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 does Cation/Anion Balance Mean?
Introduction to Cation/Anion Balance (CA Balance) Water that is potable (drinkable) should be electrically neutral. This is determined by taking into account results from the following analytical testing: pH, conductivity, total dissolved solids, and other analytical...
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...