Lab Science News - Science, chemistry and environmental news from laboratory experts

Posts Tagged ‘environmental’

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.

Reducing Errors through Multi-Increment Sampling

Wednesday, August 18th, 2010

By Gregory Salata, Ph.D.

Multi-Increment Sampling

The objective of environmental sampling is to quantify contamination at a given location. In situations where sample collection may result in discrete samples of a heterogeneous nature, results may be biased based on the particle size of each sub-aliquot collected at the site. One option to help reduce the errors associated with non-uniform sample composition is to use multi-increment sampling (MIS) to create a representative, homogeneous aliquot for analysis of analytes.

(more…)

How to Determine Aquatic Humic Substances

Monday, June 28th, 2010

By Lynda Huckestein, Project Chemist, Kelso, WA

How to Determine Aquatic Humic Substances

Aquatic Humic Substances (AHS) result from the decomposition of plant and animal residues and are found in soil, sediment, and water. They are widespread in nature and are mostly comprised from naturally occurring dissolved organic matter in water.

(more…)

EPA to Address Dioxin Food Safety Concerns

Tuesday, February 2nd, 2010

EPA to Address Dioxin Food Safety ConcernsThe United States Environmental Protection Agency (EPA) will soon release its response to a 2006 National Academy of Sciences (NAS) report recommending changes to the EPA’s 2000 draft assessment of the risks posed by 2,3,7,8 Tetrachlorodibenzo-p-Dioxin.

Dioxins are environmental contaminants according to the Food and Drug Administration’s (FDA) website (September 2009). Most human dioxin exposure, however, occurs through the diet, with more than 95% coming through dietary intake of animal fats. Dioxins enter the food chain primarily in an air-to-leaf/soil-to-animal route.

(more…)