Asbestos in Soil

The qualitative and semi-quantitative analysis method for asbestos detection in soil has been formulated in accordance to the health and safety at work (Asbestos Regulations: 2016), Resource Management (National Environmental Standard for Assessing and Managing Contaminants in Soil to Protect Human Health) Regulations 2011 (NES-CS), Method for the qualitative identification of asbestos in bulk samples (AS 4964-2004), and New Zealand Guidelines for Assessing and Managing Asbestos in Soils :2017 (BRANZ soil guidelines).

All soil samples are dried at 105°C, upon achieving a consistent weight the sample is weighed to determine the dry weight, the dried soil is then sieved and separated into 10mm, 2mm fractions. Depending on the organic matter the whole sample can be further ashed at 400°C to remove
interfering fibres such as root hairs and other organic materials.

The soil fractions are weighed and the characteristic asbestos-containing materials such as; asbestos cement, asbestos insulation board/blocks, lagging/sprays are then identified, under a low powered microscope.

For semi-quantitative analysis, The BRANZ (Building Research Association of New Zealand) method of asbestos in soil analysis is a standardised approach used to detect and quantify the presence of asbestos fibres in soil samples. the ACM (Asbestos Containing Material) found in the fractions are then separated and weighed. The asbestos in the ACM l is then separated and analysed using a polarised light microscope to further determine the type of asbestos present.

The mass of asbestos is calculated by assuming that the asbestos-containing fragments separated contain a certain percentage of asbestos based on Asbestos Survey Guide, Appendix 2, ACMS in Buildings (HSG 264 – 2012), guidelines depending on the type of material.

To conclude, the whole less than 2mm fraction (fines) of the soil subsample is analysed providing further accuracy in assessing the concentration of asbestos in soil. The whole sample is retained for a period of six months.