United States
Environmental Protection
Agency
Industrial Environmental
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-84-113 July 1984
Project Summary
Tar Sands Leachate Study
Douglas W. Grosse and Linda McGowan
The research described in the full re-
port was initiated at the USEPA's Test
and Evaluation (T&E) Facility to assess
the potential for release of contami-
nants to ground and surface waters
from in-situ and above-ground
processing of western tar sands. Initial
laboratory tests indicate that leachates
from spent tar sands may not contain
significant amounts of toxic pollutants
but may contain substantial amounts of
sulfate and total organic carbon (TOC).
Of the five priority pollutants tested
(cyanide, mercury, nickel, arsenic and
zinc), all exhibited low concentrations.
However, concentrations of sulfate and
TOC were sufficiently high to impact
surface and groundwater quality.
This Project Summary was developed
by EPA's Industrial Environmental Re-
search Laboratory, Cincinnati. OH. to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
Preliminary studies assessing the
environmental implications of in-situ
extraction, as well as above-ground
retorting, are scarce, yet there is
heightened concern in states such as
Utah about the environmental impact on
local water supplies from tar sands
mining and in-situ recovery operations.
The purpose of this effort was, therefore,
to provide information that would (1)
assist regulatory offices in permitting the
mining and processing operations, (2)
establish a data base for developing and
reviewing monitoring plans and (3)
support efforts to establish guidelines for
ultimate disposal of solid wastes
generated from tar sands operations.
Such information will assist the
development of an environmentally
acceptable tar sands industry.
Experiment
In order to determine the chemical
composition of tar sands leachate, ap-
proximately 28 feet of 3-inch tar sand
core were obtained from the TS-2C
forward combustion in-situ experiment
conducted at Asphalt Ridge by the
Laramie Environmental Technical Center
(LETC). Segments of the core were
recognized as being either combusted or
non-combusted. In addition, a fifty-five
gallon drum of processed tar sands (spent
sand) was obtained from an above-
ground retort pilot plant in Salt Lake City.
In all, three types of tar sands matrices
were extracted and analyzed: combusted
core (cc), uncombusted core (uc), and
spent sand (ss).
Shake and extraction tests were
conducted in an effort to assess the char-
acteristics of tar sands leachate. The
leachate was analyzed by the EPA
analytical support group, IERL,
Cincinnati, for parameters specified by
the drinking water quality standards and
criteria. Screening for toxic components
thought to be present in the leachate was
also performed. The Resource
Conservation and Recovery Act's (RCRA)
EP Toxicity Test (with and without acid
addition) was used to simulate tar sands
leachate generation. The ASTM shake
extraction procedure was also performed
on all tar sand matrices to generate a
third set of data for evaluation.
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Results
In all, twelve different water quality
tests plus trace metal analysis were
conducted on the leachate samples
generated from the shake and extraction
procedures.
Table 1 shows the averages of the trace
metal concentration measurements for
the three runs conducted. The combusted
core showed significantly higher
concentrations of trace metals. Calcium,
magnesium, potassium, and sodium
were present in the highest concentra-
tions. Arsenic, barium, mercury, nickel
and zinc were below the detection limit.
When the data for hazardous waste
contaminants were examined, it was
determined that only three (arsenic,
barium and mercury) are listed in the
Federal Drinking Water Quality Standards.
These values are provided as a reference
point rather than to imply that discharge
should meet drinking water standards.
Those contaminants included in the
standards which were measured in this
study are presented in Table 2.
After the results were examined, it
became apparent that none of the
hazardous constituents listed in Table 2
were in excess of the maximum allowable
concentrations.
Of the other parameters analyzed in
this study, only TOC and sulfate
determinations exhibited concentrations
high enough to cause any concern.
Whether this level of concentration can
be expected from the addition of acid for
pH adjustment during the extraction
procedure or whether organic
constituents are released is a matter that
deserves further consideration. A more
thorough characterization of specific
organics, especially phenols and
compounds associated with the various
functional groups prevalent in tar sands
bitumen, may be necessary.
Recommendations
It is therefore recommended that
Table 1. Trace Metal Analysis (mg/l)
£P Toxicity with Acid EP Toxicity no Acid ASTM
CC UC SS CC UC SS CC UC SS
Al .1 2.3 .3 8.3 .16 2.4 19.9 .15 .23
Ca 176 32 378 78 17 65 36 18 47.6
Fe .5 3.0 .83 7 .5 1.5 2.9 .6 .57
Mg 61.6 3.4 12.9 31.4 2.7 5.0 13.5 2.9 2.5
K 9.0 1.4 1.9 9.4 1.3 1.7 8.7 1.6 4.0
Na 5.6 2.9 2.3 6.4 3.8 3.2 9.2 1.5 2.1
Zn .04 .32 .08 .22 .03 .03 7.3 .04 .18
Ba All less than 1 .0
Hg* All less than .001
Ni All less than .2
As All less than .02
%R
109
102
100
98
IDS
104
100
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