PAHs are a group of over 100 different compounds formed during the incomplete burning of coal, oil & gas and other organic substances. More Details
The Physiologically Based Extraction Test (PBET) is used to provide site specific estimates of bioavailable arsenic from soil.
CLEA SGV for arsenic is 32 mg/kg. This is based on the assumption that 100% of the arsenic in soil is taken up by the systemic circulation (i.e. bioavailable).
In most cases, only a fraction of the total arsenic is bioavailable. This fraction can be quantified using the Physiologically Based Extraction Test (PBET).
The PBET recreates conditions found in the gastro-intestinal tract of a small child.
It is a 2 phase extraction – simulating conditions in the stomach and small intestine.
Extracts are analysed for arsenic by ICP-MS.
Results for total arsenic are reported along with percentage of the total, which is bioavailable.
The method can also be used for other metals such as lead, chromium, nickel, mercury, cadmium, copper and zinc.
For more information contact Our Technical Manager Keith Jones
This presentation discusses Laboratory Data Variability.
Site Investigation and the assessment of contaminated land is a complex process, involving factors such as:-
Site History, Sampling and Laboratory Data Variability
Apparent Anomalous & inconsistent laboratory results can result in delays & cost implications
An awareness and appreciation of laboratory data variability can assist the site engineer / consultant in evaluating the correlation between the site history and laboratory results as well as identifying any apparent site anomalies. ( presentation )
Assessing Petroleum Degradation using Chromatograms
Laboratories utilise a number of techniques to determine levels of TPH Degradation. As part of the process, the Chemist will review Chromatograms and will consider several factors:-
|Compound depletion||Specific compounds are more resistant to biodegradation and their presence or depletion can be used to assess weathering|
|The n-alkane distribution||The n-alkanes in middle distillates, such as diesel fuel, heating oils or kerosene, normally show an even distribution, evidenced by a bell-shaped. An uneven or jagged distribution is often evidence of degradation|
|Unresolved complex mixture (UCM)||The UCM is the hump at the base of a GC/FID trace and a mixture of complex cyclo- and iso-alkanes that are unresolvable through conventional gas chromatography(McGovern, 1999).|
|Heavy versus light n-alkanes||Under aerobic conditions, lighter n-alkanes are normally |
removed quicker compared to the heavier n-alkanes (Mohantya & Mukherji, 2008).
In addition to the above, at Chemtest, we also utilise GCxGC traces, which provide us with further lines of evidence.
Please contact Chemtest if you have any questions regarding testing samples to determine levels of degradation.
Find out more information on Environmental Forensics Here
Ref : Gil Oudijk (2012). Age Dating of Middle-Distillate Fuels Released to the Subsurface Environment, Earth Sciences, Dr. Imran Ahmad Dar (Ed.), ISBN: 978-953-307-861-8, InTech, Available from:http://www.intechopen.com/books/earth-sciences/age-dating-of-middle-distillate-fuels-released-to-thesubsurface-environment
Atrazine is part of the Triazine chemical class, which includes Simazine and Propazine due to their common mechanism of toxicity. http://bit.ly/29031tM The scientific name for Atrazine is 6-chloro-N-ethyl-N’-(1-methylethyl)-triazine-2,4-diamine. After atrazine has been applied to soils, it will remain there for several days to several months. http://bit.ly/1Jevade
What can Chemgenie do for you?
Chemgenie – An Innovative Mobile Site App for the Environmental Industry
Chemgenie is a free mobile App, available for both Apple and Android devices, which has been developed to provide clients with a quick and simple capability to manage their consumables, collections and testing, regardless of where they are. Anytime & Anywhere …
Chemgenie App allows the site engineer to
Tasks that previously required site workers to manually complete detailed paperwork, or to liaise with their office or the laboratory for assistance, can now be seamlessly fulfilled on site. Chemgenie allows clients to spend less time organising samples and containers, allowing them more time more time on everything else!
Chemgenie is now available for free in the App Store.
Download Chemgenie today.
Chemtest’s Free Autumn Training Event 20th October
Section 1: Guest Speakers (Waste, Topsoil, Environmental Case Study )- TBC
Section 2: The Laboratory Process, Deviating Samples, Understanding Laboratory Data Variability, Quality
Section 3: Asbestos, Microbiology, Scheduling correct & fit for purpose Tests
Section 4: Interactive Seminar on Advances & Innovations in Environmental Testing
Reserve your place today
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"We have worked with Chemtest for the last 5 years as strategic partners within our supply chain. They are efficient, knowledgeable and reliable, which are all key factors with regards to the services we offer our clients."