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Article written by Thomas V. Coyner, Technical Director, Analytical Products Group, Inc.
Complete article from Edition 22 APG eNewsletter
Thousands of laboratories run DMRQA samples every year, but they have never been told how they are doing. Each laboratory knew how it did individually, but it had no way to compare itself to the participants.
APG thinks it is important for laboratories to understand their relative performance in PT programs and wants to share a few measures. The table below shows the percentage of laboratories that passed each of the listed parameters over the past three DMRQA studies. The evaluation criteria did not change over this period, and each year’s DMRQA study included almost two thousand laboratories. Therefore, the numbers reflect typical performance in the APG program. Please understand that the performance in other PT providers’ DMRQA programs could be significantly different. The performance on the Metals was equally consistent. For Study 24, the percentage of laboratories passing the metals ranged from a low of 88.21% for Aluminum to a high of 96.53% for Cadmium.
Pass Percentage on DMRQA 2002-2004
| BOD |
91.45% |
95.12% |
94.67% |
| COD |
87.19% |
96.98% |
93.45% |
| Ammonia as N |
89.94% |
94.20% |
90.71% |
| TKN |
93.71% |
95.24% |
92.11% |
| pH |
95.75% |
92.32% |
96.49% |
| Total Phenolics |
94.81% |
94.81% |
90.13% |
| Total Cyanide |
89.87% |
96.06% |
91.48% |
| Residual Chlorine |
90.90% |
90.49% |
90.58% |
| Oil & Grease |
86.71% |
92.17% |
90.42% |
The performance on Mercury improved over the three year period from a low of 87.64% in 2002 to a high of 95.02% in 2004. In general, the overall performance of participants in the DMRQA Studies has been reasonably consistent over the three year period.
It should be remembered that this data does not accurately reflect the actual performance of the laboratories because the performance limits are set based upon EPA supplied regression equations. Therefore, they are measured against what the EPA expects the laboratories should be capable of achieving.
Should you have any question on your laboratory’s performance give Brent Straight, our PT Manager, a call at 800.272.4442.
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