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Building and Environment 41 (2006) 910–914

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Comparison of copper emission rates from wood treated withdifferent preservatives to the environment

Ali Temiza,�, Umit C. Yildiza, Thomas Nilssonb

aKaradeniz Technical University, Faculty of Forestry, 61080 Trabzon, TurkeybSwedish University of Agricultural Sciences, Department of Wood Science, P.O. Box 7008, SE-750 07 Uppsala, Sweden

Received 11 October 2004; received in revised form 15 March 2005; accepted 4 April 2005

Abstract

This study describes a laboratory method for the estimation of emission from preservative-treated wood in the different situations

where emissions could enter the environment for use classes 3 (not in contact with ground) and 4 and 5 (in contact with the ground,

fresh water or sea water) according to OECD Guidelines. Samples of scotch pine sapwood (Pinus sylvestris L.) were treated with

CCA (1% and 2%), ACQ-1900 (3% and 7%), ACQ-2200 (2%), Tanalith E 3491 (2% and 2.8%), and Wolmanit CX-8 (2%).

The results indicated that the lowest copper amounts were released from CCA-treated wood. Because of the higher copper

amount in the leachates from the alternative wood preservatives, the emission rate of these leachates was higher than the leachates

from CCA-treated wood.

r 2005 Elsevier Ltd. All rights reserved.

Keywords: Copper-containing wood preservatives; Leaching; OECD Guideline

1. Introduction

Treated wood is commonly used for construction ofbuilding materials, foot bridges, wetland boardwalks,and other applications where the wood is placed in orover water. Many of these applications place thewood in pristine or sensitive ecosystems [1]. Chromatedcopper arsenate (CCA) has been a major woodpreservative for more than 50 years for many applica-tions such as utility poles, children’s play grounds,residential application etc.; however, there is increasingpublic concern about environmental contaminationfrom CCA-treated wood. On February 12, 2002, theUS Environmental Protection Agency (EPA) an-nounced a voluntary decision by the pressure-treatedwood industry to phase out use of common arsenic-based wood preservative CCA in products destined for

e front matter r 2005 Elsevier Ltd. All rights reserved.

ildenv.2005.04.001

ing author. Tel.: + 90 462 377 28 51;

5 74 99.

ess: temiz@ktu.edu.tr (A. Temiz).

consumer markets in the US. From January 2004,the EPA no longer allows pressure-treated woodcontaining CCA to be used for residential appli-cations such as building constructions, children’splay structures, decks, picnic tables, landscapingtimbers, residential fencing or walkways. Because ofthe new regulations and the concern about environ-mental contamination, there is an urgent need todevelop new chemical formulations which will not causeany harmful effects on the environment and humanhealth [2].

More recently, copper-based but chromium andarsenic-free wood preservatives are being introduced asreplacements for CCA in such applications. These woodpreservatives contain copper, and organic co-biocidessuch as quaternary ammonium compounds (quats),triazoles or Cu-HDO as well as amines as complexingagents for copper [1,3,4]. However, the emissions fromnew arsenic-free preservative-treated wood to theenvironment need to be quantified to enable anenvironmental risk assessment of treated wood.

ARTICLE IN PRESSA. Temiz et al. / Building and Environment 41 (2006) 910–914 911

The objective of this study was to measure theemission from preservative treated wood in the diff-erent situations where emissions could enter theenvironment:

�

Emissions from preservative-treated wood in contactwith the ground, fresh water and sea water (use classes4 and 5). � Emissions from preservative-treated wood storedoutside in the storage yard of a preservative treatmentsite. Rain fall on the treated wood could produceemissions which run off into surface water and/or soil(use class 3). � Emissions from treated wood used were not coveredand not in contact with the ground (use class 3). Theprincipal agent for causing emissions from wood inuse class 3 is rainfall. Wood exposed in above-groundsituation is subjected to the intermittent wetting ofrainfall and the drying of the wood surface betweenthe rainfall events. These wetting and drying cycleswere simulated in laboratory conditions. It isassumed that emissions obtained by exposure torainfall are identical to emissions obtained by immer-sion in water.

2. Material and method

Samples of scotch pine sapwood (Pinus sylvestris L.)were prepared at 50mm wide by 150mm long, 10mmthick for this study. The samples were conditioned at65% relative humidity and 20 �C.

Solutions of CCA (1% and 2%), ACQ-1900 (3% and7%), ACQ-2200 (2%), Tanalith E 3491 (2% and 2.8%),Wolmanit CX-8 (2%) were prepared for impregnationprocedure.

2.1. Impregnation procedure

Test specimens were end and side sealed for use class 3and only end sealed for use classes 4 and 5 applicationswith two coats of a silicone. Test samples were treatedby prevacuum over the samples for 60min and ambientpressure for 60min. The wood samples were thenremoved from the treatment solution, wiped lightly toremove solution from the wood surface, and weighed(nearest 0.01 g) to determine gross retentions for eachtreating solution and sample. The retention for eachtreatment solution was calculated as following:

R ¼GxC

Vx10 kg=m3, (1)

where G: ðT2 � T1Þ is grams of treating solutionabsorbed by the sample (initial weight of blocksubtracted from the initial weight plus the treatingsolution absorbed), C is grams of preservative or

preservative solution in 100 g of the treating solution,V is the volume of sample in cubic centimeters.

After the wood samples were treated with chemicals,the samples were then wrapped in plastic bags for 1week at room temperature for fixation.

2.2. Immersion method

The immersion methods were carried out according toOECD guidelines [5,6]. In these guidelines, the numberof wood test specimens was four: three specimens weretreated with preservatives and one specimen wasuntreated. The immersion container was large enoughto contain sufficient water for the ratio of exposedsurface area of the test specimen to the volume of waterto which it is exposed. The volume of water was 100 and375 cm3 for use class 3 and use classes 4, 5, respectively.

For use class 3, the test specimens were exposed towater for 1min. The test specimens were removed fromthe water and allowed to drain for 10 s, allowing run offto return to the water. There were three immersion stepsper day representing ‘‘immersion day’’. After eachimmersion, the test specimens were weighed and themass, date and time recorded. The samples were allowedto dry for at least two days, but no more than four days.Then immersion process started again and continued in32 days. The water was collected for copper analysis.

For use classes 4 and 5, the test specimens wereimmersed permanently in the water and the date and timerecorded. The water was changed at a minimum intervalof one day and a maximum interval of 7 days until 27days. All the water was collected for copper analysis.

2.3. Copper analysis

Copper content of water in which the test specimenshad been immersed was determined by Atomic Absorp-tion Spectroscopy (Perkin-Elmer). Standard coppersolutions were prepared by serially diluting a commer-cial 1000 ppm standard copper solution. All the leachatesolutions were diluted to provide a suitable copperconcentration for atomic absorption analysis anddetermine copper in leachate.

The analytical result was converted to the quantityemitted in the emissiate in mg=m2 using the volume ofwater and the surface area of the test specimen in squaremeters. The emission rate was calculated by dividingquantity emitted by interval days according to OECDguidelines [5,6].

3. Results and discussion

Table 1 shows the retention for each preservative. Thedifferences of retentions could be due to variablepenetration of preservatives.

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Table 2

Quantity of emitted Cu and emission rate of treated wood for use

class 3

Days Analytic results Quantity emitted Emission rate

ðmg=mlÞ ðmg=m2Þ ðmg=m2=dayÞ

CCA 1%-treated wood

1 0.03 0.4 0.4

4 0.02 0.27 0.09

7 BDL� BDL� BDL�

11 BDL� BDL� BDL�

14 0.01 0.13 0.04

18 0.01 0.13 0.03

21 0.03 0.40 0.13

24 0.01 0.13 0.04

28 0.01 0.13 0.03

32 BDL� BDL� BDL�

ACQ-1900 3%-treated wood

1 0.94 12.53 12.53

4 0.35 4.67 1.56

7 0.27 3.60 1.20

11 0.16 2.13 0.53

14 0.17 2.27 0.76

18 0.15 2 0.50

21 0.11 1.47 0.49

24 0.14 1.87 0.62

28 0.2 2.67 0.67

32 0.24 3.20 0.80

ACQ-2200 2%-treated wood

1 0.67 8.93 8.93

4 0.22 2.93 0.98

7 0.17 2.27 0.76

11 0.42 5.60 1.40

14 0.23 3.07 1.02

18 0.08 1.07 0.27

21 0.03 0.40 0.13

24 0.03 0.40 0.13

28 0.14 1.87 0.47

32 — — —

Tanalith E 3491 2%-treated wood

1 0.52 6.93 6.93

4 0.18 2.40 0.80

7 0.17 2.27 0.76

11 0.16 2.13 0.53

14 0.07 0.93 0.31

18 0.15 2 0.50

21 0.06 0.80 0.27

24 0.04 0.53 0.18

28 0.16 2.13 0.53

32 0.09 1.20 0.30

Wolmanit CX-8 2%-treated wood

1 0.31 4.13 4.13

4 0.06 0.80 0.27

7 0.04 0.53 0.18

11 0.06 0.80 0.20

14 BDL� BDL� BDL�

18 BDL� BDL� BDL�

21 0.04 0.53 0.18

24 0.06 0.80 0.27

28 0.03 0.40 0.10

32 0.06 0.80 0.20

BDL�, Below the detection limit.

Table 1

Retention of wood preservatives

Wood preservatives Retention ðkg=m3Þ

Average Std.d

Class 3 CCA 1% 8.07 0.19

ACQ-1900 3% 16.38 0.27

ACQ-2200 2% 6.71 2.20

Tanalith E 3491 2% 14.23 1.03

Wolmanit CX-8 2% 6.81 0.82

Class 4 and 5 CCA 2% 15.27 0.44

ACQ-1900 7% 28.16 4.59

Tanalith E 3491 2.8% 15.82 2

A. Temiz et al. / Building and Environment 41 (2006) 910–914912

Most of the wood preservatives contain copperbecause of its fungicidal characteristics and copperappears to be the primary cause of toxicity to aquaticorganisms [7–9]. Therefore, the evaluated proportion ofaquatic toxicity can be attributed to the leaching ofcopper as compared to the leaching of other chemicalsfound in treated wood.

When comparing leached copper concentrations, thelowest copper amounts were released from CCA-treatedwood (Tables 2 and 3). This was followed by WolmanitCX-8 2%, Tanalith E 3491 2%, ACQ-2200 2%, andACQ-1900 3%, respectively, for use class 3 and TanalithE 3491 2.8% and ACQ-1900 7%, respectively, for useclasses 4 and 5.

Studies have also indicated that leaching rates of allpreservatives were highest initially and decrease sig-nificantly over time (Figs. 1 and 2). The higher emissionrates after several days of leaching could be due to anon-uniform leaching of preservative components.Melcher et al. [10] also reported that increase of copperdepletion of CCB-treated wood after second waterexchange. After this initial phase of four days for useclass 3 and 13 days in use classes 4 and 5, the copperseems to be fixed well and copper leaching is onlyminimal.

It appears that the copper in CCA-treated wood isstrongly bound. For the alternatives, Wolmanit CX-8,Tanalith E 3491, ACQ-2200, and ACQ-1900, it appearsas though the copper is less strongly bound than forCCA treatment.

The CCA treatment process relies on a chemicalreaction to bind the chemicals in the wood [4,11–15].The copper and organics in the other wood preservativesform complexes which probably do not involve cell wallcomponents. This suggests that different fixation me-chanisms are the primary reasons for the higher copperamount in leaching from ACQ-Wolmanit CX-8 andTanalith E 3491. Because of the higher copperconcentrations in the leachates from the alternativewood preservatives, the emission rate of these leachates

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Table 3

Quantity of emitted Cu and emission rate of treated wood for use

classes 4 and 5

Days Analytic results Quantity emitted Emission rate

ðmg=mlÞ ðmg=m2Þ ðmg=m2=dayÞ

CCA 2%-treated wood

0 — — —

4 3.02 145.02 36.26

6 2.19 108.50 54.25

8 2.37 117.33 58.67

13 3.68 181.88 36.38

20 2.64 129.89 18.55

27 2.15 105.33 15.05

ACQ-1900 7%-treated wood

0 — — —

4 13.16 605.83 151.45

6 12.60 624.10 312.05

8 11.76 583.21 291.61

13 12.30 606.10 121.22

20 18.55 577.30 82.47

27 12.44 613.59 87.66

Tanalith E 3491 2.8%-treated wood

0 — — —

4 12.34 571.85 142.96

6 8.27 409.70 204.85

8 6.47 320.68 160.34

13 7.23 353.13 70.63

20 6.45 311.23 44.46

27 6.44 314.53 44.93

0

2

4

6

8

10

12

14

1 4 7 11 14 18 21 24 28 32Days

Em

issi

on r

ate

(mg/

m2 /d

ay)

CCA 1% ACQ-1900 3% ACQ-2200 2%

Tanalith E 3491 2% Wolmanit CX-8 2%

Fig. 1. Emission rate of wood preservatives for class 3.

0

100

200

300

0 4 6 8 13 20 27Days

Em

issi

on r

ate

(mg/

m2 /d

ay)

CCA 2 % ACQ-1900 7% Tanalith E 2.8%

Fig. 2. Emission rate of wood preservatives for class 4 and 5.

A. Temiz et al. / Building and Environment 41 (2006) 910–914 913

was higher than the leachates from CCA-treated wood.However, as-containing wood preservatives have alsorecently been scrutinized under the marketing and usedirective [2,16].

Townsend et al. [17] investigated leaching and toxicityof CCA-treated and alternative-treated wood productsand concluded that percentage of copper leached fromthe wood treated with the copper-based alternativepreservatives was greater than CCA-treated wood andACQ (Alkalen Copper Quat), CBA (Copper BoronAzole) and CC (Copper Citrate) treated wood werefound to be more toxic to aquatic life forms.

Habicht et al. [18] studied the role of differentparameters such as fixation, sample size and leachingprotocols and reported that the lowest leaching valuefound was the CCA rather than ACQ and CX (Copper-HDO).

4. Conclusion

The percentage of copper leached from the woodtreated with the alternative copper-based preservativeswas greater than that of CCA-treated wood. However,this study was only based on laboratory tests, simulatingoutside conditions in contact with ground, water andnot in contact with ground. Therefore, it can only beused to compare the relative emission rates of thetreated wood. The effects of treated woods on humanhealth and environment need to be assessed by allaspects of wood preservatives. The impact of woodpreservatives on human and ecosystem should beevaluated in further studies.

Acknowledgements

One of the authors (A. Temiz) would like to thankFred G. Evans for valuable discussion. Morten Dammand Gro Brekka, Norwegian Institute of Wood Tech-nology are gratefully acknowledged and NorwegianResearch Council provided for scholarship.

References

[1] Lebow ST, Tippie M. Guide for minimizing the effect of

preservative-treated wood on sensitive environment. United

States Department of Agriculture, Forest Service, Forest Products

Laboratory, 2001, Madison, WI.

[2] Environmental Protection Agency (EPA), www.epa.gov/epahome/

headline_021202.htm.

[3] Zhang J. Interactions of copper-amine preservatives with south-

ern pine. PhD dissertation, Michigan State University, 1999.

[4] Hingston JA, Collins CD, Murphy RJ, Lester JN. Leaching of

chromated copper arsenate wood preservatives: a review.

Environmental Pollution 2001;111:53–66.

ARTICLE IN PRESSA. Temiz et al. / Building and Environment 41 (2006) 910–914914

[5] Anon. OECD guideline for testing of chemicals, proposal for a

new guideline XXX, CEN/TC 38 WG27 N039, 2003.

[6] Anon. OECD guideline for testing of chemicals, proposal for a

new guideline YYY, CEN/TC 38 WG27 N040, 2003.

[7] Weis P, Weis JS. Accumulation of metals in consumers associated

with chromated copper arsenate-treated wood panels. Marine

Environmental Research 1999;48:73–81.

[8] Brooks KM. Environmental impact of preservative-treated wood

in a wetland boardwalk. Part II. Environmental effects. Forest

Products Laboratory, Madison, WI, 2000.

[9] Breslin VT, Adler-Ivanbrook L. Release of copper, chromium and

arsenic from CCA-C treated lumber in estuaries. Estuarine

Coastal and Shelf Science 1998;46:111–25.

[10] Melcher E, Peek RD, Schoknecht U, Wegner R. Depletion of

boron and copper from CCB-treated test specimens using different

leaching protocols. IRG/WP 04-50208, 2004, International Re-

search Group on Wood Preservation, Stockholm, Sweden.

[11] Cooper PA, Ung YT, Kamden PD. Fixation and leaching of red

maple (Acer rubrum L.) treated with CCA-C. Forest Products

Journal 1997;47:70–4.

[12] Pizzi A. Chromium interactions in CCA/CCB wood preservatives.

Part I. Interactions with wood carbohydrates. Holzforshung 1990;

44:373–80.

[13] Ruddick JNR, Yamamoto K, Wong PC, Mitchell KAR. X-ray

photoelectron spectroscopy analysis of CCA-treated wood.

Holzforshung 1993;47:458–64.

[14] Hingston JA, Moore J, Bacon JN, Murphy RJ, Collins CD. The

importance of the short-term leaching dynamics of wood

preservatives. Chemosphere 2002;47:517–23.

[15] Jusoh IB. Microdistribution of chromated copper arsenate

preservative in rubberwood (Hevea brasiliensisHevea brasiliensis

Muell. arg). PhD dissertation, Michigan State University, 2000.

[16] Atkins WS. Assessment of the risks to health and to the

environment of tin organic compounds and of arsenic in certain

biocidal products and of the effects of further restrictions on their

marketing and use. European Commission Directorate General

III, Epsom, Surrey, 1998.

[17] Townsend T, Stook K, Ward M, Solo-Gabriele H. Leaching and

toxicity of CCA-treated and alternative-treated wood products.

Florida Center for Solid and Hazardous Waste Management,

Report #01-XX. 2001.

[18] Habicht J, Hantzschel D, Wittenzellner J. Influence of different

fixation and ageing procedure on the leaching behavior of copper

from selected wood preservatives in laboratory trials. IRG/WP

03-20264, 2003. International Research Group on Wood Pre-

servation, Stockholm, Sweden.