By Tim Crowther, Regional Client Services Manager, ALS Environmental – Canada
On August 15, 2013, ALS Canada will begin supplying our clients with borosilicate glass containers with Teflon® lined caps for the collection of total and dissolved mercury in all water samples. Hydrochloric acid (HCl) preservative will also be supplied. Recent literature and ALS experimental test results indicate a glass container with HCl preservation is the most effective method for reducing mercury losses following sample collection. The sample bottle and preservative pictured overpage will be the recommended container for low-level total and dissolved mercury (≥10 ng/L), which were previously collected in a high-density polyethylene (HDPE) ‘plastic’ bottle with nitric acid preservation. HDPE containers are not suitable for ultra-trace level (0.2 – 10 ng/L) mercury analysis. Ultra-trace mercury sampling requires more sample volume, as well as the use of cleaner sample handling and analysis procedures.
The British Columbia Ministry of Environment (BC MoE) will require the use of Teflon® or borosilicate glass containers with HCl preservation for the collection of water samples for mercury analysis effective November 15, 2013. The United States Environmental Protection Agency (US EPA) and the Ontario Ministry of Environment have already prescribed the same. Various other agencies are considering similar changes, including the Canadian Council of Ministers of the Environment (CCME) and Alberta Environment.
Additionally, ALS recommends that filtration for dissolved mercury analysis be conducted within one hour of sample collection using a suitable in-line filter or 0.45 μm syringe filter supplied by ALS.