 2,199 parts per
million (ppm) for endosulfan, and 8,900 ppm for endosulfan sulfate.

In comparison, endosulfan contamination in water is typically measured
in parts per *billion* (one one-thousandth the size of a
part-per-million).  The highest soil contamination numbers that I am
aware of only go up to 20-30 ppm.

In other words, the numbers for your site are several hundred times
larger than the types of numbers typically reported for endosulfan and
endosulfan sulfate contamination in the soil.

One possibility that must be considered for these numbers is that they
are mistaken.

Perhaps the laboratory inadvertently reported parts-per-million, when
they actually meant parts per billion.  If this is the case, then the
concentrations on the property are about 2 ppm endosulfan and 9 ppm
endosulfan sulfate...much more typical sorts of contamination figures.

On the other hand, the numbers may be just as the laboratory reported
them, in which case, the property -- at least the part that was
sampled -- is highly contaminated.  The types of numbers provided to
you suggest that soil was sampled directly in a location where
endosulfan was spilled in large quantities.

Please check the documents you received from the testing lab to
confirm that the numbers are, indeed, as high as you cited in your
question.  You may also want to contact the lab directly, and ask them
to re-confirm the numbers they provided.

You may also want to provide copies of the reports to your local and
state health departments and environmental agencies.  The levels you
noted are certainly something that should receive official attention.

Here are a number of resources on endosulfan that you may find useful:


ATSDR Document

In the US, the Agency for Toxic Substances and Disease Registry
(ATSDR) has the key responsibility for compiling information about
toxic chemicals that appear in the soil.   They have a number of
reports and fact sheets on endosulfan, including:
ToxFAQs for Endosulfan 
[a list of basic health-related Q&As]


[a chapter from a detailed report on endosulfan that includes
information on soil contamination]

5.4.3 Sediment and Soil

Endosulfan has been detected in only a limited number of urban and
agricultural soils in the United States. The National Soils Monitoring
Program conducted in 1972 included the collection of 1,483 soil
samples from 37 states....endosulfan and endosulfan sulfate were each
detected in only one sample at <0.01 ppm ...In soil samples collected
from five metropolitan areas in the United States as part of the Urban
Soils Monitoring Program, endosulfan sulfate was detected in samples
from two cities: Macon, Georgia (in 1 of 43 samples) and Baltimore,
Maryland (in 1 of 156 samples) at concentrations of <0.01 ppm (Carey
et al. 1979b). Surveys of agricultural soils in North America have
determined that endosulfan residue levels ...are typically less than 1

Soils sampled at two sites in creek beds and drainage ditches in an
agricultural area in the Point Mugu watershed near Oxnard, California,
contained endosulfan at concentrations between 20 and 30 ppm. The
majority of the other sites had much lower concentrations...

[Note that in the above descriptions, it is unusual to find
significant soil contamination, and concentrations are never higher
than 20-30 ppm.]


[The full toxicology report can be accessed here, but it is probably
more than you really care to know]
Toxicological Profile for Endosulfan 


[This information sheet from the Pesticides Action Network, an
environmental organization, characterizes endosulfan as one of their
"Bad Actor" pesticides]
PAN Pesticides Database - California Pesticide Use
Endosulfan - Pesticide use statistics for 2003
PAN Bad Actor Chemical -- Acute Toxicity   

Please note the disclaimer at the bottom of the page, that Google
Answers is no substitute for professional advice.  I strongly urge you
to consider the steps I mentioned above:  (1) stay off the property 
(2) confirm the numbers (3) contact the appropriate health and
environmental authorities in your area.

If you find that you need any additional information, please let me
know, and I will respond as quickly as possible.  Just post a Request
for Clarification, and I'm at your service.

All the best,


search strategy -- Google search on [ endosulfan ]

Request for Answer Clarification by dixiejack-ga on 24 May 2006 13:19 PDT
Hi there, thanks very much for your very detailed answer.  we were
really in a bit of a panic, as we've gotten to the closing stage on
this property.  here is what i have found out in addition to what i
told you yesterday.  the list of pesticides reads thus: Endosulfan II 
  2100 ug/kg, and Endosulfan Sulfate    8900 ug/kg.    The person at
the lab insists this means 8900 parts per million---however a
different lab person (from a different lab)says it means 8900 parts
per billion, and i could look it up in a metric conversion chart on
the web.  well, i did look it up, and it looks like it IS 8900 parts
per billion, which, i think, means 8.9 parts per million.  still not a
swell number, but will it damage humans?please tell me if this is
correct.  (also ug is pronounced "micrograms" per kilo-which is what
the first lab man says means ppm)and if this were your land, would you
have the grandkids over?please reply

Clarification of Answer by pafalafa-ga on 24 May 2006 14:12 PDT

I wanted to give you a quick, top-of-the-head response, since time
seems to be of the essence.  But if you need more information, or more
research, just let me know, and I'll stick with it until you have
everything you need.

First off, a ug/kg -- microgram per kilogram -- is indeed a part per
billion (one of those lab technicians should be drawn and
quartered...I'll let you decide which one).

'Micro' means a millionth, so a microgram is a millionth of a gram.  

One microgram per gram (ug/g) is a part per million.

But a kilogram is 1,000 grams, so that one microgram per kg (ug/kg) is
a part per billion.

Bottom line, the soil appears to be contamined at a maximum of 8.9
ppm, rather than the thousands of ppm's you were originally led to

Would I let the kids play in the yard?

If they are little kids, likely to get good and dirty, put their hands
in their mouth, or even take a direct taste of the dirt, then...No...I

Bigger kids, I probably would, as long as I thought they were
responsible enough to wash up after playing, and to keep their hands
out of their mouth, nose and eyes.

But let me emphasize...this is an entirely personal response.  It is
not my opinion as an environmental scientist, but merely my response
as a dad.

I let my 7-year old cross the street.  My neighbor's 7-year old isn't
allowed, yet.  It's a matter of personal choice, and what level of
risk and uncertainty one is comfortable with.

I wish I could provide a more definitive anwer, with a clear-cut Yes
or No.  But ultimately, you'll need to find your own comfort level on
this one.

As I said, let me know if there's anything else at all that I can do for you here.

dixiejack-ga rated this answer:5 out of 5 stars and gave an additional tip of: $100.00
Thanks again to pafalafa, and the two commenters also-here's the
followup-pafalafa, you were dead on-the second lab(very clean, very
sharp, very in compliance, not unreasonably priced, etc, did indeed
find a much lower leval of contamination, AND, indeed, ug/kg=ppm, so i
am glad i got your opinion, it led me to find a second lab to deal
with, and yes, we will buy the land, and the kids will be told to wash
up, frequently.also, the horses can eat the grass, all in all,
everything should work out ok. thanks again

Subject: Re: safety limts for endosulfan (a pesticide) residues in soil
From: brix24-ga on 24 May 2006 11:02 PDT
As pafalafa-ga mentions, you probably should contact a local environmental agency.

Here is a listing of endosulfan being found in soil in somewhat high amounts:

"Soil sampling (0-12") at the Horseshoe Road Site has demonstrated a
considerable level of contamination.
There is, however significant areas of contamination outside
restricted areas. Of particular concern in these accessible areas are:
PCB's (660 ppm); pesticides, eg. DDD (160 ppm), DDT (450 ppm), aldrin
(190 ppm), endosulfan (380 ppm), ...."

The following mentions a clean-up level:
"Endosulfan (I & II)

Endosulfan is a mixture of two different forms of the same chemical
(alpha- and beta- endosulfan). Endosulfan is an insecticide used to
control insects on grains, tea, fruits, vegetables, tobacco and
cotton. Endosulfan is also used as a wood preservative in the United
States. The pesticide has not been produced in the United States since
1982, although it is still used in the United States to produce other
chemicals. Endosulfan does not dissolve easily in water and may stay
in the soil for several years before it biodegrades. The residential
cleanup level for endosulfan is 470 ppm (EPA), 340 ppm (DEP). The
basis for cleanup level is non cancer endpoint in animals.
Hyperactivity, tremors, decreased respiration and salivation have been
noted in people ingesting high concentrations of the pesticide."

Search strategy: endosulfan soil contamination ppm OR ppb
Subject: Re: safety limts for endosulfan (a pesticide) residues in soil
From: brix24-ga on 24 May 2006 11:17 PDT
One other thought: In addition to the ppm and ppb issue, you might ask
the testing company how sure they are that the compounds are
endosulfan and endosulfan sulfate.

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