Tsunami and Environmental Pollution Hazards: A Note for the Restoration Process - Post-Tsunami Hazard: Reconstruction and Restoration - page 256

with creosote, although it is still often used in other exterior materials (Japan Wood
Protection Association 2011 ).
The industry has come to recognize the synergistic, toxic effects of creosote oil
on termites and other wood-destroying pests (Hale and Aneiro 1997 ). This coal-tar
preservative has over 300 chemicals containing cresols and polycyclic aromatic
hydrocarbons or PAH's (85 %), the most toxic being phenolic compounds (10 %)
(Kiilerich and Arvin 1996 ; ATSDR 2002a , b ); the low-molecular-mass heterocyclic
compounds have been identifi ed as major contributors to the acute toxicity of
creosote leachates (Kuehl et al. 1990 ). In 2013, creosote as a wood-preservative was
reviewed and subsequently determined that specifi c authorization must be received
by the USA prior to its use (Health and Safety Executive 2013 ).
Although some creosote compounds are biodegradable, others are not, hence,
creosote-treated wood has been considered to be very strong against weathering, but
its eventual loss over time results in substantial pollution of the environment. Studies
have shown that creosote's main elements continuously leach from weather-treated
wood when washed with rainfall, having the highest loss rate of any chemical wood
treatment (Hasan et al. 2010 ). Considering that some of its compounds are highly
mobile in soil, they could threaten resources (Schiøtz Hanse and Ottosen 2002 ) and
a number of its constituents, notably the O- and N-heterocyclics, which exhibit
appreciable solubility, may be transported over signifi cant distances via surface
runoff or groundwater (Enzminger and Ahlert 1987 ). Recent studies in Puget Sound
(USA) and related waterways have shown toxic creosote compounds released from
old treated wood to be very common (Sheets 2011 ).
Once creosote components reach groundwater they may persist to pose environment
and health hazards. Once in the groundwater, breakdown may take years. Most of
the components that are not water-soluble will remain in place in a tar-like mass;
breakdown in soil can take months for some components of coal-tar creosote, and
much longer for others. Small amounts of these chemicals that remain in the soil and
water will remain toxic to some animals and possibly to humans (ATSDR 2002b ).

17.2.2 CCA (Chromated Copper Arsenate)

CCA is the most common waterborne wood preservative (Townsend et al. 2005 ),
widely used in many countries for lumber treatment due to its low cost, and desir-
able characteristics of being fast-drying and a relatively leach-resistant compound
(Moghaddam and Mulligan 2008 ). In New Zealand, about 5,000 t of copper,
chromium and arsenic (CCA) salt equivalent were used to treat 650,000 m 3 of
timber annually (Love 2007 ). Copper (23-25 %) and arsenic (30-37 %) in CCA act
as fungicides and insecticides, while chromium (38-45 %) fi xes the chemicals to
the wood (APVMA 2003 ; Greaves 2003 ); this chemical mixture is injected into the
wood under pressure until saturation (Hall and Beder 2005 ).
Other studies show that the rate at which the CCA elements leach is dependent
on the treatment process as well as the environment where the wood is installed