Tsunami and Environmental Pollution Hazards: A Note for the Restoration Process - Post-Tsunami Hazard: Reconstruction and Restoration - page 257

(Hingston et al. 2001 ), while Zagury et al. ( 2003 ), Read ( 2003 ) and Cooper and
Ung ( 1997 ) showed that copper has the highest leaching rate in all environments.
The leaching rate of arsenic appears to be related to the amount of chromium,
with the minimum occurring at a chromium to arsenic ratio of between 1 and 1.3
(Read 2003 ). Leaching rates of CCA components have also been shown to decrease
over time (Hingston et al. 2001 ; Read 2003 ). Certain studies show that the amount
of leached compounds also depends on climatic and geological conditions (Hall and
Beder 2005 ).
Ultraviolet exposure increases the leaching rate of arsenic by as much as fi ve
times that which is removed through rainfall (Lebow et al. 2003 ), and weathered
wood leaches more of the penta- and toxic trivalent arsenic (Solo-Garbriele et al.
2003a , b ; Bernine et al. 2003 ). Acidity also increases leaching. The CCA chemical
itself is acidic, and if not properly applied to the wood, can result in increased levels
of chromium present in the surrounding soil. Humic acid in mulch also poses an
increased risk of leaching.
It is well known that metal concentrations in humic matter could be a thousand-fold
higher than in non-humic conditions, copper being the most conspicuous, as also
reported by Enviros Consulting and The BioComposites Centre ( 2004 ). Farm soil
treated with fertilizer containing calcium, magnesium, potassium and phosphorous
also increases the chances of leaching from CCA-treated timber.
Solo-Garbriele et al. ( 2003a , b ) found that the soil below and around CCA-treated
timber decks contained an average arsenic concentration of 28.5 mg/kg, well above
average background soil arsenic concentrations of 1.5 mg/kg. Runoff collected from
the decks contained over 1 mg/L arsenic and chromium. Soil below the CCA-treated
timber decks contained an average of 34 mg/kg chromium and 40 mg/kg of copper,
in contrast to an average background concentration of 10 mg/kg for both metals
(Townsend et al. 2001 ).

17.2.2.1 Soil and Water Contamination from CCA-Treated Wood

Townsend and Solo-Gabriele ( 2006 ) compiled a series of studies on the impacts of
CCA-treated wood, and Graham and Scott ( 2013 ) and Hall and Beder ( 2005 )
showed that CCA

treated timber can leach into both soil and groundwater. It is
therefore estimated that there is a possible risk to groundwater quality from treated
timber at debris piling sites. CCA soil concentrations were found to reach back-
ground levels very close to the source, and as this compound is easily transported by
water, it clearly presents a groundwater hazard.
CCA residues from treated wood found in the environment after a natural
catastrophe were confi rmed in the case of hurricane Katrina in 2005. As in 2003,
CCA-treated wood was the most popular wood preservative used in the USA, and
large amounts of wooden debris containing arsenic (As) presented dangerous
pollution potential (Brajesh et al. 2007 ).
Japan started using CCA from 1963 until 1996, with an annual production of
300,000 m 3 or almost 75 % of the market, after which use was reduced due to the

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