Friday, July 28, 2000, 10 am to 1:30 pm
at Florida Department of Environmental Protection
2600 Blair Stone Road, Room 609
Tallahassee, Florida 32399
Florida Center for Solid and Hazardous Waste Sponsored Research (FCSHWM)
with Florida Power and Light, matching funds
Analytical Methods Stook/Townsend
Refreshments Will Be Available.
Minutes of the July 28, 2000 Meeting Held at the
Florida Department of Environmental Protection
2600 Blair Stone Road, Room 609
Kevin Archer, Product Development Manager, Chemical Specialties Inc, Charlotte, NC
David Bullock, Wood Protection Products, Charlotte, NC
Jennifer Caldwell-Kurka, Florida Department of Environmental Protection, Tallahassee, FL
Jenna Carlson, University of Florida, Gainesville, FL
Lee Childers, Suwannee Lumber Mfg., Cross City, FL
Jan Rae Clark, Florida Department of Environmental Protection, Tallahassee, FL
Raoul Clarke, Florida Department of Environmental Protection, Tallahassee, FL
Steve Cox, Co XRF, Atlanta, GA
Keith Drescher, Environmental Specialist, Florida Power and Light, West Palm Beach , FL
David Dee, Landers and Parsons, Tallahassee, FL
Richard Gentry, Florida Home Builders Association, Tallahassee, FL
Jack Glenn, Florida Home Builders Assoc., Tallahassee, FL
Peter Goren, Florida Department of Environmental Protection, Tallahassee, FL
Phil Gornick, Florida Forestry Assn, Tallahassee, FL
Bob Gruber, Hickson Corp., Smyrna, GA
David Hahn, University of Florida, Gainesville, FL
Julie Hauserman, St. Petersburg Times, Tallahassee ,FL
Jim Healey, Koppers Industries, Inc., Gainesville, FL
Ron Henricks, Florida Department of Environmental Protection, Tallahassee, FL
Jim Hickman, Langdale Forest Products Co, Valdosta, GA
William Hinkley, Florida Department of Environmental Protection, Tallahassee, FL
Naila Hosein, University of Miami, Coral Gables, FL
Gary Hurst, Robbins Manufacturing, Tampa, FL
Robbin Jackson, Elementis, Corpus Christi, TX
Francine Joyal, Florida Department of Environmental Protection, Tallahassee, FL
Mike Kaiser, Burns and McDowell, Jacksonville, FL
Russell Ketchem, Florida Power and Light, West Palm Beach, FL
Bernine Khan, University of Miami, Coral Gables, FL
Curt Leonard, Florida Forestry Assn, Tallahassee, FL
Lena Ma, University of Florida, Gainesville, FL
Tom Marr, Osmose Inc., Griffin GA
Dave Mason, Southern Forest Products Association, Kenner, LA
Dave Mason, Florida Department of Environmental Protection, Tallahassee, FL
Daniel Moore, Dept. of Agriculture and Consumer Services, Tallahassee, FL
Karen S. Moore, Florida Department of Environmental Protection, Tallahassee, FL
Russ Morgan, Scientist, Occidental Chemical, Castle Hayne, NC
Gus Olmos, Alachua County, Gainesville, FL
John Paling, John Paling and Co, Gainesville FL
Keith Parmer, Dept. of Agriculture and Consumer Services, Tallahassee, FL
George Parris, Ph.D., American Wood Preservers Institute, Fairfax, VA
Mike Petrovich, Hopping Green Sams & Smith, P.A., Tallahassee, FL
Scott Ramminger, American Wood Preservers' Institute, Fairfax, VA
Tom Roberts, Delta Recycling, Ft. Lauderdale, FL
John Schert, Florida Center for Solid and Hazardous Waste Management, Gainesville, FL
Jay Sego, Coastal Lumber Co., Havana, FL.
Jim Seufert, Universal Forest Products, Grand Rapids, MI
Helena Solo-Gabriele, University of Miami, Coral Gables, FL
August Staats, Osmose Wood Preserving Division, Griffin, Georgia
Kristin Stook, University of Florida, Gainesville, FL
Donald Surrency, Koppers Industries, Inc., Gainesville, FL
Richard Tedder, Florida Department of Environmental Protection, Tallahassee, FL
Laurie Tenace, Florida Department of Environmental Protection, Tallahassee, FL
Thabet Tolaymat, University of Florida, Gainesville, FL
Timothy Townsend, University of Florida, Gainesville, FL
Tuck Tucker, Gulf Power, Pensacola, FL
George Varn, Jr., Varn Wood Products, Hoboken,
Attendees Via Teleconference
Bonaventure Akinlosutu U.S. Environmental Protection Agency, Washington D.C.
Winston Dang, U.S. Environmental Protection Agency, Washington D.C.
Najm Shamim, U.S. Environmental Protection Agency, Washington D.C.
The meeting began at 10:10 am and ended 1:40 pm.
1. Welcome and Introduction of Meeting Attendees
Helena Solo-Gabriele welcomed the meeting attendees
and all participants introduced themselves by stating their name and affiliation.
2. History of Research Project on CCA-Treated
Helena Solo-Gabriele indicated that funding for
this research was obtained from three sources. Funds were received for the past
four years from the Florida Center for Solid and Hazardous Waste Management
(FCSHWM). Matching funds have obtained from Florida Power and Light Company.
More recently funds have been received from Sarasota County. Faculty and students
working on the project were listed. Background information for the project was
presented, including an emphasis on the strict disposal guidelines for arsenic
and a description of retention levels for various treated wood products. The
motivation for the project was due to the elevated arsenic and chromium concentrations
found in the ash from cogeneration facilities. Data indicate that the quantities
disposed will increase by approximately a factor of 7 (to 35 million cubic feet
of wood) within the next 10 to 15 years. Through the year 2000, it is estimated
that approximately 28,000 tons of arsenic have been imported into the State
of Florida. This quantity was "scaled" against the upper 1 inch of Florida soil,
which indicates that the cumulative amount of arsenic imported into the State
has the capacity to increase background arsenic concentrations within the upper
one inch by 5 mg/kg. This quanitity is large compared to natural background
arsenic concentrations which are generally less than 1 mg/kg. The history of
the project was presented on a year by year basis. During year 1 the purpose
of the project was to develop a disposal forecast for CCA-treated wood and to
identify the reservoirs for disposal. The primary disposal route during 1996
was through construction and demolition (C&D) recycling facilities and through
wood burning facilities. The use of C&D wood as mulch appears to be gaining
a larger share of the market since 1996. The year 2 project focused on leaching
studies on CCA-treated wood ash and on sorting methods (chemical stains and
x-ray technology) for separating CCA-treated wood from other wood types. The
year 3 project focused on chemical alternatives to CCA-treated wood (ACQ, CBA,
CC, and CDDC) and on three sub-tasks focused on disposal-end management. These
sub-tasks included testing the chemical stains in the field, an evaluation of
pyrolysis technology through a literature review, and development of a resource
book for the wood disposal sector.
3. On-Line Sorting Technologies for CCA-Treated Wood
(Sarasota County, Innovative Recycling Grant).
Jennifer Caldwell-Kurka described the objectives
of the innovative recycling grants program. She mentioned that the research
for the on-line sorting technologies was ranked highly by the review committee
and that it was funded through October 2001 at $294,100.
Helena Solo-Gabriele described the objective of
the project which is to construct and operate an on-line sorting system for
separating CCA-treated wood from untreated wood. The reason that sorting is
important is because significant quantities of CCA-treated wood are co-mingled
with untreated wood at C&D recycling facilities. This wood is then recycled
as wood fuel or mulch. Studies conducted in 1996 showed that treated wood represented
roughly 6% of recycled wood waste at C&D facilities. In 1999, three facilities
tested indicated that between 9 to 30% of the wood pile consisted of CCA-treated
wood. These values are consistent with U.S. production statistics for southern
pine as reported by the Southern Forest Products Association (SFPA). According
to the SFPA, 20% of southern pine production was treated in the early 1980's.
This quantity increased to 50% in the early 90's and has since dropped to 40%.
The conceptual design for the shelter was presented which includes a detector,
conveyor, and shelter. The five tasks of the project were reviewed and the overall
timeline was presented. The goal is to have the system operational by December
2000. The specification and location of the shelter were presented by Jenna
Carlson. The shelter will consist of a metal fabricated building which will
be 30 feet by 40 feet by 15 feet high. It will consist of a portal frame with
open sides and a concrete slab. Construction details were presented including
details for the anchor bolts and location of the electric connection. Quotes
were obtained for the metal fabricated building. Costs ranged from $9,000 to
$17,000. Efforts are underway for contracting with a construction project management
firm to oversee construction details. A timeline for the shelter construction
was presented. The conveyor design was presented by Helena Solo-Gabriele. Preliminary
quotes have been obtained from American Conveyor in Miami, Florida and Powerscreen
of Lakeland, Florida. The most recent conveyor design includes a 5 foot table,
and 10 foot roller conveyor, a 15 foot flat belt conveyor, followed by a 24
foot inclined conveyor. The conveyor will be 5 feet wide. David Hahn described
the laser induced breakdown spectroscopy (LIBS) detector. The laser is focused
on the wood sample to create a plasma on the surface of the wood, which vaporizes
a small portion of the wood. There are two components to the laser system: the
laser and the spectrometer. A LIBS spectrum of CCA-treated wood was provided
along with the results from a laboratory exercise which illustrated the ability
of LIBS technology to easily distinguish between CCA-treated wood and untreated
wood. The sample configuration of the LIBS probe was provided. The particular
laser and spectrometer models considered for purchase were mentioned. A comparison
was made between LIBS and x-ray fluorescence (XRF) which included a comparison
of costs, analytical times, spatial resolution, scanned distance, and maintenance.
Helena Solo-Gabriele mentioned that ASOMA (now called Spectro) and Co XRF have
been contacted to determine whether "borrowing" agreements can be made. A home
page was developed for the Sarasota project. This home page is www.eng.miami.edu/~hmsolo/sarasota/index_sara.htm.
George Varn Jr.: What is the separation distance between the laser and the wood sample?
Response: It can be plus or minus several
inches. There is significant tolerance to accomodate the variable thicknesses
of wood samples.
George Varn Jr.: Is it necessary to place the wood as one layer on the conveyor for proper analysis by LIBS?
Response: Yes, LIBS analyzes the surface
of the sample.
Question: Will there be interferences from paint?
Response: Not likely given that LIBS penetrates
several microns of depth whereas paint tends to be thinner.
Lena Ma: What is the detection limit of the technology?
Response: LIBS can easily detect the presence
of CCA in wood treated at the lowest retention level which is roughly 0.25 pcf.
Bob Gruber: Assuming that the technology is successful, will it be used at C&D recycling facilities throughout Florida?
Response: The research team anticipates
that it can be used in the day-to-day activities of C&D recycling facilities.
It will probably be most feasible for the large C&D facilities.
Bob Gruber: What will happen to the wood once it is sorted out?
Response: In the absence of other technologies,
the wood can be disposed in lined landfills. Other technologies that are promising
include pyrolysis technologies and recycling into composite materials.
Bob Gruber: Disposal in unlined C&D landfills is permissible as per State Regulations.
Response: Yes, but environmentally it would
more desirable to put CCA-treated wood within a lined landfill.
4. Background Information Concerning the FCSHWM
John Schert described the objectives of the FCSHWM
and briefly described the other projects funded by the Center. He mentioned
that pre-proposals for the next funding cycle are due August 25th.
5. Changes to "year 3" final report and resource
Helena Solo-Gabriele mentioned that written comments
were received for both the main report and the resource book. Written responses
were mailed. Modifications to the draft report were described. The draft version
of the report should be discarded given the changes incorporated into the final
draft. The main report and the resource book will be posted on the web at www.ccaresearch.org.
Copies can also be requested through the FCSHWM at firstname.lastname@example.org
or by calling (352)392-6264.
George Varn Jr.: What happens to the report once it is finalized?
John Schert: It will be posted on the FCSHWM
web site and will be available for distribution.
6. Progress to Date on "Year 3 Supplemental"
Helena Solo-Gabriele mentioned that the purpose
of the supplemental study was to accelerate new lines of research. These lines
of research were developed as a result of hearings in Minnesota where a ban
on CCA was being considered. Many of the deliberations focused on in-service
issues and metal speciation. The five tasks included within the supplemental
study are consistent with questions raised in Minnesota. These tasks include:
depletion of Cr, Cu, and As during the service life of CCA-treated wood, quantifying
CCA-treated wood used by major industries, leaching tests on unburned CCA-treated
wood, a literature review on As and Cr speciation, and a literature review on
laboratory methods for organics analysis associated with alternative chemicals.
Tim Townsend emphasized that no leaching tests
were conducted on unburned CCA-treated wood and mulch during prior studies.
Leaching is of concern during: in-service use, storage, reuse of the mulch,
and disposal. Several different types of leaching tests were conducted on new
CCA-treated wood. These tests included batch tests (e.g. TCLP and SPLP), column
tests, and field tests. Ten samples of CCA-treated wood (new) were purchased
from home supply stores. One sample was subjected to a series of different standardized
leaching tests including TCLP, SPLP, EP Tox, WET, and MEP. The purpose of TCLP
tests is to determine if a solid waste is hazardous by toxicity characteristic
and to determine if a hazardous waste can be land disposed. The purpose of SPLP
is to determine if a land-applied waste or contaminated soil presents a risk
to groundwater from chemical leaching. The details of the TCLP and SPLP tests
were described. Results show that CCA-treated sawdust will fail TCLP for arsenic
upon occassion. Chromium passes. Although copper also leaches, there is no federal
regulatory limit established for copper. Particle size impacts the results from
TCLP tests. In general the smaller the particle size the greater the amount
of arsenic leached. The leachate concentrations between TCLP and SPLP generally
correlate for arsenic; however, for copper TCLP concentrations are generally
higher than SPLP concentrations. Arsenic leachate concentrations were similar
between the TCLP, SPLP, and EP Tox tests whereas concentrations were generally
higher for the Waste Extraction Test (WET). The WET uses a citric acid leaching
solution which differs from the other leaching solutions tested. A multiple
TCLP extraction procedure (MEP), where TCLP tests were conducted on consecutive
samples indicates that leachate concentrations continue to show leachable arsenic
concentrations after 9 consecutive extractions. The implications of the leaching
tests were that without the exclusion, CCA-treated wood would often be characterized
as a hazardous waste. If SPLP results are compared to GWCTLs results show that
CCA-treated wood should not be disposed in an unlined landfills if current policy
used for other wastes is also applied to CCA-treated wood.
Land application of mulch produced from C&D
operations was also evaluated using SPLP analysis. A total of 58 samples were
analyzed. 50 of these samples exceeded the GWCTL for arsenic. Implications of
the mulch study suggest that CCA-treated wood must be present at less than 1%
in wood mulch to meet current groundwater standards. Most C&D wood samples
are greater than 1%.
Major use sectors for CCA-treated wood focused
on quantifying the amount of arsenic associated with different products. Roughly
28,800 tons of arsenic have been imported into the State of Florida. Roughly
2,500 tons have been disposed leaving a net amount of arsenic currently in service
of roughly 26,000 tons. Industry statistics (AWPA and AWPI) indicate that the
major CCA-treated product (on a cubic foot basis) are lumber and timbers. U.S.
statistics on treated southern pine compiled by the Southern Forest Products
Association (SFPA) indicate that 36% of the treated wood volume is used for
outdoor decks, 15% for landscape timbers, 8% for fences, 18% for marine applications,
and 10% for highway uses. The focus of the current study is to double-check
the distributions of treated wood usage for Florida. Specifically the focus
is on quantifying the amount associated with the transportation sector, the
amount associated with utility poles, and the amount associated with docks.
Initial contacts have been made with the district offices of the Florida Department
of Transportation. For utility poles, data have been compiled from questionnaires
sent last year concerning treated wood usage. The responses from the questionnaires
were scaled against the population served by each responding utility and by
U.S. historical pole production statistics. Preliminary results indicate that
1600 tons of arsenic are associated with utility poles. This number represents
roughly 6% of all arsenic associated with CCA-treated wood that is currently
in service. Research on residential docks was presented by Naila Hosein. Research
on docks focused on evaluating data from three counties (Alachua, Dade, and
Leon). For each county, building permits were reviewed, contact was made with
the property appraiser's offices, aerial photographs were reviewed, and dock
manufacturers were contacted. Results were presented concerning the characteristics
of the docks within each county. The amount of arsenic associated with freshwater
docks appears to be low when compared to U.S. statistics developed by the SFPA.
Potential reasons for this discrepancy were provided.
The sampling program for evaluating the impact
of CCA-treated decks on the environment was presented by Naila Hosein. Surface
soil samples were collected in a grid-like fashion from nine decks. Three were
located in Gainesville, three in Miami, and three in Tallahassee. One of three
decks in Tallahassee was not CCA-treated. One soil core sample was collected
from each site. All decks were stained with PAN indicator to determine whether
they were CCA-treated. All were positive for CCA except for the one (Lake Talquin)
located in Tallahassee. XRF results from the sawdust from each deck also confirmed
the presence of CCA in samples that were analyzed to date. Grain size analysis
indicates that the average grain size of all the soil samples was 0.3 mm which
is typical of a sand. Results of % volatiles analysis indicates that between
sites metal concentrations were not strongly correlated with % volatiles content.
Within a site, correlations were observed.
Tim Townsend presented the results from analyzing
metal concentrations in soil under the decks evaluated. Of the 25 samples evaluated
in Gainesville, the average concentration of arsenic in the soil below the deck
was 20.2 mg/kg whereas the average concentration of the controls was 2.1 mg/kg.
For the two CCA-treated decks in Tallahassee, the mean arsenic concentration
for samples collected below the decks was 16.4 mg/kg; the average for the controls
was 1.0 mg/kg. In Miami, the mean concentration for the soil beneath the decks
was 39.1 mg/kg whereas the controls measured 1.1 mg/kg. For all samples collected
below CCA-treated decks the mean concentration below the deck was 28.5 mg/kg
whereas the concentration of the soil control samples was 1.5 mg/kg. It was
found that the mean concentration of arsenic under the 8 CCA-treated decks exceeded
the industrial Florida SCTL of 3.7 mg/kg. 61 of the 73 individual soil samples
also exceeded 3.7 mg/kg. Additional control samples were collected and analyzed
to assist with statistical comparisons. Analysis of copper and chromium has
been completed. In general a correlation was found between the concentrations
of the different metals. Results from the soil cores indicate that metals concentrations
generally decline from their high values at the surface to lower values below
the surface. Elevated metals concentrations were observed down to 4 inches.
Russ Morgan: Why was CCA-treated wood excluded as a hazardous waste?
Tom Marr: CCA-treated wood should not be disposed in shredded pieces nor as a sawdust. Usually it is disposed as large pieces.
Response: The same reasoning could be applied to other wastes that are not excluded from being classified as a hazardous waste.
David Dee: The conclusion that CCA-treated wood should not be disposed in a C&D landfill does not take into account that there is a mixing zone beneath a landfill where the leachate is diluted.
Response: There is generally no agreement
on the dilution issue. Some consider that the 20:1 ratio of liquid to waste
accounts for dilution.
Bob Gruber: How many of the mulch samples failed TCLP?
Response: The samples were not analyzed
using the TCLP.
George Parris: The red stain used on the
mulch, which is an iron compound, may affect leaching. It is likely that it
may reduce leaching.
Tom Marr: The project has a considerable
amount of good work, especially with the separation technique. We agree that
CCA-treated wood should not be used for mulch or ground into sawdust.
George Parris: Please define the term % volatiles?
Response: The % volatiles analysis is an
indirect measure of the organic content of the soil. It is determined by taking
pre-weighed dry soil, placing it in a muffle furnace, and then re-weighing the
George Varn Jr.: The work addressing leaching below decks is a departure from the solid waste management focus. Why did the research team change its direction?
Response: This new direction was identified
shortly after last year's hearings in Minnesota where a ban on CCA-treated wood
was deliberated. Many questions were raised at that meeting concerning in-service
issues and concerning metals speciation; however, there was not much scientific
data available. Therefore the research team, after receiving funding for this
work, has begun to conduct some research in this area.
Gus Staats: Do you consider that the measurement of 216 mg/kg in the soil sample to be correct?
Response: Yes, the samples were analyzed
George Parris: Why was the one sample so high at 216 mg/kg?
Response: That particular sample could
have been influenced by sawdust, perhaps.
John Schert: Why was the bridge in Gainesville treated to such a high retention level?
Response: We do not really know. The bridge
was designed by the Department of Transportation and perhaps it was treated
to a high retention level because it is located over a river within a wetland
Question: Is CCA ever re-applied to a treated deck?
Bob Gruber: No, re-application must be
done by a certified individual and it is likely that CCA was not used while
the decks were in service.
Dave Hahn: What were the levels for the soil beneath the playground in Gainesville that was sampled as part of a separate study?
Response: Concentrations varied from 5
to 40 mg/kg.
Peter Goren: Were the decks ever sealed?
Response: That is unknown. We are not aware
that sealants were used on the decks.
John Schert: The data is consistent with
other studies which show a correlation between arsenic levels and clay/organic
content of soil.
Julie Hauserman: If you take the mean soil concentration of 28.5 mg/kg and divide by the residential SCTL, does that mean that the soil is 38 times greater than the recommended level?
Response: Yes, assuming the math is correct.
Bob Gruber: Is it true that 10% of Florida's natural soils exceed the background concentrations.
Response: Another way to look at the data
is that 90% of the soils are below background.
George Parris: The background concentration
determined for Florida assumes that the soils are un-impacted by human activity.
7. Proposed Research Plan for "Year 4"
Helena Solo-Gabriele described the project objectives
for the year 4 study titled, "Fate of CCA-Treated Wood." The project is separated
into two phases: Phase I, Evaluate CCA- and alternative-chemical- treated wood
through TCLP and SPLP, and Phase II, Evaluate arsenic species in leachates collected
from landfills. There is a complimentary study funded by the Florida Dept. of
Environmental Protection that focuses on chromium speciation. Samples used for
phase I of the project include: ACQ-, CBA-, CC-, and CDDC-treated wood. Two
CCA-treated wood control samples and untreated wood will also be included. The
research team was also approached by a company requesting that their treated
wood also be included within the study. This company requires that a secrecy
agreement be signed. Untreated wood samples (2" x 4" x 16') were purchased by
the research team and cut into 2 foot lengths. A 2 foot length was randomly
chosen from each board for treatment by each company. Kristin Stook described
the leaching test plan and the proposed methods for analysis. Leaching tests
include TCLP and SPLP, as well as leaching tests conducted with deionized-distilled
water and synthetic seawater. Samples collected will be size reduced, will be
leached using standard protocols, and leachates will be analyzed. The methods
of analysis are being compiled from AWPA standards, EPA methods, and instrument
manufacturer methods. Chemicals to be analyzed include arsenic, chromium, copper,
DDAC, tebuconazole, dimethyldithiocarbamate, and citrate. Instruments needed
for analysis will include an ICP, FLAA, GFAA, GC/MS, an ion chromatograph and
titration and colorimetric methods. Toxicity tests may be conducted during year
Bernine Khan presented the research plan for arsenic
analysis. She described toxicity, mobility, and analytical methods for speciation.
Different arsenic species include arsenic in different oxidation states (+3,
+5, and -3). Inorganic arsenic species may be bound with sulfer. Organic species
include arsenic bound with carbon and hydrogen groups. Not all arsenic species
are toxic. The most toxic arsenic species is arsine gas (AsH3). Other
arsenic species in order of decreasing toxicity include inorganic arsenite (As+3),
inorganic arsenate (As+5), monomethylarsonic acid (MMAA), dimethylarsine oxide
(DMAA), trimethylarsine oxide (TMAO), arsenobetaine (AsB), and arsenocholine
(AsC). An Eh versus pH diagram was used to explain conditions during which different
species would be present. Analytical methods for arsenic analysis require "hyphenated
techniques" which include one step for separation and another for detection.
The purpose of the current arsenic speciation study was to quantify the total
arsenic and the inorganic arsenic concentrations of As+3 and As+5 species. A
chemical hydride generation method will be utilized for analysis, in particular
the SDDC method will be used. Results from testing standard solutions of arsenate
and arsenite were presented showing good reproducibility and linearity between
0 and 20 g of arsenic. The next steps for this research include determining
how best to preserve a sample, analysis of groundwater samples near C&D
landfills, and analysis of leachates from MSW and C&D landfills.
The research plan for the complimentary study
on chromium speciation was presented by Tim Townsend. The most common oxidation
states for chromium are 0, +3, and +6. Cr+6 is much more toxic and mobile than
Cr+3. The difference between Cr+6 and Cr+3 is factored into regulations. EPA's
soil screening guidance value is 78,000 mg/kg for Cr+3 and 390 mg/kg for Cr+6.
Cr+6 exists in alkaline and strongly oxidizing environments. Cr+3 exists in
moderately oxidizing and reduced environments. An Eh versus pH diagram was presented
to describe conditions during which the different species would be present.
Chromium in the CCA preservative solution is Cr+6. Upon fixation in the wood,
Cr+6 is converted to Cr+3. Cr+6 may be found if wood is improperly fixed or
potentially when CCA-treated wood is in contact with oxidizing chemicals such
as deck brighteners. In the natural environment, some oxidation may occur as
a result of interactions with manganese (hydr)oxides. The selected method for
chromium analysis is ion chromatography. The current research project titled,
"Assessing the Impact of Chromium in the Environment" is funded by the Florida
Department of Environmental Protection. Tasks in the project include a literature
review, an assessment of pH and ORP as indicators of Cr speciation, an evaluation
of the kinetics of conversion of Cr+6 to Cr+3 in natural soils, and the development
of a guidance document. Additional tasks in the project include examining the
ash from the "year 2" study for chromium species and examining the potential
of Cr+6 to form in C&D debris disposal environments.
George Parris and Several Others from the Audience: We do not consider that the unknown treated wood should be included within the leaching study.
Response: It was presented as an opportunity.
The research team does not necessarily have to include it within the analysis
Jim Healey: Who will be analyzing the wood.
Response: The leachates from the wood will
be analyzed by the research team.
Keith Parmer: Temperature and other biological
parameters may impact the amount of chemical extracted from the wood.
George Parris: A considerable amount of
toxicity information is available in the literature on biofouling. There's a
researcher by the name of Alberquerque that has some information.
George Parris: There should be no arsine
gas in biological systems.
Jim Healey: How will the samples used in the leaching study be treated.
Kevin Archer: The ACQ samples, for example,
were treated in 4 foot long research cylinders.
George Parris: Tom Roberts of the FDEP
may have a database available on arsenic speciation. There's also a professor
at the University of South Florida that may have information.
Lena Ma: There's a professor at FIU who
has conducted work on arsenic speciation. There are also kits available that
will separate the different arsenic species in the field.
George Parris: The view that chromium III
is immobile is a generalization. Chromium III combines with many different compounds,
all of which migrate differently.
8. Discussion, Including Recommendations for
"Year 5" Research
George Parris: Consider using additives
in the combustion process that will bind CCA to the ash and therefore prevent
George Varn Jr.: Sorting treated from untreated
wood will be easiest at the demolition site where the landscape timbers and
decks can be easily removed from the rest of the home. Research should focus
on separation at the true source.
Russ Morgan: What happened to the French company that was developing pyrolysis technology?
Response: The technology has been patented.
A pilot system is running in France. Transferring the technology to Florida
is difficult because of the distance issue.
Jim Healey: What is the status of other pyrolysis projects?
Response: The other project was not re-funded
by the Center.
Bob Gruber: Is the research team aware of efficacy tests that are being conducted at the University of South Florida?
Response: No, in what Department is the
research being conducted?
Lena Ma: Is it possible to add something to the wood that will make it easier to pull out once it is within the disposal stream?
Response: There is a task force through
the AWPA that focuses on handling, disposal, and reuse of treated wood. Some
ideas have been discussed during the task force meetings. One idea brought up
during the meeting is to use a similar chemical that is used to trace explosives.
George Parris: The problem with adding
a color is due to the fact that it tends to get bleached-out with U.V. light.
George Parris: Speciation should include
the methylated forms. Also, the team should consider volatilization that occurs
as a result of methylation. Dr. Brahman of the University of South Florida conducted
this research in 1982.
Bob Gruber: The problem with recycling
treated wood are the logistics. The difficult part is getting the deck from
the home to the recycling facility.
Jennifer Caldwell-Kurka: One of the large
drawbacks with pyrolysis technology is that the energy that is used to recycle
the product is usually greater than the benefit that results.
Tom Marr: By incinerating wood, you get
a considerable amount of volume reduction. After volume reduction there then
may be more options for processing the ash.
George Parris: Consider the feasibility
of flattening the wood under pressure. By flattening the wood, there may be
increased resistence to biodegredation. It may be cheaper than chipping the
Steve Cox, of Co XRF, provided a demonstration of the EDAX CT-2000 instrument for analyzing metals in environmental samples. The instrument was shown to easily detect the presence of CCA-treated wood within a matter of 30 seconds. The instrument is battery operated and easy to use. The cost, which includes a laptop computer, is $28,000.