There are many contaminants that might be found in the soil and groundwater, but none strike more
fear than arsenic. This is not because it’s particularly lethal, but because of its name, made notorious by
the 1939 play Arsenic and Old Lace.
Yes, arsenic will slowly kill you if ingested in substantial amounts, but not at the levels typically found on
old golf courses and citrus groves. It is considered carcinogenic by the risk-based assessments used to
establish limits for remediation in the state of Florida. Currently, residential exposure in soil is capped at
2.1 milligrams per kilogram, and commercial/industrial levels cannot exceed 12 mg/kg. But at low levels,
there may be mitigating factors that can be sorted out in a Phase I Environmental Site Assessment.
Back to the name. Land developers can withstand a little DDT perhaps, but not—heaven forbid—arsenic.
The word congers up all manner of panic in the populace. This makes light of an issue that must be
addressed in a Phase I ESA on extremely valuable sites. It’s always problematic when vast acreage may
be impacted from previous agricultural operations that’s now prime land for development, e.g. all
Central Florida. It’s even harder to assess when previous consultants have either been too lenient, or
have dropped the hammer. The big risk to property owners and consultants alike is another buyer
and/or consultant coming behind you and making a big deal out of the potential presence of arsenic in
the soils, possibly from former agricultural operations. LAS has handled this sticky issue with a general
methodology that makes a lot of sense, but still may not ward off aggressive assessors looking for Phase
II work. In our minds, at least the issue’s been addressed in an intelligent way.
It’s first useful to know that arsenic has been used for worthwhile purposes over the years. Arsenic dust
was sprinkled on citrus trees in the early 20 th century to sweeten citrus, particularly grapefruit. This
process was highly touted as very effective. A compound containing arsenic was also used as an
insecticide in citrus groves at one time. Arsenic has been used in chicken feed to kill parasites and
promote growth (Roxarsone), which is a factor in assessing the soils of long-time chicken farms. Up to
a few years ago, a chemical containing arsenic was widely used on golf courses as an effective
herbicide (monosodium methanearsonate or MSMA). And arsenic was the pesticide of choice in
solutions used in federally-mandated cattle dipping vats in the 1920s and 1930s. We were even told by
a descendent of a large landholder in our county that everyone had a bag of arsenic in their shed, and it
was cheap and used for everything. So, if you’re assessing a citrus grove, or golf course, or chicken farm,
or cattle dip vat, or someone’s old shed, arsenic may be the threat.
Now in our opinion, the assessment of golf courses and cattle dip vats are for another discussion. But
the presence of arsenic in soils on valuable former agricultural land must be considered on multiple
levels. Put in perspective, if you will. First, let’s say you’re working on land worth $10,000,000 or
$100,000,000, and you may find some residual arsenic in the soils if you looked. Are the developers
enthusiastic about testing thousands of acres for it? Or worried about a $40,000 cleanup. What’s the
risk if, say, all the trees will be pulled up and the land graded. Then during site development, the land
will be totally transformed with pond excavation, grading, filling, discing, roads, etc. Then houses will be
constructed with landscaping and sidewalks. All this work will, in theory, effectively “mix down” arsenic levels possibly to undetectable amounts, and the actual areas lived on will have hardly any realistic
exposure to arsenic if present. Then there’s studies on how much dirt a child must ingest in the backyard
to be threatened, and you’ve got to have “Pica” kids to begin with, i.e. those kids prone to eat dirt. One
can see the developer’s viewpoint, and why thousands of acres have been developed without a soil
sample being pulled (most of the Disney area). And the regulators haven’t even raised an eye brow.
Yet, there are consultants out there who will make a federal case about it, and so fellow consultants
factor in their own risk of being called out for not having done the testing, and remember, we’re talking
Here’s what we’ve always done. First, we look for storage facilities and potential mixing areas on-site,
such as irrigation well locations. We consider these areas as posing the highest risks for the presence of
concentrated arsenic. So, on a big project that’s not been assessed, those areas are targeted. Ultimately
some remediation may need to be done, but it will be targeted and contained. The thinking is that areas
where the chemicals were broadly applied should show lower concentrations. The rub comes when
there are no such buildings or wells. Then you’re considering land on which arsenic in herbicides or
pesticides has been broadcast in diluted form from border to border over the years– maybe. Yes, you
can pull your samples, but is the solution digging up the top 2 feet of 100% of the land for a few
milligrams per kilogram over the residential limit prior to development? In these cases, we’ll go in detail
explaining the risks and the fate of the land during and after development. Discussed in these terms, a
buyer can make an intelligent decision and look the other way—accept the risks—and another
consultant will at least consider you as “thoughtful.” ALWAYS, though, it’s not our decision to make, but
the client’s and his or her environmental attorney.
This brings me to a real sticking point. It’s helpful to resist the urge to put recommendations in your
conclusions. Why back your big-time developer into a corner? Why generate a scope of work that may
by necessity or future discovery be totally unrealistic?
Yes, arsenic is listed as a hazardous waste at high concentrations. Yes, it’s a carcinogen. Yes, it will kill
you if injected or ingested into the body at full strength. Yes, there are maximum levels allowed in the
soils (and in groundwater) on residential and commercial/industrial properties in the state of Florida.
But, use some common sense. Weigh all the factors. Be thoughtful. We’re assessing risks, not creating
Recently, I went into detail explaining the risks of assessing a large agricultural parcel considered for
purchase by a national developer. He stopped me in mid-sentence to say, “this is not our first acquisition
of this type of land.” Which was to say, just do the assessment. Say what you have to say. We’ll take it
Chapter 62-777 Florida Administrative Code
“Effect of Lead Arsenate Insecticides on Orange Trees in Florida,” by R. L. Miller, Associate Entomologist,
Ione P. Bassett, Senior Scientific Aid, and W. W. Yothers, Entomologist, Division of Fruit and Shade Tree
Insects, Bureau of Entomology, USDA, Technical Bulletin No. 350, February 1933.
“The Use of Arsenic on Citrus Fruit for Processing, A Review,” by Gray Singleton, Salada-Shirriff- Horsey,
Inc., Plant City, Florida State Horticultural Society, 1958, Pages 262-265.