Envco – Environmental Equipment

Evolution in Accepted VOC (Hydrocarbons) Soil Contamination Testing Methods and its Implications for Monitoring Practices.

Recent changes have occurred in the accepted methodology surrounding soil and sediment contamination testing for Volatile Organic Compounds (VOC’s). These changes have amounted to soil vapor testing being a viable practice for longer term monitoring of soil and sediment contamination.

Under the older methodology a drill rig was required to take soil core samples down to the desired depth which then needed to be kept cold and sent to a laboratory for analysis. This method is significantly more expensive in comparison to frequently used modern practices. With the acceptance of gas vapor measurements being suitable; manufacturers have slimmed down their implant tips to the point where these can easily be hand augured down to most desired depths (depending on substrate) and the newer screened tips can be implanted for permanent measuring points.

Direct push methods can also be employed to push drive rods down to the required depth, these are acceptable for human health risk assessment but can be difficult to fill and bentonite. The new gas vapor implants have larger screen sizes ranging from 12" (300mm) to 21"(530mm) in length to allow for greater distribution of sample area. This also eliminates issues arising from high water tables and the influence of rising water.

Temporary dedicated and retractable tips which only offer short term monitoring solution and are inefficient in comparison to the more permanent implants where hand auguring is possible:

Part number
211.00                     Dedicated Gas Vapor Tip and Umbrella  $45 NZD
210.01                     GVP Retract-A-Tip $365 NZD
21013                      Implant 6" with 1/4' swage lock fitting  $95 NZD
21014                      Implant 12" with 1/4' swage lock fitting $135 NZD