Eucalyptus wood treatment and leaching behavior of CCB (Chromated Copper Borate): a field test in Brazilian Midwest

Abstract

The use of Chromated Copper Borate (CCB) for wood treatment is known with several studies on a laboratory scale. However, there is a lack of field studies to analyze the effect of the CCB over time. This study aimed to evaluate the wood properties of Eucalyptus urophylla S.T. Blake x Eucalyptus grandis W. Mill ex Maiden (called E. urograndis), treated with CCB as well evaluate the leaching of chromium, copper and bore (Cr/Cu/B) in field test. The field experiment, with wood treated and untreated (no CCB application), was installed in 2016 and remained until 2018. Wood physico-mechanical properties were evaluated for each condition (treated and untreated) and at three different time: at 0, 1 and 2 years of field exposure. The elements (Cr/Cu/B) losses (leaching) were determined by the difference in the quantification of each element retained in the wood (retention), from year 0 (amount of original elements) in relation to years 1 and 2 of field exposure. The preservative treatment of E. urograndis wood with CCB was efficient to maintain its physical and mechanical properties (mass loss, basic density, rupture and elasticity modulus) during the 2 years of field exposure. The E. urograndis wood without CCB treatment showed reductions in the physical-mechanical properties, indicating their low natural durability. High leaching (close to 100%) for boron was observed. In addition, the total of CCB retention has not changed (statistically) after 2 years.

Effect of preservative treatment on physical and mechanical properties of bamboo (Gigantochloa scortechinii) strips

“…Although boron is a more effective preservative than zinc or copper, its low fixation in wood is always an issue (Llyod et al 2021). The same problem exists for CCB, which has higher leaching than CCA (Lima et al 2021). A study by Tomak et al (2022) reported that bamboo (Phyllostachys bambusoides Sieb.…”

Testing the durability of copper based preservatives treated bamboos in ground-contact for six years

“…The high moisture content of soil and decomposition of samples by microorganisms in soil may have an effect on the high leaching rates of the chemicals. Migration of woody elements to soil also con rms the leaching rates of chemicals (Lima et al 2021).…”