Year 4 Research Fate of CCATreated Wood Objectives

Year 4 Research Fate of CCA-Treated Wood

Objectives n Evaluate Fate of Wood Treated With Preservative Chemicals ä Evaluate CCA- and alternative-chemical- treated wood through TCLP and SPLP (Phase I) ä Evaluate arsenic species in leachates collected from landfills (Phase II) Note: Complimentary Study on Chromium Speciation

Phase I: Leaching of Alternative. Chemical Treated-Wood Products n Samples Include ä ä ä ä ACQ-Treated Wood CBA “ “ CC “ “ *** CDDC “ “ CCA “ “ Treated Through Facility A CCA “ “ Treated Through Facility B Untreated Wood Unknown Treated Wood (? )

Sample Processing n 8, 2”x 4”x 16 ft were purchased

Analytical Methods for Alternative Chemicals Description of Leaching Test Plan n Review of existing methods for analysis of alternative chemicals (AWPA, EPA, and others) n Proposed methods of analysis n Questions for TAG n

Plan for Leaching n Primary Leaching Tests ä TCLP ä SPLP n Additional Leaching Tests ä Deionized/Distilled ä Synthetic Seawater Water

Leaching Tests Wood Sample Size reduced following standard leaching protocols Leaching Test 18 hour contact, 20: 1 Liquid to Solid ratio, Rotary extraction Leachate Analysis Leachate analyzed using standardized methods

Methods of Analysis n Sources of methods: ä AWPA Standards ä EPA Methods ä Instrument Manufacturer Methods ä Other n Methods are often matrix specific ä The matrix of interest in the this study is aqueous leaching fluid

Chemicals to be Analyzed Preservative Inorganic Chemical(s) Organic Chemical(s) CCA As, Cr, Cu -- ACQ Cu DDAC CBA Cu, B Tebuconazole CDDC Cu Dimethyldithiocarbamate CC Cu Citrate

Inorganic Methods Analytical Method ICP-AES EPA Method AWPA Standard 6010 B A 21 -93 FLAA 7210 A 11 -93 GFAA 7211 A 11 -93 Note: Methods may require extraction or digestion depending on the matrix or method

Organic Chemical Analysis Organic Chemical Analytical Technique DDAC HPLC, Titration CDDC Colorimetric Tebuconazole Citrate HPLC, GC UV Spec AWPA Method (liquids) A 16 -A/17 -97 A 25 -94 * A 23 -94/A 24 -94 A 2 -98

Other Analytical Methods n Citrate by Ion Chromatography ä Dionex n methods manual Alternative Titration for DDAC ä Manufacturer suggestion

Proposed Methods n Methods selected based on resources available, time constraints, and analytical objectives

Analysis of Inorganic Chemicals n Copper and Boron will be analyzed using ICP, FLAA, or GFAA following US EPA methods (including acid digestion).

ICP

Perkin-Elmer 5100 FLAA/GFAA

Analysis of Tebuconazole A GC/MS will be used for analysis. n Based on a modified version of AWPA method A 24 -94 n Detection limit is approximately 100 mg/L n

Trace 2000 GC/MS

Analysis of DDAC (ACQ) n A two-phase titration analysis will be performed following method A 17 -97.

Titration Setup

Analysis of CDDC n Analysis will be performed using a colorimetric method specified in A 25 -94 and instrument methods manual.

Hach DR/4000 U Spectrophotometer

Analysis of Citrate n Analysis will be performed using Ion Chromatography

Dionex DX-500 Ion Chromatograph

Chromatogram

Other Possibilities n Toxicity Tests ä MET-plate ä Microtox ä Algal assay ä Yeast assay

Questions for TAG Are we missing any analytes of concern? n Suggestions on methods? n Comments on leaching tests? n

Arsenic: Toxicity, Mobility & Analytical Methods for Speciation Bernine Khan University of Miami

Outline Part I - Characteristics n Arsenic Species n Arsenic Toxicity n Arsenic Mobility Part II - Arsenic Speciation Study n Purpose of Study n Goals for Year 4 n Hydride Generation Method - SDDC

Speciation Definition Various species of an element which make up the total concentration of that element - different oxidation states (e. g. arsenic inorganic - contains sulfur organic - contains carbon/hydrogen groups +3, +5, -3)

Speciation Why are we interested in speciation? n Not all species are toxic n Total concentration - over-/under-estimate toxicity Standards n EPA’s MCL for DW- 50 mg/L (5 mg/L) As n TCLP limit - 5000 mg/L

Arsenic Species Decreasing Toxicity As. H 3 - arsine (gas) As(III) - inorganic arsenite As(V) - inorganic arsenate MMAA - monomethylarsonic acid DMAA - dimethylarsinic acid TMAO - trimethylarsine oxide As. B - arsenobetaine (marine) * As. C - arsenocholine (marine) *

Arsenic Species Decreasing Toxicity As. H 3 - arsine (gas) As(III) - inorganic arsenite As(V) - inorganic arsenate - CCA MMAA - monomethylarsonic acid DMAA - dimethylarsinic acid TMAO - trimethylarsine oxide As. B - arsenobetaine (marine) * As. C - arsenocholine(marine) *

Arsenic Species Decreasing Toxicity As. H 3 - arsine (gas) As(III) - inorganic arsenite As(V) - inorganic arsenate MMAA - monomethylarsonic acid DMAA - dimethylarsinic acid TMAO - trimethylarsine oxide As. B - arsenobetaine (marine)* As. C - arsenocholine (marine)*

Toxicity Data LD 50 (mg/kg) Animal Inorganic arsenite [As(III)] 4. 5 rat Inorganic arsenate [As(V)] 14 -18 rat MMAA - monomethylarsonic 1, 800 mouse DMAA - dimethylarsinic acid 1, 200 mouse TMAO - trimethylarsine oxide 10, 600 mouse As. B - arsenobetaine (marine) 10, 000 mouse As. C - arsenocholine (marine) 6, 000 mouse Arsenic Compound LD 50 - concentration at which 50% of a population dies. Low LD 50 - more toxic High LD 50 - less toxic

Arsenic Mobility Reducing O 2 & Eh 0. 75 As(V) +5 0. 50 Most surface waters As(III) +3 0. 25 Eh (volts) Eh-p. H diagram 0 Most ground waters As. S +3 -0. 25 measure of system state (aerobic/ anaerobic) As(III) - Oxidized As(V) - Reduced Methylation -0. 50 As(III) +3 -0. 75 As As. H 3 (aq) 0 2 4 6 8 p. H 10 12 14

Part II Arsenic Speciation Study n. Hyphenated techniques n. Separation + detection methods n. Separate As(III) and As(V) from interfering ions n. Detection methods - detect & quantify

Purpose of Study • • CCA treated wood disposed of in unlined C&D landfills • Determine the total arsenic & individual concentration of As(III) & As(V) species • Chemical Hydride Generation method Leaching studies show significant amounts of CCA leaching from wood under varying p. H solutions

Leaching Study (Warner et al. 1990) Arsenic leaching increases linearly with decreasing p. H Arsenic after 40 days - retention of 1. 99 kg/m 3 in new wood Buffer citric acid/Na. OH distilled water borax/HCl p. H 2. 5 3. 5 4. 5 5. 5 7. 0 8. 5 % As 68 52 32 17 9 Buffer H 2 SO 4 p. H 2. 5 3. 5 4. 5 % As 40 23 17

Goals for Year 4 Current Study: • Analysis of As(III) & As(V) by Chemical Hydride Generation (CHG) method • SDDC - CHG method chosen - Na. BH 4 to reduce arsenic to its gaseous form (arsine) so as to be detected • SDDC method - Test reproducibility using standard solutions

Current Study Silver Diethyldithiocarbamate (SDDC) Method 20 10 5 2 ug 1 0

Results of SDDC Methods Arsenite [As(III)] Conc. (mg) Absorbance 20 0. 185 20 0. 17 10 0. 082 10 0. 072 5 0. 038 5 0. 05 2 0. 03 2 0. 02 1 0. 018 0 0. 009

As(III) Calibration Curve

Results of SDDC Methods Arsenate [(As(V)] Conc. (mg) Absorbance 20 0. 24 10 0. 15 10 0. 142 5 0. 078 5 0. 08 2 0. 04 2 0. 037 1 0. 02 1 0. 03 0 0. 009 0 0. 015

As(V) Calibration Curve

Goals for Year 4 Next Steps: • • • Determine how best to preserve sample Analyse GW samples near C&D landfills Analyse leachate from MSW and C&D(? ) landfills

Speciation of Chromium

Chromium Speciation n Background n Methods of Analysis n Proposed Methodology

Chromium Exists as Several Chemical Species Most common oxidation states: 0, +3, +6 0: Elemental Chromium (Cr) +3: Trivalent Chromium Species: Cr+3, Cr 2 O 3 +6: Hexavalent Chromium Species: Cr. O 42 -, Cr 2 O 7 -

Chromium Speciation Important! The characteristics and properties of trivalent chromium and hexavalent chromium are greatly different. n Cr(VI) is much more toxic and mobile than Cr(III) n

Difference between Cr(VI) and Cr(III) Factored into Regulations RCRA Regulations 40 CFR 261. 4(b)(6)(i) A solid waste that is a characteristic or listed hazardous waste solely because of chromium is not hazardous if…. .

A solid waste that is a characteristic or listed hazardous waste solely because of chromium is not hazardous if…. . – (A) The chromium in the waste is exclusively (or nearly exclusively) trivalent chromium; and – (B) The waste is generated from an industrial process which uses trivalent chromium exclusively (or nearly exclusively) and the process does not generate hexavalent chromium; and – (C) The waste is typically and frequently man-aged in non-oxidizing environments.

n Ingestion: ä Cr(III): 78, 000 mg/kg ä Cr(VI): 390 mg/kg

Cr(III) versus Cr(VI) Hexavalent chromium exists in alkaline, strongly oxidizing environments n Trivalent chromium exists in moderately oxidizing and reduced environments n

1. 2 1. 0 Eh (V) Cr 2 O 7 - 0. 8 0. 6 0. 4 0. 2 Cr 3+ Cr. O 4 2 - 0. 0 -0. 2 -0. 4 Cr 2 O 3 -0. 6 0 2 4 6 8 p. H 10 12 14

Chromium in Wood Preservation The chromium in CCA preservative solution is hexavalent chromium. n Upon fixation in the wood, Cr(VI) becomes converted to Cr(III) n

When Might Cr(VI) Be Encountered? n If wood is improperly fixed (as a result, for example, of inadequate fixation time at low temperatures) n When in contact with oxidizing chemicals such as deck brighteners

Oxidation of Chromium in the Environment n In the natural environment, chromium tends to exist as Cr(III) n Oxidation of Cr(III) to Cr(VI) as a result of manganese (hydr)oxides

Methods of Cr(VI) Analysis n Typical chromium measurements are total chromium (Cr(III) + Cr(VI) + other) n Methods have been developed for Cr(VI) analysis n Sample holding time is minimal

Methods of Cr(VI) Analysis Solvent extraction followed by total chromium analysis n Colorimetric Determinations n Chromatographic Determinations n

Selected Method n Ion Chromatography

Research Project: Assessing the Impact of Chromium in the Environment n Funding provided by Florida Department of Environmental Protection

Tasks 1. Literature Review 2. Assessment of p. H and ORP as indicators or Cr speciation 3. Evaluate kinetics of conversion of Cr(VI) to Cr(III) in natural soils 4. Develop guidance document

Additional Tasks 5. Examine Cr(VI) in ash from combustion of wood containing CCA-treated wood 6. Examination of Cr(VI) formation potential in C&D debris disposal environments