The Biotic Ligand Model (BLM) takes into account many environmental conditions in order to determine if a metal exists in a form or concentration that is toxic to aquatic life. Toxicity is usually based upon the dosage of whatever it is that we are looking at. At...
TCLP or SPLP on a Solid Sample
Why is this TCLP/SPLP on a solid sample a common question? The main reason is that people don’t understand the difference between characterization and hazardous determination. The EPA developed the TCLP Program to determine when certain materials have to go to a...
What’s the difference between accuracy and precision?
Have you ever wondered what the difference between accuracy and precision is? The classic example is this: I shoot five arrows from a hundred yards and they land either in or just outside of the bullseye. The consensus from the gallery will be that I am a very...
Understanding Control Charts
What are control charts? Control charts are a visual depiction of ongoing data points that various statistics are applied to. The EPA used to require a laboratory to adjust its spike acceptance recovery percentage based upon how spikes were recovered over time...
How Low Can You Go – Well No Lower Than The MDL
There is always confusion on how low a lab can go when it comes to what their instruments can detect. The EPA and TNI came together and changed how Method Detection Limits (MDL) are established for an instrument or group of instruments. They wanted to account for the...
Significant Figures Use by Laboratories
What determines the amount of numbers you see on your report? Each test that we do has a level of sensitivity associated with it. Tests that you can do by visual inspection have the lowest sensitivity and are usually reported in whole numbers in a range of say 1 to...