APPENDIX B 
ACCOUNT OF INTERLABORATORY TESTS ON SPLIT SAMPLES 
This is a chronological account of interactions with Environ¬ 
mental Monitoring and Support Laboratory (EMSL), Office of Re¬ 
search and Development, U.S. Environmental Protection Agency, 
Cincinnati, Ohio. Contact: William L. Budde. 
October 1978 
Two dried sediment samples were each split and respective 
subsamples were sent to EMSL in Cincinnati. They were labeled: 
(1) Chester River, mouth, top sediment; (2) Tenneco Pond sediment 
(>100 ppm dioctyl phthalate). The EMSL facility was selected due 
to its fine reputation in the scientific community. 
January 1979 
EMSL advised this laboratory of their results on the two 
samples: (1) 61 ppm of DEHP in the Chester River, mouth, and 
(2) 1700 ppm DEHP in the Tenneco Pond. No error values nor blank 
values were given. In a telephone conversation prior to this re¬ 
port, EMSL communicated a preliminary verbal report indicating 
6 ppm of DEHP in the Chester River, mouth sediment. (After dis¬ 
covering a computational error, the corrected value was described 
as 58 ppm.) The value this laboratory had determined—prior to 
receiving the EMSL report—was 0.6 ppm DEHP in Chester River, 
mouth sediment and 1200 + 100 ppm DEHP in Tenneco Pond sediment. 
Due to the large discrepancy (2 orders of magnitude) this 
laboratory undertook an extensive battery of experiments to ex¬ 
plore previously undetected systematic errors, and to find a 
possible reason for its low value for DEHP in Chester River, 
mouth sediment. After 2 months of experimentation, we continued 
to obtain values less than 1 ppm. In fact, improvement of our 
methodology produced a value lower than determined previously 
0.1 ppm. 
April 1979 
Agreement for retrial was secured and a second set of split 
samples was sent to EMSL Cincinnati. This time three samples 
were sent: (1) Dry Chester River mouth sediment, (2) Wet Chester 
River mouth sediment, which EPA dried themselves, and (3) "or¬ 
ganic free" clay which we had carefully spiked with DEHP. 
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