MORE DETAIL ON METHOD DETECTION LIMITS (MDL)

Yesterday's post included comments from Jason Rice MOE/MECP) (in a letter to Tiffany Svensson) regarding why MDLs vary between ALS labs and the MECP labs. Various reasons include:

For dioxin/furan analysis ALS uses EPA Method 8290 instead of EPA Method 1613. The latter is the superior of the two and the one used by the MOE/MECP.

Regarding DDT analysis ALS labs uses Method E3487 versus ALS labs using Methods WT-TM 1102 and 1302. While those numbers are Greek to me apparently using the ALS Method results in higher Method Detection Limits (MDLs). Also the MECP use more sensitive instrument equipment than ALS which lowers MDLs. Finally The MECP lab method has a larger final volume of sample extract also lowering MDLs.

For both dioxin/furans and DDT there are also superior versus inferior clean-up steps involving the lab equipment used. Mr. Rice (MECP) believes that the ALS steps are inferior to the MOE's.

My take on all this is that you get what you pay for and hence Lanxess had no incentive to get the best lab work done as it would cost more money upfront to the lab and then later with the greater cleanup of the Creek occasioned by the greater number of criteria exceedances that the lab would find if they used the superior methods.