Potential risks of CCA-treated wood destined to landfills

Abstract: In recent years, recycling has become the first best option of dealing with waste before landfilling is considered in cases of handling difficulties. In South Africa however, 41,000 tons of solid waste is destined for landfills daily; which includes huge chunks of waste from construction and demolition activities. The continued reliance of South Africa on the landfilling system could extend a while until economical recycling alternatives are introduced. Leachate generation and percolation is expected in these landfills on account of infiltration of water into the waste body from rain and/or runoffs. Although, it has been documented that arsenic, copper and chromium percolate soil systems, it however noted that occurring physical, chemical and biological activities may influence mobility of metals from generated leachate. This is particularly evident in cases where Chromated Copper Arsenate (CCA)-treated wood are disposed in monofills with consequential impacts on the environment. Laboratory investigation using a bespoke device to explore the environmental risk of depositing CCA-treated wood in monofills and/or open dumps was done; with a view to simulating worst case scenario of an unlined disposal facility that relied on the geology of the site. This scenario best indicates high concentrations and maximum formation of heavy metals. The bespoke device was assembled with chopped untreated wood and CCA-treated wood in a bottom chamber respectively, and de-ionized water was allowed to seep through from a reservoir forming leachate. The targeted chemical ions (arsenic, copper and chromium) from the leachate were analyzed by way of full spectral method on the effluent and were compared to South African standard of drinking water. The study therefore, revealed that CCA-treated wood formed hazardous concentration levels of chromium and arsenic which if not properly contained in real cases, could inflict severe contamination consequential to human and environmental health