Environmental risk assessment of preservative treated wood
E F Baines, S J Davis
This paper reviews the status of the environmental risk assessment of preservative treated wood and confirms the distinction between the risks presented by wood preservatives and preservative treated wood. The paper proposes a tiered approach to risk assessment and discusses the rationale. Flowcharts are presented which summarise the tiered approach to risk assessment, show the tests required, and show how the results can be used to make an environmental risk assessment of preservative treated wood.
The need to generate data specifically for risk assessments, particularly PEC and PNEC values, is recognised. Test methods in existing Standards (EN 84, EN1250-2) are shown to be unsuitable to produce data which can be used in risk assessments. Realistic test methods are proposed using commodity-sized treated wood exposed to simulated in-service situations.
A test method to generate risk assessment data for wood in ground contact and wood above ground is described. The results show that boron is adsorbed by soil, and that leaching of boron from treated wood in ground contact, even after 5 days exposed to severe rainfall conditions, is less than 10% of the boron in the wood before exposure.