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Posts Tagged ‘chemistry’

Sample Containers & Preservation for Mercury Analysis in Waters

Tuesday, July 30th, 2013

By Tim Crowther, Regional Client Services Manager, ALS Environmental – Canada

**NOTE: The content in this article does not apply to ALS Environmental’s USA locations.**

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.

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Theoretical Gypsum Requirement (TGR) Models

Friday, July 6th, 2012

By John Ashworth,  ALS Environmental – Canada

ALS Environmental Lab TestingGypsum is often applied as an amendment to soils that exhibit a high sodium adsorption ratio (SAR).  The addition of gypsum can reduce a soil’s clay plasticity, thus improving drainage and ease of cultivation. Estimating the correct amount of gypsum required to remediate a particular site is an inexact science requiring experience and consideration of specific site history and conditions, but models described in the literature can produce theoretical estimates to provide guidance.  As a service to our clients, ALS now offers two theoretical calculations for gypsum requirement that are suited to two common categories of salt-impacted soil on the Canadian prairies.

Ammonia: All You’ve Ever Wanted To Know

Wednesday, June 20th, 2012

By Mark Hugdahl, Technical Director,  ALS Environmental – Canada

The synthetic production of ammonia by the Haber-Bosch process has been called the most important invention of the 20th century. Fritz Haber received the Nobel prize in 1919 for pioneering the “fixation” of nitrogen, where nitrogen gas is converted to ammonia, a reactive form of nitrogen that can easily be taken up by plants. Nitrogen from synthetic fertilizers now provides more than half of the nutrients required by the world’s crops. Without the ammonia produced from the Haber-Bosch process, our planet could not feed seven billion people.

Ammonia plays a key role in the global nitrogen cycle, and is produced naturally through the decomposition of nitrogen-rich organic matter. However, it is also a very common environmental pollutant, and in 1990 was listed as the top priority on Environment Canada’s Canadian Chemical Spill Priority List. Outside the fertilizer industry, anthropogenic point sources of ammonia include the textile industry, household chemicals, explosives, the plastics industry, oil refineries, iron and steel mills, meat processing plants, and sewage treatment plants.

At low levels, ammonia in drinking water is not considered toxic to humans. It is produced naturally in the human body, and is efficiently targeted and detoxified by specific enzymes. However, ammonia is highly toxic to fish and amphibians at very low concentrations, since they lack these enzymes.

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